[PATCH 00/34] dynamically allocate split ptl if it cannot be embedded to struct page

[PATCH 00/34] dynamically allocate split ptl if it cannot be embedded to struct page

[Kirill A. Shutemov]

In split page table lock case, we embed spinlock_t into struct page. For
obvious reason, we don't want to increase size of struct page if
spinlock_t is too big, like with DEBUG_SPINLOCK or DEBUG_LOCK_ALLOC or on
-rt kernel. So we disble split page table lock, if spinlock_t is too big.

This patchset allows to allocate the lock dynamically if spinlock_t is
big. In this page->ptl is used to store pointer to spinlock instead of
spinlock itself. It costs additional cache line for indirect access, but
fix page fault scalability for multi-threaded applications.

LOCK_STAT depends on DEBUG_SPINLOCK, so on current kernel enabling
LOCK_STAT to analyse scalability issues breaks scalability. ;)

The patchset mostly fixes this. Results for ./thp_memscale -c 80 -b 512M
on 4-socket machine:

baseline, no CONFIG_LOCK_STAT:	9.115460703 seconds time elapsed
baseline, CONFIG_LOCK_STAT=y:	53.890567123 seconds time elapsed
patched, no CONFIG_LOCK_STAT:	8.852250368 seconds time elapsed
patched, CONFIG_LOCK_STAT=y:	11.069770759 seconds time elapsed

Patch count is scary, but most of them trivial. Overview:

 Patches 1-4	Few bug fixes. No dependencies to other patches.
		Probably should applied as soon as possible.

 Patch 5	Changes signature of pgtable_page_ctor(). We will use it
		for dynamic lock allocation, so it can fail.

 Patches 6-8	Add missing constructor/destructor calls on few archs.
		It's fixes NR_PAGETABLE accounting and prepare to use
		split ptl.

 Patches 9-33	Add pgtable_page_ctor() fail handling to all archs.

 Patches 34	Finally adds support of dynamically-allocated page->pte.
		Also contains documentation for split page table lock.

Any comments?

Kirill A. Shutemov (34):
  x86: add missed pgtable_pmd_page_ctor/dtor calls for preallocated pmds
  cris: fix potential NULL-pointer dereference
  m32r: fix potential NULL-pointer dereference
  xtensa: fix potential NULL-pointer dereference
  mm: allow pgtable_page_ctor() to fail
  microblaze: add missing pgtable_page_ctor/dtor calls
  mn10300: add missing pgtable_page_ctor/dtor calls
  openrisc: add missing pgtable_page_ctor/dtor calls
  alpha: handle pgtable_page_ctor() fail
  arc: handle pgtable_page_ctor() fail
  arm: handle pgtable_page_ctor() fail
  arm64: handle pgtable_page_ctor() fail
  avr32: handle pgtable_page_ctor() fail
  cris: handle pgtable_page_ctor() fail
  frv: handle pgtable_page_ctor() fail
  hexagon: handle pgtable_page_ctor() fail
  ia64: handle pgtable_page_ctor() fail
  m32r: handle pgtable_page_ctor() fail
  m68k: handle pgtable_page_ctor() fail
  metag: handle pgtable_page_ctor() fail
  mips: handle pgtable_page_ctor() fail
  parisc: handle pgtable_page_ctor() fail
  powerpc: handle pgtable_page_ctor() fail
  s390: handle pgtable_page_ctor() fail
  score: handle pgtable_page_ctor() fail
  sh: handle pgtable_page_ctor() fail
  sparc: handle pgtable_page_ctor() fail
  tile: handle pgtable_page_ctor() fail
  um: handle pgtable_page_ctor() fail
  unicore32: handle pgtable_page_ctor() fail
  x86: handle pgtable_page_ctor() fail
  xtensa: handle pgtable_page_ctor() fail
  iommu/arm-smmu: handle pgtable_page_ctor() fail
  mm: dynamically allocate page->ptl if it cannot be embedded to struct
    page

 Documentation/vm/split_page_table_lock   | 90 ++++++++++++++++++++++++++++++++
 arch/alpha/include/asm/pgalloc.h         |  5 +-
 arch/arc/include/asm/pgalloc.h           | 11 ++--
 arch/arm/include/asm/pgalloc.h           | 12 +++--
 arch/arm64/include/asm/pgalloc.h         |  9 ++--
 arch/avr32/include/asm/pgalloc.h         |  5 +-
 arch/cris/include/asm/pgalloc.h          |  7 ++-
 arch/frv/mm/pgalloc.c                    | 12 +++--
 arch/hexagon/include/asm/pgalloc.h       | 10 ++--
 arch/ia64/include/asm/pgalloc.h          |  5 +-
 arch/m32r/include/asm/pgalloc.h          |  7 ++-
 arch/m68k/include/asm/motorola_pgalloc.h |  5 +-
 arch/m68k/include/asm/sun3_pgalloc.h     |  5 +-
 arch/metag/include/asm/pgalloc.h         |  8 ++-
 arch/microblaze/include/asm/pgalloc.h    | 12 +++--
 arch/mips/include/asm/pgalloc.h          |  9 ++--
 arch/mn10300/include/asm/pgalloc.h       |  1 +
 arch/mn10300/mm/pgtable.c                |  9 +++-
 arch/openrisc/include/asm/pgalloc.h      | 10 +++-
 arch/parisc/include/asm/pgalloc.h        |  8 ++-
 arch/powerpc/include/asm/pgalloc-64.h    |  5 +-
 arch/powerpc/mm/pgtable_32.c             |  5 +-
 arch/powerpc/mm/pgtable_64.c             |  7 +--
 arch/s390/mm/pgtable.c                   | 11 +++-
 arch/score/include/asm/pgalloc.h         |  9 ++--
 arch/sh/include/asm/pgalloc.h            |  5 +-
 arch/sparc/mm/init_64.c                  | 11 ++--
 arch/sparc/mm/srmmu.c                    |  5 +-
 arch/tile/mm/pgtable.c                   |  6 ++-
 arch/um/kernel/mem.c                     |  8 ++-
 arch/unicore32/include/asm/pgalloc.h     | 14 ++---
 arch/x86/mm/pgtable.c                    | 19 +++++--
 arch/x86/xen/mmu.c                       |  2 +-
 arch/xtensa/include/asm/pgalloc.h        | 11 +++-
 drivers/iommu/arm-smmu.c                 |  5 +-
 include/linux/mm.h                       | 73 +++++++++++++++++++-------
 include/linux/mm_types.h                 |  5 +-
 mm/Kconfig                               |  2 -
 mm/memory.c                              | 19 +++++++
 39 files changed, 365 insertions(+), 97 deletions(-)
 create mode 100644 Documentation/vm/split_page_table_lock

-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 01/34] x86: add missed pgtable_pmd_page_ctor/dtor calls for preallocated pmds

[Kirill A. Shutemov]

I've missed that we preallocate few pmds on pgd_alloc() if X86_PAE
enabled. Let's add missed constructor/destructor calls.

I haven't noticed it during testing since prep_new_page() clears
page->mapping and therefore page->ptl. It's effectively equal to
spin_lock_init(&page->ptl).

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 arch/x86/mm/pgtable.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index dfa537a03b..1a7d21342e 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -189,8 +189,10 @@ static void free_pmds(pmd_t *pmds[])
 	int i;
 
 	for(i = 0; i < PREALLOCATED_PMDS; i++)
-		if (pmds[i])
+		if (pmds[i]) {
+			pgtable_pmd_page_dtor(virt_to_page(pmds[i]));
 			free_page((unsigned long)pmds[i]);
+		}
 }
 
 static int preallocate_pmds(pmd_t *pmds[])
@@ -200,8 +202,13 @@ static int preallocate_pmds(pmd_t *pmds[])
 
 	for(i = 0; i < PREALLOCATED_PMDS; i++) {
 		pmd_t *pmd = (pmd_t *)__get_free_page(PGALLOC_GFP);
-		if (pmd == NULL)
+		if (!pmd)
+			failed = true;
+		if (pmd && !pgtable_pmd_page_ctor(virt_to_page(pmd))) {
+			free_page((unsigned long)pmds[i]);
+			pmd = NULL;
 			failed = true;
+		}
 		pmds[i] = pmd;
 	}
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 01/34] x86: add missed pgtable_pmd_page_ctor/dtor calls for preallocated pmds

[Ingo Molnar]

* Kirill A. Shutemov <kirill.shutemov@linux.intel.com> wrote:

> I've missed that we preallocate few pmds on pgd_alloc() if X86_PAE
> enabled. Let's add missed constructor/destructor calls.
> 
> I haven't noticed it during testing since prep_new_page() clears
> page->mapping and therefore page->ptl. It's effectively equal to
> spin_lock_init(&page->ptl).
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

Acked-by: Ingo Molnar <mingo@kernel.org>

Thanks,

	Ingo

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 02/34] cris: fix potential NULL-pointer dereference

[Kirill A. Shutemov]

Add missing check for memory allocation fail.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
---
 arch/cris/include/asm/pgalloc.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/cris/include/asm/pgalloc.h b/arch/cris/include/asm/pgalloc.h
index 6da975db11..d9504d38c2 100644
--- a/arch/cris/include/asm/pgalloc.h
+++ b/arch/cris/include/asm/pgalloc.h
@@ -32,6 +32,8 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long addres
 {
 	struct page *pte;
 	pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, 0);
+	if (!pte)
+		return NULL;
 	pgtable_page_ctor(pte);
 	return pte;
 }
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 02/34] cris: fix potential NULL-pointer dereference

[Jesper Nilsson]

On Thu, Oct 10, 2013 at 08:05:27PM +0200, Kirill A. Shutemov wrote:
> Add missing check for memory allocation fail.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Mikael Starvik <starvik@axis.com>

Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>

> ---
>  arch/cris/include/asm/pgalloc.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/cris/include/asm/pgalloc.h b/arch/cris/include/asm/pgalloc.h
> index 6da975db11..d9504d38c2 100644
> --- a/arch/cris/include/asm/pgalloc.h
> +++ b/arch/cris/include/asm/pgalloc.h
> @@ -32,6 +32,8 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long addres
>  {
>  	struct page *pte;
>  	pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, 0);
> +	if (!pte)
> +		return NULL;
>  	pgtable_page_ctor(pte);
>  	return pte;
>  }
> -- 
> 1.8.4.rc3

/^JN - Jesper Nilsson
-- 
               Jesper Nilsson -- jesper.nilsson@axis.com

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 03/34] m32r: fix potential NULL-pointer dereference

[Kirill A. Shutemov]

Add missing check for memory allocation fail.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
---
 arch/m32r/include/asm/pgalloc.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/m32r/include/asm/pgalloc.h b/arch/m32r/include/asm/pgalloc.h
index 0fc7361989..ac4208bcc5 100644
--- a/arch/m32r/include/asm/pgalloc.h
+++ b/arch/m32r/include/asm/pgalloc.h
@@ -43,6 +43,8 @@ static __inline__ pgtable_t pte_alloc_one(struct mm_struct *mm,
 {
 	struct page *pte = alloc_page(GFP_KERNEL|__GFP_ZERO);
 
+	if (!pte)
+		return NULL;
 	pgtable_page_ctor(pte);
 	return pte;
 }
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 04/34] xtensa: fix potential NULL-pointer dereference

[Kirill A. Shutemov]

Add missing check for memory allocation fail.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
---
 arch/xtensa/include/asm/pgalloc.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/xtensa/include/asm/pgalloc.h b/arch/xtensa/include/asm/pgalloc.h
index cf914c8c24..037671a655 100644
--- a/arch/xtensa/include/asm/pgalloc.h
+++ b/arch/xtensa/include/asm/pgalloc.h
@@ -51,9 +51,13 @@ static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
 static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
 					unsigned long addr)
 {
+	pte_t *pte;
 	struct page *page;
 
-	page = virt_to_page(pte_alloc_one_kernel(mm, addr));
+	pte = pte_alloc_one_kernel(mm, addr);
+	if (!pte)
+		return NULL;
+	page = virt_to_page(pte);
 	pgtable_page_ctor(page);
 	return page;
 }
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 05/34] mm: allow pgtable_page_ctor() to fail

[Kirill A. Shutemov]

Change pgtable_page_ctor() return type from void to bool.
Returns true, if initialization is successful and false otherwise.

Current implementation never fails, but it will change later.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/mm.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 75735f6171..f6467032a9 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1254,10 +1254,11 @@ static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long a
 #define pte_lockptr(mm, pmd)	({(void)(pmd); &(mm)->page_table_lock;})
 #endif /* USE_SPLIT_PTE_PTLOCKS */
 
-static inline void pgtable_page_ctor(struct page *page)
+static inline bool pgtable_page_ctor(struct page *page)
 {
 	pte_lock_init(page);
 	inc_zone_page_state(page, NR_PAGETABLE);
+	return true;
 }
 
 static inline void pgtable_page_dtor(struct page *page)
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 06/34] microblaze: add missing pgtable_page_ctor/dtor calls

[Kirill A. Shutemov]

It will fix NR_PAGETABLE accounting. It's also required if the arch is
going ever support split ptl.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Simek <monstr@monstr.eu>
---
 arch/microblaze/include/asm/pgalloc.h | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/microblaze/include/asm/pgalloc.h b/arch/microblaze/include/asm/pgalloc.h
index ebd3579248..7fdf7fabc7 100644
--- a/arch/microblaze/include/asm/pgalloc.h
+++ b/arch/microblaze/include/asm/pgalloc.h
@@ -122,8 +122,13 @@ static inline struct page *pte_alloc_one(struct mm_struct *mm,
 #endif
 
 	ptepage = alloc_pages(flags, 0);
-	if (ptepage)
-		clear_highpage(ptepage);
+	if (!ptepage)
+		return NULL;
+	clear_highpage(ptepage);
+	if (!pgtable_page_ctor(ptepage)) {
+		__free_page(ptepage);
+		return NULL;
+	}
 	return ptepage;
 }
 
@@ -158,8 +163,9 @@ extern inline void pte_free_slow(struct page *ptepage)
 	__free_page(ptepage);
 }
 
-extern inline void pte_free(struct mm_struct *mm, struct page *ptepage)
+static inline void pte_free(struct mm_struct *mm, struct page *ptepage)
 {
+	pgtable_page_dtor(ptepage);
 	__free_page(ptepage);
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 07/34] mn10300: add missing pgtable_page_ctor/dtor calls

[Kirill A. Shutemov]

It will fix NR_PAGETABLE accounting. It's also required if the arch is
going ever support split ptl.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
---
 arch/mn10300/include/asm/pgalloc.h | 1 +
 arch/mn10300/mm/pgtable.c          | 9 +++++++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/mn10300/include/asm/pgalloc.h b/arch/mn10300/include/asm/pgalloc.h
index 146bacf193..0f25d5fa86 100644
--- a/arch/mn10300/include/asm/pgalloc.h
+++ b/arch/mn10300/include/asm/pgalloc.h
@@ -46,6 +46,7 @@ static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
 
 static inline void pte_free(struct mm_struct *mm, struct page *pte)
 {
+	pgtable_page_dtor(pte);
 	__free_page(pte);
 }
 
diff --git a/arch/mn10300/mm/pgtable.c b/arch/mn10300/mm/pgtable.c
index bd9ada693f..e77a7c7280 100644
--- a/arch/mn10300/mm/pgtable.c
+++ b/arch/mn10300/mm/pgtable.c
@@ -78,8 +78,13 @@ struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
 #else
 	pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT, 0);
 #endif
-	if (pte)
-		clear_highpage(pte);
+	if (!pte)
+		return NULL;
+	clear_highpage(pte);
+	if (!pgtable_page_ctor(pte)) {
+		__free_page(pte);
+		return NULL;
+	}
 	return pte;
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 08/34] openrisc: add missing pgtable_page_ctor/dtor calls

[Kirill A. Shutemov]

It will fix NR_PAGETABLE accounting. It's also required if the arch is
going ever support split ptl.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jonas Bonn <jonas@southpole.se>
---
 arch/openrisc/include/asm/pgalloc.h | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/openrisc/include/asm/pgalloc.h b/arch/openrisc/include/asm/pgalloc.h
index 05c39ecd2e..21484e5b9e 100644
--- a/arch/openrisc/include/asm/pgalloc.h
+++ b/arch/openrisc/include/asm/pgalloc.h
@@ -78,8 +78,13 @@ static inline struct page *pte_alloc_one(struct mm_struct *mm,
 {
 	struct page *pte;
 	pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT, 0);
-	if (pte)
-		clear_page(page_address(pte));
+	if (!pte)
+		return NULL;
+	clear_page(page_address(pte));
+	if (!pgtable_page_ctor(pte)) {
+		__free_page(pte);
+		return NULL;
+	}
 	return pte;
 }
 
@@ -90,6 +95,7 @@ static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
 
 static inline void pte_free(struct mm_struct *mm, struct page *pte)
 {
+	pgtable_page_dtor(pte);
 	__free_page(pte);
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 09/34] alpha: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
---
 arch/alpha/include/asm/pgalloc.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/alpha/include/asm/pgalloc.h b/arch/alpha/include/asm/pgalloc.h
index bc2a0daf2d..aab14a019c 100644
--- a/arch/alpha/include/asm/pgalloc.h
+++ b/arch/alpha/include/asm/pgalloc.h
@@ -72,7 +72,10 @@ pte_alloc_one(struct mm_struct *mm, unsigned long address)
 	if (!pte)
 		return NULL;
 	page = virt_to_page(pte);
-	pgtable_page_ctor(page);
+	if (!pgtable_page_ctor(page)) {
+		__free_page(page);
+		return NULL;
+	}
 	return page;
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 10/34] arc: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
---
 arch/arc/include/asm/pgalloc.h | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/arc/include/asm/pgalloc.h b/arch/arc/include/asm/pgalloc.h
index 36a9f20c21..81208bfd9d 100644
--- a/arch/arc/include/asm/pgalloc.h
+++ b/arch/arc/include/asm/pgalloc.h
@@ -105,11 +105,16 @@ static inline pgtable_t
 pte_alloc_one(struct mm_struct *mm, unsigned long address)
 {
 	pgtable_t pte_pg;
+	struct page *page;
 
 	pte_pg = __get_free_pages(GFP_KERNEL | __GFP_REPEAT, __get_order_pte());
-	if (pte_pg) {
-		memzero((void *)pte_pg, PTRS_PER_PTE * 4);
-		pgtable_page_ctor(virt_to_page(pte_pg));
+	if (!pte_pg)
+		return 0;
+	memzero((void *)pte_pg, PTRS_PER_PTE * 4);
+	page = virt_to_page(pte_pg);
+	if (!pgtable_page_ctor(page)) {
+		__free_page(page);
+		return 0;
 	}
 
 	return pte_pg;
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 10/34] arc: handle pgtable_page_ctor() fail

[Vineet Gupta]

On 10/10/2013 11:35 PM, Kirill A. Shutemov wrote:
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

Acked-by: Vineet Gupta <vgupta@synopsys.com> [for arch/arc bits]

Thx,
-Vineet

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 11/34] arm: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Russell King <linux@arm.linux.org.uk>
---
 arch/arm/include/asm/pgalloc.h | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/arm/include/asm/pgalloc.h b/arch/arm/include/asm/pgalloc.h
index 943504f53f..78a7793616 100644
--- a/arch/arm/include/asm/pgalloc.h
+++ b/arch/arm/include/asm/pgalloc.h
@@ -102,12 +102,14 @@ pte_alloc_one(struct mm_struct *mm, unsigned long addr)
 #else
 	pte = alloc_pages(PGALLOC_GFP, 0);
 #endif
-	if (pte) {
-		if (!PageHighMem(pte))
-			clean_pte_table(page_address(pte));
-		pgtable_page_ctor(pte);
+	if (!pte)
+		return NULL;
+	if (!PageHighMem(pte))
+		clean_pte_table(page_address(pte));
+	if (!pgtable_page_ctor(pte)) {
+		__free_page(pte);
+		return NULL;
 	}
-
 	return pte;
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 11/34] arm: handle pgtable_page_ctor() fail

[Russell King - ARM Linux]

So, all I see is this patch, with such a brilliant description which
describes what this change is about, why it is being made, and so
forth, and you're sending it to me, presumably because you want me to
do something with it.  No, not really.

What context do I have to say whether this is correct or not?  How can
I test it when the mainline version of pgtable_page_ctor returns void,
so if I were to apply this patch I'd get compile errors.

Oh, I guess you're changing pgtable_page_ctor() in some way.  What is
the nature of that change?

Please, I'm not a mind reader.  Please ensure that your "generic" patch
of your series reaches the appropriate recipients: if you don't want to
explicitly Cc: all the people individually, please at least copy all
relevant mailing lists found for the entire series.

(No, I am not on the excessively noisy linux-arch: I dropped off it
years ago because it just became yet another mailing list to endlessly
talk mainly about x86 rather than being a separate list to linux-kernel
which discussed problems relevant to many arch maintainers.)

Thanks.

On Thu, Oct 10, 2013 at 09:05:36PM +0300, Kirill A. Shutemov wrote:
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Russell King <linux@arm.linux.org.uk>
> ---
>  arch/arm/include/asm/pgalloc.h | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/arm/include/asm/pgalloc.h b/arch/arm/include/asm/pgalloc.h
> index 943504f53f..78a7793616 100644
> --- a/arch/arm/include/asm/pgalloc.h
> +++ b/arch/arm/include/asm/pgalloc.h
> @@ -102,12 +102,14 @@ pte_alloc_one(struct mm_struct *mm, unsigned long addr)
>  #else
>  	pte = alloc_pages(PGALLOC_GFP, 0);
>  #endif
> -	if (pte) {
> -		if (!PageHighMem(pte))
> -			clean_pte_table(page_address(pte));
> -		pgtable_page_ctor(pte);
> +	if (!pte)
> +		return NULL;
> +	if (!PageHighMem(pte))
> +		clean_pte_table(page_address(pte));
> +	if (!pgtable_page_ctor(pte)) {
> +		__free_page(pte);
> +		return NULL;
>  	}
> -
>  	return pte;
>  }
>  
> -- 
> 1.8.4.rc3
> 

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 11/34] arm: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

[-- Attachment #1: Type: text/plain, Size: 2541 bytes --]

On Thu, Oct 10, 2013 at 09:18:05PM +0100, Russell King - ARM Linux wrote:
> So, all I see is this patch, with such a brilliant description which
> describes what this change is about, why it is being made, and so
> forth, and you're sending it to me, presumably because you want me to
> do something with it.  No, not really.

Fair enough. Description should be better.

> What context do I have to say whether this is correct or not?  How can
> I test it when the mainline version of pgtable_page_ctor returns void,
> so if I were to apply this patch I'd get compile errors.
> 
> Oh, I guess you're changing pgtable_page_ctor() in some way.  What is
> the nature of that change?
> 
> Please, I'm not a mind reader.  Please ensure that your "generic" patch
> of your series reaches the appropriate recipients: if you don't want to
> explicitly Cc: all the people individually, please at least copy all
> relevant mailing lists found for the entire series.

The patchset touches every arch with MMU -- the list would be too long.
I hoped all maintainers has access to archive of linux-kernel/linux-arch
to get context.

mbox with cover letter and three relevant patches attached.

> (No, I am not on the excessively noisy linux-arch: I dropped off it
> years ago because it just became yet another mailing list to endlessly
> talk mainly about x86 rather than being a separate list to linux-kernel
> which discussed problems relevant to many arch maintainers.)
> 
> Thanks.
> 
> On Thu, Oct 10, 2013 at 09:05:36PM +0300, Kirill A. Shutemov wrote:
> > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > Cc: Russell King <linux@arm.linux.org.uk>
> > ---
> >  arch/arm/include/asm/pgalloc.h | 12 +++++++-----
> >  1 file changed, 7 insertions(+), 5 deletions(-)
> > 
> > diff --git a/arch/arm/include/asm/pgalloc.h b/arch/arm/include/asm/pgalloc.h
> > index 943504f53f..78a7793616 100644
> > --- a/arch/arm/include/asm/pgalloc.h
> > +++ b/arch/arm/include/asm/pgalloc.h
> > @@ -102,12 +102,14 @@ pte_alloc_one(struct mm_struct *mm, unsigned long addr)
> >  #else
> >  	pte = alloc_pages(PGALLOC_GFP, 0);
> >  #endif
> > -	if (pte) {
> > -		if (!PageHighMem(pte))
> > -			clean_pte_table(page_address(pte));
> > -		pgtable_page_ctor(pte);
> > +	if (!pte)
> > +		return NULL;
> > +	if (!PageHighMem(pte))
> > +		clean_pte_table(page_address(pte));
> > +	if (!pgtable_page_ctor(pte)) {
> > +		__free_page(pte);
> > +		return NULL;
> >  	}
> > -
> >  	return pte;
> >  }
> >  
> > -- 
> > 1.8.4.rc3
> > 
-- 
 Kirill A. Shutemov

[-- Attachment #2: ptl.mbox --]
[-- Type: application/mbox, Size: 24600 bytes --]

[PATCH 12/34] arm64: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
---
 arch/arm64/include/asm/pgalloc.h | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/pgalloc.h b/arch/arm64/include/asm/pgalloc.h
index f214069ec5..9bea6e74a0 100644
--- a/arch/arm64/include/asm/pgalloc.h
+++ b/arch/arm64/include/asm/pgalloc.h
@@ -63,9 +63,12 @@ pte_alloc_one(struct mm_struct *mm, unsigned long addr)
 	struct page *pte;
 
 	pte = alloc_pages(PGALLOC_GFP, 0);
-	if (pte)
-		pgtable_page_ctor(pte);
-
+	if (!pte)
+		return NULL;
+	if (!pgtable_page_ctor(pte)) {
+		__free_page(pte);
+		return NULL;
+	}
 	return pte;
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 13/34] avr32: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
---
 arch/avr32/include/asm/pgalloc.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/avr32/include/asm/pgalloc.h b/arch/avr32/include/asm/pgalloc.h
index bc7e8ae479..1aba19d68c 100644
--- a/arch/avr32/include/asm/pgalloc.h
+++ b/arch/avr32/include/asm/pgalloc.h
@@ -68,7 +68,10 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
 		return NULL;
 
 	page = virt_to_page(pg);
-	pgtable_page_ctor(page);
+	if (!pgtable_page_ctor(page)) {
+		quicklist_free(QUICK_PT, NULL, pg);
+		return NULL;
+	}
 
 	return page;
 }
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 13/34] avr32: handle pgtable_page_ctor() fail

[Hans-Christian Egtvedt]

Around Thu 10 Oct 2013 21:05:38 +0300 or thereabout, Kirill A. Shutemov wrote:
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no>

Given [1].

> Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
> ---
>  arch/avr32/include/asm/pgalloc.h | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/avr32/include/asm/pgalloc.h b/arch/avr32/include/asm/pgalloc.h
> index bc7e8ae479..1aba19d68c 100644
> --- a/arch/avr32/include/asm/pgalloc.h
> +++ b/arch/avr32/include/asm/pgalloc.h
> @@ -68,7 +68,10 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
>  		return NULL;
>  
>  	page = virt_to_page(pg);
> -	pgtable_page_ctor(page);
> +	if (!pgtable_page_ctor(page)) {
> +		quicklist_free(QUICK_PT, NULL, pg);
> +		return NULL;
> +	}
>  
>  	return page;
>  }

1: I'm assuming that pgtable_page_ctor() now returns success/error, but there
is a patch series that I have not seen.

-- 
mvh
Hans-Christian Egtvedt

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 14/34] cris: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
---
 arch/cris/include/asm/pgalloc.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/cris/include/asm/pgalloc.h b/arch/cris/include/asm/pgalloc.h
index d9504d38c2..235ece437d 100644
--- a/arch/cris/include/asm/pgalloc.h
+++ b/arch/cris/include/asm/pgalloc.h
@@ -34,7 +34,10 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long addres
 	pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, 0);
 	if (!pte)
 		return NULL;
-	pgtable_page_ctor(pte);
+	if (!pgtable_page_ctor(pte)) {
+		__free_page(pte);
+		return NULL;
+	}
 	return pte;
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 14/34] cris: handle pgtable_page_ctor() fail

[Jesper Nilsson]

On Thu, Oct 10, 2013 at 08:05:39PM +0200, Kirill A. Shutemov wrote:
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Mikael Starvik <starvik@axis.com>

Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>

> ---
>  arch/cris/include/asm/pgalloc.h | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/cris/include/asm/pgalloc.h b/arch/cris/include/asm/pgalloc.h
> index d9504d38c2..235ece437d 100644
> --- a/arch/cris/include/asm/pgalloc.h
> +++ b/arch/cris/include/asm/pgalloc.h
> @@ -34,7 +34,10 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long addres
>  	pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, 0);
>  	if (!pte)
>  		return NULL;
> -	pgtable_page_ctor(pte);
> +	if (!pgtable_page_ctor(pte)) {
> +		__free_page(pte);
> +		return NULL;
> +	}
>  	return pte;
>  }
>  
> -- 
> 1.8.4.rc3

/^JN - Jesper Nilsson
-- 
               Jesper Nilsson -- jesper.nilsson@axis.com

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 15/34] frv: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: David Howells <dhowells@redhat.com>
---
 arch/frv/mm/pgalloc.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/arch/frv/mm/pgalloc.c b/arch/frv/mm/pgalloc.c
index f6084bc524..41907d25ed 100644
--- a/arch/frv/mm/pgalloc.c
+++ b/arch/frv/mm/pgalloc.c
@@ -37,11 +37,15 @@ pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 #else
 	page = alloc_pages(GFP_KERNEL|__GFP_REPEAT, 0);
 #endif
-	if (page) {
-		clear_highpage(page);
-		pgtable_page_ctor(page);
-		flush_dcache_page(page);
+	if (!page)
+		return NULL;
+
+	clear_highpage(page);
+	if (!pgtable_page_ctor(page)) {
+		__free_page(page);
+		return NULL;
 	}
+	flush_dcache_page(page);
 	return page;
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 16/34] hexagon: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
---
 arch/hexagon/include/asm/pgalloc.h | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/hexagon/include/asm/pgalloc.h b/arch/hexagon/include/asm/pgalloc.h
index 679bf6d664..4c9d382d77 100644
--- a/arch/hexagon/include/asm/pgalloc.h
+++ b/arch/hexagon/include/asm/pgalloc.h
@@ -65,10 +65,12 @@ static inline struct page *pte_alloc_one(struct mm_struct *mm,
 	struct page *pte;
 
 	pte = alloc_page(GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO);
-
-	if (pte)
-		pgtable_page_ctor(pte);
-
+	if (!pte)
+		return NULL;
+	if (!pgtable_page_ctor(pte)) {
+		__free_page(pte);
+		return NULL;
+	}
 	return pte;
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 17/34] ia64: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
---
 arch/ia64/include/asm/pgalloc.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/ia64/include/asm/pgalloc.h b/arch/ia64/include/asm/pgalloc.h
index 96a8d927db..5767cdfc08 100644
--- a/arch/ia64/include/asm/pgalloc.h
+++ b/arch/ia64/include/asm/pgalloc.h
@@ -91,7 +91,10 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long addr)
 	if (!pg)
 		return NULL;
 	page = virt_to_page(pg);
-	pgtable_page_ctor(page);
+	if (!pgtable_page_ctor(page)) {
+		quicklist_free(0, NULL, pg);
+		return NULL;
+	}
 	return page;
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 18/34] m32r: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
---
 arch/m32r/include/asm/pgalloc.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/m32r/include/asm/pgalloc.h b/arch/m32r/include/asm/pgalloc.h
index ac4208bcc5..2d55a064cc 100644
--- a/arch/m32r/include/asm/pgalloc.h
+++ b/arch/m32r/include/asm/pgalloc.h
@@ -45,7 +45,10 @@ static __inline__ pgtable_t pte_alloc_one(struct mm_struct *mm,
 
 	if (!pte)
 		return NULL;
-	pgtable_page_ctor(pte);
+	if (!pgtable_page_ctor(pte)) {
+		__free_page(pte);
+		return NULL;
+	}
 	return pte;
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 19/34] m68k: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
---
 arch/m68k/include/asm/motorola_pgalloc.h | 5 ++++-
 arch/m68k/include/asm/sun3_pgalloc.h     | 5 ++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/m68k/include/asm/motorola_pgalloc.h b/arch/m68k/include/asm/motorola_pgalloc.h
index 2f02f264e6..dd254eeb03 100644
--- a/arch/m68k/include/asm/motorola_pgalloc.h
+++ b/arch/m68k/include/asm/motorola_pgalloc.h
@@ -40,7 +40,10 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long addres
 	flush_tlb_kernel_page(pte);
 	nocache_page(pte);
 	kunmap(page);
-	pgtable_page_ctor(page);
+	if (!pgtable_page_ctor(page)) {
+		__free_page(page);
+		return NULL;
+	}
 	return page;
 }
 
diff --git a/arch/m68k/include/asm/sun3_pgalloc.h b/arch/m68k/include/asm/sun3_pgalloc.h
index 48d80d5a66..f868506e33 100644
--- a/arch/m68k/include/asm/sun3_pgalloc.h
+++ b/arch/m68k/include/asm/sun3_pgalloc.h
@@ -59,7 +59,10 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
 		return NULL;
 
 	clear_highpage(page);
-	pgtable_page_ctor(page);
+	if (!pgtable_page_ctor(page)) {
+		__free_page(page);
+		return NULL;
+	}
 	return page;
 
 }
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 19/34] m68k: handle pgtable_page_ctor() fail

[Geert Uytterhoeven]

On Thu, Oct 10, 2013 at 8:05 PM, Kirill A. Shutemov
<kirill.shutemov@linux.intel.com> wrote:
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> ---
>  arch/m68k/include/asm/motorola_pgalloc.h | 5 ++++-
>  arch/m68k/include/asm/sun3_pgalloc.h     | 5 ++++-
>  2 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/arch/m68k/include/asm/motorola_pgalloc.h b/arch/m68k/include/asm/motorola_pgalloc.h
> index 2f02f264e6..dd254eeb03 100644
> --- a/arch/m68k/include/asm/motorola_pgalloc.h
> +++ b/arch/m68k/include/asm/motorola_pgalloc.h
> @@ -40,7 +40,10 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long addres
>         flush_tlb_kernel_page(pte);
>         nocache_page(pte);
        ^^^^^^^^^^^^^^^^^^
>         kunmap(page);
> -       pgtable_page_ctor(page);
> +       if (!pgtable_page_ctor(page)) {
> +               __free_page(page);

Shouldn't you mark the page cacheable again, like is done in pte_free()?

> +               return NULL;
> +       }
>         return page;
>  }
>
> diff --git a/arch/m68k/include/asm/sun3_pgalloc.h b/arch/m68k/include/asm/sun3_pgalloc.h
> index 48d80d5a66..f868506e33 100644
> --- a/arch/m68k/include/asm/sun3_pgalloc.h
> +++ b/arch/m68k/include/asm/sun3_pgalloc.h
> @@ -59,7 +59,10 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
>                 return NULL;
>
>         clear_highpage(page);
> -       pgtable_page_ctor(page);
> +       if (!pgtable_page_ctor(page)) {
> +               __free_page(page);
> +               return NULL;
> +       }
>         return page;

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 19/34] m68k: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Geert Uytterhoeven wrote:
> On Thu, Oct 10, 2013 at 8:05 PM, Kirill A. Shutemov
> <kirill.shutemov@linux.intel.com> wrote:
> > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> > ---
> >  arch/m68k/include/asm/motorola_pgalloc.h | 5 ++++-
> >  arch/m68k/include/asm/sun3_pgalloc.h     | 5 ++++-
> >  2 files changed, 8 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/m68k/include/asm/motorola_pgalloc.h b/arch/m68k/include/asm/motorola_pgalloc.h
> > index 2f02f264e6..dd254eeb03 100644
> > --- a/arch/m68k/include/asm/motorola_pgalloc.h
> > +++ b/arch/m68k/include/asm/motorola_pgalloc.h
> > @@ -40,7 +40,10 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long addres
> >         flush_tlb_kernel_page(pte);
> >         nocache_page(pte);
>         ^^^^^^^^^^^^^^^^^^
> >         kunmap(page);
> > -       pgtable_page_ctor(page);
> > +       if (!pgtable_page_ctor(page)) {
> > +               __free_page(page);
> 
> Shouldn't you mark the page cacheable again, like is done in pte_free()?

Hm. You're right. Updated patch below.

BTW, what's the point of playing with kmap()/kunmap() there? Looks like
m68k doesn't support highmem.

And even if it will support, code in pte_alloc_one() doesn't make any
sense: kmap() creates temporary mapping for highmem page and it
nocache_page() sets flags in pte which will be destroyed by kunmap().

It think kmap() should be replaced by page_address() and kunmap() should
be dropped.

Re: [PATCH 19/34] m68k: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Kirill A. Shutemov wrote:
> Geert Uytterhoeven wrote:
> > On Thu, Oct 10, 2013 at 8:05 PM, Kirill A. Shutemov
> > <kirill.shutemov@linux.intel.com> wrote:
> > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > > Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> > > ---
> > >  arch/m68k/include/asm/motorola_pgalloc.h | 5 ++++-
> > >  arch/m68k/include/asm/sun3_pgalloc.h     | 5 ++++-
> > >  2 files changed, 8 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/arch/m68k/include/asm/motorola_pgalloc.h b/arch/m68k/include/asm/motorola_pgalloc.h
> > > index 2f02f264e6..dd254eeb03 100644
> > > --- a/arch/m68k/include/asm/motorola_pgalloc.h
> > > +++ b/arch/m68k/include/asm/motorola_pgalloc.h
> > > @@ -40,7 +40,10 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long addres
> > >         flush_tlb_kernel_page(pte);
> > >         nocache_page(pte);
> >         ^^^^^^^^^^^^^^^^^^
> > >         kunmap(page);
> > > -       pgtable_page_ctor(page);
> > > +       if (!pgtable_page_ctor(page)) {
> > > +               __free_page(page);
> > 
> > Shouldn't you mark the page cacheable again, like is done in pte_free()?
> 
> Hm. You're right. Updated patch below.

I also noticed that one of pte_alloc_one didn't have the constructor at
all. New patch revision bellow.

[PATCH 20/34] metag: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: James Hogan <james.hogan@imgtec.com>
---
 arch/metag/include/asm/pgalloc.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/metag/include/asm/pgalloc.h b/arch/metag/include/asm/pgalloc.h
index 275d928514..3104df0a48 100644
--- a/arch/metag/include/asm/pgalloc.h
+++ b/arch/metag/include/asm/pgalloc.h
@@ -52,8 +52,12 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
 {
 	struct page *pte;
 	pte = alloc_pages(GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO, 0);
-	if (pte)
-		pgtable_page_ctor(pte);
+	if (!pte)
+		return NULL;
+	if (!pgtable_page_ctor(pte)) {
+		__free_page(pte);
+		return NULL;
+	}
 	return pte;
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 21/34] mips: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
---
 arch/mips/include/asm/pgalloc.h | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/mips/include/asm/pgalloc.h b/arch/mips/include/asm/pgalloc.h
index 881d18b4e2..b336037e87 100644
--- a/arch/mips/include/asm/pgalloc.h
+++ b/arch/mips/include/asm/pgalloc.h
@@ -80,9 +80,12 @@ static inline struct page *pte_alloc_one(struct mm_struct *mm,
 	struct page *pte;
 
 	pte = alloc_pages(GFP_KERNEL | __GFP_REPEAT, PTE_ORDER);
-	if (pte) {
-		clear_highpage(pte);
-		pgtable_page_ctor(pte);
+	if (!pte)
+		return NULL;
+	clear_highpage(pte);
+	if (!pgtable_page_ctor(pte)) {
+		__free_page(pte);
+		return NULL;
 	}
 	return pte;
 }
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 22/34] parisc: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
---
 arch/parisc/include/asm/pgalloc.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/parisc/include/asm/pgalloc.h b/arch/parisc/include/asm/pgalloc.h
index fc987a1c12..f213f5b4c4 100644
--- a/arch/parisc/include/asm/pgalloc.h
+++ b/arch/parisc/include/asm/pgalloc.h
@@ -121,8 +121,12 @@ static inline pgtable_t
 pte_alloc_one(struct mm_struct *mm, unsigned long address)
 {
 	struct page *page = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
-	if (page)
-		pgtable_page_ctor(page);
+	if (!page)
+		return NULL;
+	if (!pgtable_page_ctor(page)) {
+		__free_page(page);
+		return NULL;
+	}
 	return page;
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 23/34] powerpc: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
---
 arch/powerpc/include/asm/pgalloc-64.h | 5 ++++-
 arch/powerpc/mm/pgtable_32.c          | 5 ++++-
 arch/powerpc/mm/pgtable_64.c          | 7 ++++---
 3 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/include/asm/pgalloc-64.h b/arch/powerpc/include/asm/pgalloc-64.h
index f65e27b09b..16cb92d215 100644
--- a/arch/powerpc/include/asm/pgalloc-64.h
+++ b/arch/powerpc/include/asm/pgalloc-64.h
@@ -91,7 +91,10 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
 	if (!pte)
 		return NULL;
 	page = virt_to_page(pte);
-	pgtable_page_ctor(page);
+	if (!pgtable_page_ctor(page)) {
+		__free_page(page);
+		return NULL;
+	}
 	return page;
 }
 
diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index 6c856fb8c1..5b96017152 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -121,7 +121,10 @@ pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 	ptepage = alloc_pages(flags, 0);
 	if (!ptepage)
 		return NULL;
-	pgtable_page_ctor(ptepage);
+	if (!pgtable_page_ctor(ptepage)) {
+		__free_page(ptepage);
+		return NULL;
+	}
 	return ptepage;
 }
 
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index 536eec72c0..9d95786aa8 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -378,6 +378,10 @@ static pte_t *__alloc_for_cache(struct mm_struct *mm, int kernel)
 				       __GFP_REPEAT | __GFP_ZERO);
 	if (!page)
 		return NULL;
+	if (!kernel && !pgtable_page_ctor(page)) {
+		__free_page(page);
+		return NULL;
+	}
 
 	ret = page_address(page);
 	spin_lock(&mm->page_table_lock);
@@ -392,9 +396,6 @@ static pte_t *__alloc_for_cache(struct mm_struct *mm, int kernel)
 	}
 	spin_unlock(&mm->page_table_lock);
 
-	if (!kernel)
-		pgtable_page_ctor(page);
-
 	return (pte_t *)ret;
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 24/34] s390: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
---
 arch/s390/mm/pgtable.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index c463e5cd3b..b109edb90b 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -754,7 +754,11 @@ static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm,
 		__free_page(page);
 		return NULL;
 	}
-	pgtable_page_ctor(page);
+	if (!pgtable_page_ctor(page)) {
+		kfree(mp);
+		__free_page(page);
+		return NULL;
+	}
 	mp->vmaddr = vmaddr & PMD_MASK;
 	INIT_LIST_HEAD(&mp->mapper);
 	page->index = (unsigned long) mp;
@@ -884,7 +888,10 @@ unsigned long *page_table_alloc(struct mm_struct *mm, unsigned long vmaddr)
 		page = alloc_page(GFP_KERNEL|__GFP_REPEAT);
 		if (!page)
 			return NULL;
-		pgtable_page_ctor(page);
+		if (!pgtable_page_ctor(page)) {
+			__free_page(page);
+			return NULL;
+		}
 		atomic_set(&page->_mapcount, 1);
 		table = (unsigned long *) page_to_phys(page);
 		clear_table(table, _PAGE_INVALID, PAGE_SIZE);
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 25/34] score: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Chen Liqin <liqin.chen@sunplusct.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
---
 arch/score/include/asm/pgalloc.h | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/score/include/asm/pgalloc.h b/arch/score/include/asm/pgalloc.h
index 059a61b707..2a861ffbd5 100644
--- a/arch/score/include/asm/pgalloc.h
+++ b/arch/score/include/asm/pgalloc.h
@@ -54,9 +54,12 @@ static inline struct page *pte_alloc_one(struct mm_struct *mm,
 	struct page *pte;
 
 	pte = alloc_pages(GFP_KERNEL | __GFP_REPEAT, PTE_ORDER);
-	if (pte) {
-		clear_highpage(pte);
-		pgtable_page_ctor(pte);
+	if (!pte)
+		return NULL;
+	clear_highpage(pte);
+	if (!pgtable_page_ctor(pte)) {
+		__free_page(pte);
+		return NULL;
 	}
 	return pte;
 }
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 25/34] score: handle pgtable_page_ctor() fail

[Lennox Wu]

[-- Attachment #1: Type: text/plain, Size: 1004 bytes --]

Thanks.

Acked-by: Lennox Wu <lennox.wu@gmail.com>

於 2013/10/11 上午 02:05, Kirill A. Shutemov 提到:
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Chen Liqin <liqin.chen@sunplusct.com>
> Cc: Lennox Wu <lennox.wu@gmail.com>
> ---
>  arch/score/include/asm/pgalloc.h | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/arch/score/include/asm/pgalloc.h b/arch/score/include/asm/pgalloc.h
> index 059a61b707..2a861ffbd5 100644
> --- a/arch/score/include/asm/pgalloc.h
> +++ b/arch/score/include/asm/pgalloc.h
> @@ -54,9 +54,12 @@ static inline struct page *pte_alloc_one(struct mm_struct *mm,
>  	struct page *pte;
>  
>  	pte = alloc_pages(GFP_KERNEL | __GFP_REPEAT, PTE_ORDER);
> -	if (pte) {
> -		clear_highpage(pte);
> -		pgtable_page_ctor(pte);
> +	if (!pte)
> +		return NULL;
> +	clear_highpage(pte);
> +	if (!pgtable_page_ctor(pte)) {
> +		__free_page(pte);
> +		return NULL;
>  	}
>  	return pte;
>  }



[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 544 bytes --]

[PATCH 26/34] sh: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Paul Mundt <lethal@linux-sh.org>
---
 arch/sh/include/asm/pgalloc.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/sh/include/asm/pgalloc.h b/arch/sh/include/asm/pgalloc.h
index 8c00785c60..a33673b368 100644
--- a/arch/sh/include/asm/pgalloc.h
+++ b/arch/sh/include/asm/pgalloc.h
@@ -47,7 +47,10 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
 	if (!pg)
 		return NULL;
 	page = virt_to_page(pg);
-	pgtable_page_ctor(page);
+	if (!pgtable_page_ctor(page)) {
+		quicklist_free(QUICK_PT, NULL, pg);
+		return NULL;
+	}
 	return page;
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 27/34] sparc: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
---
 arch/sparc/mm/init_64.c | 11 ++++++-----
 arch/sparc/mm/srmmu.c   |  5 ++++-
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index ed82edad1a..d6de9353ee 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -2519,12 +2519,13 @@ pgtable_t pte_alloc_one(struct mm_struct *mm,
 		return pte;
 
 	page = __alloc_for_cache(mm);
-	if (page) {
-		pgtable_page_ctor(page);
-		pte = (pte_t *) page_address(page);
+	if (!page)
+		return NULL;
+	if (!pgtable_page_ctor(page)) {
+		free_hot_cold_page(page, 0);
+		return NULL;
 	}
-
-	return pte;
+	return (pte_t *) page_address(page);
 }
 
 void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
diff --git a/arch/sparc/mm/srmmu.c b/arch/sparc/mm/srmmu.c
index 5d721df48a..869023abe5 100644
--- a/arch/sparc/mm/srmmu.c
+++ b/arch/sparc/mm/srmmu.c
@@ -345,7 +345,10 @@ pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 	if ((pte = (unsigned long)pte_alloc_one_kernel(mm, address)) == 0)
 		return NULL;
 	page = pfn_to_page(__nocache_pa(pte) >> PAGE_SHIFT);
-	pgtable_page_ctor(page);
+	if (!pgtable_page_ctor(page)) {
+		__free_page(page);
+		return NULL;
+	}
 	return page;
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 27/34] sparc: handle pgtable_page_ctor() fail

[David Miller]

From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Date: Thu, 10 Oct 2013 21:05:52 +0300

> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

Acked-by: David S. Miller <davem@davemloft.net>

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 28/34] tile: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
---
 arch/tile/mm/pgtable.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/tile/mm/pgtable.c b/arch/tile/mm/pgtable.c
index 4fd9ec0b58..5e86eac4bf 100644
--- a/arch/tile/mm/pgtable.c
+++ b/arch/tile/mm/pgtable.c
@@ -241,6 +241,11 @@ struct page *pgtable_alloc_one(struct mm_struct *mm, unsigned long address,
 	if (p == NULL)
 		return NULL;
 
+	if (!pgtable_page_ctor(p)) {
+		__free_pages(p, L2_USER_PGTABLE_ORDER);
+		return NULL;
+	}
+
 	/*
 	 * Make every page have a page_count() of one, not just the first.
 	 * We don't use __GFP_COMP since it doesn't look like it works
@@ -251,7 +256,6 @@ struct page *pgtable_alloc_one(struct mm_struct *mm, unsigned long address,
 		inc_zone_page_state(p+i, NR_PAGETABLE);
 	}
 
-	pgtable_page_ctor(p);
 	return p;
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 28/34] tile: handle pgtable_page_ctor() fail

[Chris Metcalf]

On 10/10/2013 2:05 PM, Kirill A. Shutemov wrote:
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Chris Metcalf <cmetcalf@tilera.com>
> ---
>  arch/tile/mm/pgtable.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)

Acked-by: Chris Metcalf <cmetcalf@tilera.com>

-- 
Chris Metcalf, Tilera Corp.
http://www.tilera.com

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 29/34] um: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
---
 arch/um/kernel/mem.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index 7ddb64baf3..8636e90542 100644
--- a/arch/um/kernel/mem.c
+++ b/arch/um/kernel/mem.c
@@ -279,8 +279,12 @@ pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 	struct page *pte;
 
 	pte = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
-	if (pte)
-		pgtable_page_ctor(pte);
+	if (!pte)
+		return NULL;
+	if (!pgtable_page_ctor(pte)) {
+		__free_page(pte);
+		return NULL;
+	}
 	return pte;
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 30/34] unicore32: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
---
 arch/unicore32/include/asm/pgalloc.h | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/arch/unicore32/include/asm/pgalloc.h b/arch/unicore32/include/asm/pgalloc.h
index 0213e373a8..2e02d1356f 100644
--- a/arch/unicore32/include/asm/pgalloc.h
+++ b/arch/unicore32/include/asm/pgalloc.h
@@ -51,12 +51,14 @@ pte_alloc_one(struct mm_struct *mm, unsigned long addr)
 	struct page *pte;
 
 	pte = alloc_pages(PGALLOC_GFP, 0);
-	if (pte) {
-		if (!PageHighMem(pte)) {
-			void *page = page_address(pte);
-			clean_dcache_area(page, PTRS_PER_PTE * sizeof(pte_t));
-		}
-		pgtable_page_ctor(pte);
+	if (!pte)
+		return NULL;
+	if (!PageHighMem(pte)) {
+		void *page = page_address(pte);
+		clean_dcache_area(page, PTRS_PER_PTE * sizeof(pte_t));
+	}
+	if (!pgtable_page_ctor(pte)) {
+		__free_page(pte);
 	}
 
 	return pte;
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 31/34] x86: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
---
 arch/x86/mm/pgtable.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 1a7d21342e..a7cccb6d7f 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -25,8 +25,12 @@ pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 	struct page *pte;
 
 	pte = alloc_pages(__userpte_alloc_gfp, 0);
-	if (pte)
-		pgtable_page_ctor(pte);
+	if (!pte)
+		return NULL;
+	if (!pgtable_page_ctor(pte)) {
+		__free_page(pte);
+		return NULL;
+	}
 	return pte;
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 32/34] xtensa: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
---
 arch/xtensa/include/asm/pgalloc.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/xtensa/include/asm/pgalloc.h b/arch/xtensa/include/asm/pgalloc.h
index 037671a655..b8774f1e21 100644
--- a/arch/xtensa/include/asm/pgalloc.h
+++ b/arch/xtensa/include/asm/pgalloc.h
@@ -58,7 +58,10 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
 	if (!pte)
 		return NULL;
 	page = virt_to_page(pte);
-	pgtable_page_ctor(page);
+	if (!pgtable_page_ctor(page)) {
+		kmem_cache_free(pgtable_cache, pte);
+		return NULL;
+	}
 	return page;
 }
 
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 33/34] iommu/arm-smmu: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
---
 drivers/iommu/arm-smmu.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index f417e89e1e..2b256a5075 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1211,7 +1211,10 @@ static int arm_smmu_alloc_init_pte(struct arm_smmu_device *smmu, pmd_t *pmd,
 
 		arm_smmu_flush_pgtable(smmu, page_address(table),
 				       ARM_SMMU_PTE_HWTABLE_SIZE);
-		pgtable_page_ctor(table);
+		if (!pgtable_page_ctor(table)) {
+			__free_page(table);
+			return -ENOMEM;
+		}
 		pmd_populate(NULL, pmd, table);
 		arm_smmu_flush_pgtable(smmu, pmd, sizeof(*pmd));
 	}
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 33/34] iommu/arm-smmu: handle pgtable_page_ctor() fail

[Will Deacon]

On Thu, Oct 10, 2013 at 07:05:58PM +0100, Kirill A. Shutemov wrote:
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Grant Likely <grant.likely@linaro.org>
> Cc: Rob Herring <rob.herring@calxeda.com>
> ---
>  drivers/iommu/arm-smmu.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index f417e89e1e..2b256a5075 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -1211,7 +1211,10 @@ static int arm_smmu_alloc_init_pte(struct arm_smmu_device *smmu, pmd_t *pmd,
>  
>  		arm_smmu_flush_pgtable(smmu, page_address(table),
>  				       ARM_SMMU_PTE_HWTABLE_SIZE);
> -		pgtable_page_ctor(table);
> +		if (!pgtable_page_ctor(table)) {
> +			__free_page(table);
> +			return -ENOMEM;
> +		}
>  		pmd_populate(NULL, pmd, table);
>  		arm_smmu_flush_pgtable(smmu, pmd, sizeof(*pmd));
>  	}

  Acked-by: Will Deacon <will.deacon@arm.com>

I have quite a few changes queued for this driver, but it doesn't look like
you'll get a conflict with the iommu tree.

Will

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 34/34] mm: dynamically allocate page->ptl if it cannot be embedded to struct page

[Kirill A. Shutemov]

If split page table lock is in use, we embed the lock into struct page
of table's page. We have to disable split lock, if spinlock_t is too big
be to be embedded, like when DEBUG_SPINLOCK or DEBUG_LOCK_ALLOC enabled.

This patch add support for dynamic allocation of split page table lock
if we can't embed it to struct page.

page->ptl is unsigned long now and we use it as spinlock_t if
sizeof(spinlock_t) <= sizeof(long), otherwise it's pointer to
spinlock_t.

The spinlock_t allocated in pgtable_page_ctor() for PTE table and in
pgtable_pmd_page_ctor() for PMD table. All other helpers converted to
support dynamically allocated page->ptl.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 Documentation/vm/split_page_table_lock | 90 ++++++++++++++++++++++++++++++++++
 arch/x86/xen/mmu.c                     |  2 +-
 include/linux/mm.h                     | 72 +++++++++++++++++++--------
 include/linux/mm_types.h               |  5 +-
 mm/Kconfig                             |  2 -
 mm/memory.c                            | 19 +++++++
 6 files changed, 166 insertions(+), 24 deletions(-)
 create mode 100644 Documentation/vm/split_page_table_lock

diff --git a/Documentation/vm/split_page_table_lock b/Documentation/vm/split_page_table_lock
new file mode 100644
index 0000000000..e2f617b732
--- /dev/null
+++ b/Documentation/vm/split_page_table_lock
@@ -0,0 +1,90 @@
+Split page table lock
+=====================
+
+Originally, mm->page_table_lock spinlock protected all page tables of the
+mm_struct. But this approach leads to poor page fault scalability of
+multi-threaded applications due high contention on the lock. To improve
+scalability, split page table lock was introduced.
+
+With split page table lock we have separate per-table lock to serialize
+access to the table. At the moment we use split lock for PTE and PMD
+tables. Access to higher level tables protected by mm->page_table_lock.
+
+There are helpers to lock/unlock a table and other accessor functions:
+ - pte_offset_map_lock()
+	maps pte and takes PTE table lock, returns pointer to the taken
+	lock;
+ - pte_unmap_unlock()
+	unlocks and unmaps PTE table;
+ - pte_alloc_map_lock()
+	allocates PTE table if needed and take the lock, returns pointer
+	to taken lock or NULL if allocation failed;
+ - pte_lockptr()
+	returns pointer to PTE table lock;
+ - pmd_lock()
+	takes PMD table lock, returns pointer to taken lock;
+ - pmd_lockptr()
+	returns pointer to PMD table lock;
+
+Split page table lock for PTE tables is enabled compile-time if
+CONFIG_SPLIT_PTLOCK_CPUS (usually 4) is less or equal to NR_CPUS.
+If split lock is disabled, all tables guaded by mm->page_table_lock.
+
+Split page table lock for PMD tables is enabled, if it's enabled for PTE
+tables and the architecture supports it (see below).
+
+Hugetlb and split page table lock
+---------------------------------
+
+Hugetlb can support several page sizes. We use split lock only for PMD
+level, but not for PUD.
+
+Hugetlb-specific helpers:
+ - huge_pte_lock()
+	takes pmd split lock for PMD_SIZE page, mm->page_table_lock
+	otherwise;
+ - huge_pte_lockptr()
+	returns pointer to table lock;
+
+Support of split page table lock by an architecture
+---------------------------------------------------
+
+There's no need in special enabling of PTE split page table lock:
+everything required is done by pgtable_page_ctor() and pgtable_page_dtor(),
+which must be called on PTE table allocation / freeing.
+
+PMD split lock only makes sense if you have more than two page table
+levels.
+
+PMD split lock enabling requires pgtable_pmd_page_ctor() call on PMD table
+allocation and pgtable_pmd_page_dtor() on freeing.
+
+Allocation usually happens in pmd_alloc_one(), freeing in pmd_free(), but
+make sure you cover all PMD table allocation / freeing paths: i.e X86_PAE
+preallocate few PMDs on pgd_alloc().
+
+With everything in place you can set CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK.
+
+NOTE: pgtable_page_ctor() and pgtable_pmd_page_ctor() can fail -- it must
+be handled properly.
+
+page->ptl
+---------
+
+page->ptl is used to access split page table lock, where 'page' is struct
+page of page containing the table. It shares storage with page->private
+(and few other fields in union).
+
+To avoid increasing size of struct page and have best performance, we use a
+trick:
+ - if spinlock_t fits into long, we use page->ptr as spinlock, so we
+   can avoid indirect access and save a cache line.
+ - if size of spinlock_t is bigger then size of long, we use page->ptl as
+   pointer to spinlock_t and allocate it dynamically. This allows to use
+   split lock with enabled DEBUG_SPINLOCK or DEBUG_LOCK_ALLOC, but costs
+   one more cache line for indirect access;
+
+The spinlock_t allocated in pgtable_page_ctor() for PTE table and in
+pgtable_pmd_page_ctor() for PMD table.
+
+Please, never access page->ptl directly -- use appropriate helper.
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 455c873ce0..49c962fe7e 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -797,7 +797,7 @@ static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
 	spinlock_t *ptl = NULL;
 
 #if USE_SPLIT_PTE_PTLOCKS
-	ptl = __pte_lockptr(page);
+	ptl = ptlock_ptr(page);
 	spin_lock_nest_lock(ptl, &mm->page_table_lock);
 #endif
 
diff --git a/include/linux/mm.h b/include/linux/mm.h
index f6467032a9..658e8b317f 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1233,32 +1233,64 @@ static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long a
 #endif /* CONFIG_MMU && !__ARCH_HAS_4LEVEL_HACK */
 
 #if USE_SPLIT_PTE_PTLOCKS
-/*
- * We tuck a spinlock to guard each pagetable page into its struct page,
- * at page->private, with BUILD_BUG_ON to make sure that this will not
- * overflow into the next struct page (as it might with DEBUG_SPINLOCK).
- * When freeing, reset page->mapping so free_pages_check won't complain.
- */
-#define __pte_lockptr(page)	&((page)->ptl)
-#define pte_lock_init(_page)	do {					\
-	spin_lock_init(__pte_lockptr(_page));				\
-} while (0)
-#define pte_lock_deinit(page)	((page)->mapping = NULL)
-#define pte_lockptr(mm, pmd)	({(void)(mm); __pte_lockptr(pmd_page(*(pmd)));})
+bool __ptlock_alloc(struct page *page);
+void __ptlock_free(struct page *page);
+static inline bool ptlock_alloc(struct page *page)
+{
+	if (sizeof(spinlock_t) > sizeof(page->ptl))
+		return __ptlock_alloc(page);
+	return true;
+}
+static inline void ptlock_free(struct page *page)
+{
+	if (sizeof(spinlock_t) > sizeof(page->ptl))
+		__ptlock_free(page);
+}
+
+static inline spinlock_t *ptlock_ptr(struct page *page)
+{
+	if (sizeof(spinlock_t) > sizeof(page->ptl))
+		return (spinlock_t *) page->ptl;
+	else
+		return (spinlock_t *) &page->ptl;
+}
+
+static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
+{
+	return ptlock_ptr(pmd_page(*pmd));
+}
+
+static inline bool ptlock_init(struct page *page)
+{
+	if (!ptlock_alloc(page))
+		return false;
+	spin_lock_init(ptlock_ptr(page));
+	return true;
+}
+
+/* Reset page->mapping so free_pages_check won't complain. */
+static inline void pte_lock_deinit(struct page *page)
+{
+	page->mapping = NULL;
+	ptlock_free(page);
+}
+
 #else	/* !USE_SPLIT_PTE_PTLOCKS */
 /*
  * We use mm->page_table_lock to guard all pagetable pages of the mm.
  */
-#define pte_lock_init(page)	do {} while (0)
-#define pte_lock_deinit(page)	do {} while (0)
-#define pte_lockptr(mm, pmd)	({(void)(pmd); &(mm)->page_table_lock;})
+static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
+{
+	return &mm->page_table_lock;
+}
+static inline bool ptlock_init(struct page *page) { return true; }
+static inline void pte_lock_deinit(struct page *page) {}
 #endif /* USE_SPLIT_PTE_PTLOCKS */
 
 static inline bool pgtable_page_ctor(struct page *page)
 {
-	pte_lock_init(page);
 	inc_zone_page_state(page, NR_PAGETABLE);
-	return true;
+	return ptlock_init(page);
 }
 
 static inline void pgtable_page_dtor(struct page *page)
@@ -1299,16 +1331,15 @@ static inline void pgtable_page_dtor(struct page *page)
 
 static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd)
 {
-	return &virt_to_page(pmd)->ptl;
+	return ptlock_ptr(virt_to_page(pmd));
 }
 
 static inline bool pgtable_pmd_page_ctor(struct page *page)
 {
-	spin_lock_init(&page->ptl);
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 	page->pmd_huge_pte = NULL;
 #endif
-	return true;
+	return ptlock_init(page);
 }
 
 static inline void pgtable_pmd_page_dtor(struct page *page)
@@ -1316,6 +1347,7 @@ static inline void pgtable_pmd_page_dtor(struct page *page)
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 	VM_BUG_ON(page->pmd_huge_pte);
 #endif
+	ptlock_free(page);
 }
 
 #define pmd_huge_pte(mm, pmd) (virt_to_page(pmd)->pmd_huge_pte)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index bacc15f078..257ac12fac 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -147,7 +147,10 @@ struct page {
 						 * system if PG_buddy is set.
 						 */
 #if USE_SPLIT_PTE_PTLOCKS
-		spinlock_t ptl;
+		unsigned long ptl; /* It's spinlock_t if it fits to long,
+				    * otherwise it's pointer to dynamicaly
+				    * allocated spinlock_t.
+				    */
 #endif
 		struct kmem_cache *slab_cache;	/* SL[AU]B: Pointer to slab */
 		struct page *first_page;	/* Compound tail pages */
diff --git a/mm/Kconfig b/mm/Kconfig
index d19f7d380b..9e8c8ae3b6 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -211,8 +211,6 @@ config SPLIT_PTLOCK_CPUS
 	int
 	default "999999" if ARM && !CPU_CACHE_VIPT
 	default "999999" if PARISC && !PA20
-	default "999999" if DEBUG_SPINLOCK || DEBUG_LOCK_ALLOC
-	default "999999" if !64BIT && GENERIC_LOCKBREAK
 	default "4"
 
 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
diff --git a/mm/memory.c b/mm/memory.c
index 1200d6230c..7e11f745bc 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4330,3 +4330,22 @@ void copy_user_huge_page(struct page *dst, struct page *src,
 	}
 }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
+
+#if USE_SPLIT_PTE_PTLOCKS
+bool __ptlock_alloc(struct page *page)
+{
+	spinlock_t *ptl;
+
+	ptl = kmalloc(sizeof(spinlock_t), GFP_KERNEL);
+	if (!ptl)
+		return false;
+	page->ptl = (unsigned long)ptl;
+	return true;
+}
+
+void __ptlock_free(struct page *page)
+{
+	if (sizeof(spinlock_t) > sizeof(page->ptl))
+		kfree((spinlock_t *)page->ptl);
+}
+#endif
-- 
1.8.4.rc3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 34/34] mm: dynamically allocate page->ptl if it cannot be embedded to struct page

[Christoph Lameter]

On Thu, 10 Oct 2013, Kirill A. Shutemov wrote:

> +static inline bool ptlock_alloc(struct page *page)
> +{
> +	if (sizeof(spinlock_t) > sizeof(page->ptl))
> +		return __ptlock_alloc(page);
> +	return true;
> +}

Could you make the check a CONFIG option? CONFIG_PTLOCK_DOES_NOT_FIT_IN_PAGE_STRUCT or
so?

> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -147,7 +147,10 @@ struct page {
>  						 * system if PG_buddy is set.
>  						 */
>  #if USE_SPLIT_PTE_PTLOCKS
> -		spinlock_t ptl;
> +		unsigned long ptl; /* It's spinlock_t if it fits to long,
> +				    * otherwise it's pointer to dynamicaly
> +				    * allocated spinlock_t.
> +				    */

If you had such a CONFIG option then you could use the proper type here.

#ifdef CONFIG_PTLOCK_NOT_FITTING
	spinlock_t *ptl;
#else
	spinlock_t ptl;
#endif

Or some such thing?

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 34/34] mm: dynamically allocate page->ptl if it cannot be embedded to struct page

[Kirill A. Shutemov]

Christoph Lameter wrote:
> On Thu, 10 Oct 2013, Kirill A. Shutemov wrote:
> 
> > +static inline bool ptlock_alloc(struct page *page)
> > +{
> > +	if (sizeof(spinlock_t) > sizeof(page->ptl))
> > +		return __ptlock_alloc(page);
> > +	return true;
> > +}
> 
> Could you make the check a CONFIG option? CONFIG_PTLOCK_DOES_NOT_FIT_IN_PAGE_STRUCT or
> so?

No. We will have to track what affects sizeof(spinlock_t) manually.
Not a fun and error prune.

C sucks. ;)

-- 
 Kirill A. Shutemov

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 34/34] mm: dynamically allocate page->ptl if it cannot be embedded to struct page

[Christoph Lameter]

On Thu, 10 Oct 2013, Kirill A. Shutemov wrote:

> Christoph Lameter wrote:
> > On Thu, 10 Oct 2013, Kirill A. Shutemov wrote:
> >
> > > +static inline bool ptlock_alloc(struct page *page)
> > > +{
> > > +	if (sizeof(spinlock_t) > sizeof(page->ptl))
> > > +		return __ptlock_alloc(page);
> > > +	return true;
> > > +}
> >
> > Could you make the check a CONFIG option? CONFIG_PTLOCK_DOES_NOT_FIT_IN_PAGE_STRUCT or
> > so?
>
> No. We will have to track what affects sizeof(spinlock_t) manually.
> Not a fun and error prune.

You can generate a config option depending on the size of the object via
Kbuild. Kbuild will determine the setting before building the kernel as a
whole by runing some small C program.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 34/34] mm: dynamically allocate page->ptl if it cannot be embedded to struct page

[Kirill A. Shutemov]

Christoph Lameter wrote:
> On Thu, 10 Oct 2013, Kirill A. Shutemov wrote:
> 
> > Christoph Lameter wrote:
> > > On Thu, 10 Oct 2013, Kirill A. Shutemov wrote:
> > >
> > > > +static inline bool ptlock_alloc(struct page *page)
> > > > +{
> > > > +	if (sizeof(spinlock_t) > sizeof(page->ptl))
> > > > +		return __ptlock_alloc(page);
> > > > +	return true;
> > > > +}
> > >
> > > Could you make the check a CONFIG option? CONFIG_PTLOCK_DOES_NOT_FIT_IN_PAGE_STRUCT or
> > > so?
> >
> > No. We will have to track what affects sizeof(spinlock_t) manually.
> > Not a fun and error prune.
> 
> You can generate a config option depending on the size of the object via
> Kbuild. Kbuild will determine the setting before building the kernel as a
> whole by runing some small C program.

I don't think it's any better than what we have there now.

-- 
 Kirill A. Shutemov

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 34/34] mm: dynamically allocate page->ptl if it cannot be embedded to struct page

[Christoph Lameter]

On Mon, 14 Oct 2013, Kirill A. Shutemov wrote:

> > > > Could you make the check a CONFIG option? CONFIG_PTLOCK_DOES_NOT_FIT_IN_PAGE_STRUCT or
> > > > so?
> > >
> > > No. We will have to track what affects sizeof(spinlock_t) manually.
> > > Not a fun and error prune.
> >
> > You can generate a config option depending on the size of the object via
> > Kbuild. Kbuild will determine the setting before building the kernel as a
> > whole by runing some small C program.
>
> I don't think it's any better than what we have there now.

Well with the CONFIG options we can then create macros etc that handle
things differently depending on the ptl being in the page or not.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 34/34] mm: dynamically allocate page->ptl if it cannot be embedded to struct page

[Kirill A. Shutemov]

Christoph Lameter wrote:
> On Mon, 14 Oct 2013, Kirill A. Shutemov wrote:
> 
> > > > > Could you make the check a CONFIG option? CONFIG_PTLOCK_DOES_NOT_FIT_IN_PAGE_STRUCT or
> > > > > so?
> > > >
> > > > No. We will have to track what affects sizeof(spinlock_t) manually.
> > > > Not a fun and error prune.
> > >
> > > You can generate a config option depending on the size of the object via
> > > Kbuild. Kbuild will determine the setting before building the kernel as a
> > > whole by runing some small C program.
> >
> > I don't think it's any better than what we have there now.
> 
> Well with the CONFIG options we can then create macros etc that handle
> things differently depending on the ptl being in the page or not.

Feel free to propose a patch. I don't see much point.

-- 
 Kirill A. Shutemov

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 34/34] mm: dynamically allocate page->ptl if it cannot be embedded to struct page

[Christoph Lameter]

On Tue, 15 Oct 2013, Kirill A. Shutemov wrote:

> Feel free to propose a patch. I don't see much point.

Right now you are using a long to stand in for a spinlock_t or a pointer
to a spinlock_t. An #ifdef would allow to define the proper type and
therefore the compiler to check that the ptl is correctly used.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 34/34] mm: dynamically allocate page->ptl if it cannot be embedded to struct page

[Kirill A. Shutemov]

Christoph Lameter wrote:
> On Tue, 15 Oct 2013, Kirill A. Shutemov wrote:
> 
> > Feel free to propose a patch. I don't see much point.
> 
> Right now you are using a long to stand in for a spinlock_t or a pointer
> to a spinlock_t. An #ifdef would allow to define the proper type and
> therefore the compiler to check that the ptl is correctly used.

You should not use it directly anyway: page->ptl is not there at all if
USE_SPLIT_PTE_PTLOCKS is 0. Compiler checks limited to few helpers and use
a kbuild hack is overkill to me.

-- 
 Kirill A. Shutemov

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 34/34] mm: dynamically allocate page->ptl if it cannot be embedded to struct page

[Andrey Wagin]

Hi Kirill,

Looks like this patch adds memory leaks.
[  116.188310] kmemleak: 15672 new suspected memory leaks (see
/sys/kernel/debug/kmemleak)
unreferenced object 0xffff8800da45a350 (size 96):
  comm "dracut-initqueu", pid 93, jiffies 4294671391 (age 362.277s)
  hex dump (first 32 bytes):
    07 00 07 00 ad 4e ad de ff ff ff ff 6b 6b 6b 6b  .....N......kkkk
    ff ff ff ff ff ff ff ff 80 24 b4 82 ff ff ff ff  .........$......
  backtrace:
    [<ffffffff817152fe>] kmemleak_alloc+0x5e/0xc0
    [<ffffffff811c34f3>] kmem_cache_alloc_trace+0x113/0x290
    [<ffffffff811920f7>] __ptlock_alloc+0x27/0x50
    [<ffffffff81192849>] __pmd_alloc+0x59/0x170
    [<ffffffff81195ffa>] copy_page_range+0x38a/0x3e0
    [<ffffffff8105a013>] dup_mm+0x313/0x540
    [<ffffffff8105b9da>] copy_process+0x161a/0x1880
    [<ffffffff8105c01b>] do_fork+0x8b/0x360
    [<ffffffff8105c306>] SyS_clone+0x16/0x20
    [<ffffffff81727b79>] stub_clone+0x69/0x90
    [<ffffffffffffffff>] 0xffffffffffffffff

It's quite serious, because my test host went to panic in a few hours.

[12000.632734] kmemleak: 74155 new suspected memory leaks (see
/sys/kernel/debug/kmemleak)
[12080.734075] zombie00[29282]: segfault at 0 ip 0000000000401862 sp
00007fffc509bc20 error 6 in zombie00[400000+5000]
[12619.799052] BUG: unable to handle kernel paging request at 000000007aa9e3a0
[12619.800044] IP: [<ffffffff810b2c07>] cpuacct_charge+0x97/0x1e0
[12619.800044] PGD 0
[12619.800044] Thread overran stack, or stack corrupted
[12619.800044] Oops: 0000 [#1] SMP
[12619.800044] Modules linked in: binfmt_misc ip6table_filter
ip6_tables tun netlink_diag af_packet_diag udp_diag tcp_diag inet_diag
unix_diag joydev microcode pcspkr i2c_piix4 virtio_balloon virtio_net
i2c_core virtio_blk floppy
[12619.800044] CPU: 1 PID: 1324 Comm: kworker/u4:2 Not tainted 3.12.0+ #142
[12619.800044] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2007
[12619.800044] Workqueue: writeback bdi_writeback_workfn (flush-252:0)
[12619.800044] task: ffff88001f1a8000 ti: ffff880096f26000 task.ti:
ffff880096f26000
[12619.800044] RIP: 0010:[<ffffffff810b2c07>]  [<ffffffff810b2c07>]
cpuacct_charge+0x97/0x1e0
[12619.800044] RSP: 0018:ffff88011b403ce8  EFLAGS: 00010002
[12619.800044] RAX: 000000000000d580 RBX: 00000000000f11b1 RCX: 0000000000000003
[12619.800044] RDX: ffffffff81c49e40 RSI: ffffffff81c4bb00 RDI: ffff88001f1a8c68
[12619.800044] RBP: ffff88011b403d18 R08: 0000000000000001 R09: 0000000000000001
[12619.800044] R10: 0000000000000001 R11: 0000000000000007 R12: ffff88001f1a8000
[12619.800044] R13: 000000001f1a8000 R14: ffffffff82a86320 R15: 000006b1bda1e433
[12619.800044] FS:  0000000000000000(0000) GS:ffff88011b400000(0000)
knlGS:0000000000000000
[12619.800044] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[12619.800044] CR2: 000000007aa9e3a0 CR3: 0000000001c0b000 CR4: 00000000000006e0
[12619.800044] Stack:
[12619.800044]  ffffffff810b2b70 0000000000000002 ffff88011b5d40c0
00000000000f11b1
[12619.800044]  ffff88001f1a8068 ffff88001f1a8000 ffff88011b403d58
ffffffff810a108f
[12619.800044]  ffff88011b403d88 ffff88001f1a8068 ffff88011b5d40c0
ffff88011b5d4000
[12619.800044] Call Trace:
[12619.800044]  <IRQ>
[12619.800044]  [<ffffffff810b2b70>] ? cpuacct_css_alloc+0xb0/0xb0
[12619.800044]  [<ffffffff810a108f>] update_curr+0x13f/0x230
[12619.800044]  [<ffffffff810a9e57>] task_tick_fair+0x2d7/0x650
[12619.800044]  [<ffffffff8109dcc8>] ? sched_clock_cpu+0xb8/0x120
[12619.800044]  [<ffffffff8109482d>] scheduler_tick+0x6d/0xf0
[12619.800044]  [<ffffffff8106afd1>] update_process_times+0x61/0x80
[12619.800044]  [<ffffffff810e38c7>] tick_sched_handle+0x37/0x80
[12619.800044]  [<ffffffff810e3e74>] tick_sched_timer+0x54/0x90
[12619.800044]  [<ffffffff8108bd21>] __run_hrtimer+0x71/0x2d0
[12619.800044]  [<ffffffff810e3e20>] ? tick_nohz_handler+0xc0/0xc0
[12619.800044]  [<ffffffff8108c246>] hrtimer_interrupt+0x116/0x2a0
[12619.800044]  [<ffffffff81062959>] ? __local_bh_enable+0x49/0x70
[12619.800044]  [<ffffffff81033dcb>] local_apic_timer_interrupt+0x3b/0x60
[12619.800044]  [<ffffffff81727c05>] smp_apic_timer_interrupt+0x45/0x60
[12619.800044]  [<ffffffff8172686f>] apic_timer_interrupt+0x6f/0x80
[12619.800044]  <EOI>
[12619.800044]  [<ffffffff810b8e10>] ? mark_held_locks+0x90/0x150
[12619.800044]  [<ffffffff8171c6f2>] ? _raw_spin_unlock_irqrestore+0x42/0x70
[12619.800044]  [<ffffffffa001b71b>] virtio_queue_rq+0xdb/0x1b0 [virtio_blk]
[12619.800044]  [<ffffffff8134647a>] __blk_mq_run_hw_queue+0x1ca/0x520
[12619.800044]  [<ffffffff81346b35>] blk_mq_run_hw_queue+0x35/0x40
[12619.800044]  [<ffffffff813470f2>] blk_mq_insert_requests+0xe2/0x190
[12619.800044]  [<ffffffff813472d4>] blk_mq_flush_plug_list+0x134/0x150
[12619.800044]  [<ffffffff8133d0cd>] blk_flush_plug_list+0xbd/0x220
[12619.800044]  [<ffffffff81346f1a>] blk_mq_make_request+0x3da/0x4d0
[12619.800044]  [<ffffffff813397aa>] generic_make_request+0xca/0x100
[12619.800044]  [<ffffffff81339856>] submit_bio+0x76/0x160
[12619.800044]  [<ffffffff81173c66>] ? test_set_page_writeback+0x36/0x2b0
[12619.800044]  [<ffffffff811a9ae0>] ? end_swap_bio_read+0xc0/0xc0
[12619.800044]  [<ffffffff811a96c8>] __swap_writepage+0x198/0x230
[12619.800044]  [<ffffffff8171c74b>] ? _raw_spin_unlock+0x2b/0x40
[12619.800044]  [<ffffffff811aaf93>] ? page_swapcount+0x53/0x70
[12619.800044]  [<ffffffff811a97a3>] swap_writepage+0x43/0x90
[12619.800044]  [<ffffffff8117c3df>] shrink_page_list+0x6cf/0xaa0
[12619.800044]  [<ffffffff8117d452>] shrink_inactive_list+0x1c2/0x5b0
[12619.800044]  [<ffffffff810b976f>] ? __lock_acquire+0x23f/0x1810
[12619.800044]  [<ffffffff8117dea5>] shrink_lruvec+0x335/0x600
[12619.800044]  [<ffffffff811d24f5>] ? mem_cgroup_iter+0x1f5/0x510
[12619.800044]  [<ffffffff8117e206>] shrink_zone+0x96/0x1d0
[12619.800044]  [<ffffffff8117ec83>] do_try_to_free_pages+0x103/0x600
[12619.800044]  [<ffffffff8109dba5>] ? sched_clock_local+0x25/0x90
[12619.800044]  [<ffffffff8117f692>] try_to_free_pages+0x222/0x440
[12619.800044]  [<ffffffff8117233f>] __alloc_pages_nodemask+0x8af/0xc70
[12619.800044]  [<ffffffff811b7fce>] alloc_pages_current+0x10e/0x1e0
[12619.800044]  [<ffffffff81167077>] ? __page_cache_alloc+0x127/0x160
[12619.800044]  [<ffffffff81167077>] __page_cache_alloc+0x127/0x160
[12619.800044]  [<ffffffff8116864f>] find_or_create_page+0x4f/0xb0
[12619.800044]  [<ffffffff8121c369>] __getblk+0x109/0x300
[12619.800044]  [<ffffffff8121c572>] __breadahead+0x12/0x40
[12619.800044]  [<ffffffff8127cf7d>] __ext4_get_inode_loc+0x30d/0x430
[12619.800044]  [<ffffffff8127d1ef>] ext4_get_inode_loc+0x1f/0x30
[12619.800044]  [<ffffffff8127d22d>] ext4_reserve_inode_write+0x2d/0xa0
[12619.800044]  [<ffffffff8127d305>] ext4_mark_inode_dirty+0x65/0x2b0
[12619.800044]  [<ffffffff812a3d7b>] __ext4_ext_dirty+0x7b/0x80
[12619.800044]  [<ffffffff812a4c97>] ext4_ext_insert_extent+0x417/0x12d0
[12619.800044]  [<ffffffff811c3eaf>] ? __kmalloc+0x1bf/0x2e0
[12619.800044]  [<ffffffff812a758b>] ext4_ext_map_blocks+0x57b/0xfb0
[12619.800044]  [<ffffffff8127a5e6>] ? ext4_map_blocks+0x126/0x470
[12619.800044]  [<ffffffff8127a624>] ext4_map_blocks+0x164/0x470
[12619.800044]  [<ffffffff8127fba5>] ext4_writepages+0x6a5/0xc80
[12619.800044]  [<ffffffff8109dba5>] ? sched_clock_local+0x25/0x90
[12619.800044]  [<ffffffff8109dd7f>] ? local_clock+0x4f/0x60
[12619.800044]  [<ffffffff81175313>] do_writepages+0x23/0x40
[12619.800044]  [<ffffffff81210995>] __writeback_single_inode+0x45/0x3c0
[12619.800044]  [<ffffffff81213c9f>] writeback_sb_inodes+0x28f/0x520
[12619.800044]  [<ffffffff8171c74b>] ? _raw_spin_unlock+0x2b/0x40
[12619.800044]  [<ffffffff81213fce>] __writeback_inodes_wb+0x9e/0xd0
[12619.800044]  [<ffffffff8121429b>] wb_writeback+0x29b/0x540
[12619.800044]  [<ffffffff810b918d>] ? trace_hardirqs_on_caller+0xfd/0x1c0
[12619.800044]  [<ffffffff8121459d>] ? wb_do_writeback+0x5d/0x290
[12619.800044]  [<ffffffff812145b2>] wb_do_writeback+0x72/0x290
[12619.800044]  [<ffffffff8109dcc8>] ? sched_clock_cpu+0xb8/0x120
[12619.800044]  [<ffffffff81214840>] bdi_writeback_workfn+0x70/0x320
[12619.800044]  [<ffffffff8107eea6>] ? process_one_work+0x176/0x610
[12619.800044]  [<ffffffff8107ef0e>] process_one_work+0x1de/0x610
[12619.800044]  [<ffffffff8107eea6>] ? process_one_work+0x176/0x610
[12619.800044]  [<ffffffff81080e40>] worker_thread+0x120/0x3a0
[12619.800044]  [<ffffffff81080d20>] ? manage_workers+0x2c0/0x2c0
[12619.800044]  [<ffffffff81087f26>] kthread+0xf6/0x120
[12619.800044]  [<ffffffff8109dd7f>] ? local_clock+0x4f/0x60
[12619.800044]  [<ffffffff81087e30>] ? __init_kthread_worker+0x70/0x70
[12619.800044]  [<ffffffff81725b6c>] ret_from_fork+0x7c/0xb0
[12619.800044]  [<ffffffff81087e30>] ? __init_kthread_worker+0x70/0x70
[12619.800044] Code: 00 00 e8 fd 03 02 00 85 c0 74 0d 80 3d 51 e5 c8
00 00 0f 84 d4 00 00 00 49 8b 56 48 4d 63 ed 0f 1f 44 00 00 48 8b 82
b8 00 00 00 <4a> 03 04 ed a0 e3 d5 81 48 01 18 48 8b 52 40 48 85 d2 75
e5 e8
[12619.800044] RIP  [<ffffffff810b2c07>] cpuacct_charge+0x97/0x1e0
[12619.800044]  RSP <ffff88011b403ce8>
[12619.800044] CR2: 000000007aa9e3a0

2013/10/10 Kirill A. Shutemov <kirill.shutemov@linux.intel.com>:
> If split page table lock is in use, we embed the lock into struct page
> of table's page. We have to disable split lock, if spinlock_t is too big
> be to be embedded, like when DEBUG_SPINLOCK or DEBUG_LOCK_ALLOC enabled.
>
> This patch add support for dynamic allocation of split page table lock
> if we can't embed it to struct page.
>
> page->ptl is unsigned long now and we use it as spinlock_t if
> sizeof(spinlock_t) <= sizeof(long), otherwise it's pointer to
> spinlock_t.
>
> The spinlock_t allocated in pgtable_page_ctor() for PTE table and in
> pgtable_pmd_page_ctor() for PMD table. All other helpers converted to
> support dynamically allocated page->ptl.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
>  Documentation/vm/split_page_table_lock | 90 ++++++++++++++++++++++++++++++++++
>  arch/x86/xen/mmu.c                     |  2 +-
>  include/linux/mm.h                     | 72 +++++++++++++++++++--------
>  include/linux/mm_types.h               |  5 +-
>  mm/Kconfig                             |  2 -
>  mm/memory.c                            | 19 +++++++
>  6 files changed, 166 insertions(+), 24 deletions(-)
>  create mode 100644 Documentation/vm/split_page_table_lock
>
> diff --git a/Documentation/vm/split_page_table_lock b/Documentation/vm/split_page_table_lock
> new file mode 100644
> index 0000000000..e2f617b732
> --- /dev/null
> +++ b/Documentation/vm/split_page_table_lock
> @@ -0,0 +1,90 @@
> +Split page table lock
> +=====================
> +
> +Originally, mm->page_table_lock spinlock protected all page tables of the
> +mm_struct. But this approach leads to poor page fault scalability of
> +multi-threaded applications due high contention on the lock. To improve
> +scalability, split page table lock was introduced.
> +
> +With split page table lock we have separate per-table lock to serialize
> +access to the table. At the moment we use split lock for PTE and PMD
> +tables. Access to higher level tables protected by mm->page_table_lock.
> +
> +There are helpers to lock/unlock a table and other accessor functions:
> + - pte_offset_map_lock()
> +       maps pte and takes PTE table lock, returns pointer to the taken
> +       lock;
> + - pte_unmap_unlock()
> +       unlocks and unmaps PTE table;
> + - pte_alloc_map_lock()
> +       allocates PTE table if needed and take the lock, returns pointer
> +       to taken lock or NULL if allocation failed;
> + - pte_lockptr()
> +       returns pointer to PTE table lock;
> + - pmd_lock()
> +       takes PMD table lock, returns pointer to taken lock;
> + - pmd_lockptr()
> +       returns pointer to PMD table lock;
> +
> +Split page table lock for PTE tables is enabled compile-time if
> +CONFIG_SPLIT_PTLOCK_CPUS (usually 4) is less or equal to NR_CPUS.
> +If split lock is disabled, all tables guaded by mm->page_table_lock.
> +
> +Split page table lock for PMD tables is enabled, if it's enabled for PTE
> +tables and the architecture supports it (see below).
> +
> +Hugetlb and split page table lock
> +---------------------------------
> +
> +Hugetlb can support several page sizes. We use split lock only for PMD
> +level, but not for PUD.
> +
> +Hugetlb-specific helpers:
> + - huge_pte_lock()
> +       takes pmd split lock for PMD_SIZE page, mm->page_table_lock
> +       otherwise;
> + - huge_pte_lockptr()
> +       returns pointer to table lock;
> +
> +Support of split page table lock by an architecture
> +---------------------------------------------------
> +
> +There's no need in special enabling of PTE split page table lock:
> +everything required is done by pgtable_page_ctor() and pgtable_page_dtor(),
> +which must be called on PTE table allocation / freeing.
> +
> +PMD split lock only makes sense if you have more than two page table
> +levels.
> +
> +PMD split lock enabling requires pgtable_pmd_page_ctor() call on PMD table
> +allocation and pgtable_pmd_page_dtor() on freeing.
> +
> +Allocation usually happens in pmd_alloc_one(), freeing in pmd_free(), but
> +make sure you cover all PMD table allocation / freeing paths: i.e X86_PAE
> +preallocate few PMDs on pgd_alloc().
> +
> +With everything in place you can set CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK.
> +
> +NOTE: pgtable_page_ctor() and pgtable_pmd_page_ctor() can fail -- it must
> +be handled properly.
> +
> +page->ptl
> +---------
> +
> +page->ptl is used to access split page table lock, where 'page' is struct
> +page of page containing the table. It shares storage with page->private
> +(and few other fields in union).
> +
> +To avoid increasing size of struct page and have best performance, we use a
> +trick:
> + - if spinlock_t fits into long, we use page->ptr as spinlock, so we
> +   can avoid indirect access and save a cache line.
> + - if size of spinlock_t is bigger then size of long, we use page->ptl as
> +   pointer to spinlock_t and allocate it dynamically. This allows to use
> +   split lock with enabled DEBUG_SPINLOCK or DEBUG_LOCK_ALLOC, but costs
> +   one more cache line for indirect access;
> +
> +The spinlock_t allocated in pgtable_page_ctor() for PTE table and in
> +pgtable_pmd_page_ctor() for PMD table.
> +
> +Please, never access page->ptl directly -- use appropriate helper.
> diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
> index 455c873ce0..49c962fe7e 100644
> --- a/arch/x86/xen/mmu.c
> +++ b/arch/x86/xen/mmu.c
> @@ -797,7 +797,7 @@ static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
>         spinlock_t *ptl = NULL;
>
>  #if USE_SPLIT_PTE_PTLOCKS
> -       ptl = __pte_lockptr(page);
> +       ptl = ptlock_ptr(page);
>         spin_lock_nest_lock(ptl, &mm->page_table_lock);
>  #endif
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index f6467032a9..658e8b317f 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1233,32 +1233,64 @@ static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long a
>  #endif /* CONFIG_MMU && !__ARCH_HAS_4LEVEL_HACK */
>
>  #if USE_SPLIT_PTE_PTLOCKS
> -/*
> - * We tuck a spinlock to guard each pagetable page into its struct page,
> - * at page->private, with BUILD_BUG_ON to make sure that this will not
> - * overflow into the next struct page (as it might with DEBUG_SPINLOCK).
> - * When freeing, reset page->mapping so free_pages_check won't complain.
> - */
> -#define __pte_lockptr(page)    &((page)->ptl)
> -#define pte_lock_init(_page)   do {                                    \
> -       spin_lock_init(__pte_lockptr(_page));                           \
> -} while (0)
> -#define pte_lock_deinit(page)  ((page)->mapping = NULL)
> -#define pte_lockptr(mm, pmd)   ({(void)(mm); __pte_lockptr(pmd_page(*(pmd)));})
> +bool __ptlock_alloc(struct page *page);
> +void __ptlock_free(struct page *page);
> +static inline bool ptlock_alloc(struct page *page)
> +{
> +       if (sizeof(spinlock_t) > sizeof(page->ptl))
> +               return __ptlock_alloc(page);
> +       return true;
> +}
> +static inline void ptlock_free(struct page *page)
> +{
> +       if (sizeof(spinlock_t) > sizeof(page->ptl))
> +               __ptlock_free(page);
> +}
> +
> +static inline spinlock_t *ptlock_ptr(struct page *page)
> +{
> +       if (sizeof(spinlock_t) > sizeof(page->ptl))
> +               return (spinlock_t *) page->ptl;
> +       else
> +               return (spinlock_t *) &page->ptl;
> +}
> +
> +static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
> +{
> +       return ptlock_ptr(pmd_page(*pmd));
> +}
> +
> +static inline bool ptlock_init(struct page *page)
> +{
> +       if (!ptlock_alloc(page))
> +               return false;
> +       spin_lock_init(ptlock_ptr(page));
> +       return true;
> +}
> +
> +/* Reset page->mapping so free_pages_check won't complain. */
> +static inline void pte_lock_deinit(struct page *page)
> +{
> +       page->mapping = NULL;
> +       ptlock_free(page);
> +}
> +
>  #else  /* !USE_SPLIT_PTE_PTLOCKS */
>  /*
>   * We use mm->page_table_lock to guard all pagetable pages of the mm.
>   */
> -#define pte_lock_init(page)    do {} while (0)
> -#define pte_lock_deinit(page)  do {} while (0)
> -#define pte_lockptr(mm, pmd)   ({(void)(pmd); &(mm)->page_table_lock;})
> +static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
> +{
> +       return &mm->page_table_lock;
> +}
> +static inline bool ptlock_init(struct page *page) { return true; }
> +static inline void pte_lock_deinit(struct page *page) {}
>  #endif /* USE_SPLIT_PTE_PTLOCKS */
>
>  static inline bool pgtable_page_ctor(struct page *page)
>  {
> -       pte_lock_init(page);
>         inc_zone_page_state(page, NR_PAGETABLE);
> -       return true;
> +       return ptlock_init(page);
>  }
>
>  static inline void pgtable_page_dtor(struct page *page)
> @@ -1299,16 +1331,15 @@ static inline void pgtable_page_dtor(struct page *page)
>
>  static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd)
>  {
> -       return &virt_to_page(pmd)->ptl;
> +       return ptlock_ptr(virt_to_page(pmd));
>  }
>
>  static inline bool pgtable_pmd_page_ctor(struct page *page)
>  {
> -       spin_lock_init(&page->ptl);
>  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>         page->pmd_huge_pte = NULL;
>  #endif
> -       return true;
> +       return ptlock_init(page);
>  }
>
>  static inline void pgtable_pmd_page_dtor(struct page *page)
> @@ -1316,6 +1347,7 @@ static inline void pgtable_pmd_page_dtor(struct page *page)
>  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>         VM_BUG_ON(page->pmd_huge_pte);
>  #endif
> +       ptlock_free(page);
>  }
>
>  #define pmd_huge_pte(mm, pmd) (virt_to_page(pmd)->pmd_huge_pte)
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index bacc15f078..257ac12fac 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -147,7 +147,10 @@ struct page {
>                                                  * system if PG_buddy is set.
>                                                  */
>  #if USE_SPLIT_PTE_PTLOCKS
> -               spinlock_t ptl;
> +               unsigned long ptl; /* It's spinlock_t if it fits to long,
> +                                   * otherwise it's pointer to dynamicaly
> +                                   * allocated spinlock_t.
> +                                   */
>  #endif
>                 struct kmem_cache *slab_cache;  /* SL[AU]B: Pointer to slab */
>                 struct page *first_page;        /* Compound tail pages */
> diff --git a/mm/Kconfig b/mm/Kconfig
> index d19f7d380b..9e8c8ae3b6 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -211,8 +211,6 @@ config SPLIT_PTLOCK_CPUS
>         int
>         default "999999" if ARM && !CPU_CACHE_VIPT
>         default "999999" if PARISC && !PA20
> -       default "999999" if DEBUG_SPINLOCK || DEBUG_LOCK_ALLOC
> -       default "999999" if !64BIT && GENERIC_LOCKBREAK
>         default "4"
>
>  config ARCH_ENABLE_SPLIT_PMD_PTLOCK
> diff --git a/mm/memory.c b/mm/memory.c
> index 1200d6230c..7e11f745bc 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -4330,3 +4330,22 @@ void copy_user_huge_page(struct page *dst, struct page *src,
>         }
>  }
>  #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
> +
> +#if USE_SPLIT_PTE_PTLOCKS
> +bool __ptlock_alloc(struct page *page)
> +{
> +       spinlock_t *ptl;
> +
> +       ptl = kmalloc(sizeof(spinlock_t), GFP_KERNEL);
> +       if (!ptl)
> +               return false;
> +       page->ptl = (unsigned long)ptl;
> +       return true;
> +}
> +
> +void __ptlock_free(struct page *page)
> +{
> +       if (sizeof(spinlock_t) > sizeof(page->ptl))
> +               kfree((spinlock_t *)page->ptl);
> +}
> +#endif
> --
> 1.8.4.rc3
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 34/34] mm: dynamically allocate page->ptl if it cannot be embedded to struct page

[Kirill A. Shutemov]

Andrey Wagin wrote:
> Hi Kirill,
> 
> Looks like this patch adds memory leaks.
> [  116.188310] kmemleak: 15672 new suspected memory leaks (see
> /sys/kernel/debug/kmemleak)
> unreferenced object 0xffff8800da45a350 (size 96):
>   comm "dracut-initqueu", pid 93, jiffies 4294671391 (age 362.277s)
>   hex dump (first 32 bytes):
>     07 00 07 00 ad 4e ad de ff ff ff ff 6b 6b 6b 6b  .....N......kkkk
>     ff ff ff ff ff ff ff ff 80 24 b4 82 ff ff ff ff  .........$......
>   backtrace:
>     [<ffffffff817152fe>] kmemleak_alloc+0x5e/0xc0
>     [<ffffffff811c34f3>] kmem_cache_alloc_trace+0x113/0x290
>     [<ffffffff811920f7>] __ptlock_alloc+0x27/0x50
>     [<ffffffff81192849>] __pmd_alloc+0x59/0x170
>     [<ffffffff81195ffa>] copy_page_range+0x38a/0x3e0
>     [<ffffffff8105a013>] dup_mm+0x313/0x540
>     [<ffffffff8105b9da>] copy_process+0x161a/0x1880
>     [<ffffffff8105c01b>] do_fork+0x8b/0x360
>     [<ffffffff8105c306>] SyS_clone+0x16/0x20
>     [<ffffffff81727b79>] stub_clone+0x69/0x90
>     [<ffffffffffffffff>] 0xffffffffffffffff
> 
> It's quite serious, because my test host went to panic in a few hours.

Sorry for that.

Could you test patch below.

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index a7cccb6d7fec..7be5809754cf 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -61,6 +61,7 @@ void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
 #if PAGETABLE_LEVELS > 2
 void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
 {
+	struct page *page = virt_to_page(pmd);
 	paravirt_release_pmd(__pa(pmd) >> PAGE_SHIFT);
 	/*
 	 * NOTE! For PAE, any changes to the top page-directory-pointer-table
@@ -69,7 +70,8 @@ void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
 #ifdef CONFIG_X86_PAE
 	tlb->need_flush_all = 1;
 #endif
-	tlb_remove_page(tlb, virt_to_page(pmd));
+	pgtable_pmd_page_dtor(page);
+	tlb_remove_page(tlb, page);
 }
 
 #if PAGETABLE_LEVELS > 3
-- 
 Kirill A. Shutemov

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 34/34] mm: dynamically allocate page->ptl if it cannot be embedded to struct page

[Andrey Wagin]

2013/11/20 Kirill A. Shutemov <kirill.shutemov@linux.intel.com>:
> Andrey Wagin wrote:
>> Hi Kirill,
>>
>> Looks like this patch adds memory leaks.
>> [  116.188310] kmemleak: 15672 new suspected memory leaks (see
>> /sys/kernel/debug/kmemleak)
>> unreferenced object 0xffff8800da45a350 (size 96):
>>   comm "dracut-initqueu", pid 93, jiffies 4294671391 (age 362.277s)
>>   hex dump (first 32 bytes):
>>     07 00 07 00 ad 4e ad de ff ff ff ff 6b 6b 6b 6b  .....N......kkkk
>>     ff ff ff ff ff ff ff ff 80 24 b4 82 ff ff ff ff  .........$......
>>   backtrace:
>>     [<ffffffff817152fe>] kmemleak_alloc+0x5e/0xc0
>>     [<ffffffff811c34f3>] kmem_cache_alloc_trace+0x113/0x290
>>     [<ffffffff811920f7>] __ptlock_alloc+0x27/0x50
>>     [<ffffffff81192849>] __pmd_alloc+0x59/0x170
>>     [<ffffffff81195ffa>] copy_page_range+0x38a/0x3e0
>>     [<ffffffff8105a013>] dup_mm+0x313/0x540
>>     [<ffffffff8105b9da>] copy_process+0x161a/0x1880
>>     [<ffffffff8105c01b>] do_fork+0x8b/0x360
>>     [<ffffffff8105c306>] SyS_clone+0x16/0x20
>>     [<ffffffff81727b79>] stub_clone+0x69/0x90
>>     [<ffffffffffffffff>] 0xffffffffffffffff
>>
>> It's quite serious, because my test host went to panic in a few hours.
>
> Sorry for that.
>
> Could you test patch below.

Yes, it works.

I found this too a few minutes ago:)

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index a7cccb6..44c366c 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -62,6 +62,7 @@ void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
 void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
 {
        paravirt_release_pmd(__pa(pmd) >> PAGE_SHIFT);
+       pgtable_pmd_page_dtor(virt_to_page(pmd));
        /*
         * NOTE! For PAE, any changes to the top page-directory-pointer-table
         * entries need a full cr3 reload to flush.

Thanks.

>
> diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
> index a7cccb6d7fec..7be5809754cf 100644
> --- a/arch/x86/mm/pgtable.c
> +++ b/arch/x86/mm/pgtable.c
> @@ -61,6 +61,7 @@ void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
>  #if PAGETABLE_LEVELS > 2
>  void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
>  {
> +       struct page *page = virt_to_page(pmd);
>         paravirt_release_pmd(__pa(pmd) >> PAGE_SHIFT);
>         /*
>          * NOTE! For PAE, any changes to the top page-directory-pointer-table
> @@ -69,7 +70,8 @@ void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
>  #ifdef CONFIG_X86_PAE
>         tlb->need_flush_all = 1;
>  #endif
> -       tlb_remove_page(tlb, virt_to_page(pmd));
> +       pgtable_pmd_page_dtor(page);
> +       tlb_remove_page(tlb, page);
>  }
>
>  #if PAGETABLE_LEVELS > 3
> --
>  Kirill A. Shutemov

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 34/34] mm: dynamically allocate page->ptl if it cannot be embedded to struct page

[Kirill A. Shutemov]

Andrey Wagin wrote:
> 2013/11/20 Kirill A. Shutemov <kirill.shutemov@linux.intel.com>:
> > Andrey Wagin wrote:
> >> Hi Kirill,
> >>
> >> Looks like this patch adds memory leaks.
> >> [  116.188310] kmemleak: 15672 new suspected memory leaks (see
> >> /sys/kernel/debug/kmemleak)
> >> unreferenced object 0xffff8800da45a350 (size 96):
> >>   comm "dracut-initqueu", pid 93, jiffies 4294671391 (age 362.277s)
> >>   hex dump (first 32 bytes):
> >>     07 00 07 00 ad 4e ad de ff ff ff ff 6b 6b 6b 6b  .....N......kkkk
> >>     ff ff ff ff ff ff ff ff 80 24 b4 82 ff ff ff ff  .........$......
> >>   backtrace:
> >>     [<ffffffff817152fe>] kmemleak_alloc+0x5e/0xc0
> >>     [<ffffffff811c34f3>] kmem_cache_alloc_trace+0x113/0x290
> >>     [<ffffffff811920f7>] __ptlock_alloc+0x27/0x50
> >>     [<ffffffff81192849>] __pmd_alloc+0x59/0x170
> >>     [<ffffffff81195ffa>] copy_page_range+0x38a/0x3e0
> >>     [<ffffffff8105a013>] dup_mm+0x313/0x540
> >>     [<ffffffff8105b9da>] copy_process+0x161a/0x1880
> >>     [<ffffffff8105c01b>] do_fork+0x8b/0x360
> >>     [<ffffffff8105c306>] SyS_clone+0x16/0x20
> >>     [<ffffffff81727b79>] stub_clone+0x69/0x90
> >>     [<ffffffffffffffff>] 0xffffffffffffffff
> >>
> >> It's quite serious, because my test host went to panic in a few hours.
> >
> > Sorry for that.
> >
> > Could you test patch below.
> 
> Yes, it works.
> 
> I found this too a few minutes ago:)

Nice

Tested-by ?

-- 
 Kirill A. Shutemov

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 34/34] mm: dynamically allocate page->ptl if it cannot be embedded to struct page

[Andrey Wagin]

2013/11/20 Kirill A. Shutemov <kirill.shutemov@linux.intel.com>:
> Andrey Wagin wrote:
>> 2013/11/20 Kirill A. Shutemov <kirill.shutemov@linux.intel.com>:
>> > Andrey Wagin wrote:
>> >> Hi Kirill,
>> >>
>> >> Looks like this patch adds memory leaks.
>> >> [  116.188310] kmemleak: 15672 new suspected memory leaks (see
>> >> /sys/kernel/debug/kmemleak)
>> >> unreferenced object 0xffff8800da45a350 (size 96):
>> >>   comm "dracut-initqueu", pid 93, jiffies 4294671391 (age 362.277s)
>> >>   hex dump (first 32 bytes):
>> >>     07 00 07 00 ad 4e ad de ff ff ff ff 6b 6b 6b 6b  .....N......kkkk
>> >>     ff ff ff ff ff ff ff ff 80 24 b4 82 ff ff ff ff  .........$......
>> >>   backtrace:
>> >>     [<ffffffff817152fe>] kmemleak_alloc+0x5e/0xc0
>> >>     [<ffffffff811c34f3>] kmem_cache_alloc_trace+0x113/0x290
>> >>     [<ffffffff811920f7>] __ptlock_alloc+0x27/0x50
>> >>     [<ffffffff81192849>] __pmd_alloc+0x59/0x170
>> >>     [<ffffffff81195ffa>] copy_page_range+0x38a/0x3e0
>> >>     [<ffffffff8105a013>] dup_mm+0x313/0x540
>> >>     [<ffffffff8105b9da>] copy_process+0x161a/0x1880
>> >>     [<ffffffff8105c01b>] do_fork+0x8b/0x360
>> >>     [<ffffffff8105c306>] SyS_clone+0x16/0x20
>> >>     [<ffffffff81727b79>] stub_clone+0x69/0x90
>> >>     [<ffffffffffffffff>] 0xffffffffffffffff
>> >>
>> >> It's quite serious, because my test host went to panic in a few hours.
>> >
>> > Sorry for that.
>> >
>> > Could you test patch below.
>>
>> Yes, it works.
>>
>> I found this too a few minutes ago:)
>
> Nice
>
> Tested-by ?

Tested-by: Andrey Vagin <avagin@openvz.org>

>
> --
>  Kirill A. Shutemov

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 00/34] dynamically allocate split ptl if it cannot be embedded to struct page

[Peter Zijlstra]

On Thu, Oct 10, 2013 at 09:05:25PM +0300, Kirill A. Shutemov wrote:
> Any comments?

Reviewed-by: Peter Zijlstra <peterz@infradead.org>

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 15/34] frv: handle pgtable_page_ctor() fail

[David Howells]

Acked-by: David Howells <dhowells@redhat.com>

for the FRV and MN10300 patches.

Can you move pte_alloc_one() to common code, at least for some arches?  I
think that the FRV and MN10300 ones should end up the same after this - and I
wouldn't be surprised if some of the other arches do too.

David

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH 15/34] frv: handle pgtable_page_ctor() fail

[Kirill A. Shutemov]

David Howells wrote:
> 
> Acked-by: David Howells <dhowells@redhat.com>
> 
> for the FRV and MN10300 patches.
> 
> Can you move pte_alloc_one() to common code, at least for some arches?  I
> think that the FRV and MN10300 ones should end up the same after this - and I
> wouldn't be surprised if some of the other arches do too.

There's no true approach for generic. It depends on what pgtable_t is:
pointer to struct page or virtual address of the allocated page table.
Some arches also use some sort of cache for page table allocator. Others
don't.

I don't see a sensible way generalize it.

-- 
 Kirill A. Shutemov

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>