[RFC][PATCH v3 00/22] __vmalloc: Propagating GFP allocation flag

[RFC][PATCH v3 00/22] __vmalloc: Propagating GFP allocation flag

[Prasad Joshi]

A filesystem might run into a problem while calling __vmalloc(GFP_NOFS)
inside a lock.

It is expected than __vmalloc when called with GFP_NOFS should not
callback the filesystem code even incase of the increased memory
pressure. But the problem is that even if we pass this flag, __vmalloc
itself allocates memory with GFP_KERNEL.

Using GFP_KERNEL allocations may go into the memory reclaim path and try
to free memory by calling file system evict_inode function. Which might
lead into deadlock.

For further details
http://marc.info/?l=linux-mm&m\x128942194520631&w=4
https://bugzilla.kernel.org/show_bug.cgi?id0702

The patch passes the gfp allocation flag all the way down to those
allocating functions.

 arch/arm/include/asm/pgalloc.h           |   11 +++++-
 arch/avr32/include/asm/pgalloc.h         |    8 ++++-
 arch/cris/include/asm/pgalloc.h          |   10 ++++-
 arch/frv/include/asm/pgalloc.h           |    3 ++
 arch/frv/include/asm/pgtable.h           |    1 +
 arch/frv/mm/pgalloc.c                    |    9 ++++-
 arch/ia64/include/asm/pgalloc.h          |   24 +++++++++++--
 arch/m32r/include/asm/pgalloc.h          |   11 ++++--
 arch/m68k/include/asm/motorola_pgalloc.h |   20 +++++++++--
 arch/m68k/include/asm/sun3_pgalloc.h     |   14 ++++++--
 arch/m68k/mm/memory.c                    |    9 ++++-
 arch/microblaze/include/asm/pgalloc.h    |    3 ++
 arch/microblaze/mm/pgtable.c             |   13 +++++--
 arch/mips/include/asm/pgalloc.h          |   22 ++++++++----
 arch/mn10300/include/asm/pgalloc.h       |    2 +
 arch/mn10300/mm/pgtable.c                |   10 ++++-
 arch/parisc/include/asm/pgalloc.h        |   21 ++++++++---
 arch/powerpc/include/asm/pgalloc-32.h    |    2 +
 arch/powerpc/include/asm/pgalloc-64.h    |   27 +++++++++++---
 arch/powerpc/mm/pgtable_32.c             |   10 ++++-
 arch/s390/include/asm/pgalloc.h          |   30 +++++++++++++---
 arch/s390/mm/pgtable.c                   |   22 +++++++++---
 arch/score/include/asm/pgalloc.h         |   13 ++++---
 arch/sh/include/asm/pgalloc.h            |    8 ++++-
 arch/sh/mm/pgtable.c                     |    8 ++++-
 arch/sparc/include/asm/pgalloc_32.h      |    5 +++
 arch/sparc/include/asm/pgalloc_64.h      |   17 ++++++++-
 arch/tile/include/asm/pgalloc.h          |   13 ++++++-
 arch/tile/mm/pgtable.c                   |   10 ++++-
 arch/um/include/asm/pgalloc.h            |    1 +
 arch/um/kernel/mem.c                     |   21 ++++++++---
 arch/x86/include/asm/pgalloc.h           |   17 ++++++++-
 arch/x86/mm/pgtable.c                    |    8 ++++-
 arch/xtensa/include/asm/pgalloc.h        |    9 ++++-
 arch/xtensa/mm/pgtable.c                 |   11 +++++-
 include/asm-generic/4level-fixup.h       |    8 +++-
 include/asm-generic/pgtable-nopmd.h      |    3 +-
 include/asm-generic/pgtable-nopud.h      |    1 +
 include/linux/mm.h                       |   40 ++++++++++++++++-----
 mm/memory.c                              |   14 ++++---
 mm/vmalloc.c                             |   57 ++++++++++++++++++++----------
 41 files changed, 427 insertions(+), 119 deletions(-)

Re: [RFC][PATCH v3 07/22] mm, sh: add gfp flags variant of pmd and

[Prasad Joshi]

- Added __pte_alloc_one_kernel() function to allow caller to allocation flag.
   Like pte_alloc_one_kernel() this newly added function calls
   quicklist_alloc() and passes the allocation flag down the call hierarchy.

- The function pte_alloc_one_kernel() is modified to call
  __pte_alloc_one_kernel() using the correct allocation flag.

- Similar changes for pmd allocations. Added function __pmd_alloc_one().

- The changes help in fixing the Bug 30702.

Signed-off-by: Prasad Joshi <prasadjoshi124@gmail.com>
Signed-off-by: Anand Mitra <mitra@kqinfotech.com>
---
 arch/sh/include/asm/pgalloc.h |    8 +++++++-
 arch/sh/mm/pgtable.c          |    8 +++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/arch/sh/include/asm/pgalloc.h b/arch/sh/include/asm/pgalloc.h
index 8c00785..aaed989 100644
--- a/arch/sh/include/asm/pgalloc.h
+++ b/arch/sh/include/asm/pgalloc.h
@@ -31,10 +31,16 @@ static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
 /*
  * Allocate and free page tables.
  */
+static inline pte_t *__pte_alloc_one_kernel(struct mm_struct *mm,
+					  unsigned long address, gfp_t gfp_mask)
+{
+	return quicklist_alloc(QUICK_PT, gfp_mask, NULL);
+}
+
 static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
 					  unsigned long address)
 {
-	return quicklist_alloc(QUICK_PT, GFP_KERNEL | __GFP_REPEAT, NULL);
+	return __pte_alloc_one_kernel(mm, address, GFP_KERNEL | __GFP_REPEAT);
 }
 
 static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
diff --git a/arch/sh/mm/pgtable.c b/arch/sh/mm/pgtable.c
index 26e03a1..b938eb8 100644
--- a/arch/sh/mm/pgtable.c
+++ b/arch/sh/mm/pgtable.c
@@ -45,9 +45,15 @@ void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
 	set_pud(pud, __pud((unsigned long)pmd));
 }
 
+pmd_t *
+__pmd_alloc_one(struct mm_struct *mm, unsigned long address, gfp_t gfp_mask)
+{
+	return kmem_cache_alloc(pmd_cachep, gfp_mask | __GFP_ZERO);
+}
+
 pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
 {
-	return kmem_cache_alloc(pmd_cachep, PGALLOC_GFP);
+	return __pmd_alloc_one(mm, address, GFP_KERNEL | __GFP_REPEAT);
 }
 
 void pmd_free(struct mm_struct *mm, pmd_t *pmd)
-- 
1.7.0.4

Re: [RFC][PATCH v3 07/22] mm, sh: add gfp flags variant of pmd and pte allocations

[Paul Mundt]

On Fri, Mar 18, 2011 at 07:53:07PM +0000, Prasad Joshi wrote:
> 
> - Added __pte_alloc_one_kernel() function to allow caller to allocation flag.
>    Like pte_alloc_one_kernel() this newly added function calls
>    quicklist_alloc() and passes the allocation flag down the call hierarchy.
> 
> - The function pte_alloc_one_kernel() is modified to call
>   __pte_alloc_one_kernel() using the correct allocation flag.
> 
> - Similar changes for pmd allocations. Added function __pmd_alloc_one().
> 
> - The changes help in fixing the Bug 30702.
> 
> Signed-off-by: Prasad Joshi <prasadjoshi124@gmail.com>
> Signed-off-by: Anand Mitra <mitra@kqinfotech.com>

Acked-by: Paul Mundt <lethal@linux-sh.org>