* [PATCH V2] mm/thp/migration: switch from flush_tlb_range to flush_pmd_tlb_range
@ 2016-02-10 15:35 ` Aneesh Kumar K.V
0 siblings, 0 replies; 7+ messages in thread
From: Aneesh Kumar K.V @ 2016-02-10 15:35 UTC (permalink / raw)
To: akpm, Mel Gorman, Kirill A. Shutemov, Vineet Gupta
Cc: linux-mm, linux-kernel, Aneesh Kumar K.V
We remove one instace of flush_tlb_range here. That was added by
f714f4f20e59ea6eea264a86b9a51fd51b88fc54 ("mm: numa: call MMU notifiers
on THP migration"). But the pmdp_huge_clear_flush_notify should have
done the require flush for us. Hence remove the extra flush.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
Changes from V1:
* fix build error
include/asm-generic/pgtable.h | 17 +++++++++++++++++
mm/migrate.c | 8 +++++---
mm/pgtable-generic.c | 14 --------------
3 files changed, 22 insertions(+), 17 deletions(-)
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index c370b261c720..9401f4819891 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -783,6 +783,23 @@ static inline int pmd_clear_huge(pmd_t *pmd)
}
#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
+#ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+/*
+ * ARCHes with special requirements for evicting THP backing TLB entries can
+ * implement this. Otherwise also, it can help optimize normal TLB flush in
+ * THP regime. stock flush_tlb_range() typically has optimization to nuke the
+ * entire TLB TLB if flush span is greater than a threshold, which will
+ * likely be true for a single huge page. Thus a single thp flush will
+ * invalidate the entire TLB which is not desitable.
+ * e.g. see arch/arc: flush_pmd_tlb_range
+ */
+#define flush_pmd_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
+#else
+#define flush_pmd_tlb_range(vma, addr, end) BUILD_BUG()
+#endif
+#endif
+
#endif /* !__ASSEMBLY__ */
#ifndef io_remap_pfn_range
diff --git a/mm/migrate.c b/mm/migrate.c
index b1034f9c77e7..c079c115d038 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1767,7 +1767,10 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
put_page(new_page);
goto out_fail;
}
-
+ /*
+ * We are not sure a pending tlb flush here is for a huge page
+ * mapping or not. Hence use the tlb range variant
+ */
if (mm_tlb_flush_pending(mm))
flush_tlb_range(vma, mmun_start, mmun_end);
@@ -1823,12 +1826,11 @@ fail_putback:
page_add_anon_rmap(new_page, vma, mmun_start, true);
pmdp_huge_clear_flush_notify(vma, mmun_start, pmd);
set_pmd_at(mm, mmun_start, pmd, entry);
- flush_tlb_range(vma, mmun_start, mmun_end);
update_mmu_cache_pmd(vma, address, &entry);
if (page_count(page) != 2) {
set_pmd_at(mm, mmun_start, pmd, orig_entry);
- flush_tlb_range(vma, mmun_start, mmun_end);
+ flush_pmd_tlb_range(vma, mmun_start, mmun_end);
mmu_notifier_invalidate_range(mm, mmun_start, mmun_end);
update_mmu_cache_pmd(vma, address, &entry);
page_remove_rmap(new_page, true);
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index 9d4767698a1c..3c9c78400300 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -84,20 +84,6 @@ pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-#ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
-
-/*
- * ARCHes with special requirements for evicting THP backing TLB entries can
- * implement this. Otherwise also, it can help optimize normal TLB flush in
- * THP regime. stock flush_tlb_range() typically has optimization to nuke the
- * entire TLB TLB if flush span is greater than a threshhold, which will
- * likely be true for a single huge page. Thus a single thp flush will
- * invalidate the entire TLB which is not desitable.
- * e.g. see arch/arc: flush_pmd_tlb_range
- */
-#define flush_pmd_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
-#endif
-
#ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
int pmdp_set_access_flags(struct vm_area_struct *vma,
unsigned long address, pmd_t *pmdp,
--
2.5.0
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH V2] mm/thp/migration: switch from flush_tlb_range to flush_pmd_tlb_range
2016-02-10 15:35 ` Aneesh Kumar K.V
@ 2016-02-10 16:14 ` Aneesh Kumar K.V
-1 siblings, 0 replies; 7+ messages in thread
From: Aneesh Kumar K.V @ 2016-02-10 16:14 UTC (permalink / raw)
To: akpm, Mel Gorman, Kirill A. Shutemov, Vineet Gupta; +Cc: linux-mm, linux-kernel
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> writes:
> We remove one instace of flush_tlb_range here. That was added by
> f714f4f20e59ea6eea264a86b9a51fd51b88fc54 ("mm: numa: call MMU notifiers
> on THP migration"). But the pmdp_huge_clear_flush_notify should have
> done the require flush for us. Hence remove the extra flush.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> ---
> Changes from V1:
> * fix build error
>
> include/asm-generic/pgtable.h | 17 +++++++++++++++++
> mm/migrate.c | 8 +++++---
> mm/pgtable-generic.c | 14 --------------
> 3 files changed, 22 insertions(+), 17 deletions(-)
>
> diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
> index c370b261c720..9401f4819891 100644
> --- a/include/asm-generic/pgtable.h
> +++ b/include/asm-generic/pgtable.h
> @@ -783,6 +783,23 @@ static inline int pmd_clear_huge(pmd_t *pmd)
> }
> #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
>
> +#ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> +/*
> + * ARCHes with special requirements for evicting THP backing TLB entries can
> + * implement this. Otherwise also, it can help optimize normal TLB flush in
> + * THP regime. stock flush_tlb_range() typically has optimization to nuke the
> + * entire TLB TLB if flush span is greater than a threshold, which will
> + * likely be true for a single huge page. Thus a single thp flush will
> + * invalidate the entire TLB which is not desitable.
> + * e.g. see arch/arc: flush_pmd_tlb_range
> + */
> +#define flush_pmd_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
> +#else
> +#define flush_pmd_tlb_range(vma, addr, end) BUILD_BUG()
> +#endif
> +#endif
> +
> #endif /* !__ASSEMBLY__ */
>
> #ifndef io_remap_pfn_range
> diff --git a/mm/migrate.c b/mm/migrate.c
> index b1034f9c77e7..c079c115d038 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -1767,7 +1767,10 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
> put_page(new_page);
> goto out_fail;
> }
> -
> + /*
> + * We are not sure a pending tlb flush here is for a huge page
> + * mapping or not. Hence use the tlb range variant
> + */
> if (mm_tlb_flush_pending(mm))
> flush_tlb_range(vma, mmun_start, mmun_end);
>
I was thinking we should be able to switch this flush_pmd_tlb_range. But
Kirill was not sure when we discussed this last time. Can we have a
pending tlb flush with PAGE_SIZE page translation, when we are parallely
trying to handle a autonuma fault on that ?
> @@ -1823,12 +1826,11 @@ fail_putback:
> page_add_anon_rmap(new_page, vma, mmun_start, true);
> pmdp_huge_clear_flush_notify(vma, mmun_start, pmd);
> set_pmd_at(mm, mmun_start, pmd, entry);
> - flush_tlb_range(vma, mmun_start, mmun_end);
> update_mmu_cache_pmd(vma, address, &entry);
>
> if (page_count(page) != 2) {
> set_pmd_at(mm, mmun_start, pmd, orig_entry);
> - flush_tlb_range(vma, mmun_start, mmun_end);
> + flush_pmd_tlb_range(vma, mmun_start, mmun_end);
> mmu_notifier_invalidate_range(mm, mmun_start, mmun_end);
> update_mmu_cache_pmd(vma, address, &entry);
> page_remove_rmap(new_page, true);
> diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
> index 9d4767698a1c..3c9c78400300 100644
> --- a/mm/pgtable-generic.c
> +++ b/mm/pgtable-generic.c
> @@ -84,20 +84,6 @@ pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
>
> #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>
> -#ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
> -
> -/*
> - * ARCHes with special requirements for evicting THP backing TLB entries can
> - * implement this. Otherwise also, it can help optimize normal TLB flush in
> - * THP regime. stock flush_tlb_range() typically has optimization to nuke the
> - * entire TLB TLB if flush span is greater than a threshhold, which will
> - * likely be true for a single huge page. Thus a single thp flush will
> - * invalidate the entire TLB which is not desitable.
> - * e.g. see arch/arc: flush_pmd_tlb_range
> - */
> -#define flush_pmd_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
> -#endif
> -
> #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
> int pmdp_set_access_flags(struct vm_area_struct *vma,
> unsigned long address, pmd_t *pmdp,
> --
> 2.5.0
-aneesh
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^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH V2] mm/thp/migration: switch from flush_tlb_range to flush_pmd_tlb_range
@ 2016-02-10 16:14 ` Aneesh Kumar K.V
0 siblings, 0 replies; 7+ messages in thread
From: Aneesh Kumar K.V @ 2016-02-10 16:14 UTC (permalink / raw)
To: akpm, Mel Gorman, Kirill A. Shutemov, Vineet Gupta; +Cc: linux-mm, linux-kernel
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> writes:
> We remove one instace of flush_tlb_range here. That was added by
> f714f4f20e59ea6eea264a86b9a51fd51b88fc54 ("mm: numa: call MMU notifiers
> on THP migration"). But the pmdp_huge_clear_flush_notify should have
> done the require flush for us. Hence remove the extra flush.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> ---
> Changes from V1:
> * fix build error
>
> include/asm-generic/pgtable.h | 17 +++++++++++++++++
> mm/migrate.c | 8 +++++---
> mm/pgtable-generic.c | 14 --------------
> 3 files changed, 22 insertions(+), 17 deletions(-)
>
> diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
> index c370b261c720..9401f4819891 100644
> --- a/include/asm-generic/pgtable.h
> +++ b/include/asm-generic/pgtable.h
> @@ -783,6 +783,23 @@ static inline int pmd_clear_huge(pmd_t *pmd)
> }
> #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
>
> +#ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> +/*
> + * ARCHes with special requirements for evicting THP backing TLB entries can
> + * implement this. Otherwise also, it can help optimize normal TLB flush in
> + * THP regime. stock flush_tlb_range() typically has optimization to nuke the
> + * entire TLB TLB if flush span is greater than a threshold, which will
> + * likely be true for a single huge page. Thus a single thp flush will
> + * invalidate the entire TLB which is not desitable.
> + * e.g. see arch/arc: flush_pmd_tlb_range
> + */
> +#define flush_pmd_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
> +#else
> +#define flush_pmd_tlb_range(vma, addr, end) BUILD_BUG()
> +#endif
> +#endif
> +
> #endif /* !__ASSEMBLY__ */
>
> #ifndef io_remap_pfn_range
> diff --git a/mm/migrate.c b/mm/migrate.c
> index b1034f9c77e7..c079c115d038 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -1767,7 +1767,10 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
> put_page(new_page);
> goto out_fail;
> }
> -
> + /*
> + * We are not sure a pending tlb flush here is for a huge page
> + * mapping or not. Hence use the tlb range variant
> + */
> if (mm_tlb_flush_pending(mm))
> flush_tlb_range(vma, mmun_start, mmun_end);
>
I was thinking we should be able to switch this flush_pmd_tlb_range. But
Kirill was not sure when we discussed this last time. Can we have a
pending tlb flush with PAGE_SIZE page translation, when we are parallely
trying to handle a autonuma fault on that ?
> @@ -1823,12 +1826,11 @@ fail_putback:
> page_add_anon_rmap(new_page, vma, mmun_start, true);
> pmdp_huge_clear_flush_notify(vma, mmun_start, pmd);
> set_pmd_at(mm, mmun_start, pmd, entry);
> - flush_tlb_range(vma, mmun_start, mmun_end);
> update_mmu_cache_pmd(vma, address, &entry);
>
> if (page_count(page) != 2) {
> set_pmd_at(mm, mmun_start, pmd, orig_entry);
> - flush_tlb_range(vma, mmun_start, mmun_end);
> + flush_pmd_tlb_range(vma, mmun_start, mmun_end);
> mmu_notifier_invalidate_range(mm, mmun_start, mmun_end);
> update_mmu_cache_pmd(vma, address, &entry);
> page_remove_rmap(new_page, true);
> diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
> index 9d4767698a1c..3c9c78400300 100644
> --- a/mm/pgtable-generic.c
> +++ b/mm/pgtable-generic.c
> @@ -84,20 +84,6 @@ pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
>
> #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>
> -#ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
> -
> -/*
> - * ARCHes with special requirements for evicting THP backing TLB entries can
> - * implement this. Otherwise also, it can help optimize normal TLB flush in
> - * THP regime. stock flush_tlb_range() typically has optimization to nuke the
> - * entire TLB TLB if flush span is greater than a threshhold, which will
> - * likely be true for a single huge page. Thus a single thp flush will
> - * invalidate the entire TLB which is not desitable.
> - * e.g. see arch/arc: flush_pmd_tlb_range
> - */
> -#define flush_pmd_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
> -#endif
> -
> #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
> int pmdp_set_access_flags(struct vm_area_struct *vma,
> unsigned long address, pmd_t *pmdp,
> --
> 2.5.0
-aneesh
^ permalink raw reply [flat|nested] 7+ messages in thread
* ARC !THP broken in linux-next (was Re: [PATCH V2] mm/thp/migration: switch from flush_tlb_range to flush_pmd_tlb_range)
2016-02-10 15:35 ` Aneesh Kumar K.V
@ 2016-03-17 9:35 ` Vineet Gupta
-1 siblings, 0 replies; 7+ messages in thread
From: Vineet Gupta @ 2016-03-17 9:35 UTC (permalink / raw)
To: Aneesh Kumar K.V, akpm, Mel Gorman, Kirill A. Shutemov,
Vineet Gupta
Cc: linux-mm, linux-kernel, linux-next
Hi Aneesh,
On Wednesday 10 February 2016 09:05 PM, Aneesh Kumar K.V wrote:
> We remove one instace of flush_tlb_range here. That was added by
> f714f4f20e59ea6eea264a86b9a51fd51b88fc54 ("mm: numa: call MMU notifiers
> on THP migration"). But the pmdp_huge_clear_flush_notify should have
> done the require flush for us. Hence remove the extra flush.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
linux-next fails for ARC with this - although this is not your fault.
Back then, per your request I did verify that ARC builds fine with this for
CONFIG_TRANSPARENT_HUGEPAGE worked. However I failed to check the !THP case which
is broken.
@Andrew could you please add the patch below to mm tree !
Thx,
Vineet
------------>
>From 8e31856c9b154cc152486aa411ee38b4c737c7c3 Mon Sep 17 00:00:00 2001
From: Vineet Gupta <vgupta@synopsys.com>
Date: Thu, 17 Mar 2016 15:00:59 +0530
Subject: [PATCH] ARC: thp: unbork !CONFIG_TRANSPARENT_HUGEPAGE build
linux-next for 4.6-rc1 timeline reported ARC build failures !THP
| arch/arc/include/asm/tlbflush.h:29:0: warning: "flush_pmd_tlb_range" redefined
[enabled by default]
| arch/arc/include/asm/tlbflush.h:29:0: warning: "flush_pmd_tlb_range" redefined
[enabled by default]
| arch/arc/include/asm/tlbflush.h:29:0: warning: "flush_pmd_tlb_range" redefined
[enabled by default]
Turns out that commit ("mm/thp/migration: switch from flush_tlb_range
to flush_pmd_tlb_range") triggered the issue while the problem was in
ARC code where THP specific helpers were not guarded with #ifdef.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
arch/arc/include/asm/tlbflush.h | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/arc/include/asm/tlbflush.h b/arch/arc/include/asm/tlbflush.h
index 1fe9c8c80280..f0d42f1e83f5 100644
--- a/arch/arc/include/asm/tlbflush.h
+++ b/arch/arc/include/asm/tlbflush.h
@@ -17,8 +17,10 @@ void local_flush_tlb_page(struct vm_area_struct *vma, unsigned
long page);
void local_flush_tlb_kernel_range(unsigned long start, unsigned long end);
void local_flush_tlb_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end);
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
void local_flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end);
+#endif
#ifndef CONFIG_SMP
#define flush_tlb_range(vma, s, e) local_flush_tlb_range(vma, s, e)
@@ -26,7 +28,9 @@ void local_flush_pmd_tlb_range(struct vm_area_struct *vma,
unsigned long start,
#define flush_tlb_kernel_range(s, e) local_flush_tlb_kernel_range(s, e)
#define flush_tlb_all() local_flush_tlb_all()
#define flush_tlb_mm(mm) local_flush_tlb_mm(mm)
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#define flush_pmd_tlb_range(vma, s, e) local_flush_pmd_tlb_range(vma, s, e)
+#endif
#else
extern void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end);
@@ -34,7 +38,8 @@ extern void flush_tlb_page(struct vm_area_struct *vma, unsigned
long page);
extern void flush_tlb_kernel_range(unsigned long start, unsigned long end);
extern void flush_tlb_all(void);
extern void flush_tlb_mm(struct mm_struct *mm);
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
extern void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end);
-
+#endif
#endif /* CONFIG_SMP */
#endif
--
2.5.0
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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^ permalink raw reply related [flat|nested] 7+ messages in thread* ARC !THP broken in linux-next (was Re: [PATCH V2] mm/thp/migration: switch from flush_tlb_range to flush_pmd_tlb_range)
@ 2016-03-17 9:35 ` Vineet Gupta
0 siblings, 0 replies; 7+ messages in thread
From: Vineet Gupta @ 2016-03-17 9:35 UTC (permalink / raw)
To: Aneesh Kumar K.V, akpm, Mel Gorman, Kirill A. Shutemov,
Vineet Gupta
Cc: linux-mm, linux-kernel, linux-next
Hi Aneesh,
On Wednesday 10 February 2016 09:05 PM, Aneesh Kumar K.V wrote:
> We remove one instace of flush_tlb_range here. That was added by
> f714f4f20e59ea6eea264a86b9a51fd51b88fc54 ("mm: numa: call MMU notifiers
> on THP migration"). But the pmdp_huge_clear_flush_notify should have
> done the require flush for us. Hence remove the extra flush.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
linux-next fails for ARC with this - although this is not your fault.
Back then, per your request I did verify that ARC builds fine with this for
CONFIG_TRANSPARENT_HUGEPAGE worked. However I failed to check the !THP case which
is broken.
@Andrew could you please add the patch below to mm tree !
Thx,
Vineet
------------>
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: ARC !THP broken in linux-next (was Re: [PATCH V2] mm/thp/migration: switch from flush_tlb_range to flush_pmd_tlb_range)
2016-03-17 9:35 ` Vineet Gupta
(?)
@ 2016-03-17 10:05 ` Vineet Gupta
-1 siblings, 0 replies; 7+ messages in thread
From: Vineet Gupta @ 2016-03-17 10:05 UTC (permalink / raw)
To: Aneesh Kumar K.V, akpm@linux-foundation.org, Mel Gorman,
Kirill A. Shutemov, Vineet Gupta
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-next
On Thursday 17 March 2016 03:06 PM, Vineet Gupta wrote:
> @Andrew could you please add the patch below to mm tree !
Never mind - I pushed it to my tree as this fix has no real dependency on original
patch and seems to be the right things with or w/o it.
Thx,
-Vineet
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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^ permalink raw reply [flat|nested] 7+ messages in thread