* [PATCH] mm: /proc/pid/clear_refs: no need to clear VM_SOFTDIRTY in clear_soft_dirty_pmd()
@ 2015-12-16 17:26 Oleg Nesterov
2015-12-16 17:43 ` Kirill A. Shutemov
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Oleg Nesterov @ 2015-12-16 17:26 UTC (permalink / raw)
To: Andrew Morton
Cc: Kirill A. Shutemov, Naoya Horiguchi, Cyrill Gorcunov,
linux-kernel
clear_soft_dirty_pmd() is called by clear_refs_write(CLEAR_REFS_SOFT_DIRTY),
VM_SOFTDIRTY was already cleared before walk_page_range().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
fs/proc/task_mmu.c | 3 ---
1 files changed, 0 insertions(+), 3 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 187b3b5..1a02b15 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -817,9 +817,6 @@ static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
pmd = pmd_wrprotect(pmd);
pmd = pmd_clear_soft_dirty(pmd);
- if (vma->vm_flags & VM_SOFTDIRTY)
- vma->vm_flags &= ~VM_SOFTDIRTY;
-
set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
}
#else
--
1.5.5.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] mm: /proc/pid/clear_refs: no need to clear VM_SOFTDIRTY in clear_soft_dirty_pmd()
2015-12-16 17:26 [PATCH] mm: /proc/pid/clear_refs: no need to clear VM_SOFTDIRTY in clear_soft_dirty_pmd() Oleg Nesterov
@ 2015-12-16 17:43 ` Kirill A. Shutemov
2015-12-16 17:51 ` Cyrill Gorcunov
2015-12-22 21:59 ` David Rientjes
2 siblings, 0 replies; 4+ messages in thread
From: Kirill A. Shutemov @ 2015-12-16 17:43 UTC (permalink / raw)
To: Oleg Nesterov
Cc: Andrew Morton, Kirill A. Shutemov, Naoya Horiguchi,
Cyrill Gorcunov, linux-kernel
On Wed, Dec 16, 2015 at 06:26:32PM +0100, Oleg Nesterov wrote:
> clear_soft_dirty_pmd() is called by clear_refs_write(CLEAR_REFS_SOFT_DIRTY),
> VM_SOFTDIRTY was already cleared before walk_page_range().
Not only that, We shouldn't [generally] change vm_flags without exclusive
mmap_sem and we have only down_read() here.
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
> fs/proc/task_mmu.c | 3 ---
> 1 files changed, 0 insertions(+), 3 deletions(-)
>
> diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
> index 187b3b5..1a02b15 100644
> --- a/fs/proc/task_mmu.c
> +++ b/fs/proc/task_mmu.c
> @@ -817,9 +817,6 @@ static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
> pmd = pmd_wrprotect(pmd);
> pmd = pmd_clear_soft_dirty(pmd);
>
> - if (vma->vm_flags & VM_SOFTDIRTY)
> - vma->vm_flags &= ~VM_SOFTDIRTY;
> -
> set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
> }
> #else
> --
> 1.5.5.1
>
>
> --
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--
Kirill A. Shutemov
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] mm: /proc/pid/clear_refs: no need to clear VM_SOFTDIRTY in clear_soft_dirty_pmd()
2015-12-16 17:26 [PATCH] mm: /proc/pid/clear_refs: no need to clear VM_SOFTDIRTY in clear_soft_dirty_pmd() Oleg Nesterov
2015-12-16 17:43 ` Kirill A. Shutemov
@ 2015-12-16 17:51 ` Cyrill Gorcunov
2015-12-22 21:59 ` David Rientjes
2 siblings, 0 replies; 4+ messages in thread
From: Cyrill Gorcunov @ 2015-12-16 17:51 UTC (permalink / raw)
To: Oleg Nesterov
Cc: Andrew Morton, Kirill A. Shutemov, Naoya Horiguchi, linux-kernel
On Wed, Dec 16, 2015 at 06:26:32PM +0100, Oleg Nesterov wrote:
> clear_soft_dirty_pmd() is called by clear_refs_write(CLEAR_REFS_SOFT_DIRTY),
> VM_SOFTDIRTY was already cleared before walk_page_range().
>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Thank you!
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] mm: /proc/pid/clear_refs: no need to clear VM_SOFTDIRTY in clear_soft_dirty_pmd()
2015-12-16 17:26 [PATCH] mm: /proc/pid/clear_refs: no need to clear VM_SOFTDIRTY in clear_soft_dirty_pmd() Oleg Nesterov
2015-12-16 17:43 ` Kirill A. Shutemov
2015-12-16 17:51 ` Cyrill Gorcunov
@ 2015-12-22 21:59 ` David Rientjes
2 siblings, 0 replies; 4+ messages in thread
From: David Rientjes @ 2015-12-22 21:59 UTC (permalink / raw)
To: Oleg Nesterov
Cc: Andrew Morton, Kirill A. Shutemov, Naoya Horiguchi,
Cyrill Gorcunov, linux-kernel
On Wed, 16 Dec 2015, Oleg Nesterov wrote:
> clear_soft_dirty_pmd() is called by clear_refs_write(CLEAR_REFS_SOFT_DIRTY),
> VM_SOFTDIRTY was already cleared before walk_page_range().
>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2015-12-16 17:26 [PATCH] mm: /proc/pid/clear_refs: no need to clear VM_SOFTDIRTY in clear_soft_dirty_pmd() Oleg Nesterov
2015-12-16 17:43 ` Kirill A. Shutemov
2015-12-16 17:51 ` Cyrill Gorcunov
2015-12-22 21:59 ` David Rientjes
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