* [PATCH 2/2] mm, THP: Clean up return value of madvise_free_huge_pmd
2016-06-28 17:36 [PATCH 1/2] MADVISE_FREE, THP: Fix madvise_free_huge_pmd return value after splitting Huang, Ying
@ 2016-06-28 17:36 ` Huang, Ying
2016-06-29 7:27 ` Minchan Kim
2016-06-29 7:26 ` [PATCH 1/2] MADVISE_FREE, THP: Fix madvise_free_huge_pmd return value after splitting Minchan Kim
1 sibling, 1 reply; 4+ messages in thread
From: Huang, Ying @ 2016-06-28 17:36 UTC (permalink / raw)
To: Andrew Morton
Cc: Huang Ying, Minchan Kim, Kirill A. Shutemov, Jerome Marchand,
Matthew Wilcox, Vlastimil Babka, Dan Williams, Mel Gorman,
Andrea Arcangeli, Ebru Akagunduz, linux-kernel, linux-mm
From: Huang Ying <ying.huang@intel.com>
The definition of return value of madvise_free_huge_pmd is not clear
before. According to the suggestion of Minchan Kim, change the type of
return value to bool and return true if we do MADV_FREE successfully on
entire pmd page, otherwise, return false. Comments are added too.
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
---
include/linux/huge_mm.h | 2 +-
mm/huge_memory.c | 15 ++++++++-------
2 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index eb81081..db97784 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -11,7 +11,7 @@ extern struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
unsigned long addr,
pmd_t *pmd,
unsigned int flags);
-extern int madvise_free_huge_pmd(struct mmu_gather *tlb,
+extern bool madvise_free_huge_pmd(struct mmu_gather *tlb,
struct vm_area_struct *vma,
pmd_t *pmd, unsigned long addr, unsigned long next);
extern int zap_huge_pmd(struct mmu_gather *tlb,
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 546cd21..d2a5224 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1249,25 +1249,26 @@ out:
return 0;
}
-int madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
+/*
+ * Return true if we do MADV_FREE successfully on entire pmd page.
+ * Otherwise, return false.
+ */
+bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
pmd_t *pmd, unsigned long addr, unsigned long next)
-
{
spinlock_t *ptl;
pmd_t orig_pmd;
struct page *page;
struct mm_struct *mm = tlb->mm;
- int ret = 0;
+ bool ret = false;
ptl = pmd_trans_huge_lock(pmd, vma);
if (!ptl)
goto out_unlocked;
orig_pmd = *pmd;
- if (is_huge_zero_pmd(orig_pmd)) {
- ret = 1;
+ if (is_huge_zero_pmd(orig_pmd))
goto out;
- }
page = pmd_page(orig_pmd);
/*
@@ -1309,7 +1310,7 @@ int madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
set_pmd_at(mm, addr, pmd, orig_pmd);
tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
}
- ret = 1;
+ ret = true;
out:
spin_unlock(ptl);
out_unlocked:
--
2.8.1
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^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH 1/2] MADVISE_FREE, THP: Fix madvise_free_huge_pmd return value after splitting
2016-06-28 17:36 [PATCH 1/2] MADVISE_FREE, THP: Fix madvise_free_huge_pmd return value after splitting Huang, Ying
2016-06-28 17:36 ` [PATCH 2/2] mm, THP: Clean up return value of madvise_free_huge_pmd Huang, Ying
@ 2016-06-29 7:26 ` Minchan Kim
1 sibling, 0 replies; 4+ messages in thread
From: Minchan Kim @ 2016-06-29 7:26 UTC (permalink / raw)
To: Huang, Ying
Cc: Andrew Morton, Kirill A. Shutemov, Vlastimil Babka,
Jerome Marchand, Andrea Arcangeli, Ebru Akagunduz, linux-mm,
linux-kernel
On Tue, Jun 28, 2016 at 10:36:29AM -0700, Huang, Ying wrote:
> From: Huang Ying <ying.huang@intel.com>
>
> madvise_free_huge_pmd should return 0 if the fallback PTE operations are
> required. In madvise_free_huge_pmd, if part pages of THP are discarded,
> the THP will be split and fallback PTE operations should be used if
> splitting succeeds. But the original code will make fallback PTE
> operations skipped, after splitting succeeds. Fix that via make
> madvise_free_huge_pmd return 0 after splitting successfully, so that the
> fallback PTE operations will be done.
>
> Cc: Minchan Kim <minchan@kernel.org>
> Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Thanks!
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^ permalink raw reply [flat|nested] 4+ messages in thread