[PATCH, RFC 05/10] mm, vmstats: new THP splitting event

From: Kirill A. Shutemov
Date: Mon Jun 09 2014 - 12:06:19 EST


The patch replaces THP_SPLIT with tree events: THP_SPLIT_PAGE,
THP_SPLIT_PAGE_FAILT and THP_SPLIT_PMD. It reflects the fact that we
now can split PMD without the compound page and that split_huge_page()
can fail.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
include/linux/vm_event_item.h | 4 +++-
mm/huge_memory.c | 2 ++
mm/vmstat.c | 4 +++-
3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index ced92345c963..b44dffa769b9 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -68,7 +68,9 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
THP_FAULT_FALLBACK,
THP_COLLAPSE_ALLOC,
THP_COLLAPSE_ALLOC_FAILED,
- THP_SPLIT,
+ THP_SPLIT_PAGE,
+ THP_SPLIT_PAGE_FAILED,
+ THP_SPLIT_PMD,
THP_ZERO_PAGE_ALLOC,
THP_ZERO_PAGE_ALLOC_FAILED,
#endif
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 752c850f6941..fec89aedcedd 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1578,6 +1578,7 @@ unlock:

int split_huge_page_to_list(struct page *page, struct list_head *list)
{
+ count_vm_event(THP_SPLIT_PAGE_FAILED);
return -EBUSY;
}

@@ -2496,6 +2497,7 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
return;
}
+ count_vm_event(THP_SPLIT_PMD);
if (is_huge_zero_pmd(*pmd)) {
__split_huge_zero_page_pmd(vma, haddr, pmd);
spin_unlock(ptl);
diff --git a/mm/vmstat.c b/mm/vmstat.c
index b37bd49bfd55..6a155f0476e8 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -855,7 +855,9 @@ const char * const vmstat_text[] = {
"thp_fault_fallback",
"thp_collapse_alloc",
"thp_collapse_alloc_failed",
- "thp_split",
+ "thp_split_page",
+ "thp_split_page_failed",
+ "thp_split_pmd",
"thp_zero_page_alloc",
"thp_zero_page_alloc_failed",
#endif
--
2.0.0.rc4

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