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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2016-03-18 00:18:45 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-18 01:09:34 +0300
commitf9719a03de51e13526d614e79d002f838770b2d6 (patch)
tree696f6164980d678f6ac8c9f796508bf7c9c778fa /mm/huge_memory.c
parent0a6b76dd23fa08c5fd7b68acdb55018a37afd4aa (diff)
downloadlinux-f9719a03de51e13526d614e79d002f838770b2d6.tar.xz
thp, vmstats: count deferred split events
Count how many times we put a THP in split queue. Currently, it happens on partial unmap of a THP. Rapidly growing value can indicate that an application behaves unfriendly wrt THP: often fault in huge page and then unmap part of it. This leads to unnecessary memory fragmentation and the application may require tuning. The event also can help with debugging kernel [mis-]behaviour. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/huge_memory.c')
-rw-r--r--mm/huge_memory.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 1ea21e203a70..1dddfb21fc22 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3455,6 +3455,7 @@ void deferred_split_huge_page(struct page *page)
spin_lock_irqsave(&pgdata->split_queue_lock, flags);
if (list_empty(page_deferred_list(page))) {
+ count_vm_event(THP_DEFERRED_SPLIT_PAGE);
list_add_tail(page_deferred_list(page), &pgdata->split_queue);
pgdata->split_queue_len++;
}