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Commit 6f60b69d authored by David Rientjes's avatar David Rientjes Committed by Linus Torvalds
Browse files

mm, thp: drop page_table_lock to uncharge memcg pages 



mm->page_table_lock is hotly contested for page fault tests and isn't
necessary to do mem_cgroup_uncharge_page() in do_huge_pmd_wp_page().

Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 096a7cf4

mm/huge_memory.c

+2 −0
Original line number Diff line number Diff line
@@ -973,8 +973,10 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, 
	spin_lock(&mm->page_table_lock);

	put_page(page);

	if (unlikely(!pmd_same(*pmd, orig_pmd))) {

		spin_unlock(&mm->page_table_lock);

		mem_cgroup_uncharge_page(new_page);

		put_page(new_page);

		goto out;

	} else {

		pmd_t entry;

		VM_BUG_ON(!PageHead(page));