Commit 7a0524cf authored Jan 12, 2012 by Johannes Weiner Committed by Linus Torvalds Jan 12, 2012

mm: memcg: remove unneeded checks from newpage_charge()



All callsites pass in freshly allocated pages and a valid mm.  As a
result, all checks pertaining to the page's mapcount, page->mapping or the
fallback to init_mm are unneeded.

Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 00c54c0b

mm/memcontrol.c

+4 −12

Original line number	Diff line number	Diff line
		@@ -2748,17 +2748,9 @@ int mem_cgroup_newpage_charge(struct page *page,
		{
		if (mem_cgroup_disabled())
		return 0;
		/*
		* If already mapped, we don't have to account.
		* If page cache, page->mapping has address_space.
		* But page->mapping may have out-of-use anon_vma pointer,
		* detecit it by PageAnon() check. newly-mapped-anon's page->mapping
		* is NULL.
		*/
		if (page_mapped(page) \|\| (page->mapping && !PageAnon(page)))
		return 0;
		if (unlikely(!mm))
		mm = &init_mm;
		VM_BUG_ON(page_mapped(page));
		VM_BUG_ON(page->mapping && !PageAnon(page));
		VM_BUG_ON(!mm);
		return mem_cgroup_charge_common(page, mm, gfp_mask,
		MEM_CGROUP_CHARGE_TYPE_MAPPED);
		}