Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 7bdd143c authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds
Browse files

mm: memcontrol: uncharge pages on swapout 



This series gets rid of the remaining page_cgroup flags, thus cutting the
memcg per-page overhead down to one pointer.

This patch (of 4):

mem_cgroup_swapout() is called with exclusive access to the page at the
end of the page's lifetime.  Instead of clearing the PCG_MEMSW flag and
deferring the uncharge, just do it right away.  This allows follow-up
patches to simplify the uncharge code.

Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
Acked-by: default avatarVladimir Davydov <vdavydov@parallels.com>
Reviewed-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b9982f8d

mm/memcontrol.c

+14 −4
Original line number Diff line number Diff line
@@ -5777,6 +5777,7 @@ static void __init enable_swap_cgroup(void) 
 */

void mem_cgroup_swapout(struct page *page, swp_entry_t entry)

{

	struct mem_cgroup *memcg;

	struct page_cgroup *pc;

	unsigned short oldid;
@@ -5793,13 +5794,22 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry) 
		return;



	VM_BUG_ON_PAGE(!(pc->flags & PCG_MEMSW), page);

	memcg = pc->mem_cgroup;



	oldid = swap_cgroup_record(entry, mem_cgroup_id(pc->mem_cgroup));

	oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg));

	VM_BUG_ON_PAGE(oldid, page);

	mem_cgroup_swap_statistics(memcg, true);



	pc->flags = 0;



	pc->flags &= ~PCG_MEMSW;

	css_get(&pc->mem_cgroup->css);

	mem_cgroup_swap_statistics(pc->mem_cgroup, true);

	if (!mem_cgroup_is_root(memcg))

		page_counter_uncharge(&memcg->memory, 1);



	/* XXX: caller holds IRQ-safe mapping->tree_lock */

	VM_BUG_ON(!irqs_disabled());



	mem_cgroup_charge_statistics(memcg, page, -1);

	memcg_check_events(memcg, page);

}



/**