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Commit 18eca2e6 authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds
Browse files

mm: memcontrol: remove unnecessary PCG_MEMSW memory+swap charge flag 



Now that mem_cgroup_swapout() fully uncharges the page, every page that is
still in use when reaching mem_cgroup_uncharge() is known to carry both
the memory and the memory+swap charge.  Simplify the uncharge path and
remove the PCG_MEMSW page flag accordingly.

Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
Reviewed-by: default avatarVladimir Davydov <vdavydov@parallels.com>
Acked-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 7bdd143c

include/linux/page_cgroup.h

+0 −1
Original line number Diff line number Diff line
@@ -5,7 +5,6 @@ enum { 
	/* flags for mem_cgroup */

	PCG_USED = 0x01,	/* This page is charged to a memcg */

	PCG_MEM = 0x02,		/* This page holds a memory charge */

	PCG_MEMSW = 0x04,	/* This page holds a memory+swap charge */

};



struct pglist_data;

mm/memcontrol.c

+12 −22
Original line number Diff line number Diff line
@@ -2614,7 +2614,7 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg, 
	 *   have the page locked

	 */

	pc->mem_cgroup = memcg;

	pc->flags = PCG_USED | PCG_MEM | (do_swap_account ? PCG_MEMSW : 0);

	pc->flags = PCG_USED | PCG_MEM;



	if (lrucare)

		unlock_page_lru(page, isolated);
@@ -5793,7 +5793,6 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry) 
	if (!PageCgroupUsed(pc))

		return;



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

	memcg = pc->mem_cgroup;



	oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg));
@@ -5989,17 +5988,16 @@ void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg) 
}



static void uncharge_batch(struct mem_cgroup *memcg, unsigned long pgpgout,

			   unsigned long nr_mem, unsigned long nr_memsw,

			   unsigned long nr_anon, unsigned long nr_file,

			   unsigned long nr_huge, struct page *dummy_page)

{

	unsigned long nr_pages = nr_anon + nr_file;

	unsigned long flags;



	if (!mem_cgroup_is_root(memcg)) {

		if (nr_mem)

			page_counter_uncharge(&memcg->memory, nr_mem);

		if (nr_memsw)

			page_counter_uncharge(&memcg->memsw, nr_memsw);

		page_counter_uncharge(&memcg->memory, nr_pages);

		if (do_swap_account)

			page_counter_uncharge(&memcg->memsw, nr_pages);

		memcg_oom_recover(memcg);

	}
@@ -6008,23 +6006,21 @@ static void uncharge_batch(struct mem_cgroup *memcg, unsigned long pgpgout, 
	__this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_CACHE], nr_file);

	__this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE], nr_huge);

	__this_cpu_add(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT], pgpgout);

	__this_cpu_add(memcg->stat->nr_page_events, nr_anon + nr_file);

	__this_cpu_add(memcg->stat->nr_page_events, nr_pages);

	memcg_check_events(memcg, dummy_page);

	local_irq_restore(flags);



	if (!mem_cgroup_is_root(memcg))

		css_put_many(&memcg->css, max(nr_mem, nr_memsw));

		css_put_many(&memcg->css, nr_pages);

}



static void uncharge_list(struct list_head *page_list)

{

	struct mem_cgroup *memcg = NULL;

	unsigned long nr_memsw = 0;

	unsigned long nr_anon = 0;

	unsigned long nr_file = 0;

	unsigned long nr_huge = 0;

	unsigned long pgpgout = 0;

	unsigned long nr_mem = 0;

	struct list_head *next;

	struct page *page;
@@ -6051,10 +6047,9 @@ static void uncharge_list(struct list_head *page_list) 


		if (memcg != pc->mem_cgroup) {

			if (memcg) {

				uncharge_batch(memcg, pgpgout, nr_mem, nr_memsw,

					       nr_anon, nr_file, nr_huge, page);

				pgpgout = nr_mem = nr_memsw = 0;

				nr_anon = nr_file = nr_huge = 0;

				uncharge_batch(memcg, pgpgout, nr_anon, nr_file,

					       nr_huge, page);

				pgpgout = nr_anon = nr_file = nr_huge = 0;

			}

			memcg = pc->mem_cgroup;

		}
@@ -6070,18 +6065,14 @@ static void uncharge_list(struct list_head *page_list) 
		else

			nr_file += nr_pages;



		if (pc->flags & PCG_MEM)

			nr_mem += nr_pages;

		if (pc->flags & PCG_MEMSW)

			nr_memsw += nr_pages;

		pc->flags = 0;



		pgpgout++;

	} while (next != page_list);



	if (memcg)

		uncharge_batch(memcg, pgpgout, nr_mem, nr_memsw,

			       nr_anon, nr_file, nr_huge, page);

		uncharge_batch(memcg, pgpgout, nr_anon, nr_file,

			       nr_huge, page);

}



/**
@@ -6166,7 +6157,6 @@ void mem_cgroup_migrate(struct page *oldpage, struct page *newpage, 
		return;



	VM_BUG_ON_PAGE(!(pc->flags & PCG_MEM), oldpage);

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



	if (lrucare)

		lock_page_lru(oldpage, &isolated);