Commit d8b38438 authored by Vladimir Davydov's avatar Vladimir Davydov Committed by Linus Torvalds
Browse files

mm: vmscan: do not scan anon pages if memcg swap limit is hit 



We don't scan anonymous memory if we ran out of swap, neither should we do
it in case memcg swap limit is hit, because swap out is impossible anyway.

Signed-off-by: default avatarVladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6f2cb2f1

include/linux/swap.h

+6 −0
Original line number Diff line number Diff line
@@ -551,6 +551,7 @@ static inline int mem_cgroup_swappiness(struct mem_cgroup *mem) 
extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry);

extern int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry);

extern void mem_cgroup_uncharge_swap(swp_entry_t entry);

extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg);

#else

static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry)

{
@@ -565,6 +566,11 @@ static inline int mem_cgroup_try_charge_swap(struct page *page, 
static inline void mem_cgroup_uncharge_swap(swp_entry_t entry)

{

}



static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)

{

	return get_nr_swap_pages();

}

#endif



#endif /* __KERNEL__*/

mm/memcontrol.c

+13 −0
Original line number Diff line number Diff line
@@ -5748,6 +5748,19 @@ void mem_cgroup_uncharge_swap(swp_entry_t entry) 
	rcu_read_unlock();

}



long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)

{

	long nr_swap_pages = get_nr_swap_pages();



	if (!do_swap_account || !cgroup_subsys_on_dfl(memory_cgrp_subsys))

		return nr_swap_pages;

	for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg))

		nr_swap_pages = min_t(long, nr_swap_pages,

				      READ_ONCE(memcg->swap.limit) -

				      page_counter_read(&memcg->swap));

	return nr_swap_pages;

}



/* for remember boot option*/

#ifdef CONFIG_MEMCG_SWAP_ENABLED

static int really_do_swap_account __initdata = 1;

mm/vmscan.c

+1 −1
Original line number Diff line number Diff line
@@ -2004,7 +2004,7 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg, 
		force_scan = true;



	/* If we have no swap space, do not bother scanning anon pages. */

	if (!sc->may_swap || (get_nr_swap_pages() <= 0)) {

	if (!sc->may_swap || mem_cgroup_get_nr_swap_pages(memcg) <= 0) {

		scan_balance = SCAN_FILE;

		goto out;

	}

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