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: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/swap.h b/include/linux/swap.h
index c2bd163..a587050 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -551,6 +551,7 @@
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 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__*/
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1ff552e..bcb3871 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5748,6 +5748,19 @@
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;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 9a8556e..3be5f9d 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2004,7 +2004,7 @@
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;
}