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@xxxxxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
---
Changes in v2:
- Do not check swap limit on the legacy hierarchy.
include/linux/swap.h | 6 ++++++
mm/memcontrol.c | 13 +++++++++++++
mm/vmscan.c | 2 +-
3 files changed, 20 insertions(+), 1 deletion(-)
diff --git a/include/linux/swap.h b/include/linux/swap.h
index f8fb4e06c4bd..c544998dfbe7 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -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__*/
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 567b56da2c23..e0e498f5ca32 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5736,6 +5736,19 @@ 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;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index b220e6cda25d..ab52d865d922 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1995,7 +1995,7 @@ 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;
}
--
2.1.4
--
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