mm, memcontrol: move swap charge handling into get_swap_page()
Patch series "mm, memcontrol: Implement memory.swap.events", v2.
This patchset implements memory.swap.events which contains max and fail
events so that userland can monitor and respond to swap running out.
This patch (of 2):
get_swap_page() is always followed by mem_cgroup_try_charge_swap().
This patch moves mem_cgroup_try_charge_swap() into get_swap_page() and
makes get_swap_page() call the function even after swap allocation
failure.
This simplifies the callers and consolidates memcg related logic and
will ease adding swap related memcg events.
Link: http://lkml.kernel.org/r/20180416230934.GH1911913@devbig577.frc2.facebook.com
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/swap_slots.c b/mm/swap_slots.c
index f264189..f51ac05 100644
--- a/mm/swap_slots.c
+++ b/mm/swap_slots.c
@@ -317,7 +317,7 @@ swp_entry_t get_swap_page(struct page *page)
if (PageTransHuge(page)) {
if (IS_ENABLED(CONFIG_THP_SWAP))
get_swap_pages(1, true, &entry);
- return entry;
+ goto out;
}
/*
@@ -347,10 +347,14 @@ swp_entry_t get_swap_page(struct page *page)
}
mutex_unlock(&cache->alloc_lock);
if (entry.val)
- return entry;
+ goto out;
}
get_swap_pages(1, false, &entry);
-
+out:
+ if (mem_cgroup_try_charge_swap(page, entry)) {
+ put_swap_page(page, entry);
+ entry.val = 0;
+ }
return entry;
}