diff options
| -rw-r--r-- | mm/memcontrol.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 7fdc001ce15f..2db2aeac8a9e 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6748,7 +6748,19 @@ int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask) memcg_check_events(memcg, page); local_irq_enable(); - if (PageSwapCache(page)) { + /* + * Cgroup1's unified memory+swap counter has been charged with the + * new swapcache page, finish the transfer by uncharging the swap + * slot. The swap slot would also get uncharged when it dies, but + * it can stick around indefinitely and we'd count the page twice + * the entire time. + * + * Cgroup2 has separate resource counters for memory and swap, + * so this is a non-issue here. Memory and swap charge lifetimes + * correspond 1:1 to page and swap slot lifetimes: we charge the + * page to memory here, and uncharge swap when the slot is freed. + */ + if (do_memsw_account() && PageSwapCache(page)) { swp_entry_t entry = { .val = page_private(page) }; /* * The swap entry might not get freed for a long time, |