This is a note to let you know that I've just added the patch titled mm/memcg: fix device private memcg accounting to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mm-memcg-fix-device-private-memcg-accounting.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit cc8037f8ef73f4b4050a57c473bc72caafc8fab0 Author: Ralph Campbell <rcampbell@xxxxxxxxxx> Date: Tue Oct 13 16:53:13 2020 -0700 mm/memcg: fix device private memcg accounting [ Upstream commit 9a137153fc8798a89d8fce895cd0a06ea5b8e37c ] The code in mc_handle_swap_pte() checks for non_swap_entry() and returns NULL before checking is_device_private_entry() so device private pages are never handled. Fix this by checking for non_swap_entry() after handling device private swap PTEs. I assume the memory cgroup accounting would be off somehow when moving a process to another memory cgroup. Currently, the device private page is charged like a normal anonymous page when allocated and is uncharged when the page is freed so I think that path is OK. Signed-off-by: Ralph Campbell <rcampbell@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx> Cc: Jerome Glisse <jglisse@xxxxxxxxxx> Cc: Balbir Singh <bsingharora@xxxxxxxxx> Cc: Ira Weiny <ira.weiny@xxxxxxxxx> Link: https://lkml.kernel.org/r/20201009215952.2726-1-rcampbell@xxxxxxxxxx xFixes: c733a82874a7 ("mm/memcontrol: support MEMORY_DEVICE_PRIVATE") Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/mm/memcontrol.c b/mm/memcontrol.c index ca1632850fb76..edf98f8588eeb 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5398,7 +5398,7 @@ static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, struct page *page = NULL; swp_entry_t ent = pte_to_swp_entry(ptent); - if (!(mc.flags & MOVE_ANON) || non_swap_entry(ent)) + if (!(mc.flags & MOVE_ANON)) return NULL; /* @@ -5417,6 +5417,9 @@ static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, return page; } + if (non_swap_entry(ent)) + return NULL; + /* * Because lookup_swap_cache() updates some statistics counter, * we call find_get_page() with swapper_space directly.