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 4.19-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-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 7300cbf745a55cabfed7ad7cb7f808f700cbd5f9
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 aa730a3d5c258..87cd5bf1b4874 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4780,7 +4780,7 @@ 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;
/*
@@ -4799,6 +4799,9 @@ 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.
