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mm/memcg: fix device private memcg accounting 

[ Upstream commit 9a137153fc ]

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@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Link: https://lkml.kernel.org/r/20201009215952.2726-1-rcampbell@nvidia.com
xFixes: c733a82874 ("mm/memcontrol: support MEMORY_DEVICE_PRIVATE")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
5.4-rM2-2.2.x-imx-squashed
Ralph Campbell 2020-10-13 16:53:13 -07:00 committed by Greg Kroah-Hartman
parent 04fabdfcbf
commit 9a1656f1d1
1 changed files with 4 additions and 1 deletions
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5
mm/memcontrol.c
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@ -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.