From: Ralph Campbell rcampbell@nvidia.com
[ 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@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: c733a82874a7 ("mm/memcontrol: support MEMORY_DEVICE_PRIVATE") Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- mm/memcontrol.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 336498908b2d..6ad8fafcdf87 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5091,7 +5091,7 @@ 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;
/* @@ -5110,6 +5110,9 @@ 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.