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authorMina Almasry <almasrymina@google.com>2020-04-02 07:11:18 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-04-02 19:35:32 +0300
commit9808895e1a4416ffb9b3a0a121d81afc5a23c18b (patch)
treebe9a7aebf239636b70e358bb076fb42a62ee7a28
parent1adc4d419aa282ed6d86f01935ce45d2215d8b8d (diff)
downloadlinux-9808895e1a4416ffb9b3a0a121d81afc5a23c18b.tar.xz
mm/hugetlb_cgroup: fix hugetlb_cgroup migration
Commit c32300516047 ("hugetlb_cgroup: add interface for charge/uncharge hugetlb reservations") mistakingly doesn't handle the migration of *both* the reservation hugetlb_cgroup and the fault hugetlb_cgroup correctly. What should happen is that both cgroups shuold be queried from the old page, then both set to NULL on the old page, then both inserted into the new page. The mistake also creates the following warning: mm/hugetlb_cgroup.c: In function 'hugetlb_cgroup_migrate': mm/hugetlb_cgroup.c:777:25: warning: variable 'h_cg' set but not used [-Wunused-but-set-variable] struct hugetlb_cgroup *h_cg; ^~~~ Solution is to add the missing steps, namly setting the reservation hugetlb_cgroup to NULL on the old page, and setting the fault hugetlb_cgroup on the new page. Fixes: c32300516047 ("hugetlb_cgroup: add interface for charge/uncharge hugetlb reservations") Reported-by: Qian Cai <cai@lca.pw> Signed-off-by: Mina Almasry <almasrymina@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: David Rientjes <rientjes@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Sandipan Das <sandipan@linux.ibm.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Shuah Khan <shuah@kernel.org> Link: http://lkml.kernel.org/r/20200218194727.46995-1-almasrymina@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/hugetlb_cgroup.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
index 0aef0f34b80a..c5c8f8e2c2db 100644
--- a/mm/hugetlb_cgroup.c
+++ b/mm/hugetlb_cgroup.c
@@ -797,8 +797,10 @@ void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage)
h_cg = hugetlb_cgroup_from_page(oldhpage);
h_cg_rsvd = hugetlb_cgroup_from_page_rsvd(oldhpage);
set_hugetlb_cgroup(oldhpage, NULL);
+ set_hugetlb_cgroup_rsvd(oldhpage, NULL);
/* move the h_cg details to new cgroup */
+ set_hugetlb_cgroup(newhpage, h_cg);
set_hugetlb_cgroup_rsvd(newhpage, h_cg_rsvd);
list_move(&newhpage->lru, &h->hugepage_activelist);
spin_unlock(&hugetlb_lock);