| Message ID | alpine.LSU.2.11.2103281706200.4623@eggly.anvils |
|---|---|
| State | New |
| Headers | show |
| Series | mm/memcg: fix 5.10 backport of splitting page memcg | expand |
On Sun, Mar 28, 2021 at 05:13:13PM -0700, Hugh Dickins wrote: > The straight backport of 5.12's e1baddf8475b ("mm/memcg: set memcg when > splitting page") works fine in 5.11, but turned out to be wrong for 5.10: > because that relies on a separate flag, which must also be set for the > memcg to be recognized and uncharged and cleared when freeing. Fix that. > > Signed-off-by: Hugh Dickins <hughd@google.com> > --- > > mm/memcontrol.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -3274,13 +3274,17 @@ void obj_cgroup_uncharge(struct obj_cgro > void split_page_memcg(struct page *head, unsigned int nr) > { > struct mem_cgroup *memcg = head->mem_cgroup; > + int kmemcg = PageKmemcg(head); > int i; > > if (mem_cgroup_disabled() || !memcg) > return; > > - for (i = 1; i < nr; i++) > + for (i = 1; i < nr; i++) { > head[i].mem_cgroup = memcg; > + if (kmemcg) > + __SetPageKmemcg(head + i); > + } > css_get_many(&memcg->css, nr - 1); > } > Thanks for the fix, now queued up. greg k-h
--- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3274,13 +3274,17 @@ void obj_cgroup_uncharge(struct obj_cgro void split_page_memcg(struct page *head, unsigned int nr) { struct mem_cgroup *memcg = head->mem_cgroup; + int kmemcg = PageKmemcg(head); int i; if (mem_cgroup_disabled() || !memcg) return; - for (i = 1; i < nr; i++) + for (i = 1; i < nr; i++) { head[i].mem_cgroup = memcg; + if (kmemcg) + __SetPageKmemcg(head + i); + } css_get_many(&memcg->css, nr - 1); }
The straight backport of 5.12's e1baddf8475b ("mm/memcg: set memcg when splitting page") works fine in 5.11, but turned out to be wrong for 5.10: because that relies on a separate flag, which must also be set for the memcg to be recognized and uncharged and cleared when freeing. Fix that. Signed-off-by: Hugh Dickins <hughd@google.com> --- mm/memcontrol.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)