Messages in this thread | | | Date | Wed, 17 Sep 2008 22:43:58 -0700 | From | Balbir Singh <> | Subject | Re: [PATCH -mm] memcg: fix handling of shmem migration(v2) |
| |
KAMEZAWA Hiroyuki wrote: > On Wed, 17 Sep 2008 15:51:12 -0700 > Andrew Morton <akpm@linux-foundation.org> wrote: > >> On Wed, 17 Sep 2008 16:55:44 +0900 >> Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> wrote: >> >>> Before this patch, if migrating shmem/tmpfs pages, newpage would be >>> charged with PAGE_CGROUP_FLAG_FILE set, while oldpage has been charged >>> without the flag. >>> >>> The problem here is mem_cgroup_move_lists doesn't clear(or set) >>> the PAGE_CGROUP_FLAG_FILE flag, so pc->flags of the newpage >>> remains PAGE_CGROUP_FLAG_FILE set even when the pc is moved to >>> another lru(anon) by mem_cgroup_move_lists. And this leads to >>> incorrect MEM_CGROUP_ZSTAT. >>> (In my test, I see an underflow of MEM_CGROUP_ZSTAT(active_file). >>> As a result, mem_cgroup_calc_reclaim returns very huge number and >>> causes soft lockup on page reclaim.) >>> >>> I'm not sure if mem_cgroup_move_lists should handle PAGE_CGROUP_FLAG_FILE >>> or not(I suppose it should be used to move between active <-> inactive, >>> not anon <-> file), I added MEM_CGROUP_CHARGE_TYPE_SHMEM for precharge >>> at shmem's page migration. >>> >>> >>> ChangeLog: v1->v2 >>> - instead of modifying migrate.c, modify memcontrol.c only. >>> - add MEM_CGROUP_CHARGE_TYPE_SHMEM. >>> >>> >>> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> >>> --- >>> mm/memcontrol.c | 13 ++++++++++--- >>> 1 files changed, 10 insertions(+), 3 deletions(-) >>> >>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c >>> index 2979d22..ef8812d 100644 >>> --- a/mm/memcontrol.c >>> +++ b/mm/memcontrol.c >>> @@ -179,6 +179,7 @@ enum charge_type { >>> MEM_CGROUP_CHARGE_TYPE_CACHE = 0, >>> MEM_CGROUP_CHARGE_TYPE_MAPPED, >>> MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */ >>> + MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */ >>> }; >>> >>> /* >>> @@ -579,8 +580,10 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, >>> pc->flags |= PAGE_CGROUP_FLAG_FILE; >>> else >>> pc->flags |= PAGE_CGROUP_FLAG_ACTIVE; >>> - } else >>> + } else if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED) >>> pc->flags = PAGE_CGROUP_FLAG_ACTIVE; >>> + else /* MEM_CGROUP_CHARGE_TYPE_SHMEM */ >>> + pc->flags = PAGE_CGROUP_FLAG_CACHE | PAGE_CGROUP_FLAG_ACTIVE; >>> >>> lock_page_cgroup(page); >>> if (unlikely(page_get_page_cgroup(page))) { >>> @@ -739,8 +742,12 @@ int mem_cgroup_prepare_migration(struct page *page, struct page *newpage) >>> if (pc) { >>> mem = pc->mem_cgroup; >>> css_get(&mem->css); >>> - if (pc->flags & PAGE_CGROUP_FLAG_CACHE) >>> - ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; >>> + if (pc->flags & PAGE_CGROUP_FLAG_CACHE) { >>> + if (page_is_file_cache(page)) >>> + ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; >>> + else >>> + ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM; >>> + } >>> } >>> unlock_page_cgroup(page); >>> if (mem) { >> I queued this as a fix against >> vmscan-split-lru-lists-into-anon-file-sets.patch. Was that appropriate? >> >> If the bug you're fixing here is also present in mainline then I'll >> need to ask for a tested patch against mainline, please. >> > I think this bug depends on split-lru patch set. > Mayne not in mainline yet...?
Yes, that sounds correct to me, this should be a -mm only patch.
-- Balbir
| |