On Wed 05-08-20 21:02:30, Alex Shi wrote: > > > 在 2020/8/5 下午8:28, Alex Shi 写道: > > The last patch has a problem on define. this version could fix it. > > > > BTW, I see some !memcg happens when MEMCG compilered but disabled by > > cgroup_disable > > > > > > [ 94.657666] ---[ end trace f1f34bfc3b32ed2f ]--- > > [ 95.138995] anon flags: > > 0x5005b48008000d(locked|uptodate|dirty|swapbacked) > > [ 95.146220] raw: 005005b48008000d dead000000000100 dead000000000122 > > ffff8897c7c76ad1 > > [ 95.154549] raw: 0000000000000022 0000000000000000 0000000200000000 > > 0000000000000000 > > [ 95.162876] page dumped because: VM_WARN_ON_ONCE_PAGE(!memcg) > > > > > > The following patch may helpful. > > >From 8bfb26a2e37e08dc61d20212bcfa5812a367ba94 Mon Sep 17 00:00:00 2001 > From: Alex Shi <[email protected]> > Date: Wed, 5 Aug 2020 20:32:12 +0800 > Subject: [PATCH] mm/memcg: don't try charge swap if memcg disabled > > If we disabled memcg by cgroup_disable=memory, the swap charges are > still called. Let's return from the funcs earlier and keep WARN_ON > monitor.
Do I get it right that this is on top of your patch to remove the memcg check or a preparatory work? Both are good but it would be better to call that out specifically for clarity (along with the warning if that is a follow up fix). > Signed-off-by: Alex Shi <[email protected]> > Cc: Johannes Weiner <[email protected]> > Cc: Michal Hocko <[email protected]> > Cc: Vladimir Davydov <[email protected]> > Cc: Andrew Morton <[email protected]> > Cc: [email protected] > Cc: [email protected] > Cc: [email protected] Acked-by: Michal Hocko <[email protected]> > --- > mm/memcontrol.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index cb07a48d53aa..65f2b42d25af 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -7163,6 +7163,9 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t > entry) > VM_BUG_ON_PAGE(PageLRU(page), page); > VM_BUG_ON_PAGE(page_count(page), page); > > + if (mem_cgroup_disabled()) > + return; > + > if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) > return; > > @@ -7228,6 +7231,9 @@ int mem_cgroup_try_charge_swap(struct page *page, > swp_entry_t entry) > struct mem_cgroup *memcg; > unsigned short oldid; > > + if (mem_cgroup_disabled()) > + return 0; > + > if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) > return 0; > > -- > 1.8.3.1 -- Michal Hocko SUSE Labs
