Re: [PATCH] mm/memcg: remove useless check on page->mem_cgroup
From: Michal Hocko <hidden>
Date: 2020-08-10 09:52:05
Also in:
linux-mm, lkml
Possibly related (same subject, not in this thread)
- 2020-08-10 · Re: [PATCH] mm/memcg: remove useless check on page->mem_cgroup · Alex Shi <hidden>
- 2020-08-10 · Re: [PATCH] mm/memcg: remove useless check on page->mem_cgroup · Michal Hocko <mhocko@suse.com>
- 2020-08-04 · Re: [PATCH] mm/memcg: remove useless check on page->mem_cgroup · Alex Shi <hidden>
- 2020-08-03 · Re: [PATCH] mm/memcg: remove useless check on page->mem_cgroup · Michal Hocko <mhocko@suse.com>
- 2020-08-01 · Re: [PATCH] mm/memcg: remove useless check on page->mem_cgroup · Alex Shi <hidden>
On Wed 05-08-20 21:02:30, Alex Shi wrote:
在 2020/8/5 下午8:28, Alex Shi 写道:quoted
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.quoted
From 8bfb26a2e37e08dc61d20212bcfa5812a367ba94 Mon Sep 17 00:00:00 2001From: Alex Shi <alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org> 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 <alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org> Cc: Johannes Weiner <redacted> Cc: Michal Hocko <redacted> Cc: Vladimir Davydov <redacted> Cc: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org> Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Acked-by: Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org>
quoted hunk ↗ jump to hunk
--- 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