linux-kernel - Re: [External] Re: [PATCH] mm/vmscan: fix infinite loop in drop_slab

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Message-ID: <20200909095915.GA1412646@chrisdown.name>
Date:   Wed, 9 Sep 2020 10:59:15 +0100
From:   Chris Down <chris@...isdown.name>
To:     Muchun Song <songmuchun@...edance.com>
Cc:     zangchunxin@...edance.com,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linux Memory Management List <linux-mm@...ck.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [External] Re: [PATCH] mm/vmscan: fix infinite loop in
 drop_slab_node

Muchun Song writes:
>1. Double the threshold currently hard coded as "10" with each iteration
>    suggested by Vlastimil. It is also a good idea.

I think this sounds reasonable, although I'd like to see what the difference in 
reclaim looks like in practice.

>2. In the while loop, we can check whether the TASK_KILLABLE
>    signal is set, if so, we should break the loop. like the following code
>    snippe. Thanks.
>
>@@ -704,6 +704,9 @@ void drop_slab_node(int nid)
>  do {
>  struct mem_cgroup *memcg = NULL;
>
>+ if (fatal_signal_pending(current))
>+ return;
>+
>  freed = 0;
>  memcg = mem_cgroup_iter(NULL, NULL, NULL);
>  do {

Regardless of anything, I think this is probably a good idea. Could you send it 
as a patch? :-)

Thanks,

Chris