linux-kernel - Re: [PATCH v5] mm/vmscan: add a fatal signals check in drop_slab

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <c80f2561-44df-f674-a740-290cce23932a@redhat.com>
Date:   Wed, 16 Sep 2020 15:17:14 +0200
From:   David Hildenbrand <david@...hat.com>
To:     zangchunxin@...edance.com, akpm@...ux-foundation.org
Cc:     chris@...isdown.name, vbabka@...e.cz, mhocko@...e.com,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Muchun Song <songmuchun@...edance.com>
Subject: Re: [PATCH v5] mm/vmscan: add a fatal signals check in drop_slab_node

On 16.09.20 04:53, zangchunxin@...edance.com wrote:
> From: Chunxin Zang <zangchunxin@...edance.com>
> 
> On our server, there are about 10k memcg in one machine. They use memory
> very frequently. We have observed that drop_caches can take a
> considerable amount of time, and can't stop it.
> 
> There are two reasons:
> 1. There is somebody constantly generating more objects to reclaim
>   on drop_caches, result the 'freed' always bigger than 10.
> 2. The process has no chance to process signals.
> 
> We can get the following info through 'ps':
> 
>  root:~# ps -aux | grep drop
>  root  357956 ... R    Aug25 21119854:55 echo 3 > /proc/sys/vm/drop_caches
>  root 1771385 ... R    Aug16 21146421:17 echo 3 > /proc/sys/vm/drop_caches
> 
> Add a bail out on the fatal signals in the main loop so that the
> operation can be terminated by userspace.
> 
> Signed-off-by: Chunxin Zang <zangchunxin@...edance.com>
> Signed-off-by: Muchun Song <songmuchun@...edance.com>

^ he did not actually send that, no? Maybe co-developed-by ?

-- 
Thanks,

David / dhildenb