linux-kernel - Re: [PATCH 3/3] mm: oom: show unreclaimable slab info when unreclaimable slabs

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Date:   Thu, 19 Oct 2017 03:09:40 +0800
From:   "Yang Shi" <yang.s@...baba-inc.com>
To:     David Rientjes <rientjes@...gle.com>
Cc:     Michal Hocko <mhocko@...nel.org>, cl@...ux.com, penberg@...nel.org,
        iamjoonsoo.kim@....com, akpm@...ux-foundation.org,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/3] mm: oom: show unreclaimable slab info when
 unreclaimable slabs > user memory



On 10/17/17 3:39 PM, David Rientjes wrote:
> On Wed, 18 Oct 2017, Yang Shi wrote:
> 
>>> Yes, this should catch occurrences of "huge unreclaimable slabs", right?
>>
>> Yes, it sounds so. Although single "huge" unreclaimable slab might not result
>> in excessive slabs use in a whole, but this would help to filter out "small"
>> unreclaimable slab.
>>
> 
> Keep in mind this is regardless of SLAB_RECLAIM_ACCOUNT: your patch has
> value beyond only unreclaimable slab, it can also be used to show
> instances where the oom killer was invoked without properly reclaiming
> slab.  If the total footprint of a slab cache exceeds 5%, I think a line
> should be emitted unconditionally to the kernel log.

OK, sounds good. I will propose an incremental patch to see the comments.

Thanks,
Yang

>