linux-kernel - Re: [PATCH] vmscan: limit concurrent reclaimers in shrink

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

Date:	Fri, 11 Dec 2009 08:51:54 -0500
From:	Rik van Riel <riel@...hat.com>
To:	Minchan Kim <minchan.kim@...il.com>
CC:	lwoodman@...hat.com, kosaki.motohiro@...fujitsu.com,
	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
	linux-mm@...ck.org, aarcange@...hat.com
Subject: Re: [PATCH] vmscan: limit concurrent reclaimers in shrink_zone

On 12/11/2009 08:41 AM, Minchan Kim wrote:
> Hi, Larry.
>
> On Fri, Dec 11, 2009 at 9:07 PM, Larry Woodman<lwoodman@...hat.com>  wrote:
>> Minchan Kim wrote:
>>>
>>> I like this. but why do you select default value as constant 8?
>>> Do you have any reason?
>>>
>>> I think it would be better to select the number proportional to NR_CPU.
>>> ex) NR_CPU * 2 or something.
>>>
>>> Otherwise looks good to me.
>>>
>>> Reviewed-by: Minchan Kim<minchan.kim@...il.com>
>>>
>>>
>>
>> This is a per-zone count so perhaps a reasonable default is the number of
>> CPUs on the
>> NUMA node that the zone resides on ?
>
> For example, It assume one CPU per node.
> It means your default value is 1.
> On the CPU, process A try to reclaim HIGH zone.
> Process B want to reclaim NORMAL zone.
> But Process B can't enter reclaim path sincev throttle default value is 1
> Even kswap can't reclaim.

1) the value is per zone, so process B can go ahead

2) kswapd is always excempt from this limit, since
    there is only 1 kswapd per node anyway

-- 
All rights reversed.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/