linux-kernel - Re: [PATCH] proc/sysctl: prune stale dentries during unregistering

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Date:   Mon, 13 Feb 2017 22:54:14 +1300
From:   ebiederm@...ssion.com (Eric W. Biederman)
To:     Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
Cc:     Al Viro <viro@...IV.linux.org.uk>, linux-kernel@...r.kernel.org,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH] proc/sysctl: prune stale dentries during unregistering

Konstantin Khlebnikov <khlebnikov@...dex-team.ru> writes:

> On 10.02.2017 10:47, Al Viro wrote:
>> On Fri, Feb 10, 2017 at 10:35:02AM +0300, Konstantin Khlebnikov wrote:
>>
>>> # time sysctl -a > /dev/null
>>> real    1m12.806s
>>> user    0m0.016s
>>> sys     1m12.400s
>>>
>>> Currently only memory reclaimer could remove this garbage.
>>> But without significant memory pressure this never happens.
>>>
>>> This patch collects sysctl inodes into list on sysctl table header and
>>> prunes all their dentries once that table unregisters.
>>
>> I'd probably go for hlist, but that's mostly cosmetic difference; how about
>> the matching stats *after* that patch?
>>
>
> dcache size doesn't grow endlessly, so stats are fine
>
> # sysctl fs.dentry-state
> fs.dentry-state = 92712	58376	45	0	0	0
>
> # time sysctl -a &>/dev/null
>
> real	0m0.013s
> user	0m0.004s
> sys	0m0.008s

Applied thanks,

Eric