From mboxrd@z Thu Jan  1 00:00:00 1970
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Subject: Re: [PATCH 0/2] fs/dcache: Track # of negative dentries
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>, Jonathan Corbet
 <corbet@lwn.net>, linux-kernel@vger.kernel.org,
 linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
 linux-doc@vger.kernel.org, "Luis R. Rodriguez" <mcgrof@kernel.org>,
 Kees Cook <keescook@chromium.org>,
 Linus Torvalds <torvalds@linux-foundation.org>, Jan Kara <jack@suse.cz>,
 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
 Ingo Molnar <mingo@kernel.org>, Miklos Szeredi <mszeredi@redhat.com>,
 Matthew Wilcox <willy@infradead.org>, Larry Woodman <lwoodman@redhat.com>,
 James Bottomley <James.Bottomley@HansenPartnership.com>,
 "Wangkai (Kevin C)" <wangkai86@huawei.com>, Michal Hocko <mhocko@kernel.org>
References: <1535476780-5773-1-git-send-email-longman@redhat.com>
 <20180828155006.a6a94a7ba64ac4ce6b8b190c@linux-foundation.org>
From: Waiman Long <longman@redhat.com>
Message-ID: <4284b67f-51bd-88d9-b7c4-8303179127b7@redhat.com>
Date: Tue, 28 Aug 2018 18:54:44 -0400
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On 08/28/2018 06:50 PM, Andrew Morton wrote:
> On Tue, 28 Aug 2018 13:19:38 -0400 Waiman Long <longman@redhat.com> wrote:
>
>> This patchset is a reduced scope version of the
>> patchset "fs/dcache: Track & limit # of negative dentries"
>> (https://lkml.org/lkml/2018/7/12/586). Only the first 2 patches are
>> included to track the number of negative dentries in the system as well
>> as making negative dentries more easily reclaimed than positive ones.
>>
>> There are controversies on limiting number of negative dentries as it may
>> make negative dentries special in term of how memory resources are to
>> be managed in the kernel. However, I don't believe I heard any concern
>> about tracking the number of negative dentries in the system. So it is
>> better to separate that out and get it done with. We can deal with the
>> controversial part later on.
> Seems reasonable.
>
> It would be nice to see testing results please.  Quite comprehensive
> ones.
>
> And again, an apparently permanent feature of this patchset is that the
> changelogs fail to provide descriptions of real-world problems with the
> existing code.  Please do provide those (comprehensive) descriptions and
> demonstrate that these changes resolve those problems.
>
> Also, a grumpynit: with 100% uniformity, the vfs presently refers to
> negative dentries with the string "negative" in the identifier.  This
> patchset abbreviates that to "neg".
>
Will do.

Cheers,
Longman