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From: Waiman Long <longman@redhat.com>
To: Alexander Viro <viro@zeniv.linux.org.uk>,
	Jonathan Corbet <corbet@lwn.net>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: 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>
Subject: Re: [PATCH v4 0/3] fs/dcache: Track # of negative dentries
Date: Fri, 5 Oct 2018 10:55:47 -0400	[thread overview]
Message-ID: <7054d7fe-5385-c743-b2ea-595e5988799f@redhat.com> (raw)
In-Reply-To: <1536773742-32687-1-git-send-email-longman@redhat.com>

On 09/12/2018 01:35 PM, Waiman Long wrote:
>  v3->v4:
>   - Drop patch 4 as it is just a minor optimization.
>   - Add a cc:stable tag to patch 1.
>   - Clean up some comments in patch 3.
>
>  v2->v3:
>   - With confirmation that the dummy array in dentry_stat structure
>     was never a replacement of a previously used field, patch 3 is now
>     reverted back to use one of dummy field as the negative dentry count
>     instead of adding a new field.
>
>  v1->v2:
>   - Clarify what the new nr_dentry_negative per-cpu counter is tracking
>     and open-code the increment and decrement as suggested by Dave Chinner.
>   - Append the new nr_dentry_negative count as the 7th element of dentry-state
>     instead of replacing one of the dummy entries.
>   - Remove patch "fs/dcache: Make negative dentries easier to be
>     reclaimed" for now as I need more time to think about what
>     to do with it.
>   - Add 2 more patches to address issues found while reviewing the
>     dentry code.
>   - Add another patch to change the conditional branch of
>     nr_dentry_negative accounting to conditional move so as to reduce
>     the performance impact of the accounting code.
>
> This patchset addresses 2 issues found in the dentry code and adds a
> new nr_dentry_negative per-cpu counter to track the total number of
> negative dentries in all the LRU lists.
>
> Patch 1 fixes a bug in the accounting of nr_dentry_unused in
> shrink_dcache_sb().
>
> Patch 2 removes the ____cacheline_aligned_in_smp tag from super_block
> LRU lists.
>
> Patch 3 adds the new nr_dentry_negative per-cpu counter.
>
> Various filesystem related tests were run and no statistically
> significant changes in performance outside of the possible noise range
> was observed.
>
> Waiman Long (3):
>   fs/dcache: Fix incorrect nr_dentry_unused accounting in
>     shrink_dcache_sb()
>   fs: Don't need to put list_lru into its own cacheline
>   fs/dcache: Track & report number of negative dentries
>
>  Documentation/sysctl/fs.txt | 26 ++++++++++++++++----------
>  fs/dcache.c                 | 38 +++++++++++++++++++++++++++++++++-----
>  include/linux/dcache.h      |  7 ++++---
>  include/linux/fs.h          |  9 +++++----
>  4 files changed, 58 insertions(+), 22 deletions(-)
>
Any comments on these patches. The first one actually is a bug fix.

Cheers,
Longman

      parent reply	other threads:[~2018-10-05 14:55 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-12 17:35 Waiman Long
2018-09-12 17:35 ` [PATCH v4 1/3] fs/dcache: Fix incorrect nr_dentry_unused accounting in shrink_dcache_sb() Waiman Long
2018-09-12 17:35 ` [PATCH v4 2/3] fs: Don't need to put list_lru into its own cacheline Waiman Long
2018-09-12 17:35 ` [PATCH v4 3/3] fs/dcache: Track & report number of negative dentries Waiman Long
2018-10-05 14:55 ` Waiman Long [this message]

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