From: Jan Kara Subject: Re: [PATCH v3 2/6] ext4: track extent status tree shrinker delay statictics Date: Wed, 27 Aug 2014 15:26:07 +0200 Message-ID: <20140827132607.GA22211@quack.suse.cz> References: <1407382553-24256-1-git-send-email-wenqing.lz@taobao.com> <1407382553-24256-3-git-send-email-wenqing.lz@taobao.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org, Theodore Ts'o , Andreas Dilger , Jan Kara , Zheng Liu To: Zheng Liu Return-path: Received: from cantor2.suse.de ([195.135.220.15]:35491 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933592AbaH0N0R (ORCPT ); Wed, 27 Aug 2014 09:26:17 -0400 Content-Disposition: inline In-Reply-To: <1407382553-24256-3-git-send-email-wenqing.lz@taobao.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu 07-08-14 11:35:49, Zheng Liu wrote: > From: Zheng Liu > > This commit adds some statictics in extent status tree shrinker. The > purpose to add these is that we want to collect more details when we > encounter a stall caused by extent status tree shrinker. Here we count > the following statictics: > stats: > the number of all objects on all extent status trees > the number of reclaimable objects on lru list > cache hits/misses > the last sorted interval > the number of inodes on lru list > average: > scan time for shrinking some objects > the number of shrunk objects > maximum: > the inode that has max nr. of objects on lru list > the maximum scan time for shrinking some objects > > The output looks like below: > $ cat /proc/fs/ext4/sda1/es_shrinker_info > stats: > 28228 objects > 6341 reclaimable objects > 5281/631 cache hits/misses > 586 ms last sorted interval > 250 inodes on lru list > average: > 153 us scan time > 128 shrunk objects > maximum: > 255 inode (255 objects, 198 reclaimable) > 125723 us max scan time When reading through this again, I realized that we probably don't want this file in /proc/fs/ext4 but rather in /sys/kernel/debug/ext4 because it's really a debugging interface and we don't want any tools to start using it. Honza -- Jan Kara SUSE Labs, CR