From: Andreas Dilger Subject: Re: [PATCH 4/4 v2] ext4: Speed up FITRIM by recording flags in ext4_group_info. Date: Thu, 10 Feb 2011 13:50:14 -0800 Message-ID: References: <1297231048-3458-4-git-send-email-tm@tao.ma> <1297323206-9874-1-git-send-email-tm@tao.ma> Mime-Version: 1.0 (iPhone Mail 8C148a) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: "linux-ext4@vger.kernel.org" , Andreas Dilger , Lukas Czerner To: Tao Ma Return-path: Received: from idcmail-mo2no.shaw.ca ([64.59.134.9]:41184 "EHLO idcmail-mo2no.shaw.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750772Ab1BKGBi (ORCPT ); Fri, 11 Feb 2011 01:01:38 -0500 In-Reply-To: <1297323206-9874-1-git-send-email-tm@tao.ma> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 2011-02-09, at 23:33, Tao Ma wrote: > After I delete some big image files and re-run the trim, > it is still much faster than iterating the whole disk. > /dev/sdb2 108G 25G 78G 24% /mnt/ext4 > > [root@boyu-tm test]# time ./ftrim /mnt/ext4/a > real 0m0.513s > user 0m0.000s > sys 0m0.069s Excellent results. > +#define EXT4_GROUP_INFO_NEED_INIT_BIT 0 > +#define EXT4_GROUP_INFO_WAS_TRIMMED_BIT 1 > > #define EXT4_MB_GRP_NEED_INIT(grp) \ > (test_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &((grp)->bb_state))) > +#define EXT4_MB_GRP_HAS_BEEN_TRIMMED(grp) \ For consistency, it would be better to call this: EXT4_MB_GRP_WAS_TRIMMED(grp) And also add and use: EXT4_MB_GRP_SET_TRIMMED(grp) And EXT4_MB_GRP_CLEAR_TRIMMED(grp) > In the code. Then you can add Reviewed-by: on this patch. Cheers, Andreas