From: Ted Ts'o <tytso@mit.edu>
To: Tao Ma <tm@tao.ma>
Cc: linux-ext4@vger.kernel.org
Subject: Re: [PATCH 2/5] ext4: speed up group trim with the right free block count.
Date: Mon, 11 Jul 2011 00:06:58 -0400 [thread overview]
Message-ID: <20110711040658.GF28763@thunk.org> (raw)
In-Reply-To: <1309534076-2784-2-git-send-email-tm@tao.ma>
On Fri, Jul 01, 2011 at 11:27:53PM +0800, Tao Ma wrote:
> From: Tao Ma <boyu.mt@taobao.com>
>
> When we trim some free blocks in a group of ext4, we should
> calculate the free blocks properly and check whether there are
> enough freed blocks left for us to trim. Current solution will
> only calculate free spaces if they are large for a trim which
> isn't appropriate.
>
> Let us see a small example:
> a group has 1.5M free which are 300k, 300k, 300k, 300k, 300k.
> And minblocks is 1M. With current solution, we have to iterate
> the whole group since these 300k will never be subtracted from
> 1.5M. But actually we should exit after we find the first 2
> free spaces since the left 3 chunks only sum up to 900K if we
> subtract the first 600K although they can't be trimed.
>
> Reviewed-by: Andreas Dilger <adilger@dilger.ca>
> Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Added to the ext4 tree, thanks.
- Ted
next prev parent reply other threads:[~2011-07-11 4:07 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-01 15:22 [PATCH 0/5 RESEND V2] ext4: trim bug fixes and improvements Tao Ma
2011-07-01 15:27 ` [PATCH 1/5] ext4: fix trim length underflow with small trim length Tao Ma
2011-07-01 15:27 ` [PATCH 2/5] ext4: speed up group trim with the right free block count Tao Ma
2011-07-11 4:06 ` Ted Ts'o [this message]
2011-07-01 15:27 ` [PATCH 3/5] ext4: Add new ext4 trim tracepoints Tao Ma
2011-07-11 4:07 ` Ted Ts'o
2011-07-01 15:27 ` [PATCH 4/5] ext4: Speed up FITRIM by recording flags in ext4_group_info Tao Ma
2011-07-11 4:07 ` Ted Ts'o
2011-07-01 15:27 ` [PATCH 5/5] ext4: Change the wrong param comment for ext4_trim_all_free Tao Ma
2011-07-11 4:07 ` Ted Ts'o
2011-07-11 4:06 ` [PATCH 1/5] ext4: fix trim length underflow with small trim length Ted Ts'o
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