linux-kernel - Re: [f2fs-dev] [PATCH v5] f2fs: introduce fragment allocation mode mount option

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Message-ID: <0e77ea3e-196e-cc41-91eb-abc89ca6d522@kernel.org>
Date:   Thu, 21 Oct 2021 19:29:33 +0800
From:   Chao Yu <chao@...nel.org>
To:     Daeho Jeong <daeho43@...il.com>, linux-kernel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net, kernel-team@...roid.com
Cc:     Daeho Jeong <daehojeong@...gle.com>
Subject: Re: [f2fs-dev] [PATCH v5] f2fs: introduce fragment allocation mode
 mount option

On 2021/9/30 2:12, Daeho Jeong wrote:
> From: Daeho Jeong <daehojeong@...gle.com>
> 
> Added two options into "mode=" mount option to make it possible for
> developers to simulate filesystem fragmentation/after-GC situation
> itself. The developers use these modes to understand filesystem
> fragmentation/after-GC condition well, and eventually get some
> insights to handle them better.
> 
> "fragment:segment": f2fs allocates a new segment in ramdom position.
> 		With this, we can simulate the after-GC condition.
> "fragment:block" : We can scatter block allocation with
> 		"max_fragment_chunk" and "max_fragment_hole" sysfs
> 		nodes. f2fs will allocate 1..<max_fragment_chunk>
> 		blocks in a chunk and make a hole in the length of
> 		1..<max_fragment_hole> by turns	in a newly allocated
> 		free segment. Plus, this mode implicitly enables
> 		"fragment:segment" option for more randomness.
> 
> Signed-off-by: Daeho Jeong <daehojeong@...gle.com>

Reviewed-by: Chao Yu <chao@...nel.org>

Thanks,