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From: Christoph Hellwig <hch@lst.de>
To: Ming Lei <ming.lei@redhat.com>
Cc: linux-kernel@vger.kernel.org,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
	Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>
Subject: Re: [PATCH] fs/buffer: try to submit writeback bio in unit of page
Date: Mon, 4 Jan 2021 09:44:15 +0100	[thread overview]
Message-ID: <20210104084415.GA28741@lst.de> (raw)
In-Reply-To: <20201230000815.3448707-1-ming.lei@redhat.com>

On Wed, Dec 30, 2020 at 08:08:15AM +0800, Ming Lei wrote:
> It is observed that __block_write_full_page() always submit bio with size of block size,
> which is often 512 bytes.
> 
> In case of sequential IO, or >=4k BS random/seq writeback IO, most of times IO
> represented by all buffer_head in each page can be done in single bio. It is actually
> done in single request IO by block layer's plug merge too.
> 
> So check if IO represented by buffer_head can be merged to single page
> IO, if yes, just submit single bio instead of submitting one bio for each buffer_head.

There is some very weird formatting in here.  From a very quick look
the changes look sensible, but I wonder if we should spend so much
time optimizing the legacy buffer_head I/O path, rather than switching
callers to saner helpers.

  reply	other threads:[~2021-01-04  8:45 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-30  0:08 [PATCH] fs/buffer: try to submit writeback bio in unit of page Ming Lei
2021-01-04  8:44 ` Christoph Hellwig [this message]
2021-01-04  9:24   ` Ming Lei

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