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From: Christoph Hellwig <hch@infradead.org>
To: Ming Lei <tom.leiming@gmail.com>
Cc: Jens Axboe <axboe@fb.com>,
	linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
	linux-fsdevel@vger.kernel.org,
	Christoph Hellwig <hch@infradead.org>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	Chris Mason <clm@fb.com>, Josef Bacik <jbacik@fb.com>,
	David Sterba <dsterba@suse.com>,
	"open list:BTRFS FILE SYSTEM" <linux-btrfs@vger.kernel.org>
Subject: Re: [PATCH 26/60] btrfs: set NO_MP for request queues behind BTRFS
Date: Mon, 31 Oct 2016 08:36:44 -0700	[thread overview]
Message-ID: <20161031153644.GK30919@infradead.org> (raw)
In-Reply-To: <1477728600-12938-27-git-send-email-tom.leiming@gmail.com>

On Sat, Oct 29, 2016 at 04:08:25PM +0800, Ming Lei wrote:
> There are lots of direct access to .bi_vcnt & .bi_io_vec
> of bio, and it isn't ready to support multipage bvecs
> for BTRFS, so set NO_MP for these request queues.

For one bio is an I/O submitter, it has absolutely no business changing
queue flags - if we need to stick to this limitation it simply needs
a version of bio_add_page that doesn't create multi-page bvecs.

Second I don't think making it multipage bvec aware is all that hard,
and we should aim for doing the proper thing.

  reply	other threads:[~2016-10-31 15:36 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1477728600-12938-1-git-send-email-tom.leiming@gmail.com>
2016-10-29  8:08 ` [PATCH 26/60] btrfs: set NO_MP for request queues behind BTRFS Ming Lei
2016-10-31 15:36   ` Christoph Hellwig [this message]
2016-10-31 17:58     ` Chris Mason
2016-10-31 18:00       ` Christoph Hellwig

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