From: Christoph Hellwig <hch@infradead.org>
To: Jens Axboe <axboe@fb.com>
Cc: Christoph Hellwig <hch@infradead.org>,
axboe@kernel.dk, linux-block@vger.kernel.org
Subject: Re: [PATCHSET] Add support for simplified async direct-io
Date: Mon, 14 Nov 2016 10:00:52 -0800 [thread overview]
Message-ID: <20161114180052.GA24476@infradead.org> (raw)
In-Reply-To: <71ce9ae3-214d-b248-3507-cc96bea41a9b@fb.com>
On Mon, Nov 14, 2016 at 10:47:46AM -0700, Jens Axboe wrote:
> This seems less clean in basically all ways, not sure I agree with you.
> We already have 4 vecs inlined in a generic bio, and we might as well
> use the fs bioset instead of creating our own. You also add a smallish
> dio to track things, I don't think we need that.
We need it unless we want unbounded allocations for the biovec. With a
1GB I/O we're at a page size allocation, and with 64MB I/Os that aren't
unheard of we'd be up to a 64 pages or an order 6 allocation which will
take down the VM. We also need to pin down all the user memory while
doing the I/O instead of having throttling on the bio mempool before
doing the get_user_pages.
next prev parent reply other threads:[~2016-11-14 18:00 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-14 17:28 [PATCHSET] Add support for simplified async direct-io Jens Axboe
2016-11-14 17:28 ` [PATCH 1/2] block: support any sized IO for simplified bdev direct-io Jens Axboe
2016-11-14 17:28 ` [PATCH 2/2] block: add support for async simple direct-io for bdevs Jens Axboe
2016-11-14 17:37 ` [PATCHSET] Add support for simplified async direct-io Christoph Hellwig
2016-11-14 17:47 ` Jens Axboe
2016-11-14 18:00 ` Christoph Hellwig [this message]
2016-11-14 18:02 ` Jens Axboe
2016-11-14 18:05 ` Christoph Hellwig
2016-11-14 18:08 ` Jens Axboe
2016-11-14 18:11 ` Christoph Hellwig
2016-11-14 18:17 ` Jens Axboe
2016-11-15 13:58 ` Christoph Hellwig
2016-11-16 16:09 ` Jens Axboe
2016-11-16 16:31 ` Christoph Hellwig
2016-11-16 16:57 ` Jens Axboe
2016-11-16 17:16 ` Christoph Hellwig
2016-11-16 20:02 ` Jens Axboe
2016-11-16 20:36 ` Jens Axboe
2016-11-16 20:51 ` Jens Axboe
2016-11-17 3:44 ` Jens Axboe
2016-11-17 4:43 ` Jens Axboe
2016-11-17 12:50 ` Christoph Hellwig
2016-11-17 13:25 ` Jens Axboe
2016-11-17 15:03 ` Jens Axboe
2016-11-17 15:16 ` Christoph Hellwig
2016-11-17 20:17 ` Christoph Hellwig
2016-11-17 20:30 ` Jens Axboe
2016-11-17 21:04 ` Christoph Hellwig
2016-11-17 21:06 ` Jens Axboe
2016-11-17 12:46 ` Christoph Hellwig
2016-11-17 13:26 ` Jens Axboe
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