From: Zach Brown <zab@redhat.com>
To: Kent Overstreet <koverstreet@google.com>
Cc: linux-bcache@vger.kernel.org, linux-kernel@vger.kernel.org,
dm-devel@redhat.com, tytso@mit.edu
Subject: Re: [PATCH 4/5] aio: vmap ringbuffer
Date: Tue, 9 Oct 2012 11:29:49 -0700 [thread overview]
Message-ID: <20121009182949.GO26187@lenny.home.zabbo.net> (raw)
In-Reply-To: <1349764760-21093-4-git-send-email-koverstreet@google.com>
On Mon, Oct 08, 2012 at 11:39:19PM -0700, Kent Overstreet wrote:
> It simplifies a lot of stuff if the ringbuffer is contiguously mapped
> into kernel space, and we can delete a lot of code - in particular, this
> is useful for converting read_events() to cmpxchg.
1) I'm concerned that Our Favourite Database Benchmarkers will see an
effect of having more TLB pressure from that mapping. kmap_atomic()
should be cheaper. We'll need to measure the difference.
2) I'm not at all convinced that the current ring semantics are safe
with cmpxchg(), more in the next patch.
- z
next prev parent reply other threads:[~2012-10-09 18:30 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-09 6:39 [PATCH 1/5] aio: Kill return value of aio_complete() Kent Overstreet
2012-10-09 6:39 ` [PATCH 2/5] aio: kiocb_cancel() Kent Overstreet
2012-10-09 18:26 ` Zach Brown
2012-10-09 21:37 ` Kent Overstreet
2012-10-10 11:03 ` Theodore Ts'o
2012-10-10 21:20 ` Zach Brown
2012-10-10 23:21 ` Theodore Ts'o
2012-10-11 2:41 ` Kent Overstreet
2012-10-09 6:39 ` [PATCH 3/5] aio: Rewrite refcounting Kent Overstreet
2012-10-09 18:27 ` Zach Brown
2012-10-09 22:21 ` Kent Overstreet
2012-10-09 22:35 ` Zach Brown
2012-10-10 0:17 ` Kent Overstreet
2012-10-09 6:39 ` [PATCH 4/5] aio: vmap ringbuffer Kent Overstreet
2012-10-09 18:29 ` Zach Brown [this message]
2012-10-09 21:31 ` Kent Overstreet
2012-10-09 22:32 ` Zach Brown
2012-10-09 22:44 ` Kent Overstreet
2012-10-09 22:58 ` Zach Brown
2012-10-10 0:16 ` Kent Overstreet
2012-10-10 0:36 ` Zach Brown
2012-10-10 1:09 ` Kent Overstreet
2012-10-09 6:39 ` [PATCH 5/5] aio: Refactor aio_read_evt, use cmxchg(), fix bug Kent Overstreet
2012-10-09 18:37 ` Zach Brown
2012-10-09 21:27 ` Kent Overstreet
2012-10-09 22:47 ` Zach Brown
2012-10-09 22:55 ` Kent Overstreet
2012-10-09 23:10 ` Zach Brown
2012-10-10 0:06 ` Kent Overstreet
2012-10-10 0:26 ` Zach Brown
2012-10-10 0:47 ` Kent Overstreet
2012-10-10 21:43 ` Zach Brown
2012-10-11 2:51 ` Kent Overstreet
2012-10-11 16:43 ` Zach Brown
2012-10-09 18:25 ` [PATCH 1/5] aio: Kill return value of aio_complete() Zach Brown
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