From: Zach Brown <zab-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: Kent Overstreet <koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
tytso-3s7WtUTddSA@public.gmane.org
Subject: Re: [PATCH 5/5] aio: Refactor aio_read_evt, use cmxchg(), fix bug
Date: Thu, 11 Oct 2012 09:43:12 -0700 [thread overview]
Message-ID: <20121011164312.GD8768@lenny.home.zabbo.net> (raw)
In-Reply-To: <20121011025102.GE24174-jC9Py7bek1znysI04z7BkA@public.gmane.org>
> Yeah, but that means the completion has to be delivered from process
> context. That's not what aio does today, and it'd be a real performance
> regression.
It'd only have to to complete from process context if it faults. The
cheapest possible delivery mechanism is simple cpu stores. In the vast
majority of cases the ring will be resident and it'll be done. In rare
cases it could fall back to a deferred completion. If apps can't
stomach that latency and want to pay the overhead of pinning to remove
that risk, they're welcome to do so.
That's my hope, anyway.
- z
next prev parent reply other threads:[~2012-10-11 16:43 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
[not found] ` <1349764760-21093-1-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-09 6:39 ` [PATCH 2/5] aio: kiocb_cancel() Kent Overstreet
[not found] ` <1349764760-21093-2-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-09 18:26 ` Zach Brown
[not found] ` <20121009182625.GM26187-fypN+1c5dIyjpB87vu3CluTW4wlIGRCZ@public.gmane.org>
2012-10-09 21:37 ` Kent Overstreet
[not found] ` <20121009213700.GF29494-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-10 11:03 ` Theodore Ts'o
[not found] ` <20121010110356.GA11468-AKGzg7BKzIDYtjvyW6yDsg@public.gmane.org>
2012-10-10 21:20 ` Zach Brown
[not found] ` <20121010212051.GD6371-fypN+1c5dIyjpB87vu3CluTW4wlIGRCZ@public.gmane.org>
2012-10-10 23:21 ` Theodore Ts'o
2012-10-11 2:41 ` Kent Overstreet
2012-10-09 6:39 ` [PATCH 5/5] aio: Refactor aio_read_evt, use cmxchg(), fix bug Kent Overstreet
[not found] ` <1349764760-21093-5-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-09 18:37 ` Zach Brown
[not found] ` <20121009183753.GP26187-fypN+1c5dIyjpB87vu3CluTW4wlIGRCZ@public.gmane.org>
2012-10-09 21:27 ` Kent Overstreet
[not found] ` <20121009212724.GD29494-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-09 22:47 ` Zach Brown
[not found] ` <20121009224703.GT26187-fypN+1c5dIyjpB87vu3CluTW4wlIGRCZ@public.gmane.org>
2012-10-09 22:55 ` Kent Overstreet
[not found] ` <20121009225509.GA26835-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-09 23:10 ` Zach Brown
[not found] ` <20121009231059.GV26187-fypN+1c5dIyjpB87vu3CluTW4wlIGRCZ@public.gmane.org>
2012-10-10 0:06 ` Kent Overstreet
[not found] ` <20121010000600.GB26835-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-10 0:26 ` Zach Brown
[not found] ` <20121010002634.GX26187-fypN+1c5dIyjpB87vu3CluTW4wlIGRCZ@public.gmane.org>
2012-10-10 0:47 ` Kent Overstreet
[not found] ` <20121010004746.GF26835-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-10 21:43 ` Zach Brown
[not found] ` <20121010214315.GE6371-fypN+1c5dIyjpB87vu3CluTW4wlIGRCZ@public.gmane.org>
2012-10-11 2:51 ` Kent Overstreet
[not found] ` <20121011025102.GE24174-jC9Py7bek1znysI04z7BkA@public.gmane.org>
2012-10-11 16:43 ` Zach Brown [this message]
2012-10-09 18:25 ` [PATCH 1/5] aio: Kill return value of aio_complete() Zach Brown
2012-10-09 6:39 ` [PATCH 3/5] aio: Rewrite refcounting Kent Overstreet
[not found] ` <1349764760-21093-3-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-09 18:27 ` Zach Brown
[not found] ` <20121009182755.GN26187-fypN+1c5dIyjpB87vu3CluTW4wlIGRCZ@public.gmane.org>
2012-10-09 22:21 ` Kent Overstreet
[not found] ` <20121009222153.GG29494-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-09 22:35 ` Zach Brown
[not found] ` <20121009223504.GS26187-fypN+1c5dIyjpB87vu3CluTW4wlIGRCZ@public.gmane.org>
2012-10-10 0:17 ` Kent Overstreet
2012-10-09 6:39 ` [PATCH 4/5] aio: vmap ringbuffer Kent Overstreet
[not found] ` <1349764760-21093-4-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-09 18:29 ` Zach Brown
2012-10-09 21:31 ` Kent Overstreet
[not found] ` <20121009213111.GE29494-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-09 22:32 ` Zach Brown
2012-10-09 22:44 ` Kent Overstreet
[not found] ` <20121009224428.GH29494-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-09 22:58 ` Zach Brown
[not found] ` <20121009225836.GU26187-fypN+1c5dIyjpB87vu3CluTW4wlIGRCZ@public.gmane.org>
2012-10-10 0:16 ` Kent Overstreet
[not found] ` <20121010001630.GC26835-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-10 0:36 ` Zach Brown
[not found] ` <20121010003626.GY26187-fypN+1c5dIyjpB87vu3CluTW4wlIGRCZ@public.gmane.org>
2012-10-10 1:09 ` Kent Overstreet
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