From: Jeff Moyer <jmoyer@redhat.com>
To: Kent Overstreet <koverstreet@google.com>
Cc: linux-kernel@vger.kernel.org, linux-aio@kvack.org,
akpm@linux-foundation.org, Zach Brown <zab@redhat.com>,
Felipe Balbi <balbi@ti.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Mark Fasheh <mfasheh@suse.com>, Joel Becker <jlbec@evilplan.org>,
Rusty Russell <rusty@rustcorp.com.au>,
Jens Axboe <axboe@kernel.dk>,
Asai Thambi S P <asamymuthupa@micron.com>,
Selvan Mani <smani@micron.com>,
Sam Bradshaw <sbradshaw@micron.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Benjamin LaHaise <bcrl@kvack.org>,
"Theodore Ts'o" <tytso@mit.edu>
Subject: Re: [PATCH 11/33] aio: make aio_put_req() lockless
Date: Fri, 12 Apr 2013 17:01:53 -0400 [thread overview]
Message-ID: <x49k3o7sbsu.fsf@segfault.boston.devel.redhat.com> (raw)
In-Reply-To: <1363883754-27966-12-git-send-email-koverstreet@google.com> (Kent Overstreet's message of "Thu, 21 Mar 2013 09:35:32 -0700")
Kent Overstreet <koverstreet@google.com> writes:
> Freeing a kiocb needed to touch the kioctx for three things:
>
> * Pull it off the reqs_active list
> * Decrementing reqs_active
> * Issuing a wakeup, if the kioctx was in the process of being freed.
>
> This patch moves these to aio_complete(), for a couple reasons:
>
> * aio_complete() already has to issue the wakeup, so if we drop the
> kioctx refcount before aio_complete does its wakeup we don't have to
> do it twice.
> * aio_complete currently has to take the kioctx lock, so it makes sense
> for it to pull the kiocb off the reqs_active list too.
> * A later patch is going to change reqs_active to include unreaped
> completions - this will mean allocating a kiocb doesn't have to look
> at the ringbuffer. So taking the decrement of reqs_active out of
> kiocb_free() is useful prep work for that patch.
>
> This doesn't really affect cancellation, since existing (usb) code that
> implements a cancel function still calls aio_complete() - we just have
> to make sure that aio_complete does the necessary teardown for cancelled
> kiocbs.
>
> It does affect code paths where we free kiocbs that were never
> submitted; they need to decrement reqs_active and pull the kiocb off the
> reqs_active list. This occurs in two places: kiocb_batch_free(), which
> is going away in a later patch, and the error path in io_submit_one.
After reading the patch description and the patch, I'm left wondering
whether you did this as a cleanup or a performance patch.
Anyway, I don't see any issue with it.
Acked-by: Jeff Moyer <jmoyer@redhat.com>
next prev parent reply other threads:[~2013-04-12 21:02 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-21 16:35 [PATCH 00/33] AIO cleanups/performance improvements Kent Overstreet
2013-03-21 16:35 ` [PATCH 01/33] mm: remove old aio use_mm() comment Kent Overstreet
2013-03-28 14:13 ` Theodore Ts'o
2013-04-12 15:42 ` Jeff Moyer
2013-03-21 16:35 ` [PATCH 02/33] aio: remove dead code from aio.h Kent Overstreet
2013-03-28 14:13 ` Theodore Ts'o
2013-04-12 15:42 ` Jeff Moyer
2013-03-21 16:35 ` [PATCH 03/33] gadget: remove only user of aio retry Kent Overstreet
2013-03-21 16:42 ` Felipe Balbi
2013-04-12 15:42 ` Jeff Moyer
2013-03-21 16:35 ` [PATCH 04/33] aio: remove retry-based AIO Kent Overstreet
2013-03-28 14:20 ` Theodore Ts'o
2013-04-12 15:43 ` Jeff Moyer
2013-03-21 16:35 ` [PATCH 05/33] char: add aio_{read,write} to /dev/{null,zero} Kent Overstreet
2013-03-28 14:20 ` Theodore Ts'o
2013-04-12 15:43 ` Jeff Moyer
2013-03-21 16:35 ` [PATCH 06/33] aio: kill return value of aio_complete() Kent Overstreet
2013-03-28 14:22 ` Theodore Ts'o
2013-04-12 15:44 ` Jeff Moyer
2013-03-21 16:35 ` [PATCH 07/33] aio: add kiocb_cancel() Kent Overstreet
2013-03-28 14:54 ` Theodore Ts'o
2013-04-12 15:58 ` Jeff Moyer
2013-03-21 16:35 ` [PATCH 08/33] aio: move private stuff out of aio.h Kent Overstreet
2013-03-29 16:07 ` Theodore Ts'o
2013-04-12 15:59 ` Jeff Moyer
2013-03-21 16:35 ` [PATCH 09/33] aio: dprintk() -> pr_debug() Kent Overstreet
2013-03-21 17:38 ` Joe Perches
2013-03-29 16:17 ` Theodore Ts'o
2013-04-12 16:01 ` Jeff Moyer
2013-03-21 16:35 ` [PATCH 10/33] aio: do fget() after aio_get_req() Kent Overstreet
2013-03-29 16:48 ` Theodore Ts'o
2013-04-12 16:51 ` Jeff Moyer
2013-03-21 16:35 ` [PATCH 11/33] aio: make aio_put_req() lockless Kent Overstreet
2013-03-29 17:14 ` Theodore Ts'o
2013-04-12 21:01 ` Jeff Moyer [this message]
2013-03-21 16:35 ` [PATCH 12/33] aio: refcounting cleanup Kent Overstreet
2013-04-02 1:32 ` Theodore Ts'o
2013-03-21 16:35 ` [PATCH 13/33] wait: add wait_event_hrtimeout() Kent Overstreet
2013-04-02 1:43 ` Theodore Ts'o
2013-03-21 16:35 ` [PATCH 14/33] aio: make aio_read_evt() more efficient, convert to hrtimers Kent Overstreet
2013-04-02 1:58 ` Theodore Ts'o
2013-03-21 16:35 ` [PATCH 15/33] aio: use flush_dcache_page() Kent Overstreet
2013-04-02 2:12 ` Theodore Ts'o
2013-04-09 21:07 ` Kent Overstreet
2013-03-21 16:35 ` [PATCH 16/33] aio: use cancellation list lazily Kent Overstreet
2013-04-02 2:36 ` Theodore Ts'o
2013-03-21 16:35 ` [PATCH 17/33] aio: change reqs_active to include unreaped completions Kent Overstreet
2013-04-02 2:53 ` Theodore Ts'o
2013-04-02 15:47 ` Theodore Ts'o
2013-03-21 16:35 ` [PATCH 18/33] aio: kill batch allocation Kent Overstreet
2013-04-02 3:03 ` Theodore Ts'o
2013-03-21 16:35 ` [PATCH 19/33] aio: kill struct aio_ring_info Kent Overstreet
2013-04-02 3:26 ` Theodore Ts'o
2013-03-21 16:35 ` [PATCH 20/33] aio: give shared kioctx fields their own cachelines Kent Overstreet
2013-04-02 3:27 ` Theodore Ts'o
2013-03-21 16:35 ` [PATCH 21/33] aio: reqs_active -> reqs_available Kent Overstreet
2013-04-02 15:48 ` Theodore Ts'o
2013-03-21 16:35 ` [PATCH 22/33] aio: percpu reqs_available Kent Overstreet
2013-04-02 16:03 ` Theodore Ts'o
2013-03-21 16:35 ` [PATCH 23/33] generic dynamic per cpu refcounting Kent Overstreet
2013-04-02 16:27 ` Theodore Ts'o
2013-04-12 19:36 ` Kent Overstreet
2013-04-16 1:41 ` Theodore Ts'o
2013-03-21 16:35 ` [PATCH 24/33] aio: percpu ioctx refcount Kent Overstreet
2013-04-02 16:28 ` Theodore Ts'o
2013-03-21 16:35 ` [PATCH 25/33] aio: use xchg() instead of completion_lock Kent Overstreet
2013-04-02 16:35 ` Theodore Ts'o
2013-03-21 16:35 ` [PATCH 26/33] aio: don't include aio.h in sched.h Kent Overstreet
2013-04-02 16:35 ` Theodore Ts'o
2013-03-21 16:35 ` [PATCH 27/33] aio: kill ki_key Kent Overstreet
2013-04-02 16:36 ` Theodore Ts'o
2013-03-21 16:35 ` [PATCH 28/33] aio: kill ki_retry Kent Overstreet
2013-04-02 18:46 ` Theodore Ts'o
2013-03-21 16:35 ` [PATCH 29/33] block: Prep work for batch completion Kent Overstreet
2013-04-02 18:48 ` Theodore Ts'o
2013-03-21 16:35 ` [PATCH 30/33] block, aio: batch completion for bios/kiocbs Kent Overstreet
2013-04-02 19:48 ` Theodore Ts'o
2013-04-10 21:59 ` Kent Overstreet
2013-04-02 19:53 ` Theodore Ts'o
2013-04-10 22:09 ` Kent Overstreet
2013-03-21 16:35 ` [PATCH 31/33] virtio-blk: convert to batch completion Kent Overstreet
2013-04-02 19:53 ` Theodore Ts'o
2013-03-21 16:35 ` [PATCH 32/33] mtip32xx: " Kent Overstreet
2013-04-02 19:54 ` Theodore Ts'o
2013-03-21 16:35 ` [PATCH 33/33] aio: fix kioctx not being freed after cancellation at exit time Kent Overstreet
2013-04-02 21:35 ` Theodore Ts'o
2013-04-09 21:15 ` Kent Overstreet
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=x49k3o7sbsu.fsf@segfault.boston.devel.redhat.com \
--to=jmoyer@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=asamymuthupa@micron.com \
--cc=axboe@kernel.dk \
--cc=balbi@ti.com \
--cc=bcrl@kvack.org \
--cc=gregkh@linuxfoundation.org \
--cc=jlbec@evilplan.org \
--cc=koverstreet@google.com \
--cc=linux-aio@kvack.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mfasheh@suse.com \
--cc=rusty@rustcorp.com.au \
--cc=sbradshaw@micron.com \
--cc=smani@micron.com \
--cc=tytso@mit.edu \
--cc=viro@zeniv.linux.org.uk \
--cc=zab@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.