From: Andi Kleen <andi@firstfloor.org>
To: Kent Overstreet <koverstreet@google.com>
Cc: Andi Kleen <andi@firstfloor.org>,
linux-kernel@vger.kernel.org, linux-aio@kvack.org,
linux-fsdevel@vger.kernel.org, zab@redhat.com, bcrl@kvack.org,
jmoyer@redhat.com, axboe@kernel.dk, viro@zeniv.linux.org.uk
Subject: Re: [PATCH 22/25] Generic dynamic per cpu refcounting
Date: Thu, 29 Nov 2012 19:59:53 +0100 [thread overview]
Message-ID: <20121129185953.GW16230@one.firstfloor.org> (raw)
In-Reply-To: <20121129185720.GE15094@google.com>
On Thu, Nov 29, 2012 at 10:57:20AM -0800, Kent Overstreet wrote:
> On Thu, Nov 29, 2012 at 10:45:04AM -0800, Andi Kleen wrote:
> > Kent Overstreet <koverstreet@google.com> writes:
> >
> > > This implements a refcount with similar semantics to
> > > atomic_get()/atomic_dec_and_test(), that starts out as just an atomic_t
> > > but dynamically switches to per cpu refcounting when the rate of
> > > gets/puts becomes too high.
> >
> > This will only work if you put on the same CPU as you get, right?
>
> Nope, no such restriction.
I don't see how you ensure you're doing the __this_cpu_dec on the same
CPU as you did the get
-Andi
next prev parent reply other threads:[~2012-11-29 18:59 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-28 16:43 [PATCH 00/25] AIO performance improvements/cleanups Kent Overstreet
2012-11-28 16:43 ` [PATCH 01/25] mm: remove old aio use_mm() comment Kent Overstreet
2012-11-28 16:43 ` [PATCH 02/25] aio: remove dead code from aio.h Kent Overstreet
2012-11-28 16:43 ` [PATCH 03/25] gadget: remove only user of aio retry Kent Overstreet
2012-11-28 16:43 ` [PATCH 04/25] aio: remove retry-based AIO Kent Overstreet
2012-11-28 16:43 ` [PATCH 05/25] char: add aio_{read,write} to /dev/{null,zero} Kent Overstreet
2012-11-28 16:43 ` [PATCH 06/25] aio: Kill return value of aio_complete() Kent Overstreet
2012-11-28 16:43 ` [PATCH 07/25] aio: kiocb_cancel() Kent Overstreet
2012-11-29 0:07 ` Zach Brown
2012-11-29 0:58 ` Kent Overstreet
2012-11-28 16:43 ` [PATCH 08/25] aio: Move private stuff out of aio.h Kent Overstreet
2012-11-28 16:43 ` [PATCH 09/25] aio: dprintk() -> pr_debug() Kent Overstreet
2012-11-28 16:43 ` [PATCH 10/25] aio: do fget() after aio_get_req() Kent Overstreet
2012-11-28 16:43 ` [PATCH 11/25] aio: Make aio_put_req() lockless Kent Overstreet
2012-11-28 16:43 ` [PATCH 12/25] aio: Refcounting cleanup Kent Overstreet
2012-11-29 0:17 ` Zach Brown
2012-11-29 1:12 ` Kent Overstreet
2012-11-29 0:46 ` Benjamin LaHaise
2012-11-29 1:38 ` Kent Overstreet
2012-11-28 16:43 ` [PATCH 13/25] aio: Convert read_events() to hrtimers Kent Overstreet
2012-11-29 0:24 ` Zach Brown
2012-11-29 1:05 ` Kent Overstreet
2012-11-28 16:43 ` [PATCH 14/25] aio: Make aio_read_evt() more efficient Kent Overstreet
2012-11-29 0:38 ` Zach Brown
2012-11-29 19:31 ` Kent Overstreet
2012-11-30 0:20 ` Kent Overstreet
2012-11-28 16:43 ` [PATCH 15/25] aio: Use cancellation list lazily Kent Overstreet
2012-11-28 16:43 ` [PATCH 16/25] aio: Change reqs_active to include unreaped completions Kent Overstreet
2012-11-28 16:43 ` [PATCH 17/25] aio: Kill batch allocation Kent Overstreet
2012-11-28 16:43 ` [PATCH 18/25] aio: Kill struct aio_ring_info Kent Overstreet
2012-11-28 16:43 ` [PATCH 19/25] aio: Give shared kioctx fields their own cachelines Kent Overstreet
2012-11-28 16:43 ` [PATCH 20/25] aio: reqs_active -> reqs_available Kent Overstreet
2012-11-28 16:43 ` [PATCH 21/25] aio: percpu reqs_available Kent Overstreet
2012-11-28 16:43 ` [PATCH 22/25] Generic dynamic per cpu refcounting Kent Overstreet
2012-11-29 18:45 ` Andi Kleen
2012-11-29 18:57 ` Kent Overstreet
2012-11-29 18:59 ` Andi Kleen [this message]
2012-11-29 19:12 ` Kent Overstreet
2012-11-29 19:20 ` Andi Kleen
2012-11-29 19:29 ` Kent Overstreet
2012-11-29 19:34 ` Benjamin LaHaise
2012-11-29 20:22 ` Kent Overstreet
2012-11-29 20:42 ` Andi Kleen
2012-11-29 20:45 ` Kent Overstreet
2012-11-29 20:54 ` Andi Kleen
2012-11-29 20:59 ` Kent Overstreet
2012-11-29 21:57 ` Jamie Lokier
2012-11-28 16:43 ` [PATCH 23/25] aio: Percpu ioctx refcount Kent Overstreet
2012-11-28 16:43 ` [PATCH 24/25] aio: use xchg() instead of completion_lock Kent Overstreet
2012-11-28 16:43 ` [PATCH 25/25] aio: Don't include aio.h in sched.h Kent Overstreet
2012-11-29 0:03 ` [PATCH 00/25] AIO performance improvements/cleanups Zach Brown
2012-11-29 19:01 ` Kent Overstreet
-- strict thread matches above, loose matches on Subject: below --
2012-11-28 3:19 Kent Overstreet
2012-11-28 3:19 ` [PATCH 22/25] Generic dynamic per cpu refcounting Kent Overstreet
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