From: Andrew Morton <akpm@linux-foundation.org>
To: Tejun Heo <tj@kernel.org>
Cc: avi@redhat.com, nate@cpanel.net, cl@linux-foundation.org,
oleg@redhat.com, axboe@kernel.dk, vgoyal@redhat.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCHSET] block, mempool, percpu: implement percpu mempool and fix blkcg percpu alloc deadlock
Date: Thu, 22 Dec 2011 14:20:58 -0800 [thread overview]
Message-ID: <20111222142058.41316ee0.akpm@linux-foundation.org> (raw)
In-Reply-To: <20111222220911.GK17084@google.com>
On Thu, 22 Dec 2011 14:09:11 -0800
Tejun Heo <tj@kernel.org> wrote:
> Hello,
>
> On Thu, Dec 22, 2011 at 01:59:25PM -0800, Andrew Morton wrote:
> > How about we just delete those statistics and then this patchset?
> >
> > Or how about we change those statistics to not do percpu allocations,
> > then delete this patchset?
>
> I'm not against above both
Don't just consider my suggestions - please try to come up with your own
alternatives too! If all else fails then this patch is a last resort.
> but apparently those percpu stats reduced
> CPU overhead significantly.
Deleting them would save even more CPU.
Or make them runtime or compile-time configurable, so only the
developers see the impact.
Some specifics on which counters are causing the problems would help here.
> > Or how about we fix the percpu memory allocation code so that it
> > propagates the gfp flags, then delete this patchset?
>
> Oh, no, this is gonna make things *way* more complex. I tried.
But there's a difference between fixing a problem and working around it.
> If
> we're gonna have many more NOIO percpu users, which I don't think we
> would or should, that might make sense but, for fringe cases,
> extending mempool to cover percpu is a much better sized solution.
I've long felt that we goofed with the gfp_flags thing and that it
should be a field in the task_struct. Now *that* would be a large
patch!
next prev parent reply other threads:[~2011-12-22 22:21 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-22 21:45 [PATCHSET] block, mempool, percpu: implement percpu mempool and fix blkcg percpu alloc deadlock Tejun Heo
2011-12-22 21:45 ` [PATCH 1/7] mempool: fix and document synchronization and memory barrier usage Tejun Heo
2011-12-22 21:45 ` [PATCH 2/7] mempool: drop unnecessary and incorrect BUG_ON() from mempool_destroy() Tejun Heo
2011-12-22 21:45 ` [PATCH 3/7] mempool: fix first round failure behavior Tejun Heo
2011-12-22 21:45 ` [PATCH 4/7] mempool: factor out mempool_fill() Tejun Heo
2011-12-22 21:45 ` [PATCH 5/7] mempool: separate out __mempool_create() Tejun Heo
2011-12-22 21:45 ` [PATCH 6/7] mempool, percpu: implement percpu mempool Tejun Heo
2011-12-22 21:45 ` [PATCH 7/7] block: fix deadlock through percpu allocation in blk-cgroup Tejun Heo
2011-12-23 1:00 ` Vivek Goyal
2011-12-23 22:54 ` Tejun Heo
2011-12-22 21:59 ` [PATCHSET] block, mempool, percpu: implement percpu mempool and fix blkcg percpu alloc deadlock Andrew Morton
2011-12-22 22:09 ` Tejun Heo
2011-12-22 22:20 ` Andrew Morton [this message]
2011-12-22 22:41 ` Tejun Heo
2011-12-22 22:54 ` Andrew Morton
2011-12-22 23:00 ` Tejun Heo
2011-12-22 23:16 ` Andrew Morton
2011-12-22 23:24 ` Tejun Heo
2011-12-22 23:41 ` Andrew Morton
2011-12-22 23:54 ` Tejun Heo
2011-12-23 1:14 ` Andrew Morton
2011-12-23 15:17 ` Vivek Goyal
2011-12-27 18:34 ` Tejun Heo
2011-12-27 21:20 ` Andrew Morton
2011-12-27 21:44 ` Tejun Heo
2011-12-27 21:58 ` Andrew Morton
2011-12-27 22:22 ` Tejun Heo
2011-12-23 1:21 ` Vivek Goyal
2011-12-23 1:38 ` Andrew Morton
2011-12-23 2:54 ` Vivek Goyal
2011-12-23 3:11 ` Andrew Morton
2011-12-23 14:58 ` Vivek Goyal
2011-12-27 21:25 ` Andrew Morton
2011-12-27 22:07 ` Tejun Heo
2011-12-27 22:21 ` Andrew Morton
2011-12-27 22:30 ` Tejun Heo
2012-01-16 15:26 ` Vivek Goyal
2011-12-23 1:40 ` Vivek Goyal
2011-12-23 1:58 ` Andrew Morton
2011-12-23 2:56 ` Vivek Goyal
2011-12-26 6:05 ` KAMEZAWA Hiroyuki
2011-12-27 17:52 ` Tejun Heo
2011-12-28 0:14 ` KAMEZAWA Hiroyuki
2011-12-28 0:41 ` Tejun Heo
2012-01-05 1:28 ` Tejun Heo
2012-01-16 15:28 ` Vivek Goyal
2012-02-09 23:58 ` Tejun Heo
2012-02-10 16:26 ` Vivek Goyal
2012-02-13 22:31 ` Tejun Heo
2012-02-15 15:43 ` Vivek Goyal
2011-12-23 14:46 ` Vivek Goyal
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