From: Michal Hocko <mhocko@kernel.org>
To: Tahsin Erdogan <tahsin@google.com>
Cc: Tejun Heo <tj@kernel.org>, Christoph Lameter <cl@linux.com>,
Andrew Morton <akpm@linux-foundation.org>,
Chris Wilson <chris@chris-wilson.co.uk>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Roman Pen <r.peniaev@gmail.com>,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
zijun_hu <zijun_hu@htc.com>, Joonsoo Kim <iamjoonsoo.kim@lge.com>,
David Rientjes <rientjes@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 3/3] percpu: improve allocation success rate for non-GFP_KERNEL callers
Date: Mon, 27 Feb 2017 18:14:04 +0100 [thread overview]
Message-ID: <20170227171404.GP26504@dhcp22.suse.cz> (raw)
In-Reply-To: <20170227170753.GO26504@dhcp22.suse.cz>
On Mon 27-02-17 18:07:53, Michal Hocko wrote:
> On Mon 27-02-17 09:01:09, Tahsin Erdogan wrote:
> > On Mon, Feb 27, 2017 at 7:25 AM, Michal Hocko <mhocko@kernel.org> wrote:
> > > /*
> > > * No space left. Create a new chunk. We don't want multiple
> > > * tasks to create chunks simultaneously. Serialize and create iff
> > > * there's still no empty chunk after grabbing the mutex.
> > > */
> > > if (is_atomic)
> > > goto fail;
> > >
> > > right before pcpu_populate_chunk so is this actually a problem?
> >
> > Yes, this prevents adding more pcpu chunks and so cause "atomic" allocations
> > to fail more easily.
>
> Then I fail to see what is the problem you are trying to fix.
To be more specific. Could you describe what more can we do in the
vmalloc layer for GFP_NOWAIT allocations? They certainly cannot sleep
and cannot perform the reclaim so you have to rely on the background
work.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2017-02-27 17:14 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-25 21:00 [PATCH " Tahsin Erdogan
2017-02-25 23:54 ` kbuild test robot
2017-02-26 0:48 ` kbuild test robot
2017-02-26 4:38 ` [PATCH v2 " Tahsin Erdogan
2017-02-27 9:52 ` Michal Hocko
2017-02-27 13:00 ` Tahsin Erdogan
2017-02-27 15:25 ` Michal Hocko
2017-02-27 17:01 ` Tahsin Erdogan
2017-02-27 17:07 ` Michal Hocko
2017-02-27 17:14 ` Michal Hocko [this message]
2017-02-27 19:32 ` Tahsin Erdogan
2017-02-27 19:47 ` Michal Hocko
2017-02-27 19:51 ` Tejun Heo
2017-02-27 20:27 ` Tahsin Erdogan
2017-02-27 20:29 ` Tejun Heo
2017-02-27 20:37 ` Tahsin Erdogan
2017-02-27 20:45 ` Tejun Heo
2017-02-27 21:12 ` Tahsin Erdogan
2017-02-27 21:28 ` Tejun Heo
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