From: Tejun Heo <tj@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Thomas Gleixner <tglx@linutronix.de>,
Frederic Weisbecker <fweisbec@gmail.com>,
Cody P Schafer <cody@linux.vnet.ibm.com>
Subject: Re: [PATCH v4 2/2] mm: make lru_add_drain_all() selective
Date: Tue, 13 Aug 2013 16:19:58 -0400 [thread overview]
Message-ID: <20130813201958.GA28996@mtj.dyndns.org> (raw)
In-Reply-To: <20130813123512.3d6865d8bf4689c05d44738c@linux-foundation.org>
Hello,
On Tue, Aug 13, 2013 at 12:35:12PM -0700, Andrew Morton wrote:
> I don't know how lots-of-kmallocs compares with alloc_percpu()
> performance-wise.
If this is actually performance sensitive, the logical thing to do
would be pre-allocating per-cpu buffers instead of depending on
dynamic allocation. Do the invocations need to be stackable?
> That being said, the `cpumask_var_t mask' which was added to
> lru_add_drain_all() is unneeded - it's just a temporary storage which
> can be eliminated by creating a schedule_on_each_cpu_cond() or whatever
> which is passed a function pointer of type `bool (*call_needed)(int
> cpu, void *data)'.
I'd really like to avoid that. Decision callbacks tend to get abused
quite often and it's rather sad to do that because cpumask cannot be
prepared and passed around. Can't it just preallocate all necessary
resources?
Thanks.
--
tejun
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next prev parent reply other threads:[~2013-08-13 20:20 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-06 20:22 [PATCH] mm: make lru_add_drain_all() selective Chris Metcalf
2013-08-06 20:22 ` [PATCH v2] " Chris Metcalf
2013-08-07 20:45 ` Tejun Heo
2013-08-07 20:49 ` [PATCH v3 1/2] workqueue: add new schedule_on_cpu_mask() API Chris Metcalf
2013-08-07 20:52 ` [PATCH v3 2/2] mm: make lru_add_drain_all() selective Chris Metcalf
2013-08-07 22:48 ` [PATCH v2] " Cody P Schafer
2013-08-07 20:49 ` [PATCH v4 1/2] workqueue: add new schedule_on_cpu_mask() API Chris Metcalf
2013-08-09 15:02 ` Tejun Heo
2013-08-09 16:12 ` Chris Metcalf
2013-08-09 16:30 ` Tejun Heo
2013-08-07 20:49 ` [PATCH v5 " Chris Metcalf
2013-08-09 17:40 ` Tejun Heo
2013-08-09 17:49 ` [PATCH v6 " Chris Metcalf
2013-08-09 17:52 ` [PATCH v6 2/2] mm: make lru_add_drain_all() selective Chris Metcalf
2013-08-07 20:52 ` [PATCH v5 " Chris Metcalf
2013-08-07 20:52 ` [PATCH v4 " Chris Metcalf
2013-08-12 21:05 ` Andrew Morton
2013-08-13 1:53 ` Chris Metcalf
2013-08-13 19:35 ` Andrew Morton
2013-08-13 20:19 ` Tejun Heo [this message]
2013-08-13 20:31 ` Andrew Morton
2013-08-13 20:59 ` Chris Metcalf
2013-08-13 21:13 ` Andrew Morton
2013-08-13 22:13 ` Chris Metcalf
2013-08-13 22:26 ` Andrew Morton
2013-08-13 23:04 ` Chris Metcalf
2013-08-13 22:51 ` [PATCH v7 1/2] workqueue: add schedule_on_each_cpu_cond Chris Metcalf
2013-08-13 22:53 ` [PATCH v7 2/2] mm: make lru_add_drain_all() selective Chris Metcalf
2013-08-13 23:29 ` Tejun Heo
2013-08-13 23:32 ` Chris Metcalf
2013-08-14 6:46 ` Andrew Morton
2013-08-14 13:05 ` Tejun Heo
2013-08-14 16:03 ` Chris Metcalf
2013-08-14 16:57 ` Tejun Heo
2013-08-14 17:18 ` Chris Metcalf
2013-08-14 20:07 ` Tejun Heo
2013-08-14 20:22 ` [PATCH v8] " Chris Metcalf
2013-08-14 20:44 ` Andrew Morton
2013-08-14 20:50 ` Tejun Heo
2013-08-14 21:03 ` Andrew Morton
2013-08-14 21:07 ` Andrew Morton
2013-08-14 21:12 ` Andrew Morton
2013-08-14 21:23 ` Chris Metcalf
2013-08-13 23:44 ` [PATCH v7 2/2] " Chris Metcalf
2013-08-13 23:51 ` Tejun Heo
2013-08-13 21:07 ` [PATCH v4 " Tejun Heo
2013-08-13 21:16 ` Andrew Morton
2013-08-13 22:07 ` Tejun Heo
2013-08-13 22:18 ` Andrew Morton
2013-08-13 22:33 ` Tejun Heo
2013-08-13 22:47 ` Andrew Morton
2013-08-13 23:03 ` Tejun Heo
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