From: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org
Subject: Re: needed lru_add_drain_all() change
Date: Fri, 29 Jun 2012 12:47:32 +0900 [thread overview]
Message-ID: <4FED2554.6020601@jp.fujitsu.com> (raw)
In-Reply-To: <CAHGf_=ra6eXSVyhox3z2X-4csrwWeeDgMjS83i-J2nJwuWpqhg@mail.gmail.com>
(2012/06/28 15:23), KOSAKI Motohiro wrote:
> On Tue, Jun 26, 2012 at 5:37 PM, Andrew Morton
> <akpm@linux-foundation.org> wrote:
>> https://bugzilla.kernel.org/show_bug.cgi?id=43811
>>
>> lru_add_drain_all() uses schedule_on_each_cpu(). But
>> schedule_on_each_cpu() hangs if a realtime thread is spinning, pinned
>> to a CPU. There's no intention to change the scheduler behaviour, so I
>> think we should remove schedule_on_each_cpu() from the kernel.
>>
>> The biggest user of schedule_on_each_cpu() is lru_add_drain_all().
>>
>> Does anyone have any thoughts on how we can do this? The obvious
>> approach is to declare these:
>>
>> static DEFINE_PER_CPU(struct pagevec[NR_LRU_LISTS], lru_add_pvecs);
>> static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs);
>> static DEFINE_PER_CPU(struct pagevec, lru_deactivate_pvecs);
>>
>> to be irq-safe and use on_each_cpu(). lru_rotate_pvecs is already
>> irq-safe and converting lru_add_pvecs and lru_deactivate_pvecs looks
>> pretty simple.
>>
>> Thoughts?
>
> I agree.
>
> But i hope more. In these days, we have plenty lru_add_drain_all()
> callsite. So,
> i think we should remove struct pagevec and should aim migration aware new
> batch mechanism. maybe. This also improve compaction success rate.
>
migration-aware means an framework which isolate_xxxx_page() can work with ?
To do that, we need to know which object points to the page. Hmm. Do you have
anyidea ?
-Kame
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next prev parent reply other threads:[~2012-06-29 3:49 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-26 21:37 Andrew Morton
2012-06-27 0:55 ` Minchan Kim
2012-06-27 1:15 ` Andrew Morton
2012-06-27 1:20 ` Minchan Kim
2012-06-27 1:29 ` Andrew Morton
2012-06-27 2:09 ` Minchan Kim
2012-06-27 5:12 ` Andrew Morton
2012-06-27 5:41 ` Minchan Kim
2012-06-27 5:55 ` Andrew Morton
2012-06-27 6:33 ` Minchan Kim
2012-06-27 6:41 ` Andrew Morton
2012-06-27 10:27 ` Peter Zijlstra
2012-06-27 6:46 ` Andrew Morton
2012-06-27 10:31 ` Peter Zijlstra
2012-06-27 12:04 ` Peter Zijlstra
2012-06-28 6:23 ` KOSAKI Motohiro
2012-06-29 3:47 ` Kamezawa Hiroyuki [this message]
2012-06-28 7:43 ` Kamezawa Hiroyuki
2012-06-28 23:42 ` Minchan Kim
2012-06-29 3:24 ` Kamezawa Hiroyuki
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