From: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Subject: Re: needed lru_add_drain_all() change
Date: Thu, 28 Jun 2012 02:23:30 -0400 [thread overview]
Message-ID: <CAHGf_=ra6eXSVyhox3z2X-4csrwWeeDgMjS83i-J2nJwuWpqhg@mail.gmail.com> (raw)
In-Reply-To: <20120626143703.396d6d66.akpm@linux-foundation.org>
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.
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next prev parent reply other threads:[~2012-06-28 6:23 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 [this message]
2012-06-29 3:47 ` Kamezawa Hiroyuki
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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