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From: Christoph Lameter <cl@linux.com>
To: Michal Hocko <mhocko@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	hannes@cmpxchg.org,
	Linaro Kernel Mailman List <linaro-kernel@lists.linaro.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	vinmenon@codeaurora.org, shashim@codeaurora.org, mgorman@suse.de,
	dave@stgolabs.net, koct9i@gmail.com,
	Linux Memory Management List <linux-mm@kvack.org>,
	Suresh Siddha <suresh.b.siddha@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [RFC] vmstat: Avoid waking up idle-cpu to service shepherd work
Date: Mon, 30 Mar 2015 10:42:55 -0500 (CDT)	[thread overview]
Message-ID: <alpine.DEB.2.11.1503301041400.7251@gentwo.org> (raw)
In-Reply-To: <20150330150818.GE3909@dhcp22.suse.cz>

On Mon, 30 Mar 2015, Michal Hocko wrote:

> Why cannot we do something like refresh_cpu_vm_stats from the IRQ
> context?  Especially the first zone stat part. The per-cpu pagesets is
> more costly and it would need a special treatment, alright. A simple
> way would be to splice the lists from the per-cpu context and then free
> those pages from the kthread context.

That would work.

> I am still wondering why those two things were squashed into a single
> place. Why kswapd is not doing the pcp cleanup?

They were squashed together by me for conveniences sake. They could be
separated. AFAICT the pcp cleanup could be done only on demand and we
already have logic for that when flushihng via IPI.


WARNING: multiple messages have this Message-ID (diff)
From: Christoph Lameter <cl@linux.com>
To: Michal Hocko <mhocko@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	hannes@cmpxchg.org,
	Linaro Kernel Mailman List <linaro-kernel@lists.linaro.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	vinmenon@codeaurora.org, shashim@codeaurora.org, mgorman@suse.de,
	dave@stgolabs.net, koct9i@gmail.com,
	Linux Memory Management List <linux-mm@kvack.org>,
	Suresh Siddha <suresh.b.siddha@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [RFC] vmstat: Avoid waking up idle-cpu to service shepherd work
Date: Mon, 30 Mar 2015 10:42:55 -0500 (CDT)	[thread overview]
Message-ID: <alpine.DEB.2.11.1503301041400.7251@gentwo.org> (raw)
In-Reply-To: <20150330150818.GE3909@dhcp22.suse.cz>

On Mon, 30 Mar 2015, Michal Hocko wrote:

> Why cannot we do something like refresh_cpu_vm_stats from the IRQ
> context?  Especially the first zone stat part. The per-cpu pagesets is
> more costly and it would need a special treatment, alright. A simple
> way would be to splice the lists from the per-cpu context and then free
> those pages from the kthread context.

That would work.

> I am still wondering why those two things were squashed into a single
> place. Why kswapd is not doing the pcp cleanup?

They were squashed together by me for conveniences sake. They could be
separated. AFAICT the pcp cleanup could be done only on demand and we
already have logic for that when flushihng via IPI.

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  parent reply	other threads:[~2015-03-30 15:43 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-26  5:39 [RFC] vmstat: Avoid waking up idle-cpu to service shepherd work Viresh Kumar
2015-03-26  5:39 ` Viresh Kumar
2015-03-26 20:18 ` Andrew Morton
2015-03-26 20:18   ` Andrew Morton
2015-03-27  4:49   ` Viresh Kumar
2015-03-27  4:49     ` Viresh Kumar
2015-03-27  9:16     ` Peter Zijlstra
2015-03-27  9:16       ` Peter Zijlstra
2015-03-27  9:30       ` Peter Zijlstra
2015-03-27  9:30         ` Peter Zijlstra
2015-03-27 11:11         ` Christoph Lameter
2015-03-27 11:11           ` Christoph Lameter
2015-03-27 12:02           ` Peter Zijlstra
2015-03-27 12:02             ` Peter Zijlstra
2015-03-27 19:45             ` Christoph Lameter
2015-03-27 19:45               ` Christoph Lameter
2015-03-28  4:28             ` Viresh Kumar
2015-03-28  4:28               ` Viresh Kumar
2015-03-28 11:41               ` Peter Zijlstra
2015-03-28 11:41                 ` Peter Zijlstra
2015-03-28  4:18         ` Viresh Kumar
2015-03-28  4:18           ` Viresh Kumar
2015-03-28  9:53           ` Peter Zijlstra
2015-03-28  9:53             ` Peter Zijlstra
2015-03-28 11:57             ` viresh kumar
2015-03-28 11:57               ` viresh kumar
2015-03-28 12:04               ` Viresh Kumar
2015-03-28 12:04                 ` Viresh Kumar
2015-03-28 13:44               ` Peter Zijlstra
2015-03-28 13:44                 ` Peter Zijlstra
2015-03-29 10:24                 ` Peter Zijlstra
2015-03-29 10:24                   ` Peter Zijlstra
2015-03-30 12:02                   ` Viresh Kumar
2015-03-30 12:02                     ` Viresh Kumar
2015-03-30 12:47                     ` Peter Zijlstra
2015-03-30 12:47                       ` Peter Zijlstra
2015-03-30 13:14                       ` Viresh Kumar
2015-03-30 13:14                         ` Viresh Kumar
2015-03-30 13:59                         ` Peter Zijlstra
2015-03-30 13:59                           ` Peter Zijlstra
2015-03-30 16:17                           ` Viresh Kumar
2015-03-30 16:17                             ` Viresh Kumar
2015-03-30 16:25                             ` Peter Zijlstra
2015-03-30 16:25                               ` Peter Zijlstra
2015-03-29 12:01                 ` Viresh Kumar
2015-03-29 12:01                   ` Viresh Kumar
2015-03-29 17:24                   ` Peter Zijlstra
2015-03-29 17:24                     ` Peter Zijlstra
2015-03-30 15:08             ` Michal Hocko
2015-03-30 15:08               ` Michal Hocko
2015-03-30 15:14               ` Peter Zijlstra
2015-03-30 15:14                 ` Peter Zijlstra
2015-03-30 15:42               ` Christoph Lameter [this message]
2015-03-30 15:42                 ` Christoph Lameter
2015-03-27 14:19 ` Michal Hocko
2015-03-27 14:19   ` Michal Hocko
2015-03-28  4:34   ` Viresh Kumar
2015-03-28  4:34     ` Viresh Kumar

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