From: Hugh Dickins <hughd@google.com>
To: Chintan Pandya <cpandya@codeaurora.org>
Cc: Hugh Dickins <hughd@google.com>,
Peter Zijlstra <peterz@infradead.org>,
akpm@linux-foundation.org, linux-mm@kvack.org,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
John Stultz <john.stultz@linaro.org>,
Ingo Molnar <mingo@redhat.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Paul McKenney <paulmck@linux.vnet.ibm.com>
Subject: Re: [PATCH v4 2/2] ksm: provide support to use deferrable timers for scanner thread
Date: Thu, 11 Sep 2014 06:25:09 -0700 (PDT) [thread overview]
Message-ID: <alpine.LSU.2.11.1409110609320.2465@eggly.anvils> (raw)
In-Reply-To: <541156C9.1080203@codeaurora.org>
On Thu, 11 Sep 2014, Chintan Pandya wrote:
> I don't mean to divert the thread too much. But just one suggestion offered
> by Harshad.
>
> Why can't we stop invoking more of a KSM scanner thread when we are
> saturating from savings ? But again, to check whether savings are saturated
> or not, we may still want to rely upon timers and we have to wake the CPUs up
> from IDLE state.
I agree that it should make sense for KSM to slow down when it sees it's
making no progress (though that would depart from the pages_to_scan and
sleep_millisecs prescription - perhaps could be tied to sleep_millisecs 0).
But not stop. That's the problem we're mainly concerned with here:
to save power we need it to stop, but then how to wake up, without
putting nasty hooks in hot paths for a minority interest?
I don't see an answer to that above.
Hugh
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prev parent reply other threads:[~2014-09-11 13:26 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-20 12:10 [PATCH v4 1/2] timer: provide an api for deferrable timeout Chintan Pandya
2014-08-20 12:10 ` [PATCH v4 2/2] ksm: provide support to use deferrable timers for scanner thread Chintan Pandya
2014-08-28 6:02 ` Hugh Dickins
2014-09-03 9:58 ` Peter Zijlstra
2014-09-03 10:32 ` Thomas Gleixner
2014-09-08 8:25 ` Hugh Dickins
2014-09-08 9:39 ` Peter Zijlstra
2014-09-09 14:52 ` Chintan Pandya
2014-09-09 20:37 ` Hugh Dickins
2014-09-09 20:14 ` Hugh Dickins
2014-09-10 8:10 ` Peter Zijlstra
2014-09-11 12:27 ` Hugh Dickins
2014-09-10 8:27 ` Peter Zijlstra
2014-09-11 12:59 ` Hugh Dickins
2014-09-11 8:01 ` Chintan Pandya
2014-09-11 13:25 ` Hugh Dickins [this message]
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