From: Minchan Kim <minchan.kim@gmail.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Shaohua Li <shaohua.li@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm <linux-mm@kvack.org>, Andi Kleen <andi@firstfloor.org>,
Rik van Riel <riel@redhat.com>, mel <mel@csn.ul.ie>,
Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH 2/2 v4]mm: batch activate_page() to reduce lock contention
Date: Tue, 15 Mar 2011 11:43:37 +0900 [thread overview]
Message-ID: <AANLkTi=1hd71TS1x48PeDyFCSJGK8_1H-oPkA64HEH2S@mail.gmail.com> (raw)
In-Reply-To: <20110315111641.3520.A69D9226@jp.fujitsu.com>
On Tue, Mar 15, 2011 at 11:32 AM, KOSAKI Motohiro
<kosaki.motohiro@jp.fujitsu.com> wrote:
>> >> Why do we need CONFIG_SMP in only activate_page_pvecs?
>> >> The per-cpu of activate_page_pvecs consumes lots of memory in UP?
>> >> I don't think so. But if it consumes lots of memory, it's a problem
>> >> of per-cpu.
>> > No, not too much memory.
>> >
>> >> I can't understand why we should hanlde activate_page_pvecs specially.
>> >> Please, enlighten me.
>> > Not it's special. akpm asked me to do it this time. Reducing little
>> > memory is still worthy anyway, so that's it. We can do it for other
>> > pvecs too, in separate patch.
>>
>> Understandable but I don't like code separation by CONFIG_SMP for just
>> little bit enhance of memory usage. In future, whenever we use percpu,
>> do we have to implement each functions for both SMP and non-SMP?
>> Is it desirable?
>> Andrew, Is it really valuable?
>>
>> If everybody agree, I don't oppose such way.
>> But now I vote code cleanness than reduce memory footprint.
>
> FWIW, The ifdef was added for embedded concern. and I believe you are
> familiar with modern embedded trend than me. then, I have no objection
> to remove it if you don't need it.
I am keen in binary size but at least in this case, the benefit isn't
big, I think.
I hope we would care of code cleanness and latency of irq than memory
footprint in this time.
>
> Thanks.
>
>
>
--
Kind regards,
Minchan Kim
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prev parent reply other threads:[~2011-03-15 2:43 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-10 5:30 Shaohua Li
2011-03-14 14:45 ` Minchan Kim
2011-03-15 1:53 ` Shaohua Li
2011-03-15 2:12 ` Minchan Kim
2011-03-15 2:28 ` Andrew Morton
2011-03-15 2:40 ` Minchan Kim
2011-03-15 2:44 ` Andrew Morton
2011-03-15 2:59 ` Minchan Kim
2011-03-15 2:32 ` KOSAKI Motohiro
2011-03-15 2:43 ` Minchan Kim [this message]
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