From: Glauber Costa <glommer@parallels.com>
To: bill4carson <bill4carson@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: Why memory.usage_in_bytes is always increasing after every mmap/dirty/unmap sequence
Date: Tue, 27 Mar 2012 10:26:28 +0200 [thread overview]
Message-ID: <4F7179B4.7080405@parallels.com> (raw)
In-Reply-To: <4F6C3B7F.1070705@gmail.com>
On 03/23/2012 09:59 AM, bill4carson wrote:
>>
> Yes, I tried to mmap/dirty/unmap in 32 times, when the usage_in_bytes
> reached 128k, it rolls back to 4k again. So it doesn't hurt any more.
>
> I haven't found the code regarding to this behavior.
That's actually quite annoying, IMHO.
I personally think that everytime one tries to read from usage, we
should flush the caches and show the correct figures, or at least as
correct as we can.
That's specially bad because under load, this is wrong by O(#cpus)...
For just reading the file, this might be okay because there is an
alternative for it (although not that intuitive), but for the threshold
code, we are probably hitting them a lot more than we should in big
machines.
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prev parent reply other threads:[~2012-03-27 8:26 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-23 8:04 bill4carson
2012-03-23 8:19 ` KAMEZAWA Hiroyuki
2012-03-23 8:43 ` bill4carson
2012-03-23 8:59 ` bill4carson
2012-03-23 9:04 ` KAMEZAWA Hiroyuki
2012-03-23 9:15 ` bill4carson
2012-03-23 9:57 ` KAMEZAWA Hiroyuki
2012-03-27 8:26 ` Glauber Costa [this message]
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