From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: akpm@linux-foundation.org
Cc: bp@alien8.de, dave@linux.vnet.ibm.com, mhocko@suse.cz,
linux-mm@kvack.org, kamezawa.hiroyu@jp.fujitsu.com,
kosaki.motohiro@jp.fujitsu.com, linux-kernel@vger.kernel.org,
rjw@sisk.pl
Subject: Re: [PATCH] add some drop_caches documentation and info messsge
Date: Wed, 24 Oct 2012 18:35:43 -0400 [thread overview]
Message-ID: <50886D3F.9050403@jp.fujitsu.com> (raw)
In-Reply-To: <20121024141303.0797d6a1.akpm@linux-foundation.org>
>> I have drop_caches in my suspend-to-disk script so that the hibernation
>> image is kept at minimum and suspend times are as small as possible.
>
> hm, that sounds smart.
>
>> Would that be a valid use-case?
>
> I'd say so, unless we change the kernel to do that internally. We do
> have the hibernation-specific shrink_all_memory() in the vmscan code.
> We didn't see fit to document _why_ that exists, but IIRC it's there to
> create enough free memory for hibernation to be able to successfully
> complete, but no more.
shrink_all_memory() drop minimum memory to be needed from hibernation.
that's trade off matter.
- drop all page cache
pros.
speed up hibernation time
cons.
after go back from hibernation, system works very slow a while until
system will get enough file cache.
- drop minimum page cache
pros.
system works quickly when go back from hibernation.
cons.
relative large hibernation time
So, I'm not fun change hibernation default. hmmm... Does adding tracepint instead of printk
makes sense?
next prev parent reply other threads:[~2012-10-24 22:35 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-12 12:57 [PATCH] add some drop_caches documentation and info messsge Michal Hocko
2012-10-12 18:54 ` KOSAKI Motohiro
2012-10-15 9:04 ` Kamezawa Hiroyuki
2012-10-15 14:05 ` Dave Hansen
2012-10-23 23:45 ` Andrew Morton
2012-10-24 6:29 ` Michal Hocko
2012-10-24 19:54 ` Andrew Morton
2012-10-24 20:28 ` Dave Hansen
2012-10-24 20:48 ` Andrew Morton
2012-10-24 21:06 ` Borislav Petkov
2012-10-24 21:13 ` Andrew Morton
2012-10-24 22:04 ` Rafael J. Wysocki
2012-10-25 1:17 ` Andrew Morton
2012-10-25 20:16 ` Rafael J. Wysocki
2012-10-29 8:59 ` Jiri Kosina
2012-10-29 9:58 ` Borislav Petkov
2012-10-29 10:01 ` Jiri Kosina
2012-10-29 10:11 ` Borislav Petkov
2012-10-31 17:31 ` Pavel Machek
2012-10-31 17:46 ` Borislav Petkov
2012-10-24 22:35 ` KOSAKI Motohiro [this message]
2012-10-25 14:21 ` Michal Hocko
2012-10-24 21:18 ` Dave Hansen
2012-10-24 22:48 ` Borislav Petkov
2012-10-24 22:57 ` Dave Hansen
2012-10-25 0:56 ` KOSAKI Motohiro
2012-10-25 9:24 ` Borislav Petkov
2012-10-25 11:57 ` Dave Hansen
2012-10-25 14:24 ` Borislav Petkov
2012-10-25 14:25 ` Michal Hocko
2012-10-26 7:45 ` Mika Boström
2012-11-01 20:26 ` Pavel Machek
2012-10-25 14:09 ` Michal Hocko
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