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From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	lnxninja@linux.vnet.ibm.com, ebiederm@xmission.com,
	kosaki.motohiro@jp.fujitsu.com
Subject: Re: [RFCv2][PATCH] add some drop_caches documentation and info messsge
Date: Tue, 21 Sep 2010 10:00:11 +0900	[thread overview]
Message-ID: <20100921100011.86f270de.kamezawa.hiroyu@jp.fujitsu.com> (raw)
In-Reply-To: <20100916165047.DAD42998@kernel.beaverton.ibm.com>

On Thu, 16 Sep 2010 09:50:47 -0700
Dave Hansen <dave@linux.vnet.ibm.com> wrote:

> 
> This version tones down the BUG_ON().  I also noticed that the
> documentation fails to mention that more than just the inode
> and dentry slabs are shrunk.
> 
> --
> 
> There is plenty of anecdotal evidence and a load of blog posts
> suggesting that using "drop_caches" periodically keeps your system
> running in "tip top shape".  Perhaps adding some kernel
> documentation will increase the amount of accurate data on its use.
> 
> If we are not shrinking caches effectively, then we have real bugs.
> Using drop_caches will simply mask the bugs and make them harder
> to find, but certainly does not fix them, nor is it an appropriate
> "workaround" to limit the size of the caches.
> 
> It's a great debugging tool, and is really handy for doing things
> like repeatable benchmark runs.  So, add a bit more documentation
> about it, and add a little KERN_NOTICE.  It should help developers
> who are chasing down reclaim-related bugs.
> 
> Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>

Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

thanks.

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      parent reply	other threads:[~2010-09-21  1:05 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-16 16:50 Dave Hansen
2010-09-17  0:26 ` KOSAKI Motohiro
2010-09-17 15:54   ` Dave Hansen
2010-09-21  0:57     ` KOSAKI Motohiro
2010-09-21  1:00 ` KAMEZAWA Hiroyuki [this message]

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