From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e5.ny.us.ibm.com (8.13.8/8.13.8) with ESMTP id l7O4ldAW016015 for ; Fri, 24 Aug 2007 00:47:39 -0400 Received: from d01av01.pok.ibm.com (d01av01.pok.ibm.com [9.56.224.215]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v8.5) with ESMTP id l7O4ld7w527574 for ; Fri, 24 Aug 2007 00:47:39 -0400 Received: from d01av01.pok.ibm.com (loopback [127.0.0.1]) by d01av01.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l7O4lcDM016103 for ; Fri, 24 Aug 2007 00:47:38 -0400 Subject: Re: Drop caches - is this safe behavior? From: Dave Kleikamp In-Reply-To: <46CE3617.6000708@redhat.com> References: <46CE3617.6000708@redhat.com> Content-Type: text/plain Date: Thu, 23 Aug 2007 23:47:37 -0500 Message-Id: <1187930857.6406.12.camel@norville.austin.ibm.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Chris Snook Cc: mike , linux-mm@kvack.org List-ID: On Thu, 2007-08-23 at 21:36 -0400, Chris Snook wrote: > If you think the system is doing the wrong thing (and it doesn't sound > like it is) you should be tweaking the vm.swappiness sysctl. The > default is 60, but lower values will make it behave more like you think > it should be behaving, though you'll still probably see a tiny bit of > swap usage. Of course, if your webservers are primarily serving up > static content, you'll want a higher value, since swapping anonymous > memory will leave more free for the pagecache you're primarily working with. swappiness deals with page cache, whereas writing "2" to drop_caches cleans out the inode and dentry caches. Mike may be better off writing a high number (say 10000) to /proc/sys/vm/vfs_cache_pressure. This would cause inode and dentry cache to be reclaimed sooner than other memory. -- David Kleikamp IBM Linux Technology Center -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org