From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from westrelay02.boulder.ibm.com (westrelay02.boulder.ibm.com [9.17.195.11]) by e33.co.us.ibm.com (8.12.11/8.12.11) with ESMTP id jB1IK24D029545 for ; Thu, 1 Dec 2005 13:20:02 -0500 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by westrelay02.boulder.ibm.com (8.12.10/NCO/VERS6.8) with ESMTP id jB1IJSSI096852 for ; Thu, 1 Dec 2005 11:19:28 -0700 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.12.11/8.13.3) with ESMTP id jB1IK1Ag006970 for ; Thu, 1 Dec 2005 11:20:02 -0700 Subject: Re: Better pagecache statistics ? From: Badari Pulavarty In-Reply-To: <20051201175711.GA17169@dmt.cnet> References: <1133377029.27824.90.camel@localhost.localdomain> <20051201152029.GA14499@dmt.cnet> <1133452790.27824.117.camel@localhost.localdomain> <1133453411.2853.67.camel@laptopd505.fenrus.org> <20051201170850.GA16235@dmt.cnet> <1133457315.21429.29.camel@localhost.localdomain> <1133457700.2853.78.camel@laptopd505.fenrus.org> <20051201175711.GA17169@dmt.cnet> Content-Type: text/plain Date: Thu, 01 Dec 2005 10:20:12 -0800 Message-Id: <1133461212.21429.49.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Marcelo Tosatti Cc: Arjan van de Ven , linux-mm , lkml List-ID: On Thu, 2005-12-01 at 15:57 -0200, Marcelo Tosatti wrote: > On Thu, Dec 01, 2005 at 06:21:39PM +0100, Arjan van de Ven wrote: > > On Thu, 2005-12-01 at 09:15 -0800, Badari Pulavarty wrote: > > > > Most of the issues you mention are null if you move the stats > > > > maintenance burden to userspace. > > > > > > > > The performance impact is also minimized since the hooks > > > > (read: overhead) can be loaded on-demand as needed. > > > > > > > > > > The overhead is - going through each mapping/inode in the system > > > and dumping out "nrpages" - to get per-file statistics. This is > > > going to be expensive, need locking and there is no single list > > > we can traverse to get it. I am not sure how to do this. > > Can't you add hooks to add_to_page_cache/remove_from_page_cache > to record pagecache activity ? In theory, yes. We already maintain info in "mapping->nrpages". Trick would be to collect all of them, send them to user space. Thanks, Badari -- 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