From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 8 Feb 2005 11:31:32 +0000 From: Ralf Baechle Subject: Re: A scrub daemon (prezeroing) Message-ID: <20050208113131.GA5143@linux-mips.org> References: <1106828124.19262.45.camel@hades.cambridge.redhat.com> <20050127131228.GB31288@lnx-holt.americas.sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050127131228.GB31288@lnx-holt.americas.sgi.com> Sender: owner-linux-mm@kvack.org Return-Path: To: Robin Holt Cc: David Woodhouse , Christoph Lameter , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Thu, Jan 27, 2005 at 07:12:29AM -0600, Robin Holt wrote: > > Some architectures tend to have spare DMA engines lying around. There's > > no need to use the CPU for zeroing pages. How feasible would it be for > > scrubd to use these? > > An earlier proposal that Christoph pushed would have used the BTE on > sn2 for this. Are you thinking of using the BTE on sn0/sn1 mips? On BCM1250 SOCs we've gone a step beyond that and use the Data Mover to clear_page(), see arch/mips/mm/pg-sb1.c. It's roughly comparable to the SN0 BTE. Broadcom has meassured a quite large performance win for such a small code change. Ralf -- 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: aart@kvack.org