From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id AC90C6B007E for ; Fri, 24 Jul 2009 08:05:34 -0400 (EDT) Date: Fri, 24 Jul 2009 08:05:19 -0400 From: Chris Mason Subject: Re: [PATCH] bump up nr_to_write in xfs_vm_writepage Message-ID: <20090724120519.GB16192@think> References: <20090709110342.2386.A69D9226@jp.fujitsu.com> <20090709130134.GH18008@think> <20090710153349.17EC.A69D9226@jp.fujitsu.com> <7149D747-2769-4559-BAF6-AAD2B6C6C941@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7149D747-2769-4559-BAF6-AAD2B6C6C941@sgi.com> Sender: owner-linux-mm@kvack.org To: Felix Blyakher Cc: KOSAKI Motohiro , Eric Sandeen , xfs mailing list , Christoph Hellwig , linux-mm@kvack.org, Olaf Weber List-ID: On Fri, Jul 24, 2009 at 12:20:32AM -0500, Felix Blyakher wrote: > > On Jul 10, 2009, at 2:12 AM, KOSAKI Motohiro wrote: >> 3. Current wbc->nr_to_write value is not proper? >> >> Current writeback_set_ratelimit() doesn't permit that ratelimit_pages >> exceed >> 4M byte. but it is too low restriction for nowadays. >> (that's my understand. right?) >> >> ======================================================= >> void writeback_set_ratelimit(void) >> { >> ratelimit_pages = vm_total_pages / (num_online_cpus() * 32); >> if (ratelimit_pages < 16) >> ratelimit_pages = 16; >> if (ratelimit_pages * PAGE_CACHE_SIZE > 4096 * 1024) >> ratelimit_pages = (4096 * 1024) / PAGE_CACHE_SIZE; >> } >> ======================================================= >> >> Yes, 4M bytes are pretty magical constant. We have three choice >> A. Remove magical 4M constant simple (a bit danger) > > That's will be outside the xfs, and seems like there is no much interest > from mm people. > >> B. Decide high border from IO capability It is worth pointing out that Jens Axboe is planning on more feedback controlled knobs as part of pdflush rework. -chris -- 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