From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <447BD63D.2080900@yahoo.com.au> Date: Tue, 30 May 2006 15:21:01 +1000 From: Nick Piggin MIME-Version: 1.0 Subject: Re: [rfc][patch] remove racy sync_page? References: <447AC011.8050708@yahoo.com.au> <20060529121556.349863b8.akpm@osdl.org> <447B8CE6.5000208@yahoo.com.au> <20060529183201.0e8173bc.akpm@osdl.org> <447BB3FD.1070707@yahoo.com.au> <447BD31E.7000503@yahoo.com.au> In-Reply-To: <447BD31E.7000503@yahoo.com.au> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Linus Torvalds Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, mason@suse.com, andrea@suse.de, hugh@veritas.com, axboe@suse.de List-ID: Nick Piggin wrote: > Linus Torvalds wrote: > >> >> Why do you think the IO layer should get larger requests? > > > For workloads where plugging helps (ie. lots of smaller, contiguous > requests going into the IO layer), should be pretty good these days > due to multiple readahead and writeback. Let me try again. For workloads where plugging helps (ie. lots of smaller, contiguous requests going into the IO layer), the request pattern should be pretty good without plugging these days, due to multiple page readahead and writeback. > >> >> I really don't understand why people dislike plugging. It's obviously >> superior to non-plugged variants, exactly because it starts the IO >> only when _needed_, Taken to its logical conclusion, you are saying readahead / dirty page writeout throttling is obviously inferior, aren't you? Non-rhetorically: Obviously there can be regressions in plugging, because you are holding the disk idle when you know there is work to be done. -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com -- 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