From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4366C188.5090607@yahoo.com.au> Date: Tue, 01 Nov 2005 12:14:48 +1100 From: Nick Piggin MIME-Version: 1.0 Subject: Re: [PATCH]: Clean up of __alloc_pages References: <20051028183326.A28611@unix-os.sc.intel.com> <4362DF80.3060802@yahoo.com.au> <1130792107.4853.24.camel@akash.sc.intel.com> In-Reply-To: <1130792107.4853.24.camel@akash.sc.intel.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Rohit Seth Cc: akpm@osdl.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: Rohit Seth wrote: > On Sat, 2005-10-29 at 12:33 +1000, Nick Piggin wrote: >>If you don't do this, then a GFP_HIGH allocator can allocate right >>down to its limit before it kicks kswapd, then it either will fail or >>will have to do direct reclaim. >> > > > You are right if there are only GFP_HIGH requests coming in then the > allocation will go down to (min - min/2) before kicking in kswapd. > Though if the requester is not ready to wait, there is another good shot > at allocation succeed before we get into direct reclaim (and this is > happening based on can_try_harder flag). > Still, it is a change in behaviour that I would rather not introduce with a cleanup patch (and is something we don't want to introduce anyway). So if you could fix that up it would be good. >>How about moving the zone_statistics up into the 'if (page)' >>test of get_page_from_freelist? This way we don't have to >>evaluate page_zone(). >> > > > Let us keep this as is for now. Will revisit once after the > pcp_prefer_allocation patches get in place. > Well page_zone is yet another cacheline that doesn't need to be touched, and that is introduced by this patch. But the line is likely to be hot, and get_page_from_freelist does not have the required 'zonelist' which I didn't notice before. So OK, revisit this later. -- 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