From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750785AbVKDSI1 (ORCPT ); Fri, 4 Nov 2005 13:08:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750789AbVKDSI0 (ORCPT ); Fri, 4 Nov 2005 13:08:26 -0500 Received: from fmr21.intel.com ([143.183.121.13]:34459 "EHLO scsfmr001.sc.intel.com") by vger.kernel.org with ESMTP id S1750785AbVKDSI0 (ORCPT ); Fri, 4 Nov 2005 13:08:26 -0500 Subject: Re: [PATCH]: Clean up of __alloc_pages From: Rohit Seth To: Nick Piggin Cc: akpm@osdl.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org In-Reply-To: <4366C188.5090607@yahoo.com.au> References: <20051028183326.A28611@unix-os.sc.intel.com> <4362DF80.3060802@yahoo.com.au> <1130792107.4853.24.camel@akash.sc.intel.com> <4366C188.5090607@yahoo.com.au> Content-Type: text/plain Organization: Intel Date: Fri, 04 Nov 2005 10:15:08 -0800 Message-Id: <1131128108.27563.11.camel@akash.sc.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.2.2 (2.2.2-5) Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 04 Nov 2005 18:08:11.0473 (UTC) FILETIME=[B7B3E410:01C5E16A] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2005-11-01 at 12:14 +1100, Nick Piggin wrote: > 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. > Nick, sorry for not responding earlier. I agree that it is slight change in behavior from original. I doubt though it will impact any one in any negative way (may be for some higher order allocations if at all). On a little positive side, less frequent calls to kswapd for some cases and clear up the code a little bit. But I really don't want to get stuck here. The pcp traversal and flushing is where I want to go next. Thanks, -rohit