Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932707AbWCPUKS (ORCPT ); Thu, 16 Mar 2006 15:10:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932712AbWCPUKR (ORCPT ); Thu, 16 Mar 2006 15:10:17 -0500 Received: from gold.veritas.com ([143.127.12.110]:65201 "EHLO gold.veritas.com") by vger.kernel.org with ESMTP id S932707AbWCPUKQ (ORCPT ); Thu, 16 Mar 2006 15:10:16 -0500 X-IronPort-AV: i="4.02,198,1139212800"; d="scan'208"; a="57290985:sNHT30534816" Date: Thu, 16 Mar 2006 20:10:53 +0000 (GMT) From: Hugh Dickins X-X-Sender: hugh@goblin.wat.veritas.com To: "Bryan O'Sullivan" cc: Andrew Morton , rdreier@cisco.com, torvalds@osdl.org, hch@infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 10 of 20] ipath - support for userspace apps using core driver In-Reply-To: <1142538765.10950.16.camel@serpentine.pathscale.com> Message-ID: References: <71644dd19420ddb07a75.1141922823@localhost.localdomain> <1141948516.10693.55.camel@serpentine.pathscale.com> <1141949262.10693.69.camel@serpentine.pathscale.com> <20060309163740.0b589ea4.akpm@osdl.org> <1142470579.6994.78.camel@localhost.localdomain> <1142475069.6994.114.camel@localhost.localdomain> <1142477579.6994.124.camel@localhost.localdomain> <20060315192813.71a5d31a.akpm@osdl.org> <1142485103.25297.13.camel@camp4.serpentine.com> <20060315213813.747b5967.akpm@osdl.org> <1142523201.25297.56.camel@camp4.serpentine.com> <1142538765.10950.16.camel@serpentine.pathscale.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-OriginalArrivalTime: 16 Mar 2006 20:10:14.0850 (UTC) FILETIME=[A34D8A20:01C64935] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1250 Lines: 27 On Thu, 16 Mar 2006, Bryan O'Sullivan wrote: > > OK. Would it be correct to say that this is what we should do, then? > > * On 2.6.15 and later kernels, use __GFP_COMP at allocation time, > and get_page in ->nopage. This is what we're doing as of this > morning, and it works. > * For backports to 2.6.14 and earlier, avoid __GFP_COMP, mark each > page with SetPageReserved at allocation time, and do nothing > special in ->nopage. Do we need to ClearPageReserved before > freeing? Yes, I believe that's exactly right - so long as you do ClearPageReserved from each of its constituent 0-order-pages before freeing the >0-order page, in the <= 2.6.14 case. You wisely remarked earlier that you'd not yet checked for memory leaks: that is of course the complementary, less obvious, error to the troubles you've been having so far: and I wish you luck when you come to check, hoping that I haven't merely misled you from one side to the other! Hugh - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/