Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964983AbVKOSJB (ORCPT ); Tue, 15 Nov 2005 13:09:01 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964986AbVKOSJB (ORCPT ); Tue, 15 Nov 2005 13:09:01 -0500 Received: from ccerelbas02.cce.hp.com ([161.114.21.105]:43205 "EHLO ccerelbas02.cce.hp.com") by vger.kernel.org with ESMTP id S964983AbVKOSJB (ORCPT ); Tue, 15 Nov 2005 13:09:01 -0500 Subject: Re: [PATCH 1/5] Swap Migration V5: LRU operations From: Lee Schermerhorn Reply-To: lee.schermerhorn@hp.com To: Christoph Lameter Cc: Andrew Morton , torvalds@osdl.org, marcelo.tosatti@cyclades.com, kravetz@us.ibm.com, raybry@mpdtxmail.amd.com, linux-kernel@vger.kernel.org, magnus.damm@gmail.com, pj@sgi.com, haveblue@us.ibm.com, kamezawa.hiroyu@jp.fujitsu.com In-Reply-To: References: <20051101031239.12488.76816.sendpatchset@schroedinger.engr.sgi.com> <20051101031244.12488.38211.sendpatchset@schroedinger.engr.sgi.com> <20051114214415.1e107c7b.akpm@osdl.org> Content-Type: text/plain Organization: LOSL, Nashua Date: Tue, 15 Nov 2005 13:08:35 -0500 Message-Id: <1132078115.5230.2.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.0.4 (2.0.4-7) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1480 Lines: 40 On Tue, 2005-11-15 at 08:38 -0800, Christoph Lameter wrote: > On Mon, 14 Nov 2005, Andrew Morton wrote: > > > > +int isolate_lru_page(struct page *page) > > > +{ > > > + int rc = 0; > > > + struct zone *zone = page_zone(page); > > > + > > > +redo: > > > + spin_lock_irq(&zone->lru_lock); > > > + rc = __isolate_lru_page(zone, page); > > > + spin_unlock_irq(&zone->lru_lock); > > > + if (rc == 0) { > > > + /* > > > + * Maybe this page is still waiting for a cpu to drain it > > > + * from one of the lru lists? > > > + */ > > > + smp_call_function(&lru_add_drain_per_cpu, NULL, 0 , 1); > > > > lru_add_drain() ends up doing spin_unlock_irq(), so we'll enable interrupts > > within the smp_call_function() handler. Is that legal on all > > architectures? > > isolate_lru_pages() is only called within a process context in the swap > migration patches. The hotplug folks may have to address this if they want > to isolate pages from interrupts etc. > I believe Andrew is refering to the calls from the interprocessor interrupt handlers triggered by the smp_call_function(). Looks like ia64 runs IPI handlers with interrupts enabled [SA_INTERRUPT], so should be OK there, but maybe not for all archs? Lee - 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/