Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755196AbZDDWOf (ORCPT ); Sat, 4 Apr 2009 18:14:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752719AbZDDWOY (ORCPT ); Sat, 4 Apr 2009 18:14:24 -0400 Received: from mx2.redhat.com ([66.187.237.31]:55887 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752234AbZDDWOX (ORCPT ); Sat, 4 Apr 2009 18:14:23 -0400 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <200904050122.42081.nickpiggin@yahoo.com.au> References: <200904050122.42081.nickpiggin@yahoo.com.au> <20090403155436.28714.23368.stgit@warthog.procyon.org.uk> <20090403155624.28714.87176.stgit@warthog.procyon.org.uk> <200904041709.31651.nickpiggin@yahoo.com.au> To: Nick Piggin Cc: dhowells@redhat.com, Andrew Morton , linux-kernel@vger.kernel.org, nfsv4@linux-nfs.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 21/41] CacheFiles: Permit the page lock state to be monitored [ver #48] Date: Sat, 04 Apr 2009 23:13:33 +0100 Message-ID: <951.1238883213@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1331 Lines: 31 Nick Piggin wrote: > On Saturday 04 April 2009 17:09:31 Nick Piggin wrote: > > On Saturday 04 April 2009 02:56:24 David Howells wrote: > > > Add a function to install a monitor on the page lock waitqueue for a > > > particular page, thus allowing the page being unlocked to be detected. > > > > > > This is used by CacheFiles to detect read completion on a page in the > > > backing filesystem so that it can then copy the data to the waiting > > > netfs page. > > > > This is the only thing I'm still worried about in core code. The extra > > page flag (which is probably unusable for any other fs, due to its > > semantics) is an issue, but Andrew seemed like he was willing to spend > > *2* page flags on this, so I'm sure he's happy with 1. > > Well that is to say it is not a such a bad concept to have... What is not such a bad concept to have? Having an extra page flag? > actually we already have exactly this concept which is what should be used. > Ie. the filesystem's io completion handler. Which filesystem's I/O completion handler? David -- 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/