From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f171.google.com (mail-ig0-f171.google.com [209.85.213.171]) by kanga.kvack.org (Postfix) with ESMTP id 5CB2382F64 for ; Tue, 3 Nov 2015 10:40:07 -0500 (EST) Received: by igbdj2 with SMTP id dj2so14835762igb.1 for ; Tue, 03 Nov 2015 07:40:07 -0800 (PST) Received: from mail-pa0-x232.google.com (mail-pa0-x232.google.com. [2607:f8b0:400e:c03::232]) by mx.google.com with ESMTPS id e19si21132328ioi.48.2015.11.03.07.40.06 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 03 Nov 2015 07:40:06 -0800 (PST) Received: by padhx2 with SMTP id hx2so13745920pad.1 for ; Tue, 03 Nov 2015 07:40:06 -0800 (PST) Date: Tue, 3 Nov 2015 07:39:53 -0800 (PST) From: Hugh Dickins Subject: Re: [PATCH] osd fs: __r4w_get_page rely on PageUptodate for uptodate In-Reply-To: <56387D3C.5020003@plexistor.com> Message-ID: References: <5635E2B4.5070308@electrozaur.com> <5637437C.4070306@electrozaur.com> <56387D3C.5020003@plexistor.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Boaz Harrosh Cc: Hugh Dickins , Andrew Morton , Trond Myklebust , Christoph Lameter , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-mm@kvack.org, osd-dev@open-osd.org On Tue, 3 Nov 2015, Boaz Harrosh wrote: > On 11/03/2015 04:49 AM, Hugh Dickins wrote: > > On Mon, 2 Nov 2015, Boaz Harrosh wrote: > >> > >> Do you think the code is actually wrong as is? > > > > Not that I know of: just a little too complicated and confusing. > > > > But becomes slightly wrong if my simplification to page migration > > goes through, since that introduces an instant when PageDirty is set > > before the new page contains the correct data and is marked Uptodate. > > Hence my patch. > > > >> > >> BTW: Very similar code is in fs/nfs/objlayout/objio_osd.c::__r4w_get_page > > > > Indeed, the patch makes the same adjustment to that code too. > > > > OK thanks. Let me setup and test your patch. On top of 4.3 is good? > I'll send you a tested-by once I'm done. Great, thanks Boaz, that will help a lot. On top of 4.3 very good. (Of course, that will not test the rare page migration race I shall introduce later; but it will test that you're doing the right thing with this change at your end, when you will be safe against the race.) Hugh -- 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