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From: Hugh Dickins <hughd@google.com>
To: Boaz Harrosh <boaz@plexistor.com>
Cc: Hugh Dickins <hughd@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Trond Myklebust <trond.myklebust@primarydata.com>,
	Christoph Lameter <cl@linux.com>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-nfs@vger.kernel.org, linux-mm@kvack.org,
	osd-dev@open-osd.org
Subject: Re: [PATCH] osd fs: __r4w_get_page rely on PageUptodate for uptodate
Date: Tue, 3 Nov 2015 07:39:53 -0800 (PST)	[thread overview]
Message-ID: <alpine.LSU.2.11.1511030734300.1856@eggly.anvils> (raw)
In-Reply-To: <56387D3C.5020003@plexistor.com>

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

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      reply	other threads:[~2015-11-03 15:40 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-29 18:43 Hugh Dickins
2015-11-01 10:00 ` Boaz Harrosh
2015-11-01 23:39   ` Hugh Dickins
2015-11-02 11:05     ` Boaz Harrosh
2015-11-03  2:49       ` Hugh Dickins
2015-11-03  9:24         ` Boaz Harrosh
2015-11-03 15:39           ` Hugh Dickins [this message]

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