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From: Christoph Hellwig <hch@infradead.org>
To: Jeff Moyer <jmoyer@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Matthew Wilcox <matthew.r.wilcox@intel.com>,
	linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
	willy@linux.intel.com
Subject: Re: [PATCH] Sync only the requested range in msync
Date: Thu, 15 May 2014 04:24:33 -0700	[thread overview]
Message-ID: <20140515112433.GA21206@infradead.org> (raw)
In-Reply-To: <x49y4y54xgq.fsf@segfault.boston.devel.redhat.com>

On Tue, May 13, 2014 at 09:31:01AM -0400, Jeff Moyer wrote:
> FWIW, I think we should apply the patch.  Anyone using the API properly
> will not get the desired result, and it could have a negative impact on
> performance.  The man page is very explicit on what you should expect,
> here.  Anyone relying on undocumented behavior gets to keep both pieces
> when it breaks.  That said, I do understand your viewpoint, Andrew,
> especially since it's so hard to get people to sync their data at all,
> much less correctly.

Agreed, we never made filesystems write out all data in the file system
in fsync either just because ext3 behaved that way.

And unlike that case I can't even see a good way to get msync wrong -
you call it on the mapped region, so expecting it to write out data
that isn't mapped at all seems rather odd.

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  reply	other threads:[~2014-05-15 11:24 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-27 23:02 [PATCH] Sync only the requested range in msync Matthew Wilcox
2014-04-23 14:11 ` Christoph Hellwig
2014-05-12 23:39   ` Andrew Morton
2014-05-13 13:31     ` Jeff Moyer
2014-05-15 11:24       ` Christoph Hellwig [this message]
2014-05-15 12:50       ` Chris Mason
2014-05-20 22:58       ` Andrew Morton

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