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Date: Wed, 28 Jan 2015 19:46:04 +0200
From: Konstantin Belousov <kostikbel@gmail.com>
To: Don Lewis <truckman@FreeBSD.org>
Subject: Re: svn commit: r277828 - in head/sys: fs/tmpfs vm
Message-ID: <20150128174604.GN42409@kib.kiev.ua>
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On Wed, Jan 28, 2015 at 09:41:06AM -0800, Don Lewis wrote:
> On 28 Jan, Konstantin Belousov wrote:
> > Author: kib
> > Date: Wed Jan 28 10:37:23 2015
> > New Revision: 277828
> > URL: https://svnweb.freebsd.org/changeset/base/277828
> > 
> > Log:
> >   Update mtime for tmpfs files modified through memory mapping.  Similar
> >   to UFS, perform updates during syncer scans, which in particular means
> >   that tmpfs now performs scan on sync.  Also, this means that a mtime
> >   update may be delayed up to 30 seconds after the write.
> 
> Maybe disable the scan if mounted noatime?
It is for mtime, not atime, updates.

In fact, I thought about per-mount option to enable/disable mtime updates,
but then decided that it is too exotic.  I will add if if real performance
complain appear, this also explains relatively long MFC timeout.