Date: Sun, 03 Jul 2005 20:43:01 -0400 From: Stephan Uphoff <ups@tree.com> To: Scott Long <scottl@samsco.org> Cc: freebsd-fs@freebsd.org Subject: Re: [saturnero@freesbie.org: Weird behaviour of mount_unionfs with executables] Message-ID: <1120437780.77984.38252.camel@palm> In-Reply-To: <42C88121.8010602@samsco.org> References: <20050703181616.GC89744@cvs.freesbie.org> <42C83643.4010506@samsco.org> <20050703201621.GD89744@cvs.freesbie.org> <1120425831.77984.37993.camel@palm> <42C87CAE.7080802@samsco.org> <1120436351.77984.38195.camel@palm> <42C88121.8010602@samsco.org>
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On Sun, 2005-07-03 at 20:21, Scott Long wrote: > Stephan Uphoff wrote: > > On Sun, 2005-07-03 at 20:02, Scott Long wrote: > > > >>Stephan Uphoff wrote: > >> > >>>I suspect the changes in revision 1.272 of kern_exec.c trigger the > >>>copy operation. > >>> > >>>Looks like you need a noatime option for union_fs. > >>> > >>>Stephan > >> > >>Does this mean that every vnode that gets executed gets dirtied and all > >>its pages resynced to the backing store, or just the inode block? > > > > > > The kernel calls VOP_SETATTR to set the access time of the file. > > union_fs detects that it does not have an upper layer copy of the file > > to modify the attributes on and decides to copy it. > > The vm layer does not (directly) come into play on this. > > > > Stephan > > > > Ok, so this is just a limitation of unionfs, not the vnode pager. You > had me scared that we'd be doing a whole lot of needless disk i/o. YES - and it looks like just specifying noatime for the union mount should fix the copy problem for FreeSBIE. Stephan
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