Date: Mon, 16 Jun 2008 01:12:16 +0400 (MSD) From: Dmitry Morozovsky <marck@rinet.ru> To: Kostik Belousov <kostikbel@gmail.com> Cc: delphij@freebsd.org, current@freebsd.org Subject: Re: tmpfs panic Message-ID: <20080616001441.J32445@woozle.rinet.ru> In-Reply-To: <20080615182012.GH94309@deviant.kiev.zoral.com.ua> References: <20080615130037.J43777@woozle.rinet.ru> <20080615101918.GA94309@deviant.kiev.zoral.com.ua> <20080615161718.R43777@woozle.rinet.ru> <20080615122331.GE94309@deviant.kiev.zoral.com.ua> <20080615163209.Y43777@woozle.rinet.ru> <20080615211951.W75021@woozle.rinet.ru> <20080615182012.GH94309@deviant.kiev.zoral.com.ua>
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On Sun, 15 Jun 2008, Kostik Belousov wrote: KB> > Also, I can observe tmpfs is doing non-optimal; I did not found KB> > straight ways to set block/frag size; I suppose for most tmpfs usage KB> > they should be decreases to the lowest values, such as 4k/512 -- what KB> > do you think? KB> Block and fragment size concepts are not applicable to the tmpfs; KB> basically, this is the point for having such fs in the system. Each file KB> on the tmpfs is presented as the swap-backed vm object. KB> KB> Besides the set of the (mostly) known problems with correctness and KB> stability, current implementation has quite unefficient implementation KB> of the mmap and buffer cache interaction. The vm object (and pages) used KB> for the vm operations are copied from the backing vm object instead of KB> being reused. This means that we get essentially twice as much memory KB> used, and copying. This, actually, was simple observations: svn base tree over ZFS comsumes a bit less than 2G, and after rsync -aH to tmpfs, repoted by du, it seems to eat approx 4G (with comparable inode cound as reported by find) Sincerely, D.Marck [DM5020, MCK-RIPE, DM3-RIPN] [ FreeBSD committer: marck@FreeBSD.org ] ------------------------------------------------------------------------ *** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck@rinet.ru *** ------------------------------------------------------------------------
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