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Message-ID: <20070821074201.GC7258@elf.ucw.cz> Date: Tue, 21 Aug 2007 09:42:01 +0200 From: Pavel Machek <pavel@....cz> To: Peter Zijlstra <peterz@...radead.org> Cc: "Ed L. Cashin" <ecashin@...aid.com>, kernel list <linux-kernel@...r.kernel.org>, ak@...e.de, Netdev list <netdev@...r.kernel.org> Subject: Re: ATA over ethernet swapping Hi! > > But I'm able to compile kernel (-j 10) on 128MB machine, and I tried > > cat /dev/zero | grep foo to exhaust memory... and could not reproduce > > the deadlock. Should I pingflood? Tweak down ammount of atomic memory > > avaialable to make deadlocks easier to reproduce? > > I usually test swap over NFS in the following manner, I setup a regular > inet service on the machine (apache or a bunch of ncat sockets piping to > files or something) and run a heavy workload on the machine (128M): > 2*64M file backed thrashers and 2*64M anonymous thrashers. Then I start > clients for the regular inet service, wait for a bit, and shut down the > NFS server. > > This makes the machine grind to a halt, I then restart the NFS server, > wait for it to reconnect and the client to come alive again. > > Without the last few swap-over-NFS patches this last bit - getting back > out of that situation - never happens. > > The basic idea is to make connectivity to the machine where swap traffic > goes very hard (pull a cable, cleanly shut down the server) and to keep > other network traffic pounding the machine. Hmm, I could not get swap-over-ata-over-ethernet to break. Maybe I should not have local / filesystem, because it allows kernel to get rid of some memory pressure by dropping clean pages? Plus I guess ata-over-ethernet has some significant advantages, as it works over ethernet directly, not over IP. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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