From: Pavel Machek <pavel@suse.cz>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: arjan@infradead.org, hch@infradead.org, tytso@mit.edu,
t-sato@yk.jp.nec.com, akpm@linux-foundation.org,
viro@ZenIV.linux.org.uk, linux-ext4@vger.kernel.org,
xfs@oss.sgi.com, dm-devel@redhat.com,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
axboe@kernel.dk, mtk.manpages@googlemail.com
Subject: Re: [PATCH 3/3] Add timeout feature
Date: Wed, 9 Jul 2008 22:48:30 +0200 [thread overview]
Message-ID: <20080709204829.GH11006@ucw.cz> (raw)
In-Reply-To: <E1KGTmZ-0006oz-Qi@pomaz-ex.szeredi.hu>
On Wed 2008-07-09 09:08:07, Miklos Szeredi wrote:
> On Tue, 8 Jul 2008, Arjan van de Ven wrote:
> > I tihnk the idea there is
> >
> > freeze . do the snapshot op . unfreeze . make backup of snapshot
>
> Ah, so then my proposal would become
>
> run_frozen mountpoint do-snapshot
> do-backup
> release-snapshot
>
> and if they are afraid of deadlocks they can just implement the
> timeout in userspace:
>
> run_frozen -t timeout mountpoint do-snapshot
>
> 'run_frozen' can be a trivial 30 line app, that can be guaranteed not
> to deadlock.
Userland apps can be swapped out and need kernel memory allocations
during syscalls.
I bet even sleep(30) uses kmalloc internally.
So yes, even trivial applications can deadlock.
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2008-07-09 20:48 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-30 12:24 [PATCH 3/3] Add timeout feature Takashi Sato
2008-07-01 8:10 ` Christoph Hellwig
2008-07-01 10:52 ` Alasdair G Kergon
2008-07-03 12:11 ` Takashi Sato
2008-07-03 12:47 ` Alasdair G Kergon
2008-07-03 22:11 ` [dm-devel] " Dave Chinner
2008-07-04 12:08 ` Takashi Sato
2008-07-03 14:45 ` Eric Sandeen
2008-07-07 11:07 ` Pavel Machek
2008-07-08 23:10 ` Dave Chinner
2008-07-08 23:20 ` Pavel Machek
[not found] ` <20080708232031.GE18195@elf.ucw.cz>
2008-07-09 0:52 ` Dave Chinner
2008-07-09 1:09 ` Theodore Tso
[not found] ` <20080709010922.GE9957@mit.edu>
2008-07-09 4:21 ` Brad Boyer
2008-07-09 6:13 ` Miklos Szeredi
2008-07-09 6:16 ` Christoph Hellwig
2008-07-09 6:22 ` Miklos Szeredi
2008-07-09 6:41 ` Arjan van de Ven
2008-07-09 6:48 ` Miklos Szeredi
2008-07-09 6:55 ` Arjan van de Ven
2008-07-09 7:08 ` Miklos Szeredi
2008-07-09 20:48 ` Pavel Machek [this message]
2008-07-09 7:13 ` Dave Chinner
2008-07-09 11:09 ` Theodore Tso
2008-07-09 11:49 ` Dave Chinner
[not found] ` <20080709114958.GV11558@disturbed>
2008-07-09 12:24 ` Theodore Tso
[not found] ` <20080709122401.GK9957@mit.edu>
2008-07-09 12:59 ` Olaf Frączyk
2008-07-09 13:57 ` Arjan van de Ven
2008-07-09 13:55 ` Arjan van de Ven
2008-07-09 13:58 ` jim owens
2008-07-09 14:13 ` jim owens
2008-07-13 12:06 ` Pavel Machek
2008-07-13 17:15 ` jim owens
2008-07-14 6:36 ` Pavel Machek
2008-07-14 13:17 ` jim owens
2008-07-14 13:12 ` Takashi Sato
2008-07-14 14:04 ` jim owens
2008-07-09 13:53 ` Arjan van de Ven
2008-07-09 6:59 ` Dave Chinner
2008-07-09 7:13 ` Miklos Szeredi
2008-07-09 7:33 ` Dave Chinner
2008-07-09 8:11 ` Miklos Szeredi
2008-07-09 11:15 ` Dave Chinner
2008-07-09 20:44 ` Pavel Machek
-- strict thread matches above, loose matches on Subject: below --
2008-09-08 11:53 Takashi Sato
2008-09-08 17:11 ` Christoph Hellwig
2008-09-25 21:06 ` Ric Wheeler
2008-09-26 8:52 ` Takashi Sato
2008-09-26 10:58 ` Ric Wheeler
2008-09-29 11:11 ` Takashi Sato
2008-09-26 12:35 ` Valdis.Kletnieks
2008-09-29 14:13 ` Christoph Hellwig
2008-09-29 14:36 ` Eric Sandeen
2008-09-29 14:37 ` Christoph Hellwig
2008-09-29 14:45 ` Eric Sandeen
2008-09-29 22:08 ` jim owens
2008-10-05 10:00 ` Pavel Machek
2008-10-09 10:12 ` Takashi Sato
2008-10-09 10:18 ` Christoph Hellwig
2008-08-18 12:28 Takashi Sato
2008-08-21 20:20 ` Andrew Morton
2008-08-22 18:16 ` Christoph Hellwig
2008-08-24 17:03 ` Oleg Nesterov
2008-08-29 9:39 ` Takashi Sato
2008-07-22 9:36 Takashi Sato
2008-06-24 7:00 Takashi Sato
2008-06-24 22:09 ` Andrew Morton
2008-06-27 11:33 ` Takashi Sato
2008-06-27 18:57 ` Andrew Morton
2008-06-29 23:13 ` Takashi Sato
2008-06-30 0:01 ` Andrew Morton
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