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From: Pavel Machek <pavel@ucw.cz>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Nigel Cunningham <nigel@nigel.suspend2.net>,
	Andres Salomon <dilinger@debian.org>,
	linux-pm@lists.linux-foundation.org, Chris Ball <cjb@laptop.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Oleg Nesterov <oleg@tv-sign.ru>
Subject: Re: [RFC][PATCH -mm 3/3] Freezer: Replace the timeout
Date: Sun, 5 Aug 2007 23:37:28 +0200	[thread overview]
Message-ID: <20070805213728.GA30770@elf.ucw.cz> (raw)
In-Reply-To: <200708011243.25276.rjw@sisk.pl>

Hi!

> > What happens on loaded ext3 filesystem, for example? Bunch of userland tasks
> > will wait on data to be synced to disk, taking more than second, no?
> 
> IMHO this only is a question of what the value of MAX_WAITS should be.
> [I took 5 because it turned to be enough in my testing, but that could be 10 or
> more.]
> 
> The point is that in 99.(9)% of cases the 20s timeout is unnecessary, because:
> (1) most often we succeed within 1s
> (2) if we are going to fail, we can say that we'll fail way before the 20s
>     expires.

Well, I've just reproduced 10seconds and 17seconds
time-to-freeze. Okay, I did 

make clean; time make -j 350

on kernel (2GB machine). Can you try with something similary evil?

> Anyway, eventually, I'd like the freezer to detect failures relatively early,
> so the user won't have to wait 20s each time it's going to fail.

It should not fail ;-). And failures are _really_ rare these days. Is
20second wait in case of kernel bug that bad? (FUSE case _is_ a kernel
bug, I'm just not sure how to solve it. It is still rare.)

								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

  reply	other threads:[~2007-08-05 21:37 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-07-25 12:01 [RFC][PATCH -mm 0/2] Freezer: Use wait queue instead of busy looping Rafael J. Wysocki
2007-07-25 12:03 ` [RFC][PATCH -mm 1/2] Freezer: Be more verbose Rafael J. Wysocki
2007-07-25 12:27   ` Pavel Machek
2007-07-25 12:09 ` [RFC][PATCH -mm 2/2] Freezer: Use wait queue instead of busy looping Rafael J. Wysocki
2007-07-25 12:28   ` Pavel Machek
2007-07-25 12:55     ` Rafael J. Wysocki
2007-07-25 13:29   ` Oleg Nesterov
2007-07-25 14:03     ` Rafael J. Wysocki
2007-07-25 14:24       ` Oleg Nesterov
2007-07-26 12:24         ` Rafael J. Wysocki
2007-07-26 12:43           ` Rafael J. Wysocki
2007-07-31  8:01           ` Pavel Machek
2007-07-31  9:39             ` Rafael J. Wysocki
2007-07-31 10:00               ` Pavel Machek
2007-07-31 10:17                 ` Rafael J. Wysocki
2007-07-31 10:08               ` Rafael J. Wysocki
2007-07-31 10:02                 ` Pavel Machek
2007-07-31 22:25                   ` [RFC][PATCH -mm 0/3] Freezer: Use wait queue instead of busy looping (updated) Rafael J. Wysocki
2007-07-31 22:26                     ` [RFC][PATCH -mm 1/3] Freezer: Use wait queue instead of busy looping Rafael J. Wysocki
2007-08-01  7:59                       ` Pavel Machek
2007-07-31 22:28                     ` [RFC][PATCH -mm 2/3] Freezer: Measure the time of freezing tasks Rafael J. Wysocki
2007-08-01  8:28                       ` Pavel Machek
2007-07-31 22:29                     ` [RFC][PATCH -mm 3/3] Freezer: Replace the timeout Rafael J. Wysocki
2007-08-01  8:31                       ` Pavel Machek
2007-08-01 10:43                         ` Rafael J. Wysocki
2007-08-05 21:37                           ` Pavel Machek [this message]
2007-08-05 22:38                             ` Rafael J. Wysocki
2007-08-05 22:53                               ` Pavel Machek

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