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From: Helge Hafting <helgehaf@aitel.hist.no>
To: Greg Stark <gsstark@mit.edu>
Cc: Ingo Oeser <ioe-lkml@rameria.de>,
	Joel Becker <Joel.Becker@oracle.com>,
	Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: statfs() / statvfs() syscall ballsup...
Date: Wed, 15 Oct 2003 20:37:10 +0200	[thread overview]
Message-ID: <20031015183710.GA1371@hh.idb.hist.no> (raw)
In-Reply-To: <87llrmbl1g.fsf@stark.dyndns.tv>

On Wed, Oct 15, 2003 at 11:03:23AM -0400, Greg Stark wrote:
> Ingo Oeser <ioe-lkml@rameria.de> writes:
> 
> > On Monday 13 October 2003 10:45, Helge Hafting wrote:
> > 
> > > This is easier than trying to tell the kernel that the job is
> > > less important, that goes wrong wether the job runs too much
> > > or too little.  Let that job  sleep a little when its services
> > > aren't needed, or when you need the disk bandwith elsewhere.
> 
> Actually I think that's exactly backwards. The problem is that if the
> user-space tries to throttle the process it doesn't know how much or when.
> The kernel knows exactly when there are other higher priority writes, it can
> schedule just enough writes from vacuum to not interfere.
> 
Isn't those higher-priority writes issued from userspace?
I am of course assuming that source for _everything_ is available.
So the process with the high-priority write can tell vacuum to
take a nap until its transaction completes.

> So if vacuum slept a bit, say every 64k of data vacuumed. It could end up
> sleeping when the disks are actually idle. Or it could be not sleeping enough
> and still be interfering with transactions.
> 
It can run at full speed normally, take voluntary pauses if it ever
detects a "nothing to do now" condition. And it can be paused
(forcibly or through cooperation) when there are important transactions
to sync. 

> Though actually this avenue has some promise. It would not be nearly as ideal
> as a kernel based solution that could take advantage of the idle times between
> transactions, but it would still work somewhat as a work-around.
> 
Don't that other process know when it is about to submit important transactions?

> > The questions are: How IO-intensive vacuum? How fast can a throttling
> > free disk bandwidth (and memory)?
> 

Helge Hafting

  reply	other threads:[~2003-10-15 18:29 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-10-09 22:16 Trond Myklebust
2003-10-09 22:26 ` Linus Torvalds
2003-10-09 23:19   ` Ulrich Drepper
2003-10-10  0:22     ` viro
2003-10-10  4:49       ` Jamie Lokier
2003-10-10  5:26         ` Trond Myklebust
2003-10-10 12:37           ` Jamie Lokier
2003-10-10 13:46             ` Trond Myklebust
2003-10-10 14:35               ` Jamie Lokier
2003-10-10 15:32                 ` Misc NFSv4 (was Re: statfs() / statvfs() syscall ballsup...) Trond Myklebust
2003-10-10 15:53                   ` Jamie Lokier
2003-10-10 16:07                     ` Trond Myklebust
2003-10-10 15:55                   ` Michael Shuey
2003-10-10 16:20                     ` Trond Myklebust
2003-10-10 16:45                     ` J. Bruce Fields
2003-10-10 14:39               ` statfs() / statvfs() syscall ballsup Jamie Lokier
2003-10-09 23:31   ` Trond Myklebust
2003-10-10 12:27   ` Joel Becker
2003-10-10 14:59     ` Linus Torvalds
2003-10-10 15:27       ` Joel Becker
2003-10-10 16:00         ` Linus Torvalds
2003-10-10 16:26           ` Joel Becker
2003-10-10 16:50             ` Linus Torvalds
2003-10-10 17:33               ` Joel Becker
2003-10-10 17:51                 ` Linus Torvalds
2003-10-10 18:13                   ` Joel Becker
2003-10-10 16:27           ` Valdis.Kletnieks
2003-10-10 16:33           ` Chris Friesen
2003-10-10 17:04             ` Linus Torvalds
2003-10-10 17:07               ` Linus Torvalds
2003-10-10 17:21                 ` Joel Becker
2003-10-10 16:01         ` Jamie Lokier
2003-10-10 16:33           ` Joel Becker
2003-10-10 16:58             ` Chris Friesen
2003-10-10 17:05               ` Trond Myklebust
2003-10-10 17:20               ` Joel Becker
2003-10-10 17:33                 ` Chris Friesen
2003-10-10 17:40                 ` Linus Torvalds
2003-10-10 17:54                   ` Trond Myklebust
2003-10-10 18:05                     ` Linus Torvalds
2003-10-10 20:40                       ` Trond Myklebust
2003-10-10 21:09                         ` Linus Torvalds
2003-10-10 22:17                           ` Trond Myklebust
2003-10-11  2:53                     ` Andrew Morton
2003-10-11  3:47                       ` Trond Myklebust
2003-10-10 18:05                   ` Joel Becker
2003-10-10 18:31                     ` Andrea Arcangeli
2003-10-10 20:33                     ` Helge Hafting
2003-10-10 20:07             ` Jamie Lokier
2003-10-12 15:31             ` Greg Stark
2003-10-12 16:13               ` Linus Torvalds
2003-10-12 22:09                 ` Greg Stark
2003-10-13  8:45                   ` Helge Hafting
2003-10-15 13:25                     ` Ingo Oeser
2003-10-15 15:03                       ` Greg Stark
2003-10-15 18:37                         ` Helge Hafting [this message]
2003-10-16 10:29                         ` Ingo Oeser
2003-10-16 14:02                           ` Greg Stark
2003-10-21 11:47                             ` Ingo Oeser
2003-10-10 18:20           ` Andrea Arcangeli
2003-10-10 18:36             ` Linus Torvalds
2003-10-10 19:03               ` Andrea Arcangeli
2003-10-09 23:16 ` Andreas Dilger
2003-10-09 23:24   ` Linus Torvalds

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