All of lore.kernel.org
 help / color / mirror / Atom feed
From: Joel Becker <Joel.Becker@oracle.com>
To: Linus Torvalds <torvalds@osdl.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: statfs() / statvfs() syscall ballsup...
Date: Fri, 10 Oct 2003 11:05:35 -0700	[thread overview]
Message-ID: <20031010180535.GE29301@ca-server1.us.oracle.com> (raw)
In-Reply-To: <Pine.LNX.4.44.0310101024200.20420-100000@home.osdl.org>

On Fri, Oct 10, 2003 at 10:40:40AM -0700, Linus Torvalds wrote:
> Actually, the kernel has a "readahead(fd, offset, size)" system call that
> will start asynchronous read-ahead on any mapping. After that, just
> touching the page will obviously map in and synchronize the result.

	Ok, a quick peruse of sys_readahead() seems to say that it
doesn't check for existing uptodate()ness.  That would be interesting.
I could have missed it, though.  

> I don't think anybody uses it, and the interface may be broken, but it was
> literally 20 lines of code, and I had a trivial test program that
> populated the cache for a directory structure really quickly using it.

	The problem we have with msync() and friends is not 'quick
population', it's "page is in the page cache already; another node
writes to the storage; must mark page as !uptodate so as to force a
re-read from disk".  I can't find where sys_readahead() checks for
uptodate, so perhaps calling sys_readahead() on a range always causes
I/O.  Correct me if I missed it.

> For example, things we can do, but don't, partly because of interface 
> issues and because there is no point in doing it if people wouldn't use 
> it:

	Lots of interesting stuff snipped.  This discussion has me
thinking, knowing now that there's possibility to move to a more optimal
interface.

Joel

-- 

Life's Little Instruction Book #464

	"Don't miss the magic of the moment by focusing on what's
	 to come."

Joel Becker
Senior Member of Technical Staff
Oracle Corporation
E-mail: joel.becker@oracle.com
Phone: (650) 506-8127

  parent reply	other threads:[~2003-10-10 18:06 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 [this message]
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
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20031010180535.GE29301@ca-server1.us.oracle.com \
    --to=joel.becker@oracle.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=torvalds@osdl.org \
    --subject='Re: statfs() / statvfs() syscall ballsup...' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.