From: Hugh Dickins <hugh@veritas.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Pavel Machek <pavel@ucw.cz>,
kernel list <linux-kernel@vger.kernel.org>,
"Rafael J. Wysocki" <rjw@sisk.pl>
Subject: Re: sync_file_range(SYNC_FILE_RANGE_WRITE) blocks?
Date: Sun, 1 Jun 2008 08:23:43 +0100 (BST) [thread overview]
Message-ID: <Pine.LNX.4.64.0806010752510.24919@blonde.site> (raw)
In-Reply-To: <20080531173950.c4f04028.akpm@linux-foundation.org>
On Sat, 31 May 2008, Andrew Morton wrote:
> On Sat, 31 May 2008 19:44:49 +0100 (BST) Hugh Dickins <hugh@veritas.com> wrote:
> >
> > All I can say so far is that I find the same as you do:
> > SYNC_FILE_RANGE_WRITE (after writing) takes a significant amount of time,
> > more than half as long as when you add in SYNC_FILE_RANGE_WAIT_AFTER too.
> >
> > Which make the sync_file_range call pretty pointless: your usage seems
> > perfectly reasonable to me, but somehow we've broken its behaviour.
> > I'll be investigating ...
>
> It will block on disk queue fullness - sysrq-W will tell.
Ah, thank you. What a disappointment, though it's understandable.
Doesn't that very severely limit the usefulness of the system call?
I admit the flag isn't called SYNC_FILE_RANGE_WRITE_WITHOUT_WAITING,
but I don't suppose Pavel and I are the only ones misled by it.
Hugh
next prev parent reply other threads:[~2008-06-01 7:24 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-30 10:26 Pavel Machek
2008-05-30 13:58 ` Hugh Dickins
2008-05-30 20:43 ` Pavel Machek
2008-05-31 18:44 ` Hugh Dickins
2008-06-01 0:39 ` Andrew Morton
2008-06-01 7:23 ` Hugh Dickins [this message]
2008-06-01 8:15 ` Andrew Morton
2008-06-01 11:40 ` Pavel Machek
2008-06-01 20:37 ` Andrew Morton
2008-06-01 22:00 ` Rafael J. Wysocki
2008-06-01 22:22 ` Pavel Machek
2008-06-01 22:47 ` Andrew Morton
2008-06-01 23:00 ` Pavel Machek
2008-06-01 23:11 ` Andrew Morton
2008-06-02 8:43 ` Hugh Dickins
2008-06-02 11:18 ` Rafael J. Wysocki
2008-06-02 12:11 ` Hugh Dickins
2008-06-02 11:43 ` Jens Axboe
2008-06-02 12:40 ` Hugh Dickins
2008-06-16 20:53 ` Rik van Riel
2008-06-17 4:54 ` Andrew Morton
2008-06-17 13:38 ` Rik van Riel
2008-06-02 16:50 ` Andrew Morton
2008-06-03 8:01 ` Michael Kerrisk
2008-06-03 8:05 ` Pavel Machek
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