From: William Lee Irwin III <wli@holomorphy.com>
To: Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
Cc: viro@parcelfarce.linux.theplanet.co.uk, linux-kernel@vger.kernel.org
Subject: Re: seq_file and exporting dynamically allocated data
Date: Mon, 17 Nov 2003 00:30:07 -0800 [thread overview]
Message-ID: <20031117083007.GA22764@holomorphy.com> (raw)
In-Reply-To: <Pine.LNX.4.44.0311170745170.1089-100000@einstein.homenet>
On Mon, Nov 17, 2003 at 08:21:34AM +0000, Tigran Aivazian wrote:
> Now, since there is no way to detect EOF, other than by reading an extra
> page and discovering that it belongs to the next iteration, we have to do
> the lseek(fd, 0, SEEK_SET) anyway.
> So, the "auto-rewinding" read would only help the cases where application
> doesn't need to differentiate between samples and is happy to just
> continuously read chunks packed into pages one by one as fast as
> possible. In this case it doesn't need to lseek to 0, so auto-rewinding on
> kernel side would prevent it from slowing down.
If you're going to repeatedly read from 0 pread() sounds like a good
alternative to read() + lseek(), plus no kernel changes required to
get rid of the lseek().
-- wli
next prev parent reply other threads:[~2003-11-17 8:30 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-11-14 20:42 seq_file and exporting dynamically allocated data Harald Welte
2003-11-14 21:01 ` Tigran Aivazian
2003-11-15 9:38 ` Harald Welte
2003-11-15 17:18 ` viro
2003-11-15 17:33 ` Harald Welte
2003-11-15 19:49 ` Tigran Aivazian
2003-11-15 20:14 ` viro
2003-11-15 20:41 ` Tigran Aivazian
2003-11-15 21:30 ` viro
2003-11-15 20:50 ` Tigran Aivazian
2003-11-15 21:33 ` viro
2003-11-15 21:54 ` Tigran Aivazian
2003-11-16 7:27 ` Tigran Aivazian
2003-11-17 5:48 ` viro
2003-11-17 8:21 ` Tigran Aivazian
2003-11-17 8:30 ` William Lee Irwin III [this message]
2003-11-17 8:38 ` Tigran Aivazian
2003-11-17 8:48 ` William Lee Irwin III
2003-11-17 9:03 ` William Lee Irwin III
2003-11-17 9:42 ` Tigran Aivazian
2003-11-17 9:50 ` William Lee Irwin III
2003-11-17 9:55 ` viro
2003-11-17 10:08 ` Tigran Aivazian
2003-11-17 10:35 ` viro
2003-11-17 9:48 ` viro
2003-11-16 20:45 ` Harald Welte
2003-11-15 20:36 ` viro
2003-11-16 20:42 ` Harald Welte
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