Alexander Indenbaum wrote:
On Mon, Mar 2, 2009 at 4:44 PM, Valery Reznic <valery_rez...@yahoo.com> wrote:
--- On Mon, 3/2/09, Alexander Indenbaum <alexander.indenb...@gmail.com> wrote:
From: Alexander Indenbaum <alexander.indenb...@gmail.com>
Subject: Re: Kernel memory management problem
To: "guy keren" <c...@actcom.co.il>
Cc: "linux-il." <linux-il@cs.huji.ac.il>
Date: Monday, March 2, 2009, 4:24 PM
On Mon, Mar 2, 2009 at 1:16 PM, guy keren
<c...@actcom.co.il> wrote:
if you don't care about the speed of copying the
data and of slowing down
the disk media consderably during this copying, try to
change the copy
program, so it will use the O_DIRECT flag when opening
the file (and then
you'll need to make sure the buffers you pass to
write() are aligned to disk
sector size, as well as being in disk sector size
multiples). this way,
you'll bypass the buffer cache altogether.
maybe someone else will come up with a better
response.
choo, nice to chat with you again. Still have an appetite
to red heads :) ?
Thank you for your answer.
While O_DIRECT is a valid way and probably will solve the
problem of
crashing, I would not want to patch wget/sftp/whatever. The
list is
long, I have better things to do mean while, instead of
burning in
Patching every single program is not nessesary.
You can use LD_PRELOAD mechanism to add O_DIRECT to each open
function call in each program (ok - to each dynamically linked program)
Nice and valid point. Thank you for idea.
of-course, it will not work, because when working with O_DIRECT, all I/O
buffers must be aligned to disk block size, and be in multiples of disk
block size. applications not written to work with O_DIRECT will crash if
you use such a trick, not to mention all the library functions that call
open underneath.
if you write such an LD_PRELOAD module, you'll need to catch all the
calls to read and write for the FDs, and then make sure you do NOT do
this for network connections ;)
--guy
_______________________________________________
Linux-il mailing list
Linux-il@cs.huji.ac.il
http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
