Re: [PATCH] SMP race in ext2 - metadata corruption.

From: Rogier Wolff (R.E.Wolff@BitWizard.nl)
Date: Sat May 05 2001 - 08:52:46 EST


Richard Gooch wrote:
>
> - next boot, init(8) checks the file, and if it exists, opens the root
> FS block device and reads in each block listed in the file. The
> effect is to warm the buffer cache extremely quickly. The head will
> move in one direction, grabbing data as it flys by. I expect this
> will take around 1 second

FYI:

Around 1992 or 1993, I rewrote Minix-fsck to do this instead of
seeking all over the place.

Cut the total time to fsck my filesystem from around 30 to 28
seconds. (remember the days of small filesystems?)

That's when I decided that this was NOT an interesting project: there
was very little to be gained.

The explanation is: A seek over a few tracks isn't much slower than a
seek over hundreds of tracks. Almost any "skip" in linear access
incurs the average 6ms rotational latency anyway.

                        Roger.

-- 
** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 **
*-- BitWizard writes Linux device drivers for any device you may have! --*
* There are old pilots, and there are bold pilots. 
* There are also old, bald pilots. 
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This archive was generated by hypermail 2b29 : Mon May 07 2001 - 21:00:22 EST