Re: Really slow /dev/zero in 2.1.9

Michael L. Galbraith (
Wed, 13 Nov 1996 16:35:05 +0100 (MET)

On Wed, 13 Nov 1996, Jeff Voskamp [MFCF] wrote:

> I just tried making a new swapfile today (needed a bit more swap for
> my latest project). It took "forever" to dd /dev/zero to the swapfile.
> So I took a look at drivers/char/mem.c. Down around line 200 is a for
> loop that's filling the user buffer _one byte at a time_ and checking
> if we need rescheduling between each byte. It should probably be using
> clear_user(), but I'm unsure if it's safe to do it in one big whack.
> Suggestions?
> Jeff Voskamp

I appreciate the vote of confidence in your cc-ing me, but let there be
a misconception, I am not even in the same galexy as linus and friends.