Re: Major mke2fs slowdown (reproducable, bisected)

From: Linus Torvalds
Date: Mon Nov 12 2007 - 13:39:41 EST




On Mon, 12 Nov 2007, Alexey Dobriyan wrote:
>
> Cross-compile farm here migrated to .ccache and build dir on separate
> disks and now I have a way to blow up .ccache without waiting half an
> hour for rm(1) to finish. It's called mke2fs(8).
>
> However, in e.g 2.6.24-rc2 mke2fs is amazingly slow if done right after
> several fat cross-compile builds. Normally it takes ~11 seconds to
> finish. After commit 5adc5be7cd1bcef6bb64f5255d2a33f20a3cf5be aka
> "Bias the placement of kernel pages at lower PFNs" it takes several
> minutes. 2.6.24-rc2 without this patch also gives normal mkfs speeds.
> I'm pretty sure bisection wasn't screwed up.

Can you (just to make sure) do a "git revert" of this commit on top of the
current tree, and verify that that makes it all work fine again too? If
so, let's just revert it.

I just want to make sure that there isn't some subtle interaction with
anything else in there.

Linus
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