Re: Linux-2.4.5

[Linus Torvalds]

On Sat, 26 May 2001, Andrea Arcangeli wrote:
> 
> getblk still needs to use SLAB_BUFFER, not sure how many callers will be
> allowed to use SLAB_KERNEL, but certainly the "async" name was not very
> appropriate to indicate if the bh allocation can fail or not.

Note that these days, on reasonable filesystems, getblk() and friends are
only used by meta-data. So on a normal setup that uses the page cache for
data (pretty much everything), you'd probably go from "100% SLAB_BUFFER"
to "less than 10% SLAB_BUFFER".

Which should cut down on the "this can happen under real load" stuff. 

Assuming, of course, that there aren't any other causes. I can imagine
schenarios where the buffer heads are the major cause of problems, and the
fact that Rik special-cased GFP_BUFFER makes me suspect that that is _his_
schenario, but there may be other, less obvious, ways to get into similar
trouble.

MM is hard. No question about it.

		Linus