Re: Locking comment on shrink_caches()

David S. Miller
2001-09-25T22:28:57Z

From: Benjamin LaHaise <bcrl@redhat.com>
Date: Tue, 25 Sep 2001 18:16:43 -0400

> Please note that the problem is lock cachelines in dirty exclusive
> state, not a "lock held for long time" issue.

Ahh, that's a cpu bug -- one my athlons don't suffer from.

Your Athlons may handle exclusive cache line acquisition more
efficiently (due to memory subsystem performance) but it still
does cost something.

True, and that is why I would like to see more of the research that
justifies these changes, as well as comparisons with alternate techniques
before any of these patches make it into the base tree. Even before that,
we need to clean up the code first.

As an aside, I actually think the per-hashchain version of the
pagecache locking is cleaner conceptually. The reason is that
it makes it more clear that we are locking the "identity of page X"
instead of "the page cache".

Franks a lot,
David S. Miller
davem@redhat.com