Re: [PATCH] per-backing dev unplugging #2

From: Chris Mason
Date: Fri Mar 12 2004 - 15:48:28 EST


On Fri, 2004-03-12 at 15:34, Jens Axboe wrote:

>
> I don't see how this can make too much of a difference, aside of perhaps
> just moving the window a little. If page->mapping can disappear here,
> that's still a possibility.

As Andrew pointed out, the mapping struct won't disappear, but
page->mapping may go null. So the idea is to use barriers to get a
trusted copy of page->mapping, and use the copy everywhere.

This could be completely bogus, and my test tree has a number of other
patches applied. So, unless someone sees a really obvious bug in this
path, please don't waste brain cells on this one.

I'll try to reproduce on something a little closer to vanilla if my
patch doesn't fix things.

-chris


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