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

[Jens Axboe]

On Fri, Mar 12 2004, Chris Mason wrote:
> 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.

So trusting an atomic assignment of mapping = page->mapping, it should
work. It feels a bit icky, though.

-- 
Jens Axboe

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