Re: Questions about the buffer+page cache in 2.4.0

[Matthew Wilcox]

On Thu, Jul 27, 2000 at 07:49:50PM +0200, Daniel Phillips wrote:
> So now it's time to start asking questions.  Just jumping in at a place I felt I
> knew pretty well back in 2.2.13, I'm now looking at the 2.4.0 getblk, and I see
> it's changed somewhat.  Finding and removing a block from the free list is now
> bracketed by a spinlock pair.  First question: why do we use atomic_set to set
> the initial buffer use count if this is already protected by a spinlock?

the usual answer to this type of question is that there is another
place which accesses the buffer use count without holding the spinlock.
I haven't audited this particular piece of code and I'm not familiar
with this area, but this may help you find the solution.

(the other answer is that this is a bug left over from a time when there
was no spinlock :-)

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