Re: [PATCH] guard mm->rss with page_table_lock (241p11)

From: Rik van Riel (riel@conectiva.com.br)
Date: Tue Jan 30 2001 - 06:23:27 EST


On Wed, 31 Jan 2001, Chris Wedgwood wrote:
> On Tue, Jan 30, 2001 at 12:39:24AM -0800, David S. Miller wrote:
>
> Please see older threads about this, it has been discussed to
> death already (hint: sizeof(atomic_t), sizeof(unsigned long)).
>
> can we not define a macro so architectures that can do do atomically
> inc/dec with unsigned long will? otherwise it uses the spinlock?

Why bother ?

In most places where we update mm->rss, we are *already*
holding the spinlock anyway, this correction is just for
a few places.

The big patch Rasmus made seems to contain spin_lock(&foo)
in places where we already have the lock, leading to
instant SMP deadlock. I suspect Rasmus' patch should be
about half the size it is currently...

regards,

Rik

--
Virtual memory is like a game you can't win;
However, without VM there's truly nothing to lose...

http://www.surriel.com/ http://www.conectiva.com/ http://distro.conectiva.com.br/

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