Re: locking question: do_mmap(), do_munmap()

Manfred Spraul (manfreds@colorfullife.com)
Sun, 10 Oct 1999 17:52:09 +0200

Andrea Arcangeli wrote:
>
> On Sun, 10 Oct 1999, Manfred Spraul wrote:
>
> >But this means that both locks are required if you modify the vma list.
> >Single reader, multiple writer synchronization. Unusual, but interesting
> >:-)
>
> Yes, that's always been this way also in 2.2.x.

and which lock protects "mm->rss"?

It's not an atomic variable, but
* increased by do_swap_page() outside lock_kernel.
* decreased by the swapper.

I've started adding "assert_down()" and "assert_kernellocked()" macros,
and now I don't see the login prompt any more...

eg. sys_mprotect calls merge_segments without lock_kernel().

--
	Manfred


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