Re: [RFC][PATCH 6/8] mm: handle_speculative_fault()

[Linus Torvalds]

On Thu, 7 Jan 2010, Christoph Lameter wrote:
> 
> page_table_lock used to serialize multiple fast brks?
> 
> CONFIG_SPLIT_PTLOCK implies that code will not use this lock in fault
> handling. So no serialization with faults.

Correct. The faults we do not need to serialize with. It doesn't matter 
whether they see the old or the new end. 

> Also the current code assumes vm_end and so on to be stable if mmap_sem is
> held. F.e. find_vma() from do_fault is now running while vm_end may be changing
> under it.

Again, it doesn't matter. Old or new - if some other thread looks up the 
vma, either is fine.

			Linus
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