Re: [patch 2/5] Reinstate ZERO_PAGE optimization in get_user_pages()and fix XIP

[Linus Torvalds]

On Tue, 24 Jun 2008, Jeff Chua wrote:

> On Tue, Jun 24, 2008 at 1:27 AM, Linus Torvalds
> <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> 
> > On the other hand, if you add a trace to the "use_zero_page()" function to
> > print out the vm_flags and other details, that probably would help.
> 
> Let me know if you still want me to test this.

No, it's fine. It really was a bug, and a long-standing one, just one that 
was probably practically impossible to hit before (because we used to only 
do the FOLL_ANON logic on missing whole page tables, and just about any 
access to any mapping even nearby the one you care about will fill in the 
page tables - so you would have had to be really unlucky to trigger the 
case before).

The patch clearly fixes an issue, and makes the code more readable and 
maintainable too, so I don't care what the exact mapping flags etc were.

> Yeh, it works great! Thank you.

Thanks for bisecting, reporting and testing. 

			Linus
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/