lkml.org 
[lkml]   [2010]   [Aug]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH] hide guard page for stacks that grow upwards
On Tue, Aug 24, 2010 at 3:03 PM, Luck, Tony <tony.luck@intel.com> wrote:
>
> This looks useful too ... but I can't see where the code is that
> made vm_start be PAGE_SIZE lower to begin with. I'd expect to have
> to make a matching change to make vm_end PAGE_SIZE higher for the
> VM_GROWSUP areas.

That's the fault path - the very check_stack_guard_page() logic itself.

In other words, nowhere do we _explicitly_ make the stack larger by
one page, but nowhere do we explicitly size the stack in the first
place! The stack grows by being populated, and every time a new page
is populated, check_stack_guard_page() will have expanded the stack
vma by one extra page.

Linus


\
 
 \ /
  Last update: 2010-08-25 00:27    [W:0.020 / U:0.324 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site