Messages in this thread | | | Date | Wed, 24 Jun 2009 00:13:02 -0700 | From | Andrew Morton <> | Subject | Re: [merged] proctxt-update-kernel-filesystem-proctxt-documentation.patch removed from -mm tree |
| |
On Wed, 24 Jun 2009 08:45:03 +0200 Stefani Seibold <stefani@seibold.net> wrote:
> Am Dienstag, den 23.06.2009, 23:32 -0700 schrieb Andrew Morton: > > On Wed, 24 Jun 2009 08:20:44 +0200 Stefani Seibold <stefani@seibold.net> wrote: > > > > > what is with the associated > > > procfs-provide-stack-information-for-threads-v08.patch > > > patch? > > > > > > There was no real objections against this patch, so why not merge it for > > > 2.6.31? > > > > Alexey pointed out that it doesn't actually work. > > That is not true... it works. With my patch the kernel does exactly know > where the thread stack is and therefor it is easy to determinate the > associated map. >
On Tue, 16 Jun 2009 02:33:33 +0400 Alexey Dobriyan <adobriyan@gmail.com> wrote:
> On Mon, Jun 15, 2009 at 03:02:05PM -0700, akpm@linux-foundation.org wrote: > > procfs-provide-stack-information-for-threads-v08.patch > > --- a/fs/proc/array.c~procfs-provide-stack-information-for-threads-v08 > > > +++ a/fs/proc/array.c > > @@ -321,6 +321,54 @@ static inline void task_context_switch_c > > p->nivcsw); > > } > > > > +static inline unsigned long get_stack_usage_in_bytes(struct vm_area_struct *vma, > > + struct task_struct *p) > > +{ > > + unsigned long i; > > + struct page *page; > > + unsigned long stkpage; > > + > > + stkpage = KSTK_ESP(p) & PAGE_MASK; > > + > > +#ifdef CONFIG_STACK_GROWSUP > > + for (i = vma->vm_end; i-PAGE_SIZE > stkpage; i -= PAGE_SIZE) { > > + > > + page = follow_page(vma, i-PAGE_SIZE, 0); > > How can this work? > > If stack page got swapped out, you'll get smaller than actual result.
Alexey's point is that follow_page() will return NULL if it hits a swapped-out stack page and the loop will exit, leading to an incorrect (ie: short) return value from get_stack_usage_in_bytes().
Is this claim wrong?
| |