[lkml]   [2012]   [Feb]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RESEND][PATCH] Mark thread stack correctly in proc/<pid>/maps
On Wed, Feb 8, 2012 at 11:27 PM, KOSAKI Motohiro
<> wrote:
> Now, we are using some bit saving hack. example,
> 1) use ifdef
> #define VM_MAPPED_COPY 0x01000000      /* T if mapped copy of data (nommu
> mmap) */
> #else
> #define VM_HUGEPAGE    0x01000000      /* MADV_HUGEPAGE marked this vma */
> #endif
> 2) use bit combination
> Maybe you can take a similar way. And of course, you can ban some useless
> flag
> bits.

I found the thread in which Linus rejected the idea of expanding vm_flags:

and based on that, I don't think I can justify the need for a new flag
for this patch since it is purely for display purposes and has nothing
to do with the actual treatment of the vma. So I figured out another
way to identify a thread stack without changing the way the vma
properties (I should have done this in the first place I think) which
is by checking if the vma contains the stack pointer of the task.

With this change:

/proc/pid/task/tid/maps: will only mark the stack that the task uses

/proc/pid/maps: will mark all stacks. This path will be slower since
it will iterate through the entire thread group for each vma.

I'll test this and attach a new version of the patch.


Siddhesh Poyarekar
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2012-02-11 11:21    [W:0.152 / U:0.048 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site