Re: [RFC][PATCH] procfs: Add /proc/<pid>/mapped_files

[Siddhesh Poyarekar]

On 14 January 2015 at 19:43, Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx> wrote:
> Just thinking out loud: Could one simply mark a VMA as being used for
> stack during the clone call (is there room in vm_flags, or does
> VM_GROWSDOWN already tell the whole story?), and then write the TID into
> a new field in the VMA - I think one could make a union with vm_pgoff so
> as not to enlarge the structure.

vm_flags does not have space IIRC (that was my first approach at
implementing this) and VM_GROWSDOWN is not sufficient.  If we can make
a union with vm_pgoff like you say, we probably don't need a flag
value; a non-zero value could indicate that it is a thread stack.

One problem with caching the value on clone like this though is that
the stack could change due to a setcontext, but AFAICT we don't care
about that for the process stack either.

Siddhesh
-- 
http://siddhesh.in
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