[PATCH v5 3/3] cgroups: make procs file writable

[Ben Blum]

On Sun, Dec 26, 2010 at 01:48:58PM -0800, David Rientjes wrote:
> On Fri, 24 Dec 2010, Ben Blum wrote:
> 
> > I'll add a patch to my current series to do this. Should I leave alone
> > the other cases where an out-of-memory causes a silent failure?
> > (cpuset_change_nodemask, scan_for_empty_cpusets)
> > 
> 
> Both are protected by cgroup_lock, so I think it should be a pretty simple 
> change.  cpuset_change_nodemask() is interesting because a task within an 
> oom cpuset may be changing its own nodemask for more memory and that could 
> easily allow the NODEMASK_ALLOC() to fail for large CONFIG_NODES_SHIFT.  
> scan_for_empty_cpusets() is interesting to avoid leaving the hierarchy in 
> an inconsistent state.  So I think both of these would benefit from having 
> a statically allocated nodemask protected by cgroup_lock().

I was going to make a macro like NODEMASK_STATIC, but it turned out that
can_attach() needed the to/from nodemasks to be shared among three
functions for the attaching, so I defined them globally without making a
macro for it. I can make a separate patch for fixing the other cases,
but I'd like to see my current patches through first. (Or should I make
a bugfix patch first and send my other ones on top of that?)

-- Ben