On Wed, Feb 26, 2014 at 09:50:48AM +0100, Peter Zijlstra wrote:
> On Tue, Feb 25, 2014 at 10:16:46AM -0800, Davidlohr Bueso wrote:
> > +void vmacache_invalidate_all(void)
> > +{
> > + struct task_struct *g, *p;
> > +
> > + rcu_read_lock();
> > + for_each_process_thread(g, p) {
> > + /*
> > + * Only flush the vmacache pointers as the
> > + * mm seqnum is already set and curr's will
> > + * be set upon invalidation when the next
> > + * lookup is done.
> > + */
> > + memset(p->vmacache, 0, sizeof(p->vmacache));
> > + }
> > + rcu_read_unlock();
> > +}
>
> With all the things being said on this particular piece already; I
> wanted to add that the iteration there is incomplete; we can clone()
> using CLONE_VM without using CLONE_THREAD.
>
> Its not common, but it can be done. In that case the above iteration
> will miss a task that shares the same mm.
Bugger; n/m that. I just spotted that it's yet another way to iterate
all tasks in the system.
Of course we need multiple macros to do this :/
Pretty horrifically expensive though.
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