Re: [PATCH 2/6] mm: mark all calls into the vmalloc subsystem as potentially sleeping

From: Chris Wilson
Date: Wed Oct 19 2016 - 15:43:47 EST

On Wed, Oct 19, 2016 at 06:31:12PM +0200, Christoph Hellwig wrote:
> On Wed, Oct 19, 2016 at 08:34:40AM -0700, Andy Lutomirski wrote:
> >
> > It would be quite awkward for a task stack to get freed from a
> > sleepable context, because the obvious sleepable context is the task
> > itself, and it still needs its stack. This was true even in the old
> > regime when task stacks were freed from RCU context.
> >
> > But vfree has a magic automatic deferral mechanism. Couldn't you make
> > the non-deferred case might_sleep()?
> But it's only magic from interrupt context..
> Chris, does this patch make virtually mapped stack work for you again?

So far, so good. No warns from anyone else.

Chris Wilson, Intel Open Source Technology Centre