[Intel-gfx] [PATCH 1/3] mm: Check if mmu notifier callbacks are allowed to fail
mhocko at kernel.org
Fri Nov 23 11:14:28 UTC 2018
On Fri 23-11-18 09:49:34, Daniel Vetter wrote:
> On Thu, Nov 22, 2018 at 04:53:34PM +0000, Chris Wilson wrote:
> > Quoting Daniel Vetter (2018-11-22 16:51:04)
> > > Just a bit of paranoia, since if we start pushing this deep into
> > > callchains it's hard to spot all places where an mmu notifier
> > > implementation might fail when it's not allowed to.
> > Most callers could handle the failure correctly. It looks like the
> > failure was not propagated for convenience.
> I have no idea whether the mm is semantically ok if pte shootdown doesn't
> work for all sorts of strange reasons. From the commit that introduced the
> error code it souded like this was very much only ok in the limited case
> of an already killed process, in the oom killer path, where it's really
> only about trying to free any kind of memory. And where the process is
> gone already, so semantics of what exactly happens don't matter that much
Yes this was indeed the case. There is still the exit path which would
do the rest of the work so we are not leaving anything behind.
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