On 2019/05/21 23:44, Daniel Vetter wrote: >>>> OOM notifiers should not depend on any locks or sleepable conditionals. >>>> If some lock directly or indirectly depended on __GFP_DIRECT_RECLAIM, >>>> it will deadlock. Thus, despite blocking API, this should effectively be >>>> non-blocking. All OOM notifier users except i915 seems to be atomic, but >>>> I can't evaluate i915 part... >>> >>> Read again what I've written, please >>> >> >> Question to Daniel: Is i915's oom_notifier function atomic? > > It's supposed to not block too much at least, I don't think it's entirely > atomic. Waking up the device (which we need to write some of the ptes) > will take some time and I think acquires a few mutexes, but not 100% sure. > > If you want to see, send a patch to intel-gfx m-l and CI will pick it up > and test with our farm of machines.
As soon as a mutex is held, we can't expect it is atomic. We need to manually inspect whether there is __GFP_DIRECT_RECLAIM dependency... Since OOM notifier will be called after shrinkers are attempted, can i915 move from OOM notifier to shrinker? _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
