Messages in this thread | | | Date | Tue, 26 Apr 2022 17:48:01 +0100 | From | Jean-Philippe Brucker <> | Subject | Re: [PATCH v4 05/11] iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exit |
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On Tue, Apr 26, 2022 at 08:27:00AM -0700, Dave Hansen wrote: > On 4/25/22 09:40, Jean-Philippe Brucker wrote: > > The problem is that we'd have to request the device driver to stop DMA > > before we can destroy the context and free the PASID. We did consider > > doing this in the release() MMU notifier, but there were concerns about > > blocking mmput() for too long (for example > > https://lore.kernel.org/linux-iommu/4d68da96-0ad5-b412-5987-2f7a6aa796c3@amd.com/ > > though I think there was a more recent discussion). We also need to drain > > the PRI and fault queues to get rid of all references to that PASID. > > Is the concern truly about blocking mmput() itself? Or, is it about > releasing the resources associated with the mm?
The latter I think, this one was about releasing pages as fast as possible if the process is picked by the OOM killer.
Thanks, Jean
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