[PATCH] drm/ttm: Don't inherit GEM object VMAs in child process

Christian König christian.koenig at amd.com
Thu Jan 6 09:05:05 UTC 2022

Am 05.01.22 um 17:16 schrieb Felix Kuehling:
> [SNIP]
>>> But KFD doesn't know anything about the inherited BOs
>>> from the parent process.
>> Ok, why that? When the KFD is reinitializing it's context why
>> shouldn't it cleanup those VMAs?
> That cleanup has to be initiated by user mode. Basically closing the old
> KFD and DRM file descriptors, cleaning up all the user mode VM state,
> unmapping all the VMAs, etc. Then it reopens KFD and the render nodes
> and starts from scratch.
> User mode will do this automatically when it tries to reinitialize ROCm.
> However, in this case the child process doesn't do that (e.g. a python
> application using the multi-processing package). The child process does
> not use ROCm. But you're left with all the dangling VMAs in the child
> process indefinitely.

Oh, not that one again. I'm unfortunately pretty sure that this is an 
clear NAK then.

This python multi-processing package is violating various specifications 
by doing this fork() and we already had multiple discussions about that.

Let's talk about this on Mondays call. Thanks for giving the whole context.


> Regards,
>    Felix

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