Re: [PATCH] drm/amdkfd: only allow heavy-weight TLB flush on some ASICs for SVM too

[Lang Yu <Lang.Yu@amd.com>]

On 04/15/ , Paul Menzel wrote:
> Dear Lang,
> 
> 
> Am 15.04.22 um 05:20 schrieb Lang Yu:
> > On 04/14/ , Paul Menzel wrote:
> 
> > > Am 14.04.22 um 10:19 schrieb Lang Yu:
> > > > The idea is from commit a50fe7078035 ("drm/amdkfd: Only apply heavy-weight
> > > > TLB flush on Aldebaran") and commit f61c40c0757a ("drm/amdkfd: enable
> > > > heavy-weight TLB flush on Arcturus"). Otherwise, we will run into problems
> > > > on some ASICs when running SVM applications.
> > > 
> > > Please list the ASICs, you know of having problems, and even add how to
> > > reproduce this.
> > 
> > Actually, this is ported from previous commits. You can find more details
> > from the commits I mentioned. At the moment the ASICs except Aldebaran
> > and Arcturus probably have the problem.
> 
> I think, it’s always good to make it as easy as possible for reviewers and,
> later, people reading a commit, and include the necessary information
> directly in the commit message. It’d be great if you amended the commit
> message.

Yes, I agree with you. Will amended the commit message.

> > And running a SVM application could reproduce the issue.
> 
> Thanks. How will it fail though?

Will describe more details in commit message.

> (Also, a small implementation note would be nice to have. Maybe: Move the
> helper function into the header `kfd_priv.h`, and use in
> `svm_range_unmap_from_gpus()`.)

Will separate this change into another patch suggested by Eric.

Thanks,
Lang

> Kind regards,
> 
> Paul
> 
> 
> > > > Signed-off-by: Lang Yu <Lang.Yu@amd.com>
> > > > ---
> > > >    drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 8 --------
> > > >    drivers/gpu/drm/amd/amdkfd/kfd_priv.h    | 8 ++++++++
> > > >    drivers/gpu/drm/amd/amdkfd/kfd_svm.c     | 4 +++-
> > > >    3 files changed, 11 insertions(+), 9 deletions(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> > > > index 91f82a9ccdaf..459f59e3d0ed 100644
> > > > --- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> > > > +++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> > > > @@ -1128,14 +1128,6 @@ static int kfd_ioctl_free_memory_of_gpu(struct file *filep,
> > > >    	return ret;
> > > >    }
> > > > -static bool kfd_flush_tlb_after_unmap(struct kfd_dev *dev)
> > > > -{
> > > > -	return KFD_GC_VERSION(dev) == IP_VERSION(9, 4, 2) ||
> > > > -		(KFD_GC_VERSION(dev) == IP_VERSION(9, 4, 1) &&
> > > > -		dev->adev->sdma.instance[0].fw_version >= 18) ||
> > > > -		KFD_GC_VERSION(dev) == IP_VERSION(9, 4, 0);
> > > > -}
> > > > -
> > > >    static int kfd_ioctl_map_memory_to_gpu(struct file *filep,
> > > >    					struct kfd_process *p, void *data)
> > > >    {
> > > > diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> > > > index 8a43def1f638..aff6f598ff2c 100644
> > > > --- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> > > > +++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> > > > @@ -1328,6 +1328,14 @@ void kfd_signal_poison_consumed_event(struct kfd_dev *dev, u32 pasid);
> > > >    void kfd_flush_tlb(struct kfd_process_device *pdd, enum TLB_FLUSH_TYPE type);
> > > > +static inline bool kfd_flush_tlb_after_unmap(struct kfd_dev *dev)
> > > > +{
> > > > +	return KFD_GC_VERSION(dev) == IP_VERSION(9, 4, 2) ||
> > > > +	       (KFD_GC_VERSION(dev) == IP_VERSION(9, 4, 1) &&
> > > > +	       dev->adev->sdma.instance[0].fw_version >= 18) ||
> > > > +	       KFD_GC_VERSION(dev) == IP_VERSION(9, 4, 0);
> > > > +}
> > > > +
> > > >    bool kfd_is_locked(void);
> > > >    /* Compute profile */
> > > > diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> > > > index 459fa07a3bcc..5afe216cf099 100644
> > > > --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> > > > +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> > > > @@ -1229,7 +1229,9 @@ svm_range_unmap_from_gpus(struct svm_range *prange, unsigned long start,
> > > >    			if (r)
> > > >    				break;
> > > >    		}
> > > > -		kfd_flush_tlb(pdd, TLB_FLUSH_HEAVYWEIGHT);
> > > > +
> > > > +		if (kfd_flush_tlb_after_unmap(pdd->dev))
> > > > +			kfd_flush_tlb(pdd, TLB_FLUSH_HEAVYWEIGHT);
> > > >    	}
> > > >    	return r;