Re: [Patch v2 3/4] drm/amdkfd: refactor runtime pm for baco

["Bhardwaj, Rajneesh" <rajneesh.bhardwaj@xxxxxxx>]

Hi Felix,

Thanks for the review feedback!

On 2/4/2020 4:28 PM, Felix Kuehling wrote:
> On 2020-01-31 10:37 p.m., Rajneesh Bhardwaj wrote:
> > So far the kfd driver implemented same routines for runtime and system
> > wide suspend and resume (s2idle or mem). During system wide suspend the
> > kfd aquires an atomic lock that prevents any more user processes to
> > create queues and interact with kfd driver and amd gpu. This mechanism
> > created problem when amdgpu device is runtime suspended with BACO
> > enabled. Any application that relies on kfd driver fails to load because
> > the driver reports a locked kfd device since gpu is runtime suspended.
> >
> > However, in an ideal case, when gpu is runtime  suspended the kfd driver
> > should be able to:
> >
> >   - auto resume amdgpu driver whenever a client requests compute service
> >   - prevent runtime suspend for amdgpu  while kfd is in use
> >
> > This change refactors the amdgpu and amdkfd drivers to support BACO and
> > runtime power management.
> >
> > Signed-off-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@xxxxxxx>
>
> One small comment inline. Other than that patches 1-3 are
>
> Reviewed-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
>
> Also, I believe patch 1 is unchanged from v1 and already got a 
> Reviewed-by from Alex. Please remember to add that tag before you submit.


You mean https://www.spinics.net/lists/amd-gfx/msg44689.html? I have 
already added Alex's RB tag.


> The last patch that enabled runtime PM by default, I'd leave the 
> decision to submit that up to Alex. There may be other considerations 
> than just KFD.


Sure, but its needed along with the series otherwise we can't test/use it.


> See inline ...
>
>
> > ---
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c | 12 +++---
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h |  8 ++--
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c |  4 +-
> >   drivers/gpu/drm/amd/amdkfd/kfd_device.c    | 29 +++++++++------
> >   drivers/gpu/drm/amd/amdkfd/kfd_priv.h      |  1 +
> >   drivers/gpu/drm/amd/amdkfd/kfd_process.c   | 43 ++++++++++++++++++++--
> >   6 files changed, 70 insertions(+), 27 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c 
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
> > index 8609287620ea..314c4a2a0354 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
> > @@ -178,18 +178,18 @@ void amdgpu_amdkfd_interrupt(struct 
> > amdgpu_device *adev,
> >           kgd2kfd_interrupt(adev->kfd.dev, ih_ring_entry);
> >   }
> >   -void amdgpu_amdkfd_suspend(struct amdgpu_device *adev)
> > +void amdgpu_amdkfd_suspend(struct amdgpu_device *adev, bool run_pm)
> >   {
> >       if (adev->kfd.dev)
> > -        kgd2kfd_suspend(adev->kfd.dev);
> > +        kgd2kfd_suspend(adev->kfd.dev, run_pm);
> >   }
> >   -int amdgpu_amdkfd_resume(struct amdgpu_device *adev)
> > +int amdgpu_amdkfd_resume(struct amdgpu_device *adev, bool run_pm)
> >   {
> >       int r = 0;
> >         if (adev->kfd.dev)
> > -        r = kgd2kfd_resume(adev->kfd.dev);
> > +        r = kgd2kfd_resume(adev->kfd.dev, run_pm);
> >         return r;
> >   }
> > @@ -713,11 +713,11 @@ void kgd2kfd_exit(void)
> >   {
> >   }
> >   -void kgd2kfd_suspend(struct kfd_dev *kfd)
> > +void kgd2kfd_suspend(struct kfd_dev *kfd, bool run_pm)
> >   {
> >   }
> >   -int kgd2kfd_resume(struct kfd_dev *kfd)
> > +int kgd2kfd_resume(struct kfd_dev *kfd, bool run_pm)
> >   {
> >       return 0;
> >   }
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h 
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
> > index 47b0f2957d1f..9e8db702d878 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
> > @@ -122,8 +122,8 @@ struct amdkfd_process_info {
> >   int amdgpu_amdkfd_init(void);
> >   void amdgpu_amdkfd_fini(void);
> >   -void amdgpu_amdkfd_suspend(struct amdgpu_device *adev);
> > -int amdgpu_amdkfd_resume(struct amdgpu_device *adev);
> > +void amdgpu_amdkfd_suspend(struct amdgpu_device *adev, bool run_pm);
> > +int amdgpu_amdkfd_resume(struct amdgpu_device *adev, bool run_pm);
> >   void amdgpu_amdkfd_interrupt(struct amdgpu_device *adev,
> >               const void *ih_ring_entry);
> >   void amdgpu_amdkfd_device_probe(struct amdgpu_device *adev);
> > @@ -249,8 +249,8 @@ bool kgd2kfd_device_init(struct kfd_dev *kfd,
> >                struct drm_device *ddev,
> >                const struct kgd2kfd_shared_resources *gpu_resources);
> >   void kgd2kfd_device_exit(struct kfd_dev *kfd);
> > -void kgd2kfd_suspend(struct kfd_dev *kfd);
> > -int kgd2kfd_resume(struct kfd_dev *kfd);
> > +void kgd2kfd_suspend(struct kfd_dev *kfd, bool run_pm);
> > +int kgd2kfd_resume(struct kfd_dev *kfd, bool run_pm);
> >   int kgd2kfd_pre_reset(struct kfd_dev *kfd);
> >   int kgd2kfd_post_reset(struct kfd_dev *kfd);
> >   void kgd2kfd_interrupt(struct kfd_dev *kfd, const void 
> > *ih_ring_entry);
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c 
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> > index 5030a09babb8..43843e6c4bcd 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> > @@ -3311,7 +3311,7 @@ int amdgpu_device_suspend(struct drm_device 
> > *dev, bool fbcon)
> >           }
> >       }
> >   -    amdgpu_amdkfd_suspend(adev);
> > +    amdgpu_amdkfd_suspend(adev, !fbcon);
> >         amdgpu_ras_suspend(adev);
> >   @@ -3395,7 +3395,7 @@ int amdgpu_device_resume(struct drm_device 
> > *dev, bool fbcon)
> >               }
> >           }
> >       }
> > -    r = amdgpu_amdkfd_resume(adev);
> > +    r = amdgpu_amdkfd_resume(adev, !fbcon);
> >       if (r)
> >           return r;
> >   diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device.c 
> > b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
> > index 798ad1c8f799..42ee9ea5c45a 100644
> > --- a/drivers/gpu/drm/amd/amdkfd/kfd_device.c
> > +++ b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
> > @@ -732,7 +732,7 @@ bool kgd2kfd_device_init(struct kfd_dev *kfd,
> >   void kgd2kfd_device_exit(struct kfd_dev *kfd)
> >   {
> >       if (kfd->init_complete) {
> > -        kgd2kfd_suspend(kfd);
> > +        kgd2kfd_suspend(kfd, false);
> >           device_queue_manager_uninit(kfd->dqm);
> >           kfd_interrupt_exit(kfd);
> >           kfd_topology_remove_device(kfd);
> > @@ -753,7 +753,7 @@ int kgd2kfd_pre_reset(struct kfd_dev *kfd)
> >         kfd->dqm->ops.pre_reset(kfd->dqm);
> >   -    kgd2kfd_suspend(kfd);
> > +    kgd2kfd_suspend(kfd, false);
> >         kfd_signal_reset_event(kfd);
> >       return 0;
> > @@ -787,21 +787,23 @@ bool kfd_is_locked(void)
> >       return  (atomic_read(&kfd_locked) > 0);
> >   }
> >   -void kgd2kfd_suspend(struct kfd_dev *kfd)
> > +void kgd2kfd_suspend(struct kfd_dev *kfd, bool run_pm)
> >   {
> >       if (!kfd->init_complete)
> >           return;
> >   -    /* For first KFD device suspend all the KFD processes */
> > -    if (atomic_inc_return(&kfd_locked) == 1)
> > -        kfd_suspend_all_processes();
> > +    /* for runtime suspend, skip locking kfd */
> > +    if (!run_pm) {
> > +        /* For first KFD device suspend all the KFD processes */
> > +        if (atomic_inc_return(&kfd_locked) == 1)
> > +            kfd_suspend_all_processes();
> > +    }
> >         kfd->dqm->ops.stop(kfd->dqm);
> > -
> >       kfd_iommu_suspend(kfd);
> >   }
> >   -int kgd2kfd_resume(struct kfd_dev *kfd)
> > +int kgd2kfd_resume(struct kfd_dev *kfd, bool run_pm)
> >   {
> >       int ret, count;
> >   @@ -812,10 +814,13 @@ int kgd2kfd_resume(struct kfd_dev *kfd)
> >       if (ret)
> >           return ret;
> >   -    count = atomic_dec_return(&kfd_locked);
> > -    WARN_ONCE(count < 0, "KFD suspend / resume ref. error");
> > -    if (count == 0)
> > -        ret = kfd_resume_all_processes();
> > +    /* for runtime resume, skip unlocking kfd */
> > +    if (!run_pm) {
> > +        count = atomic_dec_return(&kfd_locked);
> > +        WARN_ONCE(count < 0, "KFD suspend / resume ref. error");
> > +        if (count == 0)
> > +            ret = kfd_resume_all_processes();
> > +    }
> >         return ret;
> >   }
> > diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h 
> > b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> > index c0b0defc8f7a..20dd4747250d 100644
> > --- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> > +++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> > @@ -647,6 +647,7 @@ struct kfd_process_device {
> >        * function.
> >        */
> >       bool already_dequeued;
> > +    bool runtime_inuse;
> >         /* Is this process/pasid bound to this device? 
> > (amd_iommu_bind_pasid) */
> >       enum kfd_pdd_bound bound;
> > diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c 
> > b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> > index 25b90f70aecd..6907a5a2cbc8 100644
> > --- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> > +++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> > @@ -31,6 +31,7 @@
> >   #include <linux/compat.h>
> >   #include <linux/mman.h>
> >   #include <linux/file.h>
> > +#include <linux/pm_runtime.h>
> >   #include "amdgpu_amdkfd.h"
> >   #include "amdgpu.h"
> >   @@ -440,6 +441,16 @@ static void kfd_process_destroy_pdds(struct 
> > kfd_process *p)
> >           kfree(pdd->qpd.doorbell_bitmap);
> >           idr_destroy(&pdd->alloc_idr);
> >   +        /*
> > +         * before destroying pdd, make sure to report availability
> > +         * for auto suspend
> > +         */
> > +        if (pdd->runtime_inuse) {
> > + pm_runtime_mark_last_busy(pdd->dev->ddev->dev);
> > + pm_runtime_put_autosuspend(pdd->dev->ddev->dev);
> > +            pdd->runtime_inuse = false;
> > +        }
> > +
> >           kfree(pdd);
> >       }
> >   }
> > @@ -754,6 +765,7 @@ struct kfd_process_device 
> > *kfd_create_process_device_data(struct kfd_dev *dev,
> >       pdd->process = p;
> >       pdd->bound = PDD_UNBOUND;
> >       pdd->already_dequeued = false;
> > +    pdd->runtime_inuse = false;
> >       list_add(&pdd->per_device_list, &p->per_device_data);
> >         /* Init idr used for memory handle translation */
> > @@ -843,15 +855,40 @@ struct kfd_process_device 
> > *kfd_bind_process_to_device(struct kfd_dev *dev,
> >           return ERR_PTR(-ENOMEM);
> >       }
> >   +    /*
> > +     * signal runtime-pm system to auto resume and prevent
> > +     * further runtime suspend once device pdd is created until
> > +     * pdd is destroyed.
> > +     */
> > +    if (!pdd->runtime_inuse) {
> > +        err = pm_runtime_get_sync(dev->ddev->dev);
> > +        if (err < 0)
> > +            return ERR_PTR(err);
> > +    }
> > +
> >       err = kfd_iommu_bind_process_to_device(pdd);
> >       if (err)
> > -        return ERR_PTR(err);
> > +        goto out;
> >         err = kfd_process_device_init_vm(pdd, NULL);
> >       if (err)
> > -        return ERR_PTR(err);
> > +        goto out;
> >   -    return pdd;
> > +    if (!err) {
> > +        /*
> > +         * make sure that runtime_usage counter is incremented
> > +         * just once per pdd
> > +         */
> > +        if (!pdd->runtime_inuse)
> > +            pdd->runtime_inuse = true;
>
> The "if" is redundant here. You can just set pdd->runtime_inuse = true 
> unconditionally.
> Regards,
>   Felix
Thanks

Rajneesh

> > +
> > +        return pdd;
> > +    }
> > +out:
> > +    /* balance runpm reference count and exit with error */
> > +    pm_runtime_mark_last_busy(dev->ddev->dev);
> > +    pm_runtime_put_autosuspend(dev->ddev->dev);
> > +    return ERR_PTR(err);
> >   }
> >     struct kfd_process_device *kfd_get_first_process_device_data(
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