Re: [Patch v1 5/5] drm/amdkfd: refactor runtime pm for baco

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Hello Felix,

Thanks for your time to review and for your feedback.

On 1/29/2020 5:52 PM, Felix Kuehling wrote:
HI Rajneesh,

See comments inline ...

And a general question: Why do you need to set the autosuspend_delay in so many places? Amdgpu only has a single call to this function during initialization.


We don't. I have called this out in cover letter since i too feel its not the best way to do what we want to do. I have seen weird issues on dual GPUs with KFDTest that sometimes results in system hang and gpu hang etc.

Even if i try with running kfdtest on just one node in a multi gpu system, the baco exit seems to wake up all gpus and then one goes to auto suspend again while other performs the desired kfdtest operation. I have never seen any issue with a single gpu card. So in current approch, i am making sure that the GPUs are not quickly auto-suspended while the kfd operations are ongoing but once the kfdtest is finished, the runtime suspend call with ensure to reset the timeout back to 5 seconds.


I would like to avoid this and appreciate some pointers where i can put get_sync calls while unbinding. I have tried a number of places but saw some issues. So any help will be highly appreciated, to identify the proper logical inverse of kfd_bind_process_to_device.



On 2020-01-27 20:29, 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 runtime power management.

Signed-off-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@xxxxxxx>
---
  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    | 31 +++++++++++++---------
  drivers/gpu/drm/amd/amdkfd/kfd_iommu.c     |  5 +++-
  drivers/gpu/drm/amd/amdkfd/kfd_process.c   | 19 ++++++++++---
  6 files changed, 51 insertions(+), 28 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 0fa898d30207..3dce4a51e522 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
@@ -123,8 +123,8 @@ 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);
@@ -250,8 +250,8 @@ 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 d9e5eac182d3..787d49e9f4de 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -3314,7 +3314,7 @@ int amdgpu_device_suspend(struct drm_device *dev, bool fbcon)
          }
      }
  -    amdgpu_amdkfd_suspend(adev);
+    amdgpu_amdkfd_suspend(adev, fbcon);

The logic seems inverted here. There are four different pmops callbacks that use different values for this parameter:

* amdgpu_pmops_suspend: true
* amdgpu_pmops_freeze: true
* amdgpu_pmops_poweroff: true
* amdgpu_pmops_runtime_suspend: false

It looks like runtime_suspend uses false, so you should pass the run_pm parameter as !fbcon.

Ok. will fix in v2.




        amdgpu_ras_suspend(adev);
  @@ -3398,7 +3398,7 @@ 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 2a9e40131735..e9f00c3a067a 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
@@ -23,6 +23,7 @@
  #include <linux/bsearch.h>
  #include <linux/pci.h>
  #include <linux/slab.h>
+#include <linux/pm_runtime.h>
  #include "kfd_priv.h"
  #include "kfd_device_queue_manager.h"
  #include "kfd_pm4_headers_vi.h"
@@ -710,7 +711,7 @@ 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, true);
          device_queue_manager_uninit(kfd->dqm);
          kfd_interrupt_exit(kfd);
          kfd_topology_remove_device(kfd);
@@ -731,7 +732,7 @@ int kgd2kfd_pre_reset(struct kfd_dev *kfd)
        kfd->dqm->ops.pre_reset(kfd->dqm);
  -    kgd2kfd_suspend(kfd);
+    kgd2kfd_suspend(kfd, true);

This should use false. This is not runtime PM.


        kfd_signal_reset_event(kfd);
      return 0;
@@ -765,21 +766,24 @@ 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) {

This should be done for the non-runtime PM case: if (!run_pm).


+        /* For first KFD device suspend all the KFD processes */
+        if (atomic_inc_return(&kfd_locked) == 1)
+            kfd_suspend_all_processes();
+    }
  +    pm_runtime_set_autosuspend_delay(kfd->ddev->dev, 5000);
      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;
  @@ -790,10 +794,13 @@ 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) {

Same as above.


+        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_iommu.c b/drivers/gpu/drm/amd/amdkfd/kfd_iommu.c
index 8d871514671e..6301d77ed3d6 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_iommu.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_iommu.c
@@ -25,6 +25,7 @@
  #include <linux/slab.h>
  #include <linux/pci.h>
  #include <linux/amd-iommu.h>
+#include <linux/pm_runtime.h>
  #include "kfd_priv.h"
  #include "kfd_dbgmgr.h"
  #include "kfd_topology.h"
@@ -134,8 +135,10 @@ void kfd_iommu_unbind_process(struct kfd_process *p)
      struct kfd_process_device *pdd;
        list_for_each_entry(pdd, &p->per_device_data, per_device_list)
-        if (pdd->bound == PDD_BOUND)
+        if (pdd->bound == PDD_BOUND) {
              amd_iommu_unbind_pasid(pdd->dev->pdev, p->pasid);
+ pm_runtime_set_autosuspend_delay(pdd->dev->ddev->dev, 5000);

I don't think this is the right place. This code should only run on APUs with IOMMUv2 enabled. Probably missing a check at the start of the function. On kernels with IOMMU disabled, this source file is not compiled at all.

I think this code should go into kfd_process_destroy_pdds.


Ok. will fix in v2. So can we consider this as logical inverse of bind_process_to_device?




+        }
  }
    /* Callback for process shutdown invoked by the IOMMU driver */
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
index 25b90f70aecd..d19d5e97405c 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"
  @@ -843,15 +844,27 @@ struct kfd_process_device *kfd_bind_process_to_device(struct kfd_dev *dev,
          return ERR_PTR(-ENOMEM);
      }
  +    err = pm_runtime_get_sync(dev->ddev->dev);
+    pm_runtime_set_autosuspend_delay(dev->ddev->dev, 60000);

Why are you using a different hard-coded delay (60s?) here?


It needs to be fixed. Explained above the reason for such deviation.



Regards,
  Felix


Thanks
Rajneesh


+    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;
+out:
+    pm_runtime_mark_last_busy(dev->ddev->dev);
+    pm_runtime_put_autosuspend(dev->ddev->dev);
+
+    if (!err)
+        return pdd;
+    else
+        return ERR_PTR(err);
  }
    struct kfd_process_device *kfd_get_first_process_device_data(
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