[PATCH 22/24] drm/amdkfd: add pc sampling release when process release

[Yat Sin, David]

[AMD Official Use Only - General]

> -----Original Message-----
> From: Zhu, James <James.Zhu at amd.com>
> Sent: Friday, November 3, 2023 9:12 AM
> To: amd-gfx at lists.freedesktop.org
> Cc: Kuehling, Felix <Felix.Kuehling at amd.com>; Greathouse, Joseph
> <Joseph.Greathouse at amd.com>; Yat Sin, David <David.YatSin at amd.com>; Zhu,
> James <James.Zhu at amd.com>
> Subject: [PATCH 22/24] drm/amdkfd: add pc sampling release when process
> release
>
> Add pc sampling release when process release, it will force to stop all activate
> sessions with this process.
>
> Signed-off-by: James Zhu <James.Zhu at amd.com>
> ---
>  drivers/gpu/drm/amd/amdkfd/kfd_pc_sampling.c | 26
> ++++++++++++++++++++  drivers/gpu/drm/amd/amdkfd/kfd_pc_sampling.h |
> 1 +
>  drivers/gpu/drm/amd/amdkfd/kfd_process.c     |  3 +++
>  3 files changed, 30 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_pc_sampling.c
> b/drivers/gpu/drm/amd/amdkfd/kfd_pc_sampling.c
> index 66670cdb813a..00d8d3f400a9 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_pc_sampling.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_pc_sampling.c
> @@ -274,6 +274,32 @@ static int kfd_pc_sample_destroy(struct
> kfd_process_device *pdd, uint32_t trace_
>       return 0;
>  }
>
> +void kfd_pc_sample_release(struct kfd_process_device *pdd) {
> +     struct pc_sampling_entry *pcs_entry;
> +     struct idr *idp;
> +     uint32_t id;
> +
> +     if (sched_policy == KFD_SCHED_POLICY_NO_HWS) {
> +             pr_err("PC Sampling does not support sched_policy %i",
> sched_policy);
> +             return;
> +     }
You do not need to check the sched_policy here, already checked in kfd_ioctl_pc_sample(..) , so cannot have a hosttrap session if policy is NO_HWS.
> +
> +     /* force to release all PC sampling task for this process */
> +     idp = &pdd->dev->pcs_data.hosttrap_entry.base.pc_sampling_idr;
> +     mutex_lock(&pdd->dev->pcs_data.mutex);
> +     idr_for_each_entry(idp, pcs_entry, id) {
> +             if (pcs_entry->pdd != pdd)
> +                     continue;
> +             mutex_unlock(&pdd->dev->pcs_data.mutex);
Can we not release the mutex here and just tell the worker thread to exit by setting the stop_enable bit.
I find we have a lot of places where we are acquiring/releasing the mutex within loops and this results in a
lot of extra states that we have to account for during the start/stop/destroy calls.
> +             if (pcs_entry->enabled)
> +                     kfd_pc_sample_stop(pdd, pcs_entry);
> +             kfd_pc_sample_destroy(pdd, id, pcs_entry);
> +             mutex_lock(&pdd->dev->pcs_data.mutex);
> +     }
> +     mutex_unlock(&pdd->dev->pcs_data.mutex);
> +}
> +
>  int kfd_pc_sample(struct kfd_process_device *pdd,
>                                       struct kfd_ioctl_pc_sample_args __user
> *args)  { diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_pc_sampling.h
> b/drivers/gpu/drm/amd/amdkfd/kfd_pc_sampling.h
> index cb93909e6bd3..4ea064fdaa98 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_pc_sampling.h
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_pc_sampling.h
> @@ -30,6 +30,7 @@
>
>  int kfd_pc_sample(struct kfd_process_device *pdd,
>                                       struct kfd_ioctl_pc_sample_args __user
> *args);
> +void kfd_pc_sample_release(struct kfd_process_device *pdd);
>  void kfd_pc_sample_handler(struct work_struct *work);
>
>  #endif /* KFD_PC_SAMPLING_H_ */
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> index d22d804f180d..54f3db7eaae2 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> @@ -43,6 +43,7 @@ struct mm_struct;
>  #include "kfd_svm.h"
>  #include "kfd_smi_events.h"
>  #include "kfd_debug.h"
> +#include "kfd_pc_sampling.h"
>
>  /*
>   * List of struct kfd_process (field kfd_process).
> @@ -1020,6 +1021,8 @@ static void kfd_process_destroy_pdds(struct
> kfd_process *p)
>               pr_debug("Releasing pdd (topology id %d) for process (pasid
> 0x%x)\n",
>                               pdd->dev->id, p->pasid);
>
> +             kfd_pc_sample_release(pdd);
> +
>               kfd_process_device_destroy_cwsr_dgpu(pdd);
>               kfd_process_device_destroy_ib_mem(pdd);
>
> --
> 2.25.1