Re: [PATCH 5/5] drm/amdgpu: Refactor GPU reset for XGMI hive case.

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Am 22.11.18 um 16:44 schrieb Grodzovsky, Andrey:

On 11/22/2018 06:16 AM, Christian König wrote:
How about using a lock per hive and then acquiring that with trylock()
instead?

This way you should at least catch cases where multiple causes try to
reset the same hive at the same time. True that there is still some
racing involved, but it's at least a good start.
What about using per hive work_struct which when scheduled will execute
amdgpu_device_gpu_recover ? Since work queue rejects duplicates we will
get per hive serialization automatically from that without need of using
any new mutex. Also this might be necessary anyway for RAS as I believe
RAS will trigger interrupt when errors are detected and might then
decide to reset the GPU so we will have to switch to button half context
anyway. And I don't think it's a problem to schedule this work from job
timeout handler if needed.

Mhm, what is the advantage to the trylock variant? The key problem with that is how to get the offending job into the background worker.

E.g. we have trouble guaranteeing that the job isn't destroyed when this is in a background worker.



Additional to that I would try improve the pre, middle, post handling
towards checking if we made some progress in between.

In other words we stop all schedulers in the pre handling and
disconnect the scheduler fences from the hardware fence like I did in
patch "drm/sched: fix timeout handling v2".

Then before we do the actual reset in the middle handling we check if
the offending job has completed or at least made some progress in the
meantime.
I understand how to check if the job completed - if it's fence already
signaled, but how do I test if the job made 'at least some progress' ?

Good question. Maybe we can somehow query from the hardware the number of primitives or pixels processed so far and then compare after a moment?

Another question - what's the purpose of this progress check - if I've
already completed the pre handling sequence  I can't bail out even if
the guilty job is is signaled by the time I do the progress check, I
have to complete at least the post handling to. Do you mean I can at
least skip the ASIC reset phase in that case ?

Yes exactly. We have a rather big race problem in the current reset logic between completing the job and resetting the hardware.

In other words when the job completes exactly in the moment we reset the GPU we try to signal it twice etc etc... The whole handling here is not really thought through.

Christian.


Andrey

In the case of a manual reset we skip that because we don't have an
offending job to check.

In the post handling we stitch everything together again and start the
scheduler to go on with job submission.

Christian.

Am 21.11.18 um 23:02 schrieb Grodzovsky, Andrey:
Depends what was the reason for triggering the reset for that node how
do we know ?
If the reason was RAS error that probably not hard to check all errors
are cleared, but
if the reason was job timeout on that specific node I will need to
recheck that no jobs are left in incomplete state
state. And if the reason is manual gpu reset trigger from sysfs, then
what's the policy ?
Sounds to me it's just easier to go ahead and allow all the pending
resets to proceed unless there is
a clear and quick criteria you can check after you grab the mutex then
sure - but I don't know what it would be.

Andrey

On 11/21/2018 03:49 PM, Liu, Shaoyun wrote:
I saw you use the  global xgmi_mutex to prevent concurrent reset to be
triggered by different nodes ,  but after the  mutex been released ,
current node may grap the mutex and continue to do another reset .
Maybe  we should check the GPU status and  skip the  reset in this case
since the  GPU may already be in good state .

Regards

shaoyun.liu

On 2018-11-21 1:10 p.m., Andrey Grodzovsky wrote:
For XGMI hive case do reset in steps where each step iterates over
all devs in hive. This especially important for asic reset
since all PSP FW in hive must come up within a limited time
(around 1 sec) to properply negotiate the link.
Do this by  refactoring  amdgpu_device_gpu_recover and
amdgpu_device_reset
into pre_asic_reset, asic_reset and post_asic_reset functions where
is part
is exectued for all the GPUs in the hive before going to the next
step.

Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@xxxxxxx>
---
     drivers/gpu/drm/amd/amdgpu/amdgpu.h        |   5 +-
     drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 375
++++++++++++++++++++---------
     2 files changed, 264 insertions(+), 116 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 4ef5f7a..bd06d45 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1026,6 +1026,9 @@ struct amdgpu_device {
         unsigned long last_mm_index;
         bool                            in_gpu_reset;
         struct mutex  lock_reset;
+
+    int asic_reset_res;
+    int resched;
     };
         static inline struct amdgpu_device *amdgpu_ttm_adev(struct
ttm_bo_device *bdev)
@@ -1232,7 +1235,7 @@ struct amdgpu_hive_info;
         struct list_head *amdgpu_xgmi_get_adev_list_handle(struct
amdgpu_hive_info *hive);
     struct amdgpu_hive_info *amdgpu_get_xgmi_hive(struct
amdgpu_device *adev);
-int amdgpu_xgmi_update_topology(struct amdgpu_hive_info *hive);
+int amdgpu_xgmi_update_topology(struct amdgpu_hive_info *hive,
struct amdgpu_device *adev);
     int amdgpu_xgmi_add_device(struct amdgpu_device *adev);
         /*
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index cb06e68..8e94d7f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -3157,86 +3157,6 @@ static int amdgpu_device_recover_vram(struct
amdgpu_device *adev)
         return 0;
     }
     -/**
- * amdgpu_device_reset - reset ASIC/GPU for bare-metal or passthrough
- *
- * @adev: amdgpu device pointer
- *
- * attempt to do soft-reset or full-reset and reinitialize Asic
- * return 0 means succeeded otherwise failed
- */
-static int amdgpu_device_reset(struct amdgpu_device *adev)
-{
-    bool need_full_reset, vram_lost = 0;
-    int r;
-
-    need_full_reset = amdgpu_device_ip_need_full_reset(adev);
-
-    if (!need_full_reset) {
-        amdgpu_device_ip_pre_soft_reset(adev);
-        r = amdgpu_device_ip_soft_reset(adev);
-        amdgpu_device_ip_post_soft_reset(adev);
-        if (r || amdgpu_device_ip_check_soft_reset(adev)) {
-            DRM_INFO("soft reset failed, will fallback to full
reset!\n");
-            need_full_reset = true;
-        }
-    }
-
-    if (need_full_reset) {
-        r = amdgpu_device_ip_suspend(adev);
-
-retry:
-        r = amdgpu_asic_reset(adev);
-        /* post card */
- amdgpu_atom_asic_init(adev->mode_info.atom_context);
-
-        if (!r) {
-            dev_info(adev->dev, "GPU reset succeeded, trying to
resume\n");
-            r = amdgpu_device_ip_resume_phase1(adev);
-            if (r)
-                goto out;
-
-            vram_lost = amdgpu_device_check_vram_lost(adev);
-            if (vram_lost) {
-                DRM_ERROR("VRAM is lost!\n");
- atomic_inc(&adev->vram_lost_counter);
-            }
-
-            r = amdgpu_gtt_mgr_recover(
-                &adev->mman.bdev.man[TTM_PL_TT]);
-            if (r)
-                goto out;
-
-            r = amdgpu_device_fw_loading(adev);
-            if (r)
-                return r;
-
-            r = amdgpu_device_ip_resume_phase2(adev);
-            if (r)
-                goto out;
-
-            if (vram_lost)
-                amdgpu_device_fill_reset_magic(adev);
-        }
-    }
-
-out:
-    if (!r) {
-        amdgpu_irq_gpu_reset_resume_helper(adev);
-        r = amdgpu_ib_ring_tests(adev);
-        if (r) {
-            dev_err(adev->dev, "ib ring test failed (%d).\n", r);
-            r = amdgpu_device_ip_suspend(adev);
-            need_full_reset = true;
-            goto retry;
-        }
-    }
-
-    if (!r)
-        r = amdgpu_device_recover_vram(adev);
-
-    return r;
-}
         /**
      * amdgpu_device_reset_sriov - reset ASIC for SR-IOV vf
@@ -3335,31 +3255,16 @@ bool
amdgpu_device_should_recover_gpu(struct amdgpu_device *adev)
             return false;
     }
     -/**
- * amdgpu_device_gpu_recover - reset the asic and recover scheduler
- *
- * @adev: amdgpu device pointer
- * @job: which job trigger hang
- *
- * Attempt to reset the GPU if it has hung (all asics).
- * Returns 0 for success or an error on failure.
- */
-int amdgpu_device_gpu_recover(struct amdgpu_device *adev,
-                  struct amdgpu_job *job)
-{
-    int i, r, resched;
-
-    dev_info(adev->dev, "GPU reset begin!\n");
-
-    mutex_lock(&adev->lock_reset);
-    atomic_inc(&adev->gpu_reset_counter);
-    adev->in_gpu_reset = 1;
     -    /* Block kfd */
-    amdgpu_amdkfd_pre_reset(adev);
+static int amdgpu_device_pre_asic_reset(struct amdgpu_device *adev,
+                    struct amdgpu_job *job,
+                    bool *need_full_reset_arg)
+{
+    int i, r = 0;
+    bool need_full_reset  = *need_full_reset_arg;
             /* block TTM */
-    resched = ttm_bo_lock_delayed_workqueue(&adev->mman.bdev);
+    adev->resched = ttm_bo_lock_delayed_workqueue(&adev->mman.bdev);
             /* block all schedulers and reset given job's ring */
         for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
@@ -3379,10 +3284,121 @@ int amdgpu_device_gpu_recover(struct
amdgpu_device *adev,
             amdgpu_fence_driver_force_completion(ring);
         }
     -    if (amdgpu_sriov_vf(adev))
-        r = amdgpu_device_reset_sriov(adev, job ? false : true);
-    else
-        r = amdgpu_device_reset(adev);
+    if (!amdgpu_sriov_vf(adev)) {
+
+        if (!need_full_reset)
+            need_full_reset = amdgpu_device_ip_need_full_reset(adev);
+
+        if (!need_full_reset) {
+            amdgpu_device_ip_pre_soft_reset(adev);
+            r = amdgpu_device_ip_soft_reset(adev);
+            amdgpu_device_ip_post_soft_reset(adev);
+            if (r || amdgpu_device_ip_check_soft_reset(adev)) {
+                DRM_INFO("soft reset failed, will fallback to full
reset!\n");
+                need_full_reset = true;
+            }
+        }
+
+        if (need_full_reset)
+            r = amdgpu_device_ip_suspend(adev);
+
+        *need_full_reset_arg = need_full_reset;
+    }
+
+    return r;
+}
+
+static int amdgpu_do_asic_reset(struct amdgpu_hive_info *hive,
+                   struct list_head *device_list_handle,
+                   bool *need_full_reset_arg)
+{
+    struct amdgpu_device *tmp_adev = NULL;
+    bool need_full_reset = *need_full_reset_arg, vram_lost = false;
+    int r = 0;
+
+    /*
+     * ASIC reset has to be done on all HGMI hive nodes ASAP
+     * to allow proper links negotiation in FW (within 1 sec)
+     */
+    if (need_full_reset) {
+        list_for_each_entry(tmp_adev, device_list_handle,
gmc.xgmi.head) {
+            r = amdgpu_asic_reset(tmp_adev);
+            if (r)
+                DRM_WARN("ASIC reset failed with err r, %d for drm
dev, %s",
+                     r, tmp_adev->ddev->unique);
+        }
+    }
+
+
+    list_for_each_entry(tmp_adev, device_list_handle,
gmc.xgmi.head) {
+        if (need_full_reset) {
+            /* post card */
+            if
(amdgpu_atom_asic_init(tmp_adev->mode_info.atom_context))
+                DRM_WARN("asic atom init failed!");
+
+            if (!r) {
+                dev_info(tmp_adev->dev, "GPU reset succeeded,
trying to resume\n");
+                r = amdgpu_device_ip_resume_phase1(tmp_adev);
+                if (r)
+                    goto out;
+
+                vram_lost = amdgpu_device_check_vram_lost(tmp_adev);
+                if (vram_lost) {
+                    DRM_ERROR("VRAM is lost!\n");
+ atomic_inc(&tmp_adev->vram_lost_counter);
+                }
+
+                r = amdgpu_gtt_mgr_recover(
+ &tmp_adev->mman.bdev.man[TTM_PL_TT]);
+                if (r)
+                    goto out;
+
+                r = amdgpu_device_fw_loading(tmp_adev);
+                if (r)
+                    return r;
+
+                r = amdgpu_device_ip_resume_phase2(tmp_adev);
+                if (r)
+                    goto out;
+
+                if (vram_lost)
+ amdgpu_device_fill_reset_magic(tmp_adev);
+
+                /* Update PSP FW topology after reset */
+                if (tmp_adev->gmc.xgmi.num_physical_nodes > 1)
+                    r = amdgpu_xgmi_update_topology(hive, tmp_adev);
+            }
+        }
+
+
+out:
+        if (!r) {
+            amdgpu_irq_gpu_reset_resume_helper(tmp_adev);
+            r = amdgpu_ib_ring_tests(tmp_adev);
+            if (r) {
+                dev_err(tmp_adev->dev, "ib ring test failed
(%d).\n", r);
+                r = amdgpu_device_ip_suspend(tmp_adev);
+                need_full_reset = true;
+                r = -EAGAIN;
+                goto end;
+            }
+        }
+
+        if (!r)
+            r = amdgpu_device_recover_vram(tmp_adev);
+        else
+            tmp_adev->asic_reset_res = r;
+    }
+
+end:
+    *need_full_reset_arg = need_full_reset;
+    return r;
+}
+
+static void amdgpu_device_post_asic_reset(struct amdgpu_device *adev,
+                      struct amdgpu_job *job)
+{
+    int i;
             for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
             struct amdgpu_ring *ring = adev->rings[i];
@@ -3394,7 +3410,7 @@ int amdgpu_device_gpu_recover(struct
amdgpu_device *adev,
              * or all rings (in the case @job is NULL)
              * after above amdgpu_reset accomplished
              */
-        if ((!job || job->base.sched == &ring->sched) && !r)
+        if ((!job || job->base.sched == &ring->sched) &&
!adev->asic_reset_res)
                 drm_sched_job_recovery(&ring->sched);
                 kthread_unpark(ring->sched.thread);
@@ -3404,21 +3420,150 @@ int amdgpu_device_gpu_recover(struct
amdgpu_device *adev,
             drm_helper_resume_force_mode(adev->ddev);
         }
     - ttm_bo_unlock_delayed_workqueue(&adev->mman.bdev, resched);
+ ttm_bo_unlock_delayed_workqueue(&adev->mman.bdev, adev->resched);
     -    if (r) {
-        /* bad news, how to tell it to userspace ? */
-        dev_info(adev->dev, "GPU reset(%d) failed\n",
atomic_read(&adev->gpu_reset_counter));
-        amdgpu_vf_error_put(adev, AMDGIM_ERROR_VF_GPU_RESET_FAIL,
0, r);
-    } else {
-        dev_info(adev->dev, "GPU reset(%d)
succeeded!\n",atomic_read(&adev->gpu_reset_counter));
-    }
+    adev->asic_reset_res = adev->resched = 0;
+
+}
     +static void amdgpu_lock_adev(struct amdgpu_device *adev)
+{
+    mutex_lock(&adev->lock_reset);
+    atomic_inc(&adev->gpu_reset_counter);
+    adev->in_gpu_reset = 1;
+    /* Block kfd */
+    amdgpu_amdkfd_pre_reset(adev);
+}
+
+static void amdgpu_unlock_adev(struct amdgpu_device *adev)
+{
         /*unlock kfd */
         amdgpu_amdkfd_post_reset(adev);
         amdgpu_vf_error_trans_all(adev);
         adev->in_gpu_reset = 0;
         mutex_unlock(&adev->lock_reset);
+}
+
+
+/**
+ * amdgpu_device_gpu_recover - reset the asic and recover scheduler
+ *
+ * @adev: amdgpu device pointer
+ * @job: which job trigger hang
+ *
+ * Attempt to reset the GPU if it has hung (all asics).
+ * Attempt to do soft-reset or full-reset and reinitialize Asic
+ * Returns 0 for success or an error on failure.
+ */
+
+int amdgpu_device_gpu_recover(struct amdgpu_device *adev,
+                  struct amdgpu_job *job)
+{
+    int r;
+    struct amdgpu_hive_info *hive = NULL;
+    bool need_full_reset = false;
+    struct amdgpu_device *tmp_adev = NULL;
+    struct list_head device_list, *device_list_handle = NULL;
+
+    INIT_LIST_HEAD(&device_list);
+
+    dev_info(adev->dev, "GPU reset begin!\n");
+
+    /*
+     * In case of XGMI hive disallow concurrent resets to be
triggered
+     * by different nodes.
+     */
+    if (adev->gmc.xgmi.num_physical_nodes > 1)
+        mutex_lock(&xgmi_mutex);
+
+    /* Start with adev pre asic reset first for soft reset check.*/
+    amdgpu_lock_adev(adev);
+    r = amdgpu_device_pre_asic_reset(adev,
+                     job,
+                     &need_full_reset);
+    if (r) {
+        /*TODO Should we stop ?*/
+        DRM_ERROR("GPU pre asic reset failed with err, %d for drm
dev, %s ",
+              r, adev->ddev->unique);
+        adev->asic_reset_res = r;
+    }
+
+    /* Build list of devices to reset */
+    if  (need_full_reset && adev->gmc.xgmi.num_physical_nodes > 1) {
+        hive = amdgpu_get_xgmi_hive(adev);
+        if (!hive) {
+            r = -ENODEV;
+
+            amdgpu_unlock_adev(adev);
+
+            if (adev->gmc.xgmi.num_physical_nodes > 1)
+                mutex_unlock(&xgmi_mutex);
+            return r;
+        }
+
+        /*
+         * In case we are in XGMI hive mode device reset is done
for all the
+         * nodes in the hive to retrain all XGMI links and hence
the reset
+         * sequence is executed in loop on all nodes.
+         */
+        device_list_handle = amdgpu_xgmi_get_adev_list_handle(hive);
+    } else {
+        list_add_tail(&adev->gmc.xgmi.head, &device_list);
+        device_list_handle = &device_list;
+    }
+
+retry:    /* Rest of adevs pre asic reset from XGMI hive. */
+    list_for_each_entry(tmp_adev, device_list_handle,
gmc.xgmi.head) {
+
+        if (tmp_adev == adev)
+            continue;
+
+        dev_info(tmp_adev->dev, "GPU reset begin for drm dev
%s!\n", adev->ddev->unique);
+
+        amdgpu_lock_adev(tmp_adev);
+        r = amdgpu_device_pre_asic_reset(tmp_adev,
+                         NULL,
+                         &need_full_reset);
+        /*TODO Should we stop ?*/
+        if (r) {
+            DRM_ERROR("GPU pre asic reset failed with err, %d for
drm dev, %s ",
+                  r, tmp_adev->ddev->unique);
+            tmp_adev->asic_reset_res = r;
+        }
+    }
+
+    /* Actual ASIC resets if needed.*/
+    /* TODO Implement XGMI hive reset logic for SRIOV */
+    if (amdgpu_sriov_vf(adev)) {
+        r = amdgpu_device_reset_sriov(adev, job ? false : true);
+        if (r)
+            adev->asic_reset_res = r;
+    } else {
+        r  = amdgpu_do_asic_reset(hive, device_list_handle,
&need_full_reset);
+        if (r && r == -EAGAIN)
+            goto retry;
+    }
+
+    /* Post ASIC reset for all devs .*/
+    list_for_each_entry(tmp_adev, device_list_handle,
gmc.xgmi.head) {
+        amdgpu_device_post_asic_reset(tmp_adev, tmp_adev == adev ?
job : NULL);
+
+        if (r) {
+            /* bad news, how to tell it to userspace ? */
+            dev_info(tmp_adev->dev, "GPU reset(%d) failed\n",
atomic_read(&adev->gpu_reset_counter));
+            amdgpu_vf_error_put(tmp_adev,
AMDGIM_ERROR_VF_GPU_RESET_FAIL, 0, r);
+        } else {
+            dev_info(tmp_adev->dev, "GPU reset(%d) succeeded!\n",
atomic_read(&adev->gpu_reset_counter));
+        }
+
+        amdgpu_unlock_adev(tmp_adev);
+    }
+
+    if (adev->gmc.xgmi.num_physical_nodes > 1)
+        mutex_unlock(&xgmi_mutex);
+
+    if (r)
+        dev_info(adev->dev, "GPU reset end with ret = %d\n", r);
         return r;
     }
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