Re: [PATCH] drm/amdkfd: Only apply heavy-weight TLB flush on Aldebaran

[Eric Huang]

Hi Felix,

I was not able to reproduce the VM fault issue of SWDEV-249241, which is 
the only regression reported on MI200. So the patch is valid to review. 
Please take a look.

Thanks,
Eric

On 2021-07-09 1:45 a.m., Chen, Guchun wrote:
[Public]

Original patch will cause regressions on Aldebaran as well, so this workaround 
is still invalid.

Regards,
Guchun

-----Original Message-----
From: amd-gfx <amd-gfx-boun...@lists.freedesktop.org> On Behalf Of Eric Huang
Sent: Friday, July 9, 2021 3:54 AM
To: amd-gfx@lists.freedesktop.org
Cc: Huang, JinHuiEric <jinhuieric.hu...@amd.com>; Kuehling, Felix 
<felix.kuehl...@amd.com>
Subject: [PATCH] drm/amdkfd: Only apply heavy-weight TLB flush on Aldebaran

It is to workaround HW bug on other Asics and based on reverting two commits:
   drm/amdkfd: Add heavy-weight TLB flush after unmapping
   drm/amdkfd: Add memory sync before TLB flush on unmap

Signed-off-by: Eric Huang <jinhuieric.hu...@amd.com>
---
  drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 37 +++++++++++++-----------
  1 file changed, 20 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
index ebb4872c5a9d..5f2655cf0162 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
@@ -1773,26 +1773,29 @@ static int kfd_ioctl_unmap_memory_from_gpu(struct file 
*filep,
        }
        mutex_unlock(&p->mutex);
  
-	err = amdgpu_amdkfd_gpuvm_sync_memory(dev->kgd, (struct kgd_mem *) mem, true);
-       if (err) {
-               pr_debug("Sync memory failed, wait interrupted by user 
signal\n");
-               goto sync_memory_failed;
-       }
+       if (dev->device_info->asic_family == CHIP_ALDEBARAN) {
+               err = amdgpu_amdkfd_gpuvm_sync_memory(dev->kgd,
+                               (struct kgd_mem *) mem, true);
  
-	/* Flush TLBs after waiting for the page table updates to complete */
-       for (i = 0; i < args->n_devices; i++) {
-               peer = kfd_device_by_id(devices_arr[i]);
-               if (WARN_ON_ONCE(!peer))
-                       continue;
-               peer_pdd = kfd_get_process_device_data(peer, p);
-               if (WARN_ON_ONCE(!peer_pdd))
-                       continue;
-               if (!amdgpu_read_lock(peer->ddev, true)) {
-                       kfd_flush_tlb(peer_pdd, TLB_FLUSH_HEAVYWEIGHT);
-                       amdgpu_read_unlock(peer->ddev);
+               if (err) {
+                       pr_debug("Sync memory failed, wait interrupted by user 
signal\n");
+                       goto sync_memory_failed;
                }
-       }
  
+		/* Flush TLBs after waiting for the page table updates to complete */
+               for (i = 0; i < args->n_devices; i++) {
+                       peer = kfd_device_by_id(devices_arr[i]);
+                       if (WARN_ON_ONCE(!peer))
+                               continue;
+                       peer_pdd = kfd_get_process_device_data(peer, p);
+                       if (WARN_ON_ONCE(!peer_pdd))
+                               continue;
+                       if (!amdgpu_read_lock(peer->ddev, true)) {
+                               kfd_flush_tlb(peer_pdd, TLB_FLUSH_HEAVYWEIGHT);
+                               amdgpu_read_unlock(peer->ddev);
+                       }
+               }
+       }
        kfree(devices_arr);
  
  	return 0;
--
2.25.1

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