Re: [PATCH 2/2] drm/amdgpu: make an improvement on amdgpu_hmm_range_get_pages

[James Zhu]

On 2023-12-11 05:38, Christian König wrote:

Am 09.12.23 um 00:01 schrieb James Zhu:

Needn't do schedule for each hmm_range_fault, and use cond_resched
to replace schedule.

cond_resched() is usually NAKed upstream since it is a NO-OP in most situations.

[JZ] then let me change back to schedule(); Thanks!

IIRC there was even a patch set to completely remove it.

Christian.

Signed-off-by: James Zhu <james....@amd.com>
---
  drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c

index b24eb5821fd1..c77c4eceea46 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c

@@ -199,6 +199,7 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,

          hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
          r = hmm_range_fault(hmm_range);
          if (unlikely(r)) {
+            cond_resched();
              /*
               * FIXME: This timeout should encompass the retry from
               * mmu_interval_read_retry() as well.

@@ -212,7 +213,6 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,

              break;
          hmm_range->hmm_pfns += MAX_WALK_BYTE >> PAGE_SHIFT;
          hmm_range->start = hmm_range->end;
-        schedule();
      } while (hmm_range->end < end);
        hmm_range->start = start;