Commit 9095e554 authored by Philip Yang's avatar Philip Yang Committed by Alex Deucher
Browse files

drm/amdkfd: Remove arbitrary timeout for hmm_range_fault 



On system with khugepaged enabled and user cases with THP buffer, the
hmm_range_fault may takes > 15 seconds to return -EBUSY, the arbitrary
timeout value is not accurate, cause memory allocation failure.

Remove the arbitrary timeout value, return EAGAIN to application if
hmm_range_fault return EBUSY, then userspace libdrm and Thunk will call
ioctl again.

Change EAGAIN to debug message as this is not error.

Signed-off-by: default avatarPhilip Yang <Philip.Yang@amd.com>
Reviewed-by: default avatarFelix Kuehling <felix.kuehling@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 10f624ef

drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c

+4 −1
Original line number Diff line number Diff line
@@ -1088,6 +1088,9 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr, 


	ret = amdgpu_ttm_tt_get_user_pages(bo, bo->tbo.ttm->pages, &range);

	if (ret) {

		if (ret == -EAGAIN)

			pr_debug("Failed to get user pages, try again\n");

		else

			pr_err("%s: Failed to get user pages: %d\n", __func__, ret);

		goto unregister_out;

	}

drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c

+3 −9
Original line number Diff line number Diff line
@@ -202,20 +202,12 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier, 
		pr_debug("hmm range: start = 0x%lx, end = 0x%lx",

			hmm_range->start, hmm_range->end);



		/* Assuming 64MB takes maximum 1 second to fault page address */

		timeout = max((hmm_range->end - hmm_range->start) >> 26, 1UL);

		timeout *= HMM_RANGE_DEFAULT_TIMEOUT;

		timeout = jiffies + msecs_to_jiffies(timeout);

		timeout = jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);



retry:

		hmm_range->notifier_seq = mmu_interval_read_begin(notifier);

		r = hmm_range_fault(hmm_range);

		if (unlikely(r)) {

			schedule();

			/*

			 * FIXME: This timeout should encompass the retry from

			 * mmu_interval_read_retry() as well.

			 */

			if (r == -EBUSY && !time_after(jiffies, timeout))

				goto retry;

			goto out_free_pfns;
@@ -247,6 +239,8 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier, 
out_free_range:

	kfree(hmm_range);



	if (r == -EBUSY)

		r = -EAGAIN;

	return r;

}

drivers/gpu/drm/amd/amdkfd/kfd_svm.c

+1 −4
Original line number Diff line number Diff line
@@ -1690,11 +1690,8 @@ static int svm_range_validate_and_map(struct mm_struct *mm, 
						       readonly, owner, NULL,

						       &hmm_range);

			WRITE_ONCE(p->svms.faulting_task, NULL);

			if (r) {

			if (r)

				pr_debug("failed %d to get svm range pages\n", r);

				if (r == -EBUSY)

					r = -EAGAIN;

			}

		} else {

			r = -EFAULT;

		}