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From: Andrew Morton <akpm@linux-foundation.org>
To: mm-commits@vger.kernel.org,wei.liu@kernel.org,vbabka@kernel.org,tzimmermann@suse.de,surenb@google.com,shuah@kernel.org,rppt@kernel.org,oleg@redhat.com,ogabbay@kernel.org,mripard@kernel.org,mhocko@suse.com,maarten.lankhorst@linux.intel.com,lyude@redhat.com,longli@microsoft.com,ljs@kernel.org,lizhi.hou@amd.com,liam@infradead.org,leon@kernel.org,kys@microsoft.com,kees@kernel.org,jgg@nvidia.com,haiyangz@microsoft.com,decui@microsoft.com,david@kernel.org,dakr@kernel.org,corbet@lwn.net,airlied@gmail.com,skinsburskii@gmail.com,akpm@linux-foundation.org
Subject: + drm-gpusvm-use-hmm_range_fault_unlocked_timeout-for-range-faults-fix.patch added to mm-unstable branch
Date: Tue, 14 Jul 2026 19:18:02 -0700	[thread overview]
Message-ID: <20260715021803.5C51F1F000E9@smtp.kernel.org> (raw)


The patch titled
     Subject: drm-gpusvm-use-hmm_range_fault_unlocked_timeout-for-range-faults-fix
has been added to the -mm mm-unstable branch.  Its filename is
     drm-gpusvm-use-hmm_range_fault_unlocked_timeout-for-range-faults-fix.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/drm-gpusvm-use-hmm_range_fault_unlocked_timeout-for-range-faults-fix.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Stanislav Kinsburskii <skinsburskii@gmail.com>
Subject: drm-gpusvm-use-hmm_range_fault_unlocked_timeout-for-range-faults-fix
Date: Tue, 14 Jul 2026 15:21:49 -0700

The timeout passed to hmm_range_fault_unlocked_timeout() is a relative
retry budget for HMM's internal mmu-notifier retry loop.  drm_gpusvm was
still keeping an absolute deadline around the outer driver retry logic and
passing the remaining time into HMM.

Pass HMM_RANGE_DEFAULT_TIMEOUT directly to
hmm_range_fault_unlocked_timeout() on each HMM fault attempt instead.  If
HMM succeeds but the later drm_gpusvm-side mmu_interval_read_retry() check
observes an invalidation, retry with a fresh HMM retry budget.

This keeps the timeout focused on repeated notifier retries inside HMM,
while avoiding an outer deadline that also accounts unrelated driver-side
work after HMM has made progress.

Link: https://lore.kernel.org/178406770964.1106335.10099816010446253543.stgit@skinsburskii
Signed-off-by: Stanislav Kinsburskii <skinsburskii@gmail.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kees Cook <kees@kernel.org>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lizhi Hou <lizhi.hou@amd.com>
Cc: Long Li <longli@microsoft.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Lyude <lyude@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oded Gabbay <ogabbay@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/gpu/drm/drm_gpusvm.c |   21 ++++++---------------
 1 file changed, 6 insertions(+), 15 deletions(-)

--- a/drivers/gpu/drm/drm_gpusvm.c~drm-gpusvm-use-hmm_range_fault_unlocked_timeout-for-range-faults-fix
+++ a/drivers/gpu/drm/drm_gpusvm.c
@@ -773,8 +773,7 @@ enum drm_gpusvm_scan_result drm_gpusvm_s
 		.end = end,
 		.dev_private_owner = dev_private_owner,
 	};
-	unsigned long timeout =
-		jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
+	unsigned long timeout = msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
 	enum drm_gpusvm_scan_result state = DRM_GPUSVM_SCAN_UNPOPULATED, new_state;
 	unsigned long *pfns;
 	unsigned long npages = npages_in_range(start, end);
@@ -788,8 +787,7 @@ enum drm_gpusvm_scan_result drm_gpusvm_s
 	hmm_range.hmm_pfns = pfns;
 
 retry:
-	err = hmm_range_fault_unlocked_timeout(&hmm_range,
-					       max(timeout - jiffies, 1L));
+	err = hmm_range_fault_unlocked_timeout(&hmm_range, timeout);
 	if (err)
 		goto err_free;
 
@@ -1392,8 +1390,7 @@ int drm_gpusvm_get_pages(struct drm_gpus
 		.dev_private_owner = ctx->device_private_page_owner,
 	};
 	void *zdd;
-	unsigned long timeout =
-		jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
+	unsigned long timeout = msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
 	unsigned long i, j;
 	unsigned long npages = npages_in_range(pages_start, pages_end);
 	unsigned long num_dma_mapped;
@@ -1408,9 +1405,6 @@ int drm_gpusvm_get_pages(struct drm_gpus
 	struct dma_iova_state *state = &svm_pages->state;
 
 retry:
-	if (time_after(jiffies, timeout))
-		return -EBUSY;
-
 	hmm_range.notifier_seq = mmu_interval_read_begin(notifier);
 	if (drm_gpusvm_pages_valid_unlocked(gpusvm, svm_pages))
 		goto set_seqno;
@@ -1425,8 +1419,7 @@ retry:
 	}
 
 	hmm_range.hmm_pfns = pfns;
-	err = hmm_range_fault_unlocked_timeout(&hmm_range,
-				max_t(long, timeout - jiffies, 1));
+	err = hmm_range_fault_unlocked_timeout(&hmm_range, timeout);
 	mmput(mm);
 	if (err)
 		goto err_free;
@@ -1693,8 +1686,7 @@ int drm_gpusvm_range_evict(struct drm_gp
 		.end = drm_gpusvm_range_end(range),
 		.dev_private_owner = NULL,
 	};
-	unsigned long timeout =
-		jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
+	unsigned long timeout = msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
 	unsigned long *pfns;
 	unsigned long npages = npages_in_range(drm_gpusvm_range_start(range),
 					       drm_gpusvm_range_end(range));
@@ -1709,8 +1701,7 @@ int drm_gpusvm_range_evict(struct drm_gp
 		return -ENOMEM;
 
 	hmm_range.hmm_pfns = pfns;
-	err = hmm_range_fault_unlocked_timeout(&hmm_range,
-				max_t(long, timeout - jiffies, 1));
+	err = hmm_range_fault_unlocked_timeout(&hmm_range, timeout);
 
 	kvfree(pfns);
 	mmput(mm);
_

Patches currently in -mm which might be from skinsburskii@gmail.com are

lib-test_hmm-use-device-devt-for-coherent-device-range-selection.patch
mm-hmm-move-page-fault-handling-out-of-walk-callbacks.patch
mm-hmm-add-hmm_range_fault_unlocked_timeout-for-mmap-lock-drop-support.patch
mm-hmm-add-hmm_range_fault_unlocked_timeout-for-mmap-lock-drop-support-fix.patch
selftests-mm-add-hmm-test-for-mmap-lock-dropping-faults.patch
mshv-use-hmm_range_fault_unlocked_timeout-for-region-faults.patch
drm-nouveau-use-hmm_range_fault_unlocked_timeout-for-svm-faults.patch
drm-nouveau-use-hmm_range_fault_unlocked_timeout-for-svm-faults-fix.patch
rdma-umem-use-hmm_range_fault_unlocked_timeout-for-odp-faults.patch
accel-amdxdna-use-hmm_range_fault_unlocked_timeout-for-range-population.patch
accel-amdxdna-use-hmm_range_fault_unlocked_timeout-for-range-population-fix.patch
drm-gpusvm-use-hmm_range_fault_unlocked_timeout-for-range-faults.patch
drm-gpusvm-use-hmm_range_fault_unlocked_timeout-for-range-faults-fix.patch


                 reply	other threads:[~2026-07-15  2:18 UTC|newest]

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