drm/xe: Use pool of ordered wq for GuC submission

To appease lockdep, use a pool of ordered wq for GuC submission rather
tha leaving the ordered wq allocation to the drm sched. Without this change
eventually lockdep runs out of hash entries (MAX_LOCKDEP_CHAINS is
exceeded) as each user allocated exec queue adds more hash table entries
to lockdep. A pool old of 256 ordered wq should be enough to have
similar behavior with and without lockdep enabled.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
index d0e60349fc5a174a9b3fecac048153b05df069e1..8d5af11fb80d325ceec822be3a334579316bc4e9 100644 (file)
--- a/drivers/gpu/drm/xe/xe_guc_submit.c
+++ b/drivers/gpu/drm/xe/xe_guc_submit.c
@@ -188,6 +188,58 @@ static bool exec_queue_killed_or_banned(struct xe_exec_queue *q)
        return exec_queue_killed(q) || exec_queue_banned(q);
 }
 
+#ifdef CONFIG_PROVE_LOCKING
+static int alloc_submit_wq(struct xe_guc *guc)
+{
+       int i;
+
+       for (i = 0; i < NUM_SUBMIT_WQ; ++i) {
+               guc->submission_state.submit_wq_pool[i] =
+                       alloc_ordered_workqueue("submit_wq", 0);
+               if (!guc->submission_state.submit_wq_pool[i])
+                       goto err_free;
+       }
+
+       return 0;
+
+err_free:
+       while (i)
+               destroy_workqueue(guc->submission_state.submit_wq_pool[--i]);
+
+       return -ENOMEM;
+}
+
+static void free_submit_wq(struct xe_guc *guc)
+{
+       int i;
+
+       for (i = 0; i < NUM_SUBMIT_WQ; ++i)
+               destroy_workqueue(guc->submission_state.submit_wq_pool[i]);
+}
+
+static struct workqueue_struct *get_submit_wq(struct xe_guc *guc)
+{
+       int idx = guc->submission_state.submit_wq_idx++ % NUM_SUBMIT_WQ;
+
+       return guc->submission_state.submit_wq_pool[idx];
+}
+#else
+static int alloc_submit_wq(struct xe_guc *guc)
+{
+       return 0;
+}
+
+static void free_submit_wq(struct xe_guc *guc)
+{
+
+}
+
+static struct workqueue_struct *get_submit_wq(struct xe_guc *guc)
+{
+       return NULL;
+}
+#endif
+
 static void guc_submit_fini(struct drm_device *drm, void *arg)
 {
        struct xe_guc *guc = arg;
@@ -195,6 +247,7 @@ static void guc_submit_fini(struct drm_device *drm, void *arg)
        xa_destroy(&guc->submission_state.exec_queue_lookup);
        ida_destroy(&guc->submission_state.guc_ids);
        bitmap_free(guc->submission_state.guc_ids_bitmap);
+       free_submit_wq(guc);
        mutex_destroy(&guc->submission_state.lock);
 }
 
@@ -230,6 +283,12 @@ int xe_guc_submit_init(struct xe_guc *guc)
        if (!guc->submission_state.guc_ids_bitmap)
                return -ENOMEM;
 
+       err = alloc_submit_wq(guc);
+       if (err) {
+               bitmap_free(guc->submission_state.guc_ids_bitmap);
+               return err;
+       }
+
        gt->exec_queue_ops = &guc_exec_queue_ops;
 
        mutex_init(&guc->submission_state.lock);
@@ -1166,10 +1225,11 @@ static int guc_exec_queue_init(struct xe_exec_queue *q)
 
        timeout = (q->vm && xe_vm_no_dma_fences(q->vm)) ? MAX_SCHEDULE_TIMEOUT :
                  q->hwe->eclass->sched_props.job_timeout_ms;
-       err = xe_sched_init(&ge->sched, &drm_sched_ops, &xe_sched_ops, NULL,
-                            q->lrc[0].ring.size / MAX_JOB_SIZE_BYTES,
-                            64, timeout, guc_to_gt(guc)->ordered_wq, NULL,
-                            q->name, gt_to_xe(q->gt)->drm.dev);
+       err = xe_sched_init(&ge->sched, &drm_sched_ops, &xe_sched_ops,
+                           get_submit_wq(guc),
+                           q->lrc[0].ring.size / MAX_JOB_SIZE_BYTES, 64,
+                           timeout, guc_to_gt(guc)->ordered_wq, NULL,
+                           q->name, gt_to_xe(q->gt)->drm.dev);
        if (err)
                goto err_free;
 

diff --git a/drivers/gpu/drm/xe/xe_guc_types.h b/drivers/gpu/drm/xe/xe_guc_types.h
index a5e58917a4994bcd7f354a74c2d9daee3b3f5039..0fdcc05dc16a663c1bd425a1f04dd746c77a065d 100644 (file)
--- a/drivers/gpu/drm/xe/xe_guc_types.h
+++ b/drivers/gpu/drm/xe/xe_guc_types.h
@@ -61,6 +61,13 @@ struct xe_guc {
                        /** @patch: patch version of GuC submission */
                        u32 patch;
                } version;
+#ifdef CONFIG_PROVE_LOCKING
+#define NUM_SUBMIT_WQ  256
+               /** @submit_wq_pool: submission ordered workqueues pool */
+               struct workqueue_struct *submit_wq_pool[NUM_SUBMIT_WQ];
+               /** @submit_wq_idx: submission ordered workqueue index */
+               int submit_wq_idx;
+#endif
                /** @enabled: submission is enabled */
                bool enabled;
        } submission_state;