* [CI 2/3] drm/i915: Pull scheduling under standalone lock
2018-10-01 14:47 [CI 1/3] drm/i915: Priority boost for new clients Chris Wilson
@ 2018-10-01 14:47 ` Chris Wilson
2018-10-01 14:47 ` [CI 3/3] drm/i915: Priority boost for waiting clients Chris Wilson
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: Chris Wilson @ 2018-10-01 14:47 UTC (permalink / raw)
To: intel-gfx
Currently, the backend scheduling code abuses struct_mutex into order to
have a global lock to manipulate a temporary list (without widespread
allocation) and to protect against list modifications. This is an
extraneous coupling to struct_mutex and further can not extend beyond
the local device.
Pull all the code that needs to be under the one true lock into
i915_scheduler.c, and make it so.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
drivers/gpu/drm/i915/Makefile | 1 +
drivers/gpu/drm/i915/i915_request.c | 85 ------
drivers/gpu/drm/i915/i915_request.h | 8 -
drivers/gpu/drm/i915/i915_scheduler.c | 377 ++++++++++++++++++++++++
drivers/gpu/drm/i915/i915_scheduler.h | 25 ++
drivers/gpu/drm/i915/intel_display.c | 3 +-
drivers/gpu/drm/i915/intel_lrc.c | 268 +----------------
drivers/gpu/drm/i915/intel_ringbuffer.h | 5 +-
8 files changed, 411 insertions(+), 361 deletions(-)
create mode 100644 drivers/gpu/drm/i915/i915_scheduler.c
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 5794f102f9b8..ef1480c14e4e 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -75,6 +75,7 @@ i915-y += i915_cmd_parser.o \
i915_gemfs.o \
i915_query.o \
i915_request.o \
+ i915_scheduler.o \
i915_timeline.o \
i915_trace_points.o \
i915_vma.o \
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 56140ca054e8..d73ad490a261 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -111,91 +111,6 @@ i915_request_remove_from_client(struct i915_request *request)
spin_unlock(&file_priv->mm.lock);
}
-static struct i915_dependency *
-i915_dependency_alloc(struct drm_i915_private *i915)
-{
- return kmem_cache_alloc(i915->dependencies, GFP_KERNEL);
-}
-
-static void
-i915_dependency_free(struct drm_i915_private *i915,
- struct i915_dependency *dep)
-{
- kmem_cache_free(i915->dependencies, dep);
-}
-
-static void
-__i915_sched_node_add_dependency(struct i915_sched_node *node,
- struct i915_sched_node *signal,
- struct i915_dependency *dep,
- unsigned long flags)
-{
- INIT_LIST_HEAD(&dep->dfs_link);
- list_add(&dep->wait_link, &signal->waiters_list);
- list_add(&dep->signal_link, &node->signalers_list);
- dep->signaler = signal;
- dep->flags = flags;
-}
-
-static int
-i915_sched_node_add_dependency(struct drm_i915_private *i915,
- struct i915_sched_node *node,
- struct i915_sched_node *signal)
-{
- struct i915_dependency *dep;
-
- dep = i915_dependency_alloc(i915);
- if (!dep)
- return -ENOMEM;
-
- __i915_sched_node_add_dependency(node, signal, dep,
- I915_DEPENDENCY_ALLOC);
- return 0;
-}
-
-static void
-i915_sched_node_fini(struct drm_i915_private *i915,
- struct i915_sched_node *node)
-{
- struct i915_dependency *dep, *tmp;
-
- GEM_BUG_ON(!list_empty(&node->link));
-
- /*
- * Everyone we depended upon (the fences we wait to be signaled)
- * should retire before us and remove themselves from our list.
- * However, retirement is run independently on each timeline and
- * so we may be called out-of-order.
- */
- list_for_each_entry_safe(dep, tmp, &node->signalers_list, signal_link) {
- GEM_BUG_ON(!i915_sched_node_signaled(dep->signaler));
- GEM_BUG_ON(!list_empty(&dep->dfs_link));
-
- list_del(&dep->wait_link);
- if (dep->flags & I915_DEPENDENCY_ALLOC)
- i915_dependency_free(i915, dep);
- }
-
- /* Remove ourselves from everyone who depends upon us */
- list_for_each_entry_safe(dep, tmp, &node->waiters_list, wait_link) {
- GEM_BUG_ON(dep->signaler != node);
- GEM_BUG_ON(!list_empty(&dep->dfs_link));
-
- list_del(&dep->signal_link);
- if (dep->flags & I915_DEPENDENCY_ALLOC)
- i915_dependency_free(i915, dep);
- }
-}
-
-static void
-i915_sched_node_init(struct i915_sched_node *node)
-{
- INIT_LIST_HEAD(&node->signalers_list);
- INIT_LIST_HEAD(&node->waiters_list);
- INIT_LIST_HEAD(&node->link);
- node->attr.priority = I915_PRIORITY_INVALID;
-}
-
static int reset_all_global_seqno(struct drm_i915_private *i915, u32 seqno)
{
struct intel_engine_cs *engine;
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index 7fa94b024968..5f7361e0fca6 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -332,14 +332,6 @@ static inline bool i915_request_completed(const struct i915_request *rq)
return __i915_request_completed(rq, seqno);
}
-static inline bool i915_sched_node_signaled(const struct i915_sched_node *node)
-{
- const struct i915_request *rq =
- container_of(node, const struct i915_request, sched);
-
- return i915_request_completed(rq);
-}
-
void i915_retire_requests(struct drm_i915_private *i915);
/*
diff --git a/drivers/gpu/drm/i915/i915_scheduler.c b/drivers/gpu/drm/i915/i915_scheduler.c
new file mode 100644
index 000000000000..de9a2ba7c3bc
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_scheduler.c
@@ -0,0 +1,377 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2018 Intel Corporation
+ */
+
+#include <linux/mutex.h>
+
+#include "i915_drv.h"
+#include "i915_request.h"
+#include "i915_scheduler.h"
+
+static DEFINE_SPINLOCK(schedule_lock);
+
+static const struct i915_request *
+node_to_request(const struct i915_sched_node *node)
+{
+ return container_of(node, const struct i915_request, sched);
+}
+
+static inline bool node_signaled(const struct i915_sched_node *node)
+{
+ return i915_request_completed(node_to_request(node));
+}
+
+void i915_sched_node_init(struct i915_sched_node *node)
+{
+ INIT_LIST_HEAD(&node->signalers_list);
+ INIT_LIST_HEAD(&node->waiters_list);
+ INIT_LIST_HEAD(&node->link);
+ node->attr.priority = I915_PRIORITY_INVALID;
+}
+
+static struct i915_dependency *
+i915_dependency_alloc(struct drm_i915_private *i915)
+{
+ return kmem_cache_alloc(i915->dependencies, GFP_KERNEL);
+}
+
+static void
+i915_dependency_free(struct drm_i915_private *i915,
+ struct i915_dependency *dep)
+{
+ kmem_cache_free(i915->dependencies, dep);
+}
+
+bool __i915_sched_node_add_dependency(struct i915_sched_node *node,
+ struct i915_sched_node *signal,
+ struct i915_dependency *dep,
+ unsigned long flags)
+{
+ bool ret = false;
+
+ spin_lock(&schedule_lock);
+
+ if (!node_signaled(signal)) {
+ INIT_LIST_HEAD(&dep->dfs_link);
+ list_add(&dep->wait_link, &signal->waiters_list);
+ list_add(&dep->signal_link, &node->signalers_list);
+ dep->signaler = signal;
+ dep->flags = flags;
+
+ ret = true;
+ }
+
+ spin_unlock(&schedule_lock);
+
+ return ret;
+}
+
+int i915_sched_node_add_dependency(struct drm_i915_private *i915,
+ struct i915_sched_node *node,
+ struct i915_sched_node *signal)
+{
+ struct i915_dependency *dep;
+
+ dep = i915_dependency_alloc(i915);
+ if (!dep)
+ return -ENOMEM;
+
+ if (!__i915_sched_node_add_dependency(node, signal, dep,
+ I915_DEPENDENCY_ALLOC))
+ i915_dependency_free(i915, dep);
+
+ return 0;
+}
+
+void i915_sched_node_fini(struct drm_i915_private *i915,
+ struct i915_sched_node *node)
+{
+ struct i915_dependency *dep, *tmp;
+
+ GEM_BUG_ON(!list_empty(&node->link));
+
+ spin_lock(&schedule_lock);
+
+ /*
+ * Everyone we depended upon (the fences we wait to be signaled)
+ * should retire before us and remove themselves from our list.
+ * However, retirement is run independently on each timeline and
+ * so we may be called out-of-order.
+ */
+ list_for_each_entry_safe(dep, tmp, &node->signalers_list, signal_link) {
+ GEM_BUG_ON(!node_signaled(dep->signaler));
+ GEM_BUG_ON(!list_empty(&dep->dfs_link));
+
+ list_del(&dep->wait_link);
+ if (dep->flags & I915_DEPENDENCY_ALLOC)
+ i915_dependency_free(i915, dep);
+ }
+
+ /* Remove ourselves from everyone who depends upon us */
+ list_for_each_entry_safe(dep, tmp, &node->waiters_list, wait_link) {
+ GEM_BUG_ON(dep->signaler != node);
+ GEM_BUG_ON(!list_empty(&dep->dfs_link));
+
+ list_del(&dep->signal_link);
+ if (dep->flags & I915_DEPENDENCY_ALLOC)
+ i915_dependency_free(i915, dep);
+ }
+
+ spin_unlock(&schedule_lock);
+}
+
+static inline struct i915_priolist *to_priolist(struct rb_node *rb)
+{
+ return rb_entry(rb, struct i915_priolist, node);
+}
+
+static void assert_priolists(struct intel_engine_execlists * const execlists,
+ long queue_priority)
+{
+ struct rb_node *rb;
+ long last_prio, i;
+
+ if (!IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
+ return;
+
+ GEM_BUG_ON(rb_first_cached(&execlists->queue) !=
+ rb_first(&execlists->queue.rb_root));
+
+ last_prio = (queue_priority >> I915_USER_PRIORITY_SHIFT) + 1;
+ for (rb = rb_first_cached(&execlists->queue); rb; rb = rb_next(rb)) {
+ const struct i915_priolist *p = to_priolist(rb);
+
+ GEM_BUG_ON(p->priority >= last_prio);
+ last_prio = p->priority;
+
+ GEM_BUG_ON(!p->used);
+ for (i = 0; i < ARRAY_SIZE(p->requests); i++) {
+ if (list_empty(&p->requests[i]))
+ continue;
+
+ GEM_BUG_ON(!(p->used & BIT(i)));
+ }
+ }
+}
+
+struct list_head *
+i915_sched_lookup_priolist(struct intel_engine_cs *engine, int prio)
+{
+ struct intel_engine_execlists * const execlists = &engine->execlists;
+ struct i915_priolist *p;
+ struct rb_node **parent, *rb;
+ bool first = true;
+ int idx, i;
+
+ lockdep_assert_held(&engine->timeline.lock);
+ assert_priolists(execlists, INT_MAX);
+
+ /* buckets sorted from highest [in slot 0] to lowest priority */
+ idx = I915_PRIORITY_COUNT - (prio & I915_PRIORITY_MASK) - 1;
+ prio >>= I915_USER_PRIORITY_SHIFT;
+ if (unlikely(execlists->no_priolist))
+ prio = I915_PRIORITY_NORMAL;
+
+find_priolist:
+ /* most positive priority is scheduled first, equal priorities fifo */
+ rb = NULL;
+ parent = &execlists->queue.rb_root.rb_node;
+ while (*parent) {
+ rb = *parent;
+ p = to_priolist(rb);
+ if (prio > p->priority) {
+ parent = &rb->rb_left;
+ } else if (prio < p->priority) {
+ parent = &rb->rb_right;
+ first = false;
+ } else {
+ goto out;
+ }
+ }
+
+ if (prio == I915_PRIORITY_NORMAL) {
+ p = &execlists->default_priolist;
+ } else {
+ p = kmem_cache_alloc(engine->i915->priorities, GFP_ATOMIC);
+ /* Convert an allocation failure to a priority bump */
+ if (unlikely(!p)) {
+ prio = I915_PRIORITY_NORMAL; /* recurses just once */
+
+ /* To maintain ordering with all rendering, after an
+ * allocation failure we have to disable all scheduling.
+ * Requests will then be executed in fifo, and schedule
+ * will ensure that dependencies are emitted in fifo.
+ * There will be still some reordering with existing
+ * requests, so if userspace lied about their
+ * dependencies that reordering may be visible.
+ */
+ execlists->no_priolist = true;
+ goto find_priolist;
+ }
+ }
+
+ p->priority = prio;
+ for (i = 0; i < ARRAY_SIZE(p->requests); i++)
+ INIT_LIST_HEAD(&p->requests[i]);
+ rb_link_node(&p->node, rb, parent);
+ rb_insert_color_cached(&p->node, &execlists->queue, first);
+ p->used = 0;
+
+out:
+ p->used |= BIT(idx);
+ return &p->requests[idx];
+}
+
+static struct intel_engine_cs *
+sched_lock_engine(struct i915_sched_node *node, struct intel_engine_cs *locked)
+{
+ struct intel_engine_cs *engine = node_to_request(node)->engine;
+
+ GEM_BUG_ON(!locked);
+
+ if (engine != locked) {
+ spin_unlock(&locked->timeline.lock);
+ spin_lock(&engine->timeline.lock);
+ }
+
+ return engine;
+}
+
+void i915_schedule(struct i915_request *rq, const struct i915_sched_attr *attr)
+{
+ struct list_head *uninitialized_var(pl);
+ struct intel_engine_cs *engine, *last;
+ struct i915_dependency *dep, *p;
+ struct i915_dependency stack;
+ const int prio = attr->priority;
+ LIST_HEAD(dfs);
+
+ GEM_BUG_ON(prio == I915_PRIORITY_INVALID);
+
+ if (i915_request_completed(rq))
+ return;
+
+ if (prio <= READ_ONCE(rq->sched.attr.priority))
+ return;
+
+ /* Needed in order to use the temporary link inside i915_dependency */
+ spin_lock(&schedule_lock);
+
+ stack.signaler = &rq->sched;
+ list_add(&stack.dfs_link, &dfs);
+
+ /*
+ * Recursively bump all dependent priorities to match the new request.
+ *
+ * A naive approach would be to use recursion:
+ * static void update_priorities(struct i915_sched_node *node, prio) {
+ * list_for_each_entry(dep, &node->signalers_list, signal_link)
+ * update_priorities(dep->signal, prio)
+ * queue_request(node);
+ * }
+ * but that may have unlimited recursion depth and so runs a very
+ * real risk of overunning the kernel stack. Instead, we build
+ * a flat list of all dependencies starting with the current request.
+ * As we walk the list of dependencies, we add all of its dependencies
+ * to the end of the list (this may include an already visited
+ * request) and continue to walk onwards onto the new dependencies. The
+ * end result is a topological list of requests in reverse order, the
+ * last element in the list is the request we must execute first.
+ */
+ list_for_each_entry(dep, &dfs, dfs_link) {
+ struct i915_sched_node *node = dep->signaler;
+
+ /*
+ * Within an engine, there can be no cycle, but we may
+ * refer to the same dependency chain multiple times
+ * (redundant dependencies are not eliminated) and across
+ * engines.
+ */
+ list_for_each_entry(p, &node->signalers_list, signal_link) {
+ GEM_BUG_ON(p == dep); /* no cycles! */
+
+ if (node_signaled(p->signaler))
+ continue;
+
+ GEM_BUG_ON(p->signaler->attr.priority < node->attr.priority);
+ if (prio > READ_ONCE(p->signaler->attr.priority))
+ list_move_tail(&p->dfs_link, &dfs);
+ }
+ }
+
+ /*
+ * If we didn't need to bump any existing priorities, and we haven't
+ * yet submitted this request (i.e. there is no potential race with
+ * execlists_submit_request()), we can set our own priority and skip
+ * acquiring the engine locks.
+ */
+ if (rq->sched.attr.priority == I915_PRIORITY_INVALID) {
+ GEM_BUG_ON(!list_empty(&rq->sched.link));
+ rq->sched.attr = *attr;
+
+ if (stack.dfs_link.next == stack.dfs_link.prev)
+ goto out_unlock;
+
+ __list_del_entry(&stack.dfs_link);
+ }
+
+ last = NULL;
+ engine = rq->engine;
+ spin_lock_irq(&engine->timeline.lock);
+
+ /* Fifo and depth-first replacement ensure our deps execute before us */
+ list_for_each_entry_safe_reverse(dep, p, &dfs, dfs_link) {
+ struct i915_sched_node *node = dep->signaler;
+
+ INIT_LIST_HEAD(&dep->dfs_link);
+
+ engine = sched_lock_engine(node, engine);
+
+ /* Recheck after acquiring the engine->timeline.lock */
+ if (prio <= node->attr.priority || node_signaled(node))
+ continue;
+
+ node->attr.priority = prio;
+ if (!list_empty(&node->link)) {
+ if (last != engine) {
+ pl = i915_sched_lookup_priolist(engine, prio);
+ last = engine;
+ }
+ list_move_tail(&node->link, pl);
+ } else {
+ /*
+ * If the request is not in the priolist queue because
+ * it is not yet runnable, then it doesn't contribute
+ * to our preemption decisions. On the other hand,
+ * if the request is on the HW, it too is not in the
+ * queue; but in that case we may still need to reorder
+ * the inflight requests.
+ */
+ if (!i915_sw_fence_done(&node_to_request(node)->submit))
+ continue;
+ }
+
+ if (prio <= engine->execlists.queue_priority)
+ continue;
+
+ /*
+ * If we are already the currently executing context, don't
+ * bother evaluating if we should preempt ourselves.
+ */
+ if (node_to_request(node)->global_seqno &&
+ i915_seqno_passed(port_request(engine->execlists.port)->global_seqno,
+ node_to_request(node)->global_seqno))
+ continue;
+
+ /* Defer (tasklet) submission until after all of our updates. */
+ engine->execlists.queue_priority = prio;
+ tasklet_hi_schedule(&engine->execlists.tasklet);
+ }
+
+ spin_unlock_irq(&engine->timeline.lock);
+
+out_unlock:
+ spin_unlock(&schedule_lock);
+}
diff --git a/drivers/gpu/drm/i915/i915_scheduler.h b/drivers/gpu/drm/i915/i915_scheduler.h
index 53dc7dbf88b9..68d84a45ad7f 100644
--- a/drivers/gpu/drm/i915/i915_scheduler.h
+++ b/drivers/gpu/drm/i915/i915_scheduler.h
@@ -8,9 +8,14 @@
#define _I915_SCHEDULER_H_
#include <linux/bitops.h>
+#include <linux/kernel.h>
#include <uapi/drm/i915_drm.h>
+struct drm_i915_private;
+struct i915_request;
+struct intel_engine_cs;
+
enum {
I915_PRIORITY_MIN = I915_CONTEXT_MIN_USER_PRIORITY - 1,
I915_PRIORITY_NORMAL = I915_CONTEXT_DEFAULT_PRIORITY,
@@ -77,4 +82,24 @@ struct i915_dependency {
#define I915_DEPENDENCY_ALLOC BIT(0)
};
+void i915_sched_node_init(struct i915_sched_node *node);
+
+bool __i915_sched_node_add_dependency(struct i915_sched_node *node,
+ struct i915_sched_node *signal,
+ struct i915_dependency *dep,
+ unsigned long flags);
+
+int i915_sched_node_add_dependency(struct drm_i915_private *i915,
+ struct i915_sched_node *node,
+ struct i915_sched_node *signal);
+
+void i915_sched_node_fini(struct drm_i915_private *i915,
+ struct i915_sched_node *node);
+
+void i915_schedule(struct i915_request *request,
+ const struct i915_sched_attr *attr);
+
+struct list_head *
+i915_sched_lookup_priolist(struct intel_engine_cs *engine, int prio);
+
#endif /* _I915_SCHEDULER_H_ */
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 4c5c2b39e65c..650e01f0c197 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -13188,13 +13188,12 @@ intel_prepare_plane_fb(struct drm_plane *plane,
ret = intel_plane_pin_fb(to_intel_plane_state(new_state));
- fb_obj_bump_render_priority(obj);
-
mutex_unlock(&dev_priv->drm.struct_mutex);
i915_gem_object_unpin_pages(obj);
if (ret)
return ret;
+ fb_obj_bump_render_priority(obj);
intel_fb_obj_flush(obj, ORIGIN_DIRTYFB);
if (!new_state->fence) { /* implicit fencing */
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 5f324d6b44d5..28d56387edf5 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -259,102 +259,6 @@ intel_lr_context_descriptor_update(struct i915_gem_context *ctx,
ce->lrc_desc = desc;
}
-static void assert_priolists(struct intel_engine_execlists * const execlists,
- long queue_priority)
-{
- struct rb_node *rb;
- long last_prio, i;
-
- if (!IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
- return;
-
- GEM_BUG_ON(rb_first_cached(&execlists->queue) !=
- rb_first(&execlists->queue.rb_root));
-
- last_prio = (queue_priority >> I915_USER_PRIORITY_SHIFT) + 1;
- for (rb = rb_first_cached(&execlists->queue); rb; rb = rb_next(rb)) {
- struct i915_priolist *p = to_priolist(rb);
-
- GEM_BUG_ON(p->priority >= last_prio);
- last_prio = p->priority;
-
- GEM_BUG_ON(!p->used);
- for (i = 0; i < ARRAY_SIZE(p->requests); i++) {
- if (list_empty(&p->requests[i]))
- continue;
-
- GEM_BUG_ON(!(p->used & BIT(i)));
- }
- }
-}
-
-static struct list_head *
-lookup_priolist(struct intel_engine_cs *engine, int prio)
-{
- struct intel_engine_execlists * const execlists = &engine->execlists;
- struct i915_priolist *p;
- struct rb_node **parent, *rb;
- bool first = true;
- int idx, i;
-
- assert_priolists(execlists, INT_MAX);
-
- /* buckets sorted from highest [in slot 0] to lowest priority */
- idx = I915_PRIORITY_COUNT - (prio & I915_PRIORITY_MASK) - 1;
- prio >>= I915_USER_PRIORITY_SHIFT;
- if (unlikely(execlists->no_priolist))
- prio = I915_PRIORITY_NORMAL;
-
-find_priolist:
- /* most positive priority is scheduled first, equal priorities fifo */
- rb = NULL;
- parent = &execlists->queue.rb_root.rb_node;
- while (*parent) {
- rb = *parent;
- p = to_priolist(rb);
- if (prio > p->priority) {
- parent = &rb->rb_left;
- } else if (prio < p->priority) {
- parent = &rb->rb_right;
- first = false;
- } else {
- goto out;
- }
- }
-
- if (prio == I915_PRIORITY_NORMAL) {
- p = &execlists->default_priolist;
- } else {
- p = kmem_cache_alloc(engine->i915->priorities, GFP_ATOMIC);
- /* Convert an allocation failure to a priority bump */
- if (unlikely(!p)) {
- prio = I915_PRIORITY_NORMAL; /* recurses just once */
-
- /* To maintain ordering with all rendering, after an
- * allocation failure we have to disable all scheduling.
- * Requests will then be executed in fifo, and schedule
- * will ensure that dependencies are emitted in fifo.
- * There will be still some reordering with existing
- * requests, so if userspace lied about their
- * dependencies that reordering may be visible.
- */
- execlists->no_priolist = true;
- goto find_priolist;
- }
- }
-
- p->priority = prio;
- for (i = 0; i < ARRAY_SIZE(p->requests); i++)
- INIT_LIST_HEAD(&p->requests[i]);
- rb_link_node(&p->node, rb, parent);
- rb_insert_color_cached(&p->node, &execlists->queue, first);
- p->used = 0;
-
-out:
- p->used |= BIT(idx);
- return &p->requests[idx];
-}
-
static void unwind_wa_tail(struct i915_request *rq)
{
rq->tail = intel_ring_wrap(rq->ring, rq->wa_tail - WA_TAIL_BYTES);
@@ -381,7 +285,7 @@ static void __unwind_incomplete_requests(struct intel_engine_cs *engine)
GEM_BUG_ON(rq_prio(rq) == I915_PRIORITY_INVALID);
if (rq_prio(rq) != prio) {
prio = rq_prio(rq);
- pl = lookup_priolist(engine, prio);
+ pl = i915_sched_lookup_priolist(engine, prio);
}
GEM_BUG_ON(RB_EMPTY_ROOT(&engine->execlists.queue.rb_root));
@@ -398,7 +302,7 @@ static void __unwind_incomplete_requests(struct intel_engine_cs *engine)
if (!(prio & I915_PRIORITY_NEWCLIENT)) {
prio |= I915_PRIORITY_NEWCLIENT;
list_move_tail(&active->sched.link,
- lookup_priolist(engine, prio));
+ i915_sched_lookup_priolist(engine, prio));
}
}
@@ -792,7 +696,6 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
*/
execlists->queue_priority =
port != execlists->port ? rq_prio(last) : INT_MIN;
- assert_priolists(execlists, execlists->queue_priority);
if (submit) {
port_assign(port, last);
@@ -1119,12 +1022,7 @@ static void queue_request(struct intel_engine_cs *engine,
struct i915_sched_node *node,
int prio)
{
- list_add_tail(&node->link, lookup_priolist(engine, prio));
-}
-
-static void __update_queue(struct intel_engine_cs *engine, int prio)
-{
- engine->execlists.queue_priority = prio;
+ list_add_tail(&node->link, i915_sched_lookup_priolist(engine, prio));
}
static void __submit_queue_imm(struct intel_engine_cs *engine)
@@ -1143,7 +1041,7 @@ static void __submit_queue_imm(struct intel_engine_cs *engine)
static void submit_queue(struct intel_engine_cs *engine, int prio)
{
if (prio > engine->execlists.queue_priority) {
- __update_queue(engine, prio);
+ engine->execlists.queue_priority = prio;
__submit_queue_imm(engine);
}
}
@@ -1166,162 +1064,6 @@ static void execlists_submit_request(struct i915_request *request)
spin_unlock_irqrestore(&engine->timeline.lock, flags);
}
-static struct i915_request *sched_to_request(struct i915_sched_node *node)
-{
- return container_of(node, struct i915_request, sched);
-}
-
-static struct intel_engine_cs *
-sched_lock_engine(struct i915_sched_node *node, struct intel_engine_cs *locked)
-{
- struct intel_engine_cs *engine = sched_to_request(node)->engine;
-
- GEM_BUG_ON(!locked);
-
- if (engine != locked) {
- spin_unlock(&locked->timeline.lock);
- spin_lock(&engine->timeline.lock);
- }
-
- return engine;
-}
-
-static void execlists_schedule(struct i915_request *request,
- const struct i915_sched_attr *attr)
-{
- struct list_head *uninitialized_var(pl);
- struct intel_engine_cs *engine, *last;
- struct i915_dependency *dep, *p;
- struct i915_dependency stack;
- const int prio = attr->priority;
- LIST_HEAD(dfs);
-
- GEM_BUG_ON(prio == I915_PRIORITY_INVALID);
-
- if (i915_request_completed(request))
- return;
-
- if (prio <= READ_ONCE(request->sched.attr.priority))
- return;
-
- /* Need BKL in order to use the temporary link inside i915_dependency */
- lockdep_assert_held(&request->i915->drm.struct_mutex);
-
- stack.signaler = &request->sched;
- list_add(&stack.dfs_link, &dfs);
-
- /*
- * Recursively bump all dependent priorities to match the new request.
- *
- * A naive approach would be to use recursion:
- * static void update_priorities(struct i915_sched_node *node, prio) {
- * list_for_each_entry(dep, &node->signalers_list, signal_link)
- * update_priorities(dep->signal, prio)
- * queue_request(node);
- * }
- * but that may have unlimited recursion depth and so runs a very
- * real risk of overunning the kernel stack. Instead, we build
- * a flat list of all dependencies starting with the current request.
- * As we walk the list of dependencies, we add all of its dependencies
- * to the end of the list (this may include an already visited
- * request) and continue to walk onwards onto the new dependencies. The
- * end result is a topological list of requests in reverse order, the
- * last element in the list is the request we must execute first.
- */
- list_for_each_entry(dep, &dfs, dfs_link) {
- struct i915_sched_node *node = dep->signaler;
-
- /*
- * Within an engine, there can be no cycle, but we may
- * refer to the same dependency chain multiple times
- * (redundant dependencies are not eliminated) and across
- * engines.
- */
- list_for_each_entry(p, &node->signalers_list, signal_link) {
- GEM_BUG_ON(p == dep); /* no cycles! */
-
- if (i915_sched_node_signaled(p->signaler))
- continue;
-
- GEM_BUG_ON(p->signaler->attr.priority < node->attr.priority);
- if (prio > READ_ONCE(p->signaler->attr.priority))
- list_move_tail(&p->dfs_link, &dfs);
- }
- }
-
- /*
- * If we didn't need to bump any existing priorities, and we haven't
- * yet submitted this request (i.e. there is no potential race with
- * execlists_submit_request()), we can set our own priority and skip
- * acquiring the engine locks.
- */
- if (request->sched.attr.priority == I915_PRIORITY_INVALID) {
- GEM_BUG_ON(!list_empty(&request->sched.link));
- request->sched.attr = *attr;
- if (stack.dfs_link.next == stack.dfs_link.prev)
- return;
- __list_del_entry(&stack.dfs_link);
- }
-
- last = NULL;
- engine = request->engine;
- spin_lock_irq(&engine->timeline.lock);
-
- /* Fifo and depth-first replacement ensure our deps execute before us */
- list_for_each_entry_safe_reverse(dep, p, &dfs, dfs_link) {
- struct i915_sched_node *node = dep->signaler;
-
- INIT_LIST_HEAD(&dep->dfs_link);
-
- engine = sched_lock_engine(node, engine);
-
- /* Recheck after acquiring the engine->timeline.lock */
- if (prio <= node->attr.priority)
- continue;
-
- if (i915_sched_node_signaled(node))
- continue;
-
- node->attr.priority = prio;
- if (!list_empty(&node->link)) {
- if (last != engine) {
- pl = lookup_priolist(engine, prio);
- last = engine;
- }
- list_move_tail(&node->link, pl);
- } else {
- /*
- * If the request is not in the priolist queue because
- * it is not yet runnable, then it doesn't contribute
- * to our preemption decisions. On the other hand,
- * if the request is on the HW, it too is not in the
- * queue; but in that case we may still need to reorder
- * the inflight requests.
- */
- if (!i915_sw_fence_done(&sched_to_request(node)->submit))
- continue;
- }
-
- if (prio <= engine->execlists.queue_priority)
- continue;
-
- /*
- * If we are already the currently executing context, don't
- * bother evaluating if we should preempt ourselves.
- */
- if (sched_to_request(node)->global_seqno &&
- i915_seqno_passed(port_request(engine->execlists.port)->global_seqno,
- sched_to_request(node)->global_seqno))
- continue;
-
- /* Defer (tasklet) submission until after all of our updates. */
- __update_queue(engine, prio);
- tasklet_hi_schedule(&engine->execlists.tasklet);
- }
-
- spin_unlock_irq(&engine->timeline.lock);
-}
-
static void execlists_context_destroy(struct intel_context *ce)
{
GEM_BUG_ON(ce->pin_count);
@@ -2359,7 +2101,7 @@ void intel_execlists_set_default_submission(struct intel_engine_cs *engine)
{
engine->submit_request = execlists_submit_request;
engine->cancel_requests = execlists_cancel_requests;
- engine->schedule = execlists_schedule;
+ engine->schedule = i915_schedule;
engine->execlists.tasklet.func = execlists_submission_tasklet;
engine->reset.prepare = execlists_reset_prepare;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 1534de5bb852..f6ec48a75a69 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -498,11 +498,10 @@ struct intel_engine_cs {
*/
void (*submit_request)(struct i915_request *rq);
- /* Call when the priority on a request has changed and it and its
+ /*
+ * Call when the priority on a request has changed and it and its
* dependencies may need rescheduling. Note the request itself may
* not be ready to run!
- *
- * Called under the struct_mutex.
*/
void (*schedule)(struct i915_request *request,
const struct i915_sched_attr *attr);
--
2.19.0
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https://lists.freedesktop.org/mailman/listinfo/intel-gfx
^ permalink raw reply related [flat|nested] 7+ messages in thread* [CI 3/3] drm/i915: Priority boost for waiting clients
2018-10-01 14:47 [CI 1/3] drm/i915: Priority boost for new clients Chris Wilson
2018-10-01 14:47 ` [CI 2/3] drm/i915: Pull scheduling under standalone lock Chris Wilson
@ 2018-10-01 14:47 ` Chris Wilson
2018-10-01 16:12 ` ✗ Fi.CI.CHECKPATCH: warning for series starting with [CI,1/3] drm/i915: Priority boost for new clients Patchwork
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: Chris Wilson @ 2018-10-01 14:47 UTC (permalink / raw)
To: intel-gfx
Latency is in the eye of the beholder. In the case where a client stops
and waits for the gpu, give that request chain a small priority boost
(not so that it overtakes higher priority clients, to preserve the
external ordering) so that ideally the wait completes earlier.
v2: Tvrtko recommends to keep the boost-from-user-stall as small as
possible and to allow new client flows to be preferred for interactivity
over stalls.
Testcase: igt/gem_sync/switch-default
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Dmitry Rogozhkin <dmitry.v.rogozhkin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
drivers/gpu/drm/i915/i915_gem.c | 5 +++-
drivers/gpu/drm/i915/i915_request.c | 2 ++
drivers/gpu/drm/i915/i915_request.h | 5 ++--
drivers/gpu/drm/i915/i915_scheduler.c | 34 ++++++++++++++++++++++-----
drivers/gpu/drm/i915/i915_scheduler.h | 7 ++++--
5 files changed, 42 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 28e943ee8b5e..7d45e71100bc 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1748,6 +1748,7 @@ i915_gem_set_domain_ioctl(struct drm_device *dev, void *data,
*/
err = i915_gem_object_wait(obj,
I915_WAIT_INTERRUPTIBLE |
+ I915_WAIT_PRIORITY |
(write_domain ? I915_WAIT_ALL : 0),
MAX_SCHEDULE_TIMEOUT,
to_rps_client(file));
@@ -3751,7 +3752,9 @@ i915_gem_wait_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
start = ktime_get();
ret = i915_gem_object_wait(obj,
- I915_WAIT_INTERRUPTIBLE | I915_WAIT_ALL,
+ I915_WAIT_INTERRUPTIBLE |
+ I915_WAIT_PRIORITY |
+ I915_WAIT_ALL,
to_wait_timeout(args->timeout_ns),
to_rps_client(file));
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index d73ad490a261..abd4dacbab8e 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -1237,6 +1237,8 @@ long i915_request_wait(struct i915_request *rq,
add_wait_queue(errq, &reset);
intel_wait_init(&wait);
+ if (flags & I915_WAIT_PRIORITY)
+ i915_schedule_bump_priority(rq, I915_PRIORITY_WAIT);
restart:
do {
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index 5f7361e0fca6..90e9d170a0cd 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -277,8 +277,9 @@ long i915_request_wait(struct i915_request *rq,
__attribute__((nonnull(1)));
#define I915_WAIT_INTERRUPTIBLE BIT(0)
#define I915_WAIT_LOCKED BIT(1) /* struct_mutex held, handle GPU reset */
-#define I915_WAIT_ALL BIT(2) /* used by i915_gem_object_wait() */
-#define I915_WAIT_FOR_IDLE_BOOST BIT(3)
+#define I915_WAIT_PRIORITY BIT(2) /* small priority bump for the request */
+#define I915_WAIT_ALL BIT(3) /* used by i915_gem_object_wait() */
+#define I915_WAIT_FOR_IDLE_BOOST BIT(4)
static inline bool intel_engine_has_started(struct intel_engine_cs *engine,
u32 seqno);
diff --git a/drivers/gpu/drm/i915/i915_scheduler.c b/drivers/gpu/drm/i915/i915_scheduler.c
index de9a2ba7c3bc..340faea6c08a 100644
--- a/drivers/gpu/drm/i915/i915_scheduler.c
+++ b/drivers/gpu/drm/i915/i915_scheduler.c
@@ -239,7 +239,8 @@ sched_lock_engine(struct i915_sched_node *node, struct intel_engine_cs *locked)
return engine;
}
-void i915_schedule(struct i915_request *rq, const struct i915_sched_attr *attr)
+static void __i915_schedule(struct i915_request *rq,
+ const struct i915_sched_attr *attr)
{
struct list_head *uninitialized_var(pl);
struct intel_engine_cs *engine, *last;
@@ -248,6 +249,8 @@ void i915_schedule(struct i915_request *rq, const struct i915_sched_attr *attr)
const int prio = attr->priority;
LIST_HEAD(dfs);
+ /* Needed in order to use the temporary link inside i915_dependency */
+ lockdep_assert_held(&schedule_lock);
GEM_BUG_ON(prio == I915_PRIORITY_INVALID);
if (i915_request_completed(rq))
@@ -256,9 +259,6 @@ void i915_schedule(struct i915_request *rq, const struct i915_sched_attr *attr)
if (prio <= READ_ONCE(rq->sched.attr.priority))
return;
- /* Needed in order to use the temporary link inside i915_dependency */
- spin_lock(&schedule_lock);
-
stack.signaler = &rq->sched;
list_add(&stack.dfs_link, &dfs);
@@ -312,7 +312,7 @@ void i915_schedule(struct i915_request *rq, const struct i915_sched_attr *attr)
rq->sched.attr = *attr;
if (stack.dfs_link.next == stack.dfs_link.prev)
- goto out_unlock;
+ return;
__list_del_entry(&stack.dfs_link);
}
@@ -371,7 +371,29 @@ void i915_schedule(struct i915_request *rq, const struct i915_sched_attr *attr)
}
spin_unlock_irq(&engine->timeline.lock);
+}
-out_unlock:
+void i915_schedule(struct i915_request *rq, const struct i915_sched_attr *attr)
+{
+ spin_lock(&schedule_lock);
+ __i915_schedule(rq, attr);
spin_unlock(&schedule_lock);
}
+
+void i915_schedule_bump_priority(struct i915_request *rq, unsigned int bump)
+{
+ struct i915_sched_attr attr;
+
+ GEM_BUG_ON(bump & ~I915_PRIORITY_MASK);
+
+ if (READ_ONCE(rq->sched.attr.priority) == I915_PRIORITY_INVALID)
+ return;
+
+ spin_lock_bh(&schedule_lock);
+
+ attr = rq->sched.attr;
+ attr.priority |= bump;
+ __i915_schedule(rq, &attr);
+
+ spin_unlock_bh(&schedule_lock);
+}
diff --git a/drivers/gpu/drm/i915/i915_scheduler.h b/drivers/gpu/drm/i915/i915_scheduler.h
index 68d84a45ad7f..dbe9cb7ecd82 100644
--- a/drivers/gpu/drm/i915/i915_scheduler.h
+++ b/drivers/gpu/drm/i915/i915_scheduler.h
@@ -24,13 +24,14 @@ enum {
I915_PRIORITY_INVALID = INT_MIN
};
-#define I915_USER_PRIORITY_SHIFT 1
+#define I915_USER_PRIORITY_SHIFT 2
#define I915_USER_PRIORITY(x) ((x) << I915_USER_PRIORITY_SHIFT)
#define I915_PRIORITY_COUNT BIT(I915_USER_PRIORITY_SHIFT)
#define I915_PRIORITY_MASK (I915_PRIORITY_COUNT - 1)
-#define I915_PRIORITY_NEWCLIENT ((u8)BIT(0))
+#define I915_PRIORITY_WAIT ((u8)BIT(0))
+#define I915_PRIORITY_NEWCLIENT ((u8)BIT(1))
struct i915_sched_attr {
/**
@@ -99,6 +100,8 @@ void i915_sched_node_fini(struct drm_i915_private *i915,
void i915_schedule(struct i915_request *request,
const struct i915_sched_attr *attr);
+void i915_schedule_bump_priority(struct i915_request *rq, unsigned int bump);
+
struct list_head *
i915_sched_lookup_priolist(struct intel_engine_cs *engine, int prio);
--
2.19.0
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^ permalink raw reply related [flat|nested] 7+ messages in thread