mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 09:19:51 +00:00
![Chris Wilson](/assets/img/avatar_default.png)
In monitoring a transcode pipeline that is latency sensitive (it waits between submitting frames, and each frame requires work on rcs/vcs/vecs engines), it is found that it took longer than a single jiffy for it to sustain its workload. Allowing an extra jiffy headroom for the userspace prevents us from prematurely parking and having to exit powersaving immediately. Link: https://gitlab.freedesktop.org/drm/intel/-/issues/6284 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Karolina Drobnik <karolina.drobnik@intel.com> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/e37911ec087a9ce50630d6faf61fa2c0d5f96d44.1657289332.git.karolina.drobnik@intel.com
1165 lines
28 KiB
C
1165 lines
28 KiB
C
/*
|
|
* SPDX-License-Identifier: MIT
|
|
*
|
|
* Copyright © 2019 Intel Corporation
|
|
*/
|
|
|
|
#include <linux/debugobjects.h>
|
|
|
|
#include "gt/intel_context.h"
|
|
#include "gt/intel_engine_heartbeat.h"
|
|
#include "gt/intel_engine_pm.h"
|
|
#include "gt/intel_ring.h"
|
|
|
|
#include "i915_drv.h"
|
|
#include "i915_active.h"
|
|
|
|
/*
|
|
* Active refs memory management
|
|
*
|
|
* To be more economical with memory, we reap all the i915_active trees as
|
|
* they idle (when we know the active requests are inactive) and allocate the
|
|
* nodes from a local slab cache to hopefully reduce the fragmentation.
|
|
*/
|
|
static struct kmem_cache *slab_cache;
|
|
|
|
struct active_node {
|
|
struct rb_node node;
|
|
struct i915_active_fence base;
|
|
struct i915_active *ref;
|
|
u64 timeline;
|
|
};
|
|
|
|
#define fetch_node(x) rb_entry(READ_ONCE(x), typeof(struct active_node), node)
|
|
|
|
static inline struct active_node *
|
|
node_from_active(struct i915_active_fence *active)
|
|
{
|
|
return container_of(active, struct active_node, base);
|
|
}
|
|
|
|
#define take_preallocated_barriers(x) llist_del_all(&(x)->preallocated_barriers)
|
|
|
|
static inline bool is_barrier(const struct i915_active_fence *active)
|
|
{
|
|
return IS_ERR(rcu_access_pointer(active->fence));
|
|
}
|
|
|
|
static inline struct llist_node *barrier_to_ll(struct active_node *node)
|
|
{
|
|
GEM_BUG_ON(!is_barrier(&node->base));
|
|
return (struct llist_node *)&node->base.cb.node;
|
|
}
|
|
|
|
static inline struct intel_engine_cs *
|
|
__barrier_to_engine(struct active_node *node)
|
|
{
|
|
return (struct intel_engine_cs *)READ_ONCE(node->base.cb.node.prev);
|
|
}
|
|
|
|
static inline struct intel_engine_cs *
|
|
barrier_to_engine(struct active_node *node)
|
|
{
|
|
GEM_BUG_ON(!is_barrier(&node->base));
|
|
return __barrier_to_engine(node);
|
|
}
|
|
|
|
static inline struct active_node *barrier_from_ll(struct llist_node *x)
|
|
{
|
|
return container_of((struct list_head *)x,
|
|
struct active_node, base.cb.node);
|
|
}
|
|
|
|
#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM) && IS_ENABLED(CONFIG_DEBUG_OBJECTS)
|
|
|
|
static void *active_debug_hint(void *addr)
|
|
{
|
|
struct i915_active *ref = addr;
|
|
|
|
return (void *)ref->active ?: (void *)ref->retire ?: (void *)ref;
|
|
}
|
|
|
|
static const struct debug_obj_descr active_debug_desc = {
|
|
.name = "i915_active",
|
|
.debug_hint = active_debug_hint,
|
|
};
|
|
|
|
static void debug_active_init(struct i915_active *ref)
|
|
{
|
|
debug_object_init(ref, &active_debug_desc);
|
|
}
|
|
|
|
static void debug_active_activate(struct i915_active *ref)
|
|
{
|
|
lockdep_assert_held(&ref->tree_lock);
|
|
if (!atomic_read(&ref->count)) /* before the first inc */
|
|
debug_object_activate(ref, &active_debug_desc);
|
|
}
|
|
|
|
static void debug_active_deactivate(struct i915_active *ref)
|
|
{
|
|
lockdep_assert_held(&ref->tree_lock);
|
|
if (!atomic_read(&ref->count)) /* after the last dec */
|
|
debug_object_deactivate(ref, &active_debug_desc);
|
|
}
|
|
|
|
static void debug_active_fini(struct i915_active *ref)
|
|
{
|
|
debug_object_free(ref, &active_debug_desc);
|
|
}
|
|
|
|
static void debug_active_assert(struct i915_active *ref)
|
|
{
|
|
debug_object_assert_init(ref, &active_debug_desc);
|
|
}
|
|
|
|
#else
|
|
|
|
static inline void debug_active_init(struct i915_active *ref) { }
|
|
static inline void debug_active_activate(struct i915_active *ref) { }
|
|
static inline void debug_active_deactivate(struct i915_active *ref) { }
|
|
static inline void debug_active_fini(struct i915_active *ref) { }
|
|
static inline void debug_active_assert(struct i915_active *ref) { }
|
|
|
|
#endif
|
|
|
|
static void
|
|
__active_retire(struct i915_active *ref)
|
|
{
|
|
struct rb_root root = RB_ROOT;
|
|
struct active_node *it, *n;
|
|
unsigned long flags;
|
|
|
|
GEM_BUG_ON(i915_active_is_idle(ref));
|
|
|
|
/* return the unused nodes to our slabcache -- flushing the allocator */
|
|
if (!atomic_dec_and_lock_irqsave(&ref->count, &ref->tree_lock, flags))
|
|
return;
|
|
|
|
GEM_BUG_ON(rcu_access_pointer(ref->excl.fence));
|
|
debug_active_deactivate(ref);
|
|
|
|
/* Even if we have not used the cache, we may still have a barrier */
|
|
if (!ref->cache)
|
|
ref->cache = fetch_node(ref->tree.rb_node);
|
|
|
|
/* Keep the MRU cached node for reuse */
|
|
if (ref->cache) {
|
|
/* Discard all other nodes in the tree */
|
|
rb_erase(&ref->cache->node, &ref->tree);
|
|
root = ref->tree;
|
|
|
|
/* Rebuild the tree with only the cached node */
|
|
rb_link_node(&ref->cache->node, NULL, &ref->tree.rb_node);
|
|
rb_insert_color(&ref->cache->node, &ref->tree);
|
|
GEM_BUG_ON(ref->tree.rb_node != &ref->cache->node);
|
|
|
|
/* Make the cached node available for reuse with any timeline */
|
|
ref->cache->timeline = 0; /* needs cmpxchg(u64) */
|
|
}
|
|
|
|
spin_unlock_irqrestore(&ref->tree_lock, flags);
|
|
|
|
/* After the final retire, the entire struct may be freed */
|
|
if (ref->retire)
|
|
ref->retire(ref);
|
|
|
|
/* ... except if you wait on it, you must manage your own references! */
|
|
wake_up_var(ref);
|
|
|
|
/* Finally free the discarded timeline tree */
|
|
rbtree_postorder_for_each_entry_safe(it, n, &root, node) {
|
|
GEM_BUG_ON(i915_active_fence_isset(&it->base));
|
|
kmem_cache_free(slab_cache, it);
|
|
}
|
|
}
|
|
|
|
static void
|
|
active_work(struct work_struct *wrk)
|
|
{
|
|
struct i915_active *ref = container_of(wrk, typeof(*ref), work);
|
|
|
|
GEM_BUG_ON(!atomic_read(&ref->count));
|
|
if (atomic_add_unless(&ref->count, -1, 1))
|
|
return;
|
|
|
|
__active_retire(ref);
|
|
}
|
|
|
|
static void
|
|
active_retire(struct i915_active *ref)
|
|
{
|
|
GEM_BUG_ON(!atomic_read(&ref->count));
|
|
if (atomic_add_unless(&ref->count, -1, 1))
|
|
return;
|
|
|
|
if (ref->flags & I915_ACTIVE_RETIRE_SLEEPS) {
|
|
queue_work(system_unbound_wq, &ref->work);
|
|
return;
|
|
}
|
|
|
|
__active_retire(ref);
|
|
}
|
|
|
|
static inline struct dma_fence **
|
|
__active_fence_slot(struct i915_active_fence *active)
|
|
{
|
|
return (struct dma_fence ** __force)&active->fence;
|
|
}
|
|
|
|
static inline bool
|
|
active_fence_cb(struct dma_fence *fence, struct dma_fence_cb *cb)
|
|
{
|
|
struct i915_active_fence *active =
|
|
container_of(cb, typeof(*active), cb);
|
|
|
|
return cmpxchg(__active_fence_slot(active), fence, NULL) == fence;
|
|
}
|
|
|
|
static void
|
|
node_retire(struct dma_fence *fence, struct dma_fence_cb *cb)
|
|
{
|
|
if (active_fence_cb(fence, cb))
|
|
active_retire(container_of(cb, struct active_node, base.cb)->ref);
|
|
}
|
|
|
|
static void
|
|
excl_retire(struct dma_fence *fence, struct dma_fence_cb *cb)
|
|
{
|
|
if (active_fence_cb(fence, cb))
|
|
active_retire(container_of(cb, struct i915_active, excl.cb));
|
|
}
|
|
|
|
static struct active_node *__active_lookup(struct i915_active *ref, u64 idx)
|
|
{
|
|
struct active_node *it;
|
|
|
|
GEM_BUG_ON(idx == 0); /* 0 is the unordered timeline, rsvd for cache */
|
|
|
|
/*
|
|
* We track the most recently used timeline to skip a rbtree search
|
|
* for the common case, under typical loads we never need the rbtree
|
|
* at all. We can reuse the last slot if it is empty, that is
|
|
* after the previous activity has been retired, or if it matches the
|
|
* current timeline.
|
|
*/
|
|
it = READ_ONCE(ref->cache);
|
|
if (it) {
|
|
u64 cached = READ_ONCE(it->timeline);
|
|
|
|
/* Once claimed, this slot will only belong to this idx */
|
|
if (cached == idx)
|
|
return it;
|
|
|
|
/*
|
|
* An unclaimed cache [.timeline=0] can only be claimed once.
|
|
*
|
|
* If the value is already non-zero, some other thread has
|
|
* claimed the cache and we know that is does not match our
|
|
* idx. If, and only if, the timeline is currently zero is it
|
|
* worth competing to claim it atomically for ourselves (for
|
|
* only the winner of that race will cmpxchg return the old
|
|
* value of 0).
|
|
*/
|
|
if (!cached && !cmpxchg64(&it->timeline, 0, idx))
|
|
return it;
|
|
}
|
|
|
|
BUILD_BUG_ON(offsetof(typeof(*it), node));
|
|
|
|
/* While active, the tree can only be built; not destroyed */
|
|
GEM_BUG_ON(i915_active_is_idle(ref));
|
|
|
|
it = fetch_node(ref->tree.rb_node);
|
|
while (it) {
|
|
if (it->timeline < idx) {
|
|
it = fetch_node(it->node.rb_right);
|
|
} else if (it->timeline > idx) {
|
|
it = fetch_node(it->node.rb_left);
|
|
} else {
|
|
WRITE_ONCE(ref->cache, it);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* NB: If the tree rotated beneath us, we may miss our target. */
|
|
return it;
|
|
}
|
|
|
|
static struct i915_active_fence *
|
|
active_instance(struct i915_active *ref, u64 idx)
|
|
{
|
|
struct active_node *node;
|
|
struct rb_node **p, *parent;
|
|
|
|
node = __active_lookup(ref, idx);
|
|
if (likely(node))
|
|
return &node->base;
|
|
|
|
spin_lock_irq(&ref->tree_lock);
|
|
GEM_BUG_ON(i915_active_is_idle(ref));
|
|
|
|
parent = NULL;
|
|
p = &ref->tree.rb_node;
|
|
while (*p) {
|
|
parent = *p;
|
|
|
|
node = rb_entry(parent, struct active_node, node);
|
|
if (node->timeline == idx)
|
|
goto out;
|
|
|
|
if (node->timeline < idx)
|
|
p = &parent->rb_right;
|
|
else
|
|
p = &parent->rb_left;
|
|
}
|
|
|
|
/*
|
|
* XXX: We should preallocate this before i915_active_ref() is ever
|
|
* called, but we cannot call into fs_reclaim() anyway, so use GFP_ATOMIC.
|
|
*/
|
|
node = kmem_cache_alloc(slab_cache, GFP_ATOMIC);
|
|
if (!node)
|
|
goto out;
|
|
|
|
__i915_active_fence_init(&node->base, NULL, node_retire);
|
|
node->ref = ref;
|
|
node->timeline = idx;
|
|
|
|
rb_link_node(&node->node, parent, p);
|
|
rb_insert_color(&node->node, &ref->tree);
|
|
|
|
out:
|
|
WRITE_ONCE(ref->cache, node);
|
|
spin_unlock_irq(&ref->tree_lock);
|
|
|
|
return &node->base;
|
|
}
|
|
|
|
void __i915_active_init(struct i915_active *ref,
|
|
int (*active)(struct i915_active *ref),
|
|
void (*retire)(struct i915_active *ref),
|
|
unsigned long flags,
|
|
struct lock_class_key *mkey,
|
|
struct lock_class_key *wkey)
|
|
{
|
|
debug_active_init(ref);
|
|
|
|
ref->flags = flags;
|
|
ref->active = active;
|
|
ref->retire = retire;
|
|
|
|
spin_lock_init(&ref->tree_lock);
|
|
ref->tree = RB_ROOT;
|
|
ref->cache = NULL;
|
|
|
|
init_llist_head(&ref->preallocated_barriers);
|
|
atomic_set(&ref->count, 0);
|
|
__mutex_init(&ref->mutex, "i915_active", mkey);
|
|
__i915_active_fence_init(&ref->excl, NULL, excl_retire);
|
|
INIT_WORK(&ref->work, active_work);
|
|
#if IS_ENABLED(CONFIG_LOCKDEP)
|
|
lockdep_init_map(&ref->work.lockdep_map, "i915_active.work", wkey, 0);
|
|
#endif
|
|
}
|
|
|
|
static bool ____active_del_barrier(struct i915_active *ref,
|
|
struct active_node *node,
|
|
struct intel_engine_cs *engine)
|
|
|
|
{
|
|
struct llist_node *head = NULL, *tail = NULL;
|
|
struct llist_node *pos, *next;
|
|
|
|
GEM_BUG_ON(node->timeline != engine->kernel_context->timeline->fence_context);
|
|
|
|
/*
|
|
* Rebuild the llist excluding our node. We may perform this
|
|
* outside of the kernel_context timeline mutex and so someone
|
|
* else may be manipulating the engine->barrier_tasks, in
|
|
* which case either we or they will be upset :)
|
|
*
|
|
* A second __active_del_barrier() will report failure to claim
|
|
* the active_node and the caller will just shrug and know not to
|
|
* claim ownership of its node.
|
|
*
|
|
* A concurrent i915_request_add_active_barriers() will miss adding
|
|
* any of the tasks, but we will try again on the next -- and since
|
|
* we are actively using the barrier, we know that there will be
|
|
* at least another opportunity when we idle.
|
|
*/
|
|
llist_for_each_safe(pos, next, llist_del_all(&engine->barrier_tasks)) {
|
|
if (node == barrier_from_ll(pos)) {
|
|
node = NULL;
|
|
continue;
|
|
}
|
|
|
|
pos->next = head;
|
|
head = pos;
|
|
if (!tail)
|
|
tail = pos;
|
|
}
|
|
if (head)
|
|
llist_add_batch(head, tail, &engine->barrier_tasks);
|
|
|
|
return !node;
|
|
}
|
|
|
|
static bool
|
|
__active_del_barrier(struct i915_active *ref, struct active_node *node)
|
|
{
|
|
return ____active_del_barrier(ref, node, barrier_to_engine(node));
|
|
}
|
|
|
|
static bool
|
|
replace_barrier(struct i915_active *ref, struct i915_active_fence *active)
|
|
{
|
|
if (!is_barrier(active)) /* proto-node used by our idle barrier? */
|
|
return false;
|
|
|
|
/*
|
|
* This request is on the kernel_context timeline, and so
|
|
* we can use it to substitute for the pending idle-barrer
|
|
* request that we want to emit on the kernel_context.
|
|
*/
|
|
__active_del_barrier(ref, node_from_active(active));
|
|
return true;
|
|
}
|
|
|
|
int i915_active_add_request(struct i915_active *ref, struct i915_request *rq)
|
|
{
|
|
struct dma_fence *fence = &rq->fence;
|
|
struct i915_active_fence *active;
|
|
int err;
|
|
|
|
/* Prevent reaping in case we malloc/wait while building the tree */
|
|
err = i915_active_acquire(ref);
|
|
if (err)
|
|
return err;
|
|
|
|
active = active_instance(ref, i915_request_timeline(rq)->fence_context);
|
|
if (!active) {
|
|
err = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
if (replace_barrier(ref, active)) {
|
|
RCU_INIT_POINTER(active->fence, NULL);
|
|
atomic_dec(&ref->count);
|
|
}
|
|
if (!__i915_active_fence_set(active, fence))
|
|
__i915_active_acquire(ref);
|
|
|
|
out:
|
|
i915_active_release(ref);
|
|
return err;
|
|
}
|
|
|
|
static struct dma_fence *
|
|
__i915_active_set_fence(struct i915_active *ref,
|
|
struct i915_active_fence *active,
|
|
struct dma_fence *fence)
|
|
{
|
|
struct dma_fence *prev;
|
|
|
|
if (replace_barrier(ref, active)) {
|
|
RCU_INIT_POINTER(active->fence, fence);
|
|
return NULL;
|
|
}
|
|
|
|
rcu_read_lock();
|
|
prev = __i915_active_fence_set(active, fence);
|
|
if (prev)
|
|
prev = dma_fence_get_rcu(prev);
|
|
else
|
|
__i915_active_acquire(ref);
|
|
rcu_read_unlock();
|
|
|
|
return prev;
|
|
}
|
|
|
|
struct dma_fence *
|
|
i915_active_set_exclusive(struct i915_active *ref, struct dma_fence *f)
|
|
{
|
|
/* We expect the caller to manage the exclusive timeline ordering */
|
|
return __i915_active_set_fence(ref, &ref->excl, f);
|
|
}
|
|
|
|
bool i915_active_acquire_if_busy(struct i915_active *ref)
|
|
{
|
|
debug_active_assert(ref);
|
|
return atomic_add_unless(&ref->count, 1, 0);
|
|
}
|
|
|
|
static void __i915_active_activate(struct i915_active *ref)
|
|
{
|
|
spin_lock_irq(&ref->tree_lock); /* __active_retire() */
|
|
if (!atomic_fetch_inc(&ref->count))
|
|
debug_active_activate(ref);
|
|
spin_unlock_irq(&ref->tree_lock);
|
|
}
|
|
|
|
int i915_active_acquire(struct i915_active *ref)
|
|
{
|
|
int err;
|
|
|
|
if (i915_active_acquire_if_busy(ref))
|
|
return 0;
|
|
|
|
if (!ref->active) {
|
|
__i915_active_activate(ref);
|
|
return 0;
|
|
}
|
|
|
|
err = mutex_lock_interruptible(&ref->mutex);
|
|
if (err)
|
|
return err;
|
|
|
|
if (likely(!i915_active_acquire_if_busy(ref))) {
|
|
err = ref->active(ref);
|
|
if (!err)
|
|
__i915_active_activate(ref);
|
|
}
|
|
|
|
mutex_unlock(&ref->mutex);
|
|
|
|
return err;
|
|
}
|
|
|
|
int i915_active_acquire_for_context(struct i915_active *ref, u64 idx)
|
|
{
|
|
struct i915_active_fence *active;
|
|
int err;
|
|
|
|
err = i915_active_acquire(ref);
|
|
if (err)
|
|
return err;
|
|
|
|
active = active_instance(ref, idx);
|
|
if (!active) {
|
|
i915_active_release(ref);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
return 0; /* return with active ref */
|
|
}
|
|
|
|
void i915_active_release(struct i915_active *ref)
|
|
{
|
|
debug_active_assert(ref);
|
|
active_retire(ref);
|
|
}
|
|
|
|
static void enable_signaling(struct i915_active_fence *active)
|
|
{
|
|
struct dma_fence *fence;
|
|
|
|
if (unlikely(is_barrier(active)))
|
|
return;
|
|
|
|
fence = i915_active_fence_get(active);
|
|
if (!fence)
|
|
return;
|
|
|
|
dma_fence_enable_sw_signaling(fence);
|
|
dma_fence_put(fence);
|
|
}
|
|
|
|
static int flush_barrier(struct active_node *it)
|
|
{
|
|
struct intel_engine_cs *engine;
|
|
|
|
if (likely(!is_barrier(&it->base)))
|
|
return 0;
|
|
|
|
engine = __barrier_to_engine(it);
|
|
smp_rmb(); /* serialise with add_active_barriers */
|
|
if (!is_barrier(&it->base))
|
|
return 0;
|
|
|
|
return intel_engine_flush_barriers(engine);
|
|
}
|
|
|
|
static int flush_lazy_signals(struct i915_active *ref)
|
|
{
|
|
struct active_node *it, *n;
|
|
int err = 0;
|
|
|
|
enable_signaling(&ref->excl);
|
|
rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) {
|
|
err = flush_barrier(it); /* unconnected idle barrier? */
|
|
if (err)
|
|
break;
|
|
|
|
enable_signaling(&it->base);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
int __i915_active_wait(struct i915_active *ref, int state)
|
|
{
|
|
might_sleep();
|
|
|
|
/* Any fence added after the wait begins will not be auto-signaled */
|
|
if (i915_active_acquire_if_busy(ref)) {
|
|
int err;
|
|
|
|
err = flush_lazy_signals(ref);
|
|
i915_active_release(ref);
|
|
if (err)
|
|
return err;
|
|
|
|
if (___wait_var_event(ref, i915_active_is_idle(ref),
|
|
state, 0, 0, schedule()))
|
|
return -EINTR;
|
|
}
|
|
|
|
/*
|
|
* After the wait is complete, the caller may free the active.
|
|
* We have to flush any concurrent retirement before returning.
|
|
*/
|
|
flush_work(&ref->work);
|
|
return 0;
|
|
}
|
|
|
|
static int __await_active(struct i915_active_fence *active,
|
|
int (*fn)(void *arg, struct dma_fence *fence),
|
|
void *arg)
|
|
{
|
|
struct dma_fence *fence;
|
|
|
|
if (is_barrier(active)) /* XXX flush the barrier? */
|
|
return 0;
|
|
|
|
fence = i915_active_fence_get(active);
|
|
if (fence) {
|
|
int err;
|
|
|
|
err = fn(arg, fence);
|
|
dma_fence_put(fence);
|
|
if (err < 0)
|
|
return err;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
struct wait_barrier {
|
|
struct wait_queue_entry base;
|
|
struct i915_active *ref;
|
|
};
|
|
|
|
static int
|
|
barrier_wake(wait_queue_entry_t *wq, unsigned int mode, int flags, void *key)
|
|
{
|
|
struct wait_barrier *wb = container_of(wq, typeof(*wb), base);
|
|
|
|
if (i915_active_is_idle(wb->ref)) {
|
|
list_del(&wq->entry);
|
|
i915_sw_fence_complete(wq->private);
|
|
kfree(wq);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __await_barrier(struct i915_active *ref, struct i915_sw_fence *fence)
|
|
{
|
|
struct wait_barrier *wb;
|
|
|
|
wb = kmalloc(sizeof(*wb), GFP_KERNEL);
|
|
if (unlikely(!wb))
|
|
return -ENOMEM;
|
|
|
|
GEM_BUG_ON(i915_active_is_idle(ref));
|
|
if (!i915_sw_fence_await(fence)) {
|
|
kfree(wb);
|
|
return -EINVAL;
|
|
}
|
|
|
|
wb->base.flags = 0;
|
|
wb->base.func = barrier_wake;
|
|
wb->base.private = fence;
|
|
wb->ref = ref;
|
|
|
|
add_wait_queue(__var_waitqueue(ref), &wb->base);
|
|
return 0;
|
|
}
|
|
|
|
static int await_active(struct i915_active *ref,
|
|
unsigned int flags,
|
|
int (*fn)(void *arg, struct dma_fence *fence),
|
|
void *arg, struct i915_sw_fence *barrier)
|
|
{
|
|
int err = 0;
|
|
|
|
if (!i915_active_acquire_if_busy(ref))
|
|
return 0;
|
|
|
|
if (flags & I915_ACTIVE_AWAIT_EXCL &&
|
|
rcu_access_pointer(ref->excl.fence)) {
|
|
err = __await_active(&ref->excl, fn, arg);
|
|
if (err)
|
|
goto out;
|
|
}
|
|
|
|
if (flags & I915_ACTIVE_AWAIT_ACTIVE) {
|
|
struct active_node *it, *n;
|
|
|
|
rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) {
|
|
err = __await_active(&it->base, fn, arg);
|
|
if (err)
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
if (flags & I915_ACTIVE_AWAIT_BARRIER) {
|
|
err = flush_lazy_signals(ref);
|
|
if (err)
|
|
goto out;
|
|
|
|
err = __await_barrier(ref, barrier);
|
|
if (err)
|
|
goto out;
|
|
}
|
|
|
|
out:
|
|
i915_active_release(ref);
|
|
return err;
|
|
}
|
|
|
|
static int rq_await_fence(void *arg, struct dma_fence *fence)
|
|
{
|
|
return i915_request_await_dma_fence(arg, fence);
|
|
}
|
|
|
|
int i915_request_await_active(struct i915_request *rq,
|
|
struct i915_active *ref,
|
|
unsigned int flags)
|
|
{
|
|
return await_active(ref, flags, rq_await_fence, rq, &rq->submit);
|
|
}
|
|
|
|
static int sw_await_fence(void *arg, struct dma_fence *fence)
|
|
{
|
|
return i915_sw_fence_await_dma_fence(arg, fence, 0,
|
|
GFP_NOWAIT | __GFP_NOWARN);
|
|
}
|
|
|
|
int i915_sw_fence_await_active(struct i915_sw_fence *fence,
|
|
struct i915_active *ref,
|
|
unsigned int flags)
|
|
{
|
|
return await_active(ref, flags, sw_await_fence, fence, fence);
|
|
}
|
|
|
|
void i915_active_fini(struct i915_active *ref)
|
|
{
|
|
debug_active_fini(ref);
|
|
GEM_BUG_ON(atomic_read(&ref->count));
|
|
GEM_BUG_ON(work_pending(&ref->work));
|
|
mutex_destroy(&ref->mutex);
|
|
|
|
if (ref->cache)
|
|
kmem_cache_free(slab_cache, ref->cache);
|
|
}
|
|
|
|
static inline bool is_idle_barrier(struct active_node *node, u64 idx)
|
|
{
|
|
return node->timeline == idx && !i915_active_fence_isset(&node->base);
|
|
}
|
|
|
|
static struct active_node *reuse_idle_barrier(struct i915_active *ref, u64 idx)
|
|
{
|
|
struct rb_node *prev, *p;
|
|
|
|
if (RB_EMPTY_ROOT(&ref->tree))
|
|
return NULL;
|
|
|
|
GEM_BUG_ON(i915_active_is_idle(ref));
|
|
|
|
/*
|
|
* Try to reuse any existing barrier nodes already allocated for this
|
|
* i915_active, due to overlapping active phases there is likely a
|
|
* node kept alive (as we reuse before parking). We prefer to reuse
|
|
* completely idle barriers (less hassle in manipulating the llists),
|
|
* but otherwise any will do.
|
|
*/
|
|
if (ref->cache && is_idle_barrier(ref->cache, idx)) {
|
|
p = &ref->cache->node;
|
|
goto match;
|
|
}
|
|
|
|
prev = NULL;
|
|
p = ref->tree.rb_node;
|
|
while (p) {
|
|
struct active_node *node =
|
|
rb_entry(p, struct active_node, node);
|
|
|
|
if (is_idle_barrier(node, idx))
|
|
goto match;
|
|
|
|
prev = p;
|
|
if (node->timeline < idx)
|
|
p = READ_ONCE(p->rb_right);
|
|
else
|
|
p = READ_ONCE(p->rb_left);
|
|
}
|
|
|
|
/*
|
|
* No quick match, but we did find the leftmost rb_node for the
|
|
* kernel_context. Walk the rb_tree in-order to see if there were
|
|
* any idle-barriers on this timeline that we missed, or just use
|
|
* the first pending barrier.
|
|
*/
|
|
for (p = prev; p; p = rb_next(p)) {
|
|
struct active_node *node =
|
|
rb_entry(p, struct active_node, node);
|
|
struct intel_engine_cs *engine;
|
|
|
|
if (node->timeline > idx)
|
|
break;
|
|
|
|
if (node->timeline < idx)
|
|
continue;
|
|
|
|
if (is_idle_barrier(node, idx))
|
|
goto match;
|
|
|
|
/*
|
|
* The list of pending barriers is protected by the
|
|
* kernel_context timeline, which notably we do not hold
|
|
* here. i915_request_add_active_barriers() may consume
|
|
* the barrier before we claim it, so we have to check
|
|
* for success.
|
|
*/
|
|
engine = __barrier_to_engine(node);
|
|
smp_rmb(); /* serialise with add_active_barriers */
|
|
if (is_barrier(&node->base) &&
|
|
____active_del_barrier(ref, node, engine))
|
|
goto match;
|
|
}
|
|
|
|
return NULL;
|
|
|
|
match:
|
|
spin_lock_irq(&ref->tree_lock);
|
|
rb_erase(p, &ref->tree); /* Hide from waits and sibling allocations */
|
|
if (p == &ref->cache->node)
|
|
WRITE_ONCE(ref->cache, NULL);
|
|
spin_unlock_irq(&ref->tree_lock);
|
|
|
|
return rb_entry(p, struct active_node, node);
|
|
}
|
|
|
|
int i915_active_acquire_preallocate_barrier(struct i915_active *ref,
|
|
struct intel_engine_cs *engine)
|
|
{
|
|
intel_engine_mask_t tmp, mask = engine->mask;
|
|
struct llist_node *first = NULL, *last = NULL;
|
|
struct intel_gt *gt = engine->gt;
|
|
|
|
GEM_BUG_ON(i915_active_is_idle(ref));
|
|
|
|
/* Wait until the previous preallocation is completed */
|
|
while (!llist_empty(&ref->preallocated_barriers))
|
|
cond_resched();
|
|
|
|
/*
|
|
* Preallocate a node for each physical engine supporting the target
|
|
* engine (remember virtual engines have more than one sibling).
|
|
* We can then use the preallocated nodes in
|
|
* i915_active_acquire_barrier()
|
|
*/
|
|
GEM_BUG_ON(!mask);
|
|
for_each_engine_masked(engine, gt, mask, tmp) {
|
|
u64 idx = engine->kernel_context->timeline->fence_context;
|
|
struct llist_node *prev = first;
|
|
struct active_node *node;
|
|
|
|
rcu_read_lock();
|
|
node = reuse_idle_barrier(ref, idx);
|
|
rcu_read_unlock();
|
|
if (!node) {
|
|
node = kmem_cache_alloc(slab_cache, GFP_KERNEL);
|
|
if (!node)
|
|
goto unwind;
|
|
|
|
RCU_INIT_POINTER(node->base.fence, NULL);
|
|
node->base.cb.func = node_retire;
|
|
node->timeline = idx;
|
|
node->ref = ref;
|
|
}
|
|
|
|
if (!i915_active_fence_isset(&node->base)) {
|
|
/*
|
|
* Mark this as being *our* unconnected proto-node.
|
|
*
|
|
* Since this node is not in any list, and we have
|
|
* decoupled it from the rbtree, we can reuse the
|
|
* request to indicate this is an idle-barrier node
|
|
* and then we can use the rb_node and list pointers
|
|
* for our tracking of the pending barrier.
|
|
*/
|
|
RCU_INIT_POINTER(node->base.fence, ERR_PTR(-EAGAIN));
|
|
node->base.cb.node.prev = (void *)engine;
|
|
__i915_active_acquire(ref);
|
|
}
|
|
GEM_BUG_ON(rcu_access_pointer(node->base.fence) != ERR_PTR(-EAGAIN));
|
|
|
|
GEM_BUG_ON(barrier_to_engine(node) != engine);
|
|
first = barrier_to_ll(node);
|
|
first->next = prev;
|
|
if (!last)
|
|
last = first;
|
|
intel_engine_pm_get(engine);
|
|
}
|
|
|
|
GEM_BUG_ON(!llist_empty(&ref->preallocated_barriers));
|
|
llist_add_batch(first, last, &ref->preallocated_barriers);
|
|
|
|
return 0;
|
|
|
|
unwind:
|
|
while (first) {
|
|
struct active_node *node = barrier_from_ll(first);
|
|
|
|
first = first->next;
|
|
|
|
atomic_dec(&ref->count);
|
|
intel_engine_pm_put(barrier_to_engine(node));
|
|
|
|
kmem_cache_free(slab_cache, node);
|
|
}
|
|
return -ENOMEM;
|
|
}
|
|
|
|
void i915_active_acquire_barrier(struct i915_active *ref)
|
|
{
|
|
struct llist_node *pos, *next;
|
|
unsigned long flags;
|
|
|
|
GEM_BUG_ON(i915_active_is_idle(ref));
|
|
|
|
/*
|
|
* Transfer the list of preallocated barriers into the
|
|
* i915_active rbtree, but only as proto-nodes. They will be
|
|
* populated by i915_request_add_active_barriers() to point to the
|
|
* request that will eventually release them.
|
|
*/
|
|
llist_for_each_safe(pos, next, take_preallocated_barriers(ref)) {
|
|
struct active_node *node = barrier_from_ll(pos);
|
|
struct intel_engine_cs *engine = barrier_to_engine(node);
|
|
struct rb_node **p, *parent;
|
|
|
|
spin_lock_irqsave_nested(&ref->tree_lock, flags,
|
|
SINGLE_DEPTH_NESTING);
|
|
parent = NULL;
|
|
p = &ref->tree.rb_node;
|
|
while (*p) {
|
|
struct active_node *it;
|
|
|
|
parent = *p;
|
|
|
|
it = rb_entry(parent, struct active_node, node);
|
|
if (it->timeline < node->timeline)
|
|
p = &parent->rb_right;
|
|
else
|
|
p = &parent->rb_left;
|
|
}
|
|
rb_link_node(&node->node, parent, p);
|
|
rb_insert_color(&node->node, &ref->tree);
|
|
spin_unlock_irqrestore(&ref->tree_lock, flags);
|
|
|
|
GEM_BUG_ON(!intel_engine_pm_is_awake(engine));
|
|
llist_add(barrier_to_ll(node), &engine->barrier_tasks);
|
|
intel_engine_pm_put_delay(engine, 2);
|
|
}
|
|
}
|
|
|
|
static struct dma_fence **ll_to_fence_slot(struct llist_node *node)
|
|
{
|
|
return __active_fence_slot(&barrier_from_ll(node)->base);
|
|
}
|
|
|
|
void i915_request_add_active_barriers(struct i915_request *rq)
|
|
{
|
|
struct intel_engine_cs *engine = rq->engine;
|
|
struct llist_node *node, *next;
|
|
unsigned long flags;
|
|
|
|
GEM_BUG_ON(!intel_context_is_barrier(rq->context));
|
|
GEM_BUG_ON(intel_engine_is_virtual(engine));
|
|
GEM_BUG_ON(i915_request_timeline(rq) != engine->kernel_context->timeline);
|
|
|
|
node = llist_del_all(&engine->barrier_tasks);
|
|
if (!node)
|
|
return;
|
|
/*
|
|
* Attach the list of proto-fences to the in-flight request such
|
|
* that the parent i915_active will be released when this request
|
|
* is retired.
|
|
*/
|
|
spin_lock_irqsave(&rq->lock, flags);
|
|
llist_for_each_safe(node, next, node) {
|
|
/* serialise with reuse_idle_barrier */
|
|
smp_store_mb(*ll_to_fence_slot(node), &rq->fence);
|
|
list_add_tail((struct list_head *)node, &rq->fence.cb_list);
|
|
}
|
|
spin_unlock_irqrestore(&rq->lock, flags);
|
|
}
|
|
|
|
/*
|
|
* __i915_active_fence_set: Update the last active fence along its timeline
|
|
* @active: the active tracker
|
|
* @fence: the new fence (under construction)
|
|
*
|
|
* Records the new @fence as the last active fence along its timeline in
|
|
* this active tracker, moving the tracking callbacks from the previous
|
|
* fence onto this one. Returns the previous fence (if not already completed),
|
|
* which the caller must ensure is executed before the new fence. To ensure
|
|
* that the order of fences within the timeline of the i915_active_fence is
|
|
* understood, it should be locked by the caller.
|
|
*/
|
|
struct dma_fence *
|
|
__i915_active_fence_set(struct i915_active_fence *active,
|
|
struct dma_fence *fence)
|
|
{
|
|
struct dma_fence *prev;
|
|
unsigned long flags;
|
|
|
|
if (fence == rcu_access_pointer(active->fence))
|
|
return fence;
|
|
|
|
GEM_BUG_ON(test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags));
|
|
|
|
/*
|
|
* Consider that we have two threads arriving (A and B), with
|
|
* C already resident as the active->fence.
|
|
*
|
|
* A does the xchg first, and so it sees C or NULL depending
|
|
* on the timing of the interrupt handler. If it is NULL, the
|
|
* previous fence must have been signaled and we know that
|
|
* we are first on the timeline. If it is still present,
|
|
* we acquire the lock on that fence and serialise with the interrupt
|
|
* handler, in the process removing it from any future interrupt
|
|
* callback. A will then wait on C before executing (if present).
|
|
*
|
|
* As B is second, it sees A as the previous fence and so waits for
|
|
* it to complete its transition and takes over the occupancy for
|
|
* itself -- remembering that it needs to wait on A before executing.
|
|
*
|
|
* Note the strong ordering of the timeline also provides consistent
|
|
* nesting rules for the fence->lock; the inner lock is always the
|
|
* older lock.
|
|
*/
|
|
spin_lock_irqsave(fence->lock, flags);
|
|
prev = xchg(__active_fence_slot(active), fence);
|
|
if (prev) {
|
|
GEM_BUG_ON(prev == fence);
|
|
spin_lock_nested(prev->lock, SINGLE_DEPTH_NESTING);
|
|
__list_del_entry(&active->cb.node);
|
|
spin_unlock(prev->lock); /* serialise with prev->cb_list */
|
|
}
|
|
list_add_tail(&active->cb.node, &fence->cb_list);
|
|
spin_unlock_irqrestore(fence->lock, flags);
|
|
|
|
return prev;
|
|
}
|
|
|
|
int i915_active_fence_set(struct i915_active_fence *active,
|
|
struct i915_request *rq)
|
|
{
|
|
struct dma_fence *fence;
|
|
int err = 0;
|
|
|
|
/* Must maintain timeline ordering wrt previous active requests */
|
|
rcu_read_lock();
|
|
fence = __i915_active_fence_set(active, &rq->fence);
|
|
if (fence) /* but the previous fence may not belong to that timeline! */
|
|
fence = dma_fence_get_rcu(fence);
|
|
rcu_read_unlock();
|
|
if (fence) {
|
|
err = i915_request_await_dma_fence(rq, fence);
|
|
dma_fence_put(fence);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
void i915_active_noop(struct dma_fence *fence, struct dma_fence_cb *cb)
|
|
{
|
|
active_fence_cb(fence, cb);
|
|
}
|
|
|
|
struct auto_active {
|
|
struct i915_active base;
|
|
struct kref ref;
|
|
};
|
|
|
|
struct i915_active *i915_active_get(struct i915_active *ref)
|
|
{
|
|
struct auto_active *aa = container_of(ref, typeof(*aa), base);
|
|
|
|
kref_get(&aa->ref);
|
|
return &aa->base;
|
|
}
|
|
|
|
static void auto_release(struct kref *ref)
|
|
{
|
|
struct auto_active *aa = container_of(ref, typeof(*aa), ref);
|
|
|
|
i915_active_fini(&aa->base);
|
|
kfree(aa);
|
|
}
|
|
|
|
void i915_active_put(struct i915_active *ref)
|
|
{
|
|
struct auto_active *aa = container_of(ref, typeof(*aa), base);
|
|
|
|
kref_put(&aa->ref, auto_release);
|
|
}
|
|
|
|
static int auto_active(struct i915_active *ref)
|
|
{
|
|
i915_active_get(ref);
|
|
return 0;
|
|
}
|
|
|
|
static void auto_retire(struct i915_active *ref)
|
|
{
|
|
i915_active_put(ref);
|
|
}
|
|
|
|
struct i915_active *i915_active_create(void)
|
|
{
|
|
struct auto_active *aa;
|
|
|
|
aa = kmalloc(sizeof(*aa), GFP_KERNEL);
|
|
if (!aa)
|
|
return NULL;
|
|
|
|
kref_init(&aa->ref);
|
|
i915_active_init(&aa->base, auto_active, auto_retire, 0);
|
|
|
|
return &aa->base;
|
|
}
|
|
|
|
#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
|
|
#include "selftests/i915_active.c"
|
|
#endif
|
|
|
|
void i915_active_module_exit(void)
|
|
{
|
|
kmem_cache_destroy(slab_cache);
|
|
}
|
|
|
|
int __init i915_active_module_init(void)
|
|
{
|
|
slab_cache = KMEM_CACHE(active_node, SLAB_HWCACHE_ALIGN);
|
|
if (!slab_cache)
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|