linux_dsm_epyc7002/drivers/gpu/drm/i915/i915_active.c

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/*
* SPDX-License-Identifier: MIT
*
* Copyright © 2019 Intel Corporation
*/
#include "i915_drv.h"
#include "i915_active.h"
#define BKL(ref) (&(ref)->i915->drm.struct_mutex)
/*
* 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 i915_global_active {
struct kmem_cache *slab_cache;
} global;
struct active_node {
struct i915_active_request base;
struct i915_active *ref;
struct rb_node node;
u64 timeline;
};
static void
__active_park(struct i915_active *ref)
{
struct active_node *it, *n;
rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) {
GEM_BUG_ON(i915_active_request_isset(&it->base));
kmem_cache_free(global.slab_cache, it);
}
ref->tree = RB_ROOT;
}
static void
__active_retire(struct i915_active *ref)
{
GEM_BUG_ON(!ref->count);
if (--ref->count)
return;
/* return the unused nodes to our slabcache */
__active_park(ref);
ref->retire(ref);
}
static void
node_retire(struct i915_active_request *base, struct i915_request *rq)
{
__active_retire(container_of(base, struct active_node, base)->ref);
}
static void
last_retire(struct i915_active_request *base, struct i915_request *rq)
{
__active_retire(container_of(base, struct i915_active, last));
}
static struct i915_active_request *
active_instance(struct i915_active *ref, u64 idx)
{
struct active_node *node;
struct rb_node **p, *parent;
struct i915_request *old;
/*
* 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.
*
* Note that we allow the timeline to be active simultaneously in
* the rbtree and the last cache. We do this to avoid having
* to search and replace the rbtree element for a new timeline, with
* the cost being that we must be aware that the ref may be retired
* twice for the same timeline (as the older rbtree element will be
* retired before the new request added to last).
*/
old = i915_active_request_raw(&ref->last, BKL(ref));
if (!old || old->fence.context == idx)
goto out;
/* Move the currently active fence into the rbtree */
idx = old->fence.context;
parent = NULL;
p = &ref->tree.rb_node;
while (*p) {
parent = *p;
node = rb_entry(parent, struct active_node, node);
if (node->timeline == idx)
goto replace;
if (node->timeline < idx)
p = &parent->rb_right;
else
p = &parent->rb_left;
}
node = kmem_cache_alloc(global.slab_cache, GFP_KERNEL);
/* kmalloc may retire the ref->last (thanks shrinker)! */
if (unlikely(!i915_active_request_raw(&ref->last, BKL(ref)))) {
kmem_cache_free(global.slab_cache, node);
goto out;
}
if (unlikely(!node))
return ERR_PTR(-ENOMEM);
i915_active_request_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);
replace:
/*
* Overwrite the previous active slot in the rbtree with last,
* leaving last zeroed. If the previous slot is still active,
* we must be careful as we now only expect to receive one retire
* callback not two, and so much undo the active counting for the
* overwritten slot.
*/
if (i915_active_request_isset(&node->base)) {
/* Retire ourselves from the old rq->active_list */
__list_del_entry(&node->base.link);
ref->count--;
GEM_BUG_ON(!ref->count);
}
GEM_BUG_ON(list_empty(&ref->last.link));
list_replace_init(&ref->last.link, &node->base.link);
node->base.request = fetch_and_zero(&ref->last.request);
out:
return &ref->last;
}
void i915_active_init(struct drm_i915_private *i915,
struct i915_active *ref,
void (*retire)(struct i915_active *ref))
{
ref->i915 = i915;
ref->retire = retire;
ref->tree = RB_ROOT;
i915_active_request_init(&ref->last, NULL, last_retire);
ref->count = 0;
}
int i915_active_ref(struct i915_active *ref,
u64 timeline,
struct i915_request *rq)
{
struct i915_active_request *active;
active = active_instance(ref, timeline);
if (IS_ERR(active))
return PTR_ERR(active);
if (!i915_active_request_isset(active))
ref->count++;
__i915_active_request_set(active, rq);
GEM_BUG_ON(!ref->count);
return 0;
}
bool i915_active_acquire(struct i915_active *ref)
{
lockdep_assert_held(BKL(ref));
return !ref->count++;
}
void i915_active_release(struct i915_active *ref)
{
lockdep_assert_held(BKL(ref));
__active_retire(ref);
}
int i915_active_wait(struct i915_active *ref)
{
struct active_node *it, *n;
int ret = 0;
if (i915_active_acquire(ref))
goto out_release;
ret = i915_active_request_retire(&ref->last, BKL(ref));
if (ret)
goto out_release;
rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) {
ret = i915_active_request_retire(&it->base, BKL(ref));
if (ret)
break;
}
out_release:
i915_active_release(ref);
return ret;
}
int i915_request_await_active_request(struct i915_request *rq,
struct i915_active_request *active)
{
struct i915_request *barrier =
i915_active_request_raw(active, &rq->i915->drm.struct_mutex);
return barrier ? i915_request_await_dma_fence(rq, &barrier->fence) : 0;
}
int i915_request_await_active(struct i915_request *rq, struct i915_active *ref)
{
struct active_node *it, *n;
int ret;
ret = i915_request_await_active_request(rq, &ref->last);
if (ret)
return ret;
rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) {
ret = i915_request_await_active_request(rq, &it->base);
if (ret)
return ret;
}
return 0;
}
#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)
void i915_active_fini(struct i915_active *ref)
{
GEM_BUG_ON(i915_active_request_isset(&ref->last));
GEM_BUG_ON(!RB_EMPTY_ROOT(&ref->tree));
GEM_BUG_ON(ref->count);
}
#endif
int i915_active_request_set(struct i915_active_request *active,
struct i915_request *rq)
{
int err;
/* Must maintain ordering wrt previous active requests */
err = i915_request_await_active_request(rq, active);
if (err)
return err;
__i915_active_request_set(active, rq);
return 0;
}
void i915_active_retire_noop(struct i915_active_request *active,
struct i915_request *request)
{
/* Space left intentionally blank */
}
#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
#include "selftests/i915_active.c"
#endif
int __init i915_global_active_init(void)
{
global.slab_cache = KMEM_CACHE(active_node, SLAB_HWCACHE_ALIGN);
if (!global.slab_cache)
return -ENOMEM;
return 0;
}
void __exit i915_global_active_exit(void)
{
kmem_cache_destroy(global.slab_cache);
}