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dma-buf/sw-sync: Use an rbtree to sort fences in the timeline 

Reduce the list iteration when incrementing the timeline by storing the
fences in increasing order.

v2: Prevent spinlock recursion on free during create
v3: Fixup rebase conflict inside comments that escaped the compiler.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170629211253.22766-1-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2017-06-29 22:12:53 +01:00 committed by Gustavo Padovan
parent d3862e44da
commit f1e8c67123
2 changed files with 48 additions and 6 deletions
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49
drivers/dma-buf/sw_sync.c
View File

@ -96,6 +96,7 @@ static struct sync_timeline *sync_timeline_create(const char *name)
obj->context = dma_fence_context_alloc(1);
strlcpy(obj->name, name, sizeof(obj->name));
obj->pt_tree = RB_ROOT;
INIT_LIST_HEAD(&obj->pt_list);
spin_lock_init(&obj->lock);
@ -142,9 +143,13 @@ static void sync_timeline_signal(struct sync_timeline *obj, unsigned int inc)
obj->value += inc;
list_for_each_entry_safe(pt, next, &obj->pt_list, link)
if (dma_fence_is_signaled_locked(&pt->base))
list_del_init(&pt->link);
list_for_each_entry_safe(pt, next, &obj->pt_list, link) {
if (!dma_fence_is_signaled_locked(&pt->base))
break;
list_del_init(&pt->link);
rb_erase(&pt->node, &obj->pt_tree);
}
spin_unlock_irq(&obj->lock);
}
@ -174,8 +179,38 @@ static struct sync_pt *sync_pt_create(struct sync_timeline *obj,
INIT_LIST_HEAD(&pt->link);
spin_lock_irq(&obj->lock);
if (!dma_fence_is_signaled_locked(&pt->base))
list_add_tail(&pt->link, &obj->pt_list);
if (!dma_fence_is_signaled_locked(&pt->base)) {
struct rb_node **p = &obj->pt_tree.rb_node;
struct rb_node *parent = NULL;
while (*p) {
struct sync_pt *other;
int cmp;
parent = *p;
other = rb_entry(parent, typeof(*pt), node);
cmp = value - other->base.seqno;
if (cmp > 0) {
p = &parent->rb_right;
} else if (cmp < 0) {
p = &parent->rb_left;
} else {
if (dma_fence_get_rcu(&other->base)) {
dma_fence_put(&pt->base);
pt = other;
goto unlock;
}
p = &parent->rb_left;
}
}
rb_link_node(&pt->node, parent, p);
rb_insert_color(&pt->node, &obj->pt_tree);
parent = rb_next(&pt->node);
list_add_tail(&pt->link,
parent ? &rb_entry(parent, typeof(*pt), node)->link : &obj->pt_list);
}
unlock:
spin_unlock_irq(&obj->lock);
return pt;
@ -202,8 +237,10 @@ static void timeline_fence_release(struct dma_fence *fence)
unsigned long flags;
spin_lock_irqsave(fence->lock, flags);
if (!list_empty(&pt->link))
if (!list_empty(&pt->link)) {
list_del(&pt->link);
rb_erase(&pt->node, &parent->pt_tree);
}
spin_unlock_irqrestore(fence->lock, flags);
}

5
drivers/dma-buf/sync_debug.h
View File

@ -14,6 +14,7 @@
#define _LINUX_SYNC_H
#include <linux/list.h>
#include <linux/rbtree.h>
#include <linux/spinlock.h>
#include <linux/dma-fence.h>
@ -25,6 +26,7 @@
* @kref: reference count on fence.
* @name: name of the sync_timeline. Useful for debugging
* @lock: lock protecting @pt_list and @value
* @pt_tree: rbtree of active (unsignaled/errored) sync_pts
* @pt_list: list of active (unsignaled/errored) sync_pts
* @sync_timeline_list: membership in global sync_timeline_list
*/
@ -36,6 +38,7 @@ struct sync_timeline {
u64 context;
int value;
struct rb_root pt_tree;
struct list_head pt_list;
spinlock_t lock;
@ -51,10 +54,12 @@ static inline struct sync_timeline *dma_fence_parent(struct dma_fence *fence)
* struct sync_pt - sync_pt object
* @base: base fence object
* @link: link on the sync timeline's list
* @node: node in the sync timeline's tree
*/
struct sync_pt {
struct dma_fence base;
struct list_head link;
struct rb_node node;
};
#ifdef CONFIG_SW_SYNC