This is a note to let you know that I've just added the patch titled
dma-buf/sw-sync: Use an rbtree to sort fences in the timeline
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dma-buf-sw-sync-use-an-rbtree-to-sort-fences-in-the-timeline.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From f1e8c67123cf171e2b0357e885e426328b241d7d Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Date: Thu, 29 Jun 2017 22:12:53 +0100
Subject: dma-buf/sw-sync: Use an rbtree to sort fences in the timeline
From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
commit f1e8c67123cf171e2b0357e885e426328b241d7d upstream.
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@xxxxxxxxxxxxxxxxxx>
Cc: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
Cc: Sean Paul <seanpaul@xxxxxxxxxxxx>
Cc: Gustavo Padovan <gustavo@xxxxxxxxxxx>
Reviewed-by: Sean Paul <seanpaul@xxxxxxxxxxxx>
Signed-off-by: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx>
Link: http://patchwork.freedesktop.org/patch/msgid/20170629211253.22766-1-chris@xxxxxxxxxxxxxxxxxx
[s/dma_fence/fence/g - gregkh]
Cc: Jisheng Zhang <Jisheng.Zhang@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/dma-buf/sw_sync.c | 49 +++++++++++++++++++++++++++++++++++++------
drivers/dma-buf/sync_debug.h | 5 ++++
2 files changed, 48 insertions(+), 6 deletions(-)
--- a/drivers/dma-buf/sw_sync.c
+++ b/drivers/dma-buf/sw_sync.c
@@ -96,6 +96,7 @@ struct sync_timeline *sync_timeline_crea
obj->context = 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
obj->value += inc;
- list_for_each_entry_safe(pt, next, &obj->pt_list, link)
- if (fence_is_signaled_locked(&pt->base))
- list_del_init(&pt->link);
+ list_for_each_entry_safe(pt, next, &obj->pt_list, link) {
+ if (!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(st
INIT_LIST_HEAD(&pt->link);
spin_lock_irq(&obj->lock);
- if (!fence_is_signaled_locked(&pt->base))
- list_add_tail(&pt->link, &obj->pt_list);
+ if (!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 (fence_get_rcu(&other->base)) {
+ 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(struc
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);
}
--- a/drivers/dma-buf/sync_debug.h
+++ b/drivers/dma-buf/sync_debug.h
@@ -14,6 +14,7 @@
#define _LINUX_SYNC_H
#include <linux/list.h>
+#include <linux/rbtree.h>
#include <linux/spinlock.h>
#include <linux/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 *fenc
* 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 fence base;
struct list_head link;
+ struct rb_node node;
};
#ifdef CONFIG_SW_SYNC
Patches currently in stable-queue which might be from chris@xxxxxxxxxxxxxxxxxx are
queue-4.9/dma-buf-sw-sync-fix-the-is-signaled-test-to-handle-u32-wraparound.patch
queue-4.9/dma-fence-clear-fence-status-during-dma_fence_init.patch
queue-4.9/dma-buf-sw-sync-fix-locking-around-sync_timeline-lists.patch
queue-4.9/dma-fence-wrap-querying-the-fence-status.patch
queue-4.9/dma-buf-sw_sync-clean-up-list-before-signaling-the-fence.patch
queue-4.9/dma-buf-sw-sync-reduce-irqsave-irqrestore-from-known-context.patch
queue-4.9/dma-buf-sw_sync-move-timeline_fence_ops-around.patch
queue-4.9/dma-buf-sw-sync-prevent-user-overflow-on-timeline-advance.patch
queue-4.9/dma-fence-introduce-drm_fence_set_error-helper.patch
queue-4.9/dma-buf-sw_sync-force-signal-all-unsignaled-fences-on-dying-timeline.patch
queue-4.9/dma-buf-sw-sync-use-an-rbtree-to-sort-fences-in-the-timeline.patch
queue-4.9/dma-buf-sw-sync-sync_pt-is-private-and-of-fixed-size.patch
queue-4.9/dma-buf-dma-fence-extract-__dma_fence_is_later.patch