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tools: Update rbtree implementation

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There have been a number of changes in the kernel's rbrtee
implementation, including loose lockless searching guarantees and
rb_root_cached, which later patches will use as an optimization.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20181206191819.30182-2-dave@stgolabs.net
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Davidlohr Bueso
2018-12-06 11:18:13 -08:00
committed by Arnaldo Carvalho de Melo
parent 95420d338e
commit 3aef2cad5d
3 changed files with 229 additions and 61 deletions
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52
tools/include/linux/rbtree.h
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@@ -43,13 +43,28 @@ struct rb_root {
struct rb_node *rb_node;
};
/*
* Leftmost-cached rbtrees.
*
* We do not cache the rightmost node based on footprint
* size vs number of potential users that could benefit
* from O(1) rb_last(). Just not worth it, users that want
* this feature can always implement the logic explicitly.
* Furthermore, users that want to cache both pointers may
* find it a bit asymmetric, but that's ok.
*/
struct rb_root_cached {
struct rb_root rb_root;
struct rb_node *rb_leftmost;
};
#define rb_parent(r) ((struct rb_node *)((r)->__rb_parent_color & ~3))
#define RB_ROOT (struct rb_root) { NULL, }
#define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, NULL }
#define rb_entry(ptr, type, member) container_of(ptr, type, member)
#define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL)
#define RB_EMPTY_ROOT(root) (READ_ONCE((root)->rb_node) == NULL)
/* 'empty' nodes are nodes that are known not to be inserted in an rbtree */
#define RB_EMPTY_NODE(node) \
@@ -68,6 +83,12 @@ extern struct rb_node *rb_prev(const struct rb_node *);
extern struct rb_node *rb_first(const struct rb_root *);
extern struct rb_node *rb_last(const struct rb_root *);
extern void rb_insert_color_cached(struct rb_node *,
struct rb_root_cached *, bool);
extern void rb_erase_cached(struct rb_node *node, struct rb_root_cached *);
/* Same as rb_first(), but O(1) */
#define rb_first_cached(root) (root)->rb_leftmost
/* Postorder iteration - always visit the parent after its children */
extern struct rb_node *rb_first_postorder(const struct rb_root *);
extern struct rb_node *rb_next_postorder(const struct rb_node *);
@@ -75,6 +96,8 @@ extern struct rb_node *rb_next_postorder(const struct rb_node *);
/* Fast replacement of a single node without remove/rebalance/add/rebalance */
extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
struct rb_root *root);
extern void rb_replace_node_cached(struct rb_node *victim, struct rb_node *new,
struct rb_root_cached *root);
static inline void rb_link_node(struct rb_node *node, struct rb_node *parent,
struct rb_node **rb_link)
@@ -90,12 +113,29 @@ static inline void rb_link_node(struct rb_node *node, struct rb_node *parent,
____ptr ? rb_entry(____ptr, type, member) : NULL; \
})
/*
* Handy for checking that we are not deleting an entry that is
* already in a list, found in block/{blk-throttle,cfq-iosched}.c,
* probably should be moved to lib/rbtree.c...
/**
* rbtree_postorder_for_each_entry_safe - iterate in post-order over rb_root of
* given type allowing the backing memory of @pos to be invalidated
*
* @pos: the 'type *' to use as a loop cursor.
* @n: another 'type *' to use as temporary storage
* @root: 'rb_root *' of the rbtree.
* @field: the name of the rb_node field within 'type'.
*
* rbtree_postorder_for_each_entry_safe() provides a similar guarantee as
* list_for_each_entry_safe() and allows the iteration to continue independent
* of changes to @pos by the body of the loop.
*
* Note, however, that it cannot handle other modifications that re-order the
* rbtree it is iterating over. This includes calling rb_erase() on @pos, as
* rb_erase() may rebalance the tree, causing us to miss some nodes.
*/
#define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \
for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \
pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \
typeof(*pos), field); 1; }); \
pos = n)
static inline void rb_erase_init(struct rb_node *n, struct rb_root *root)
{
rb_erase(n, root);