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perf/core: Cleanup the rb-tree code
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Trivial comment and code fixups..

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Carrillo-Cisneros <davidcc@google.com>
Cc: Dmitri Prokhorov <Dmitry.Prohorov@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Valery Cherepennikov <valery.cherepennikov@intel.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Peter Zijlstra authored and Ingo Molnar committed Mar 12, 2018
1 parent 8e1a203 commit 161c85f
Showing 1 changed file with 40 additions and 44 deletions.
84 changes: 40 additions & 44 deletions kernel/events/core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1461,17 +1461,17 @@ static enum event_type_t get_event_type(struct perf_event *event)
}

/*
* Helper function to initialize group leader event;
* Helper function to initialize event group nodes.
*/
void init_event_group(struct perf_event *event)
static void init_event_group(struct perf_event *event)
{
RB_CLEAR_NODE(&event->group_node);
event->group_index = 0;
}

/*
* Extract pinned or flexible groups from the context
* based on event attrs bits;
* based on event attrs bits.
*/
static struct perf_event_groups *
get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
Expand All @@ -1483,45 +1483,44 @@ get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
}

/*
* Helper function to initializes perf event groups object;
* Helper function to initializes perf_event_group trees.
*/
void perf_event_groups_init(struct perf_event_groups *groups)
static void perf_event_groups_init(struct perf_event_groups *groups)
{
groups->tree = RB_ROOT;
groups->index = 0;
}

/*
* Compare function for event groups;
* Implements complex key that first sorts by CPU and then by
* virtual index which provides ordering when rotating
* groups for the same CPU;
*
* Implements complex key that first sorts by CPU and then by virtual index
* which provides ordering when rotating groups for the same CPU.
*/
int perf_event_groups_less(struct perf_event *left, struct perf_event *right)
static bool
perf_event_groups_less(struct perf_event *left, struct perf_event *right)
{
if (left->cpu < right->cpu) {
return 1;
} else if (left->cpu > right->cpu) {
return 0;
} else {
if (left->group_index < right->group_index) {
return 1;
} else if(left->group_index > right->group_index) {
return 0;
} else {
return 0;
}
}
if (left->cpu < right->cpu)
return true;
if (left->cpu > right->cpu)
return false;

if (left->group_index < right->group_index)
return true;
if (left->group_index > right->group_index)
return false;

return false;
}

/*
* Insert a group into a tree using event->cpu as a key. If event->cpu node
* is already attached to the tree then the event is added to the attached
* group's group_list list.
* Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
* key (see perf_event_groups_less). This places it last inside the CPU
* subtree.
*/
static void
perf_event_groups_insert(struct perf_event_groups *groups,
struct perf_event *event)
struct perf_event *event)
{
struct perf_event *node_event;
struct rb_node *parent;
Expand All @@ -1534,8 +1533,7 @@ perf_event_groups_insert(struct perf_event_groups *groups,

while (*node) {
parent = *node;
node_event = container_of(*node,
struct perf_event, group_node);
node_event = container_of(*node, struct perf_event, group_node);

if (perf_event_groups_less(event, node_event))
node = &parent->rb_left;
Expand All @@ -1548,8 +1546,7 @@ perf_event_groups_insert(struct perf_event_groups *groups,
}

/*
* Helper function to insert event into the pinned or
* flexible groups;
* Helper function to insert event into the pinned or flexible groups.
*/
static void
add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
Expand All @@ -1561,22 +1558,21 @@ add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
}

/*
* Delete a group from a tree. If the group is directly attached to the tree
* it also detaches all groups on the group's group_list list.
* Delete a group from a tree.
*/
static void
perf_event_groups_delete(struct perf_event_groups *groups,
struct perf_event *event)
struct perf_event *event)
{
if (!RB_EMPTY_NODE(&event->group_node) &&
!RB_EMPTY_ROOT(&groups->tree))
rb_erase(&event->group_node, &groups->tree);
WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
RB_EMPTY_ROOT(&groups->tree));

rb_erase(&event->group_node, &groups->tree);
init_event_group(event);
}

/*
* Helper function to delete event from its groups;
* Helper function to delete event from its groups.
*/
static void
del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
Expand All @@ -1588,7 +1584,7 @@ del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
}

/*
* Get a group by a cpu key from groups tree with the least group_index;
* Get the leftmost event in the @cpu subtree.
*/
static struct perf_event *
perf_event_groups_first(struct perf_event_groups *groups, int cpu)
Expand All @@ -1597,8 +1593,7 @@ perf_event_groups_first(struct perf_event_groups *groups, int cpu)
struct rb_node *node = groups->tree.rb_node;

while (node) {
node_event = container_of(node,
struct perf_event, group_node);
node_event = container_of(node, struct perf_event, group_node);

if (cpu < node_event->cpu) {
node = node->rb_left;
Expand All @@ -1614,13 +1609,14 @@ perf_event_groups_first(struct perf_event_groups *groups, int cpu)
}

/*
* Find group list by a cpu key and rotate it.
* Rotate the @cpu subtree.
*
* Re-insert the leftmost event at the tail of the subtree.
*/
static void
perf_event_groups_rotate(struct perf_event_groups *groups, int cpu)
{
struct perf_event *event =
perf_event_groups_first(groups, cpu);
struct perf_event *event = perf_event_groups_first(groups, cpu);

if (event) {
perf_event_groups_delete(groups, event);
Expand All @@ -1629,7 +1625,7 @@ perf_event_groups_rotate(struct perf_event_groups *groups, int cpu)
}

/*
* Iterate event groups thru the whole tree.
* Iterate through the whole groups tree.
*/
#define perf_event_groups_for_each(event, groups, node) \
for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
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