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perf tools: Reference count struct thread

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We need to do that to stop accumulating entries in the dead_threads
linked list, i.e. we were keeping references to threads in struct hists
that continue to exist even after a thread exited and was removed from
the machine threads rbtree.

We still keep the dead_threads list, but just for debugging, allowing us
to iterate at any given point over the threads that still are referenced
by things like struct hist_entry.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-3ejvfyed0r7ue61dkurzjux4@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo
2015-03-02 22:21:35 -03:00
parent 2ed11312eb
commit f3b623b849
11 changed files with 66 additions and 36 deletions
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44
tools/perf/util/machine.c
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@@ -14,6 +14,8 @@
#include "unwind.h"
#include "linux/hash.h"
static void machine__remove_thread(struct machine *machine, struct thread *th);
static void dsos__init(struct dsos *dsos)
{
INIT_LIST_HEAD(&dsos->head);
@@ -89,16 +91,6 @@ static void dsos__delete(struct dsos *dsos)
}
}
void machine__delete_dead_threads(struct machine *machine)
{
struct thread *n, *t;
list_for_each_entry_safe(t, n, &machine->dead_threads, node) {
list_del(&t->node);
thread__delete(t);
}
}
void machine__delete_threads(struct machine *machine)
{
struct rb_node *nd = rb_first(&machine->threads);
@@ -106,9 +98,8 @@ void machine__delete_threads(struct machine *machine)
while (nd) {
struct thread *t = rb_entry(nd, struct thread, rb_node);
rb_erase(&t->rb_node, &machine->threads);
nd = rb_next(nd);
thread__delete(t);
machine__remove_thread(machine, t);
}
}
@@ -361,9 +352,13 @@ static struct thread *__machine__findnew_thread(struct machine *machine,
* the full rbtree:
*/
th = machine->last_match;
if (th && th->tid == tid) {
machine__update_thread_pid(machine, th, pid);
return th;
if (th != NULL) {
if (th->tid == tid) {
machine__update_thread_pid(machine, th, pid);
return th;
}
thread__zput(machine->last_match);
}
while (*p != NULL) {
@@ -371,7 +366,7 @@ static struct thread *__machine__findnew_thread(struct machine *machine,
th = rb_entry(parent, struct thread, rb_node);
if (th->tid == tid) {
machine->last_match = th;
machine->last_match = thread__get(th);
machine__update_thread_pid(machine, th, pid);
return th;
}
@@ -403,8 +398,11 @@ static struct thread *__machine__findnew_thread(struct machine *machine,
thread__delete(th);
return NULL;
}
machine->last_match = th;
/*
* It is now in the rbtree, get a ref
*/
thread__get(th);
machine->last_match = thread__get(th);
}
return th;
@@ -1238,13 +1236,17 @@ out_problem:
static void machine__remove_thread(struct machine *machine, struct thread *th)
{
machine->last_match = NULL;
if (machine->last_match == th)
thread__zput(machine->last_match);
rb_erase(&th->rb_node, &machine->threads);
/*
* We may have references to this thread, for instance in some hist_entry
* instances, so just move them to a separate list.
* Move it first to the dead_threads list, then drop the reference,
* if this is the last reference, then the thread__delete destructor
* will be called and we will remove it from the dead_threads list.
*/
list_add_tail(&th->node, &machine->dead_threads);
thread__put(th);
}
int machine__process_fork_event(struct machine *machine, union perf_event *event,