Commit b32ee9e5 authored by Kan Liang's avatar Kan Liang Committed by Arnaldo Carvalho de Melo
Browse files

perf tools: Lock to protect namespaces and comm list 



Add two locks to protect namespaces_list and comm_list.

The lock is only needed for multithreaded code, so using mutex wrappers
provided by perf tool.

Not all the comm_list/namespaces_list accessing are protected, e.g.
thread__exec_comm. Because the multithread code for perf top event
synthesizing does not touch them. They don't need a lock.

Signed-off-by: default avatarKan Liang <kan.liang@intel.com>
Acked-by: default avatarJiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Lukasz Odzioba <lukasz.odzioba@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1506696477-146932-2-git-send-email-kan.liang@intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 22905582

tools/perf/util/thread.c

+48 −5
Original line number Diff line number Diff line
@@ -45,6 +45,8 @@ struct thread *thread__new(pid_t pid, pid_t tid) 
		thread->cpu = -1;

		INIT_LIST_HEAD(&thread->namespaces_list);

		INIT_LIST_HEAD(&thread->comm_list);

		init_rwsem(&thread->namespaces_lock);

		init_rwsem(&thread->comm_lock);



		comm_str = malloc(32);

		if (!comm_str)
@@ -83,18 +85,26 @@ void thread__delete(struct thread *thread) 
		map_groups__put(thread->mg);

		thread->mg = NULL;

	}

	down_write(&thread->namespaces_lock);

	list_for_each_entry_safe(namespaces, tmp_namespaces,

				 &thread->namespaces_list, list) {

		list_del(&namespaces->list);

		namespaces__free(namespaces);

	}

	up_write(&thread->namespaces_lock);



	down_write(&thread->comm_lock);

	list_for_each_entry_safe(comm, tmp_comm, &thread->comm_list, list) {

		list_del(&comm->list);

		comm__free(comm);

	}

	up_write(&thread->comm_lock);



	unwind__finish_access(thread);

	nsinfo__zput(thread->nsinfo);



	exit_rwsem(&thread->namespaces_lock);

	exit_rwsem(&thread->comm_lock);

	free(thread);

}
@@ -125,7 +135,7 @@ struct namespaces *thread__namespaces(const struct thread *thread) 
	return list_first_entry(&thread->namespaces_list, struct namespaces, list);

}



int thread__set_namespaces(struct thread *thread, u64 timestamp,

static int __thread__set_namespaces(struct thread *thread, u64 timestamp,

				    struct namespaces_event *event)

{

	struct namespaces *new, *curr = thread__namespaces(thread);
@@ -149,6 +159,17 @@ int thread__set_namespaces(struct thread *thread, u64 timestamp, 
	return 0;

}



int thread__set_namespaces(struct thread *thread, u64 timestamp,

			   struct namespaces_event *event)

{

	int ret;



	down_write(&thread->namespaces_lock);

	ret = __thread__set_namespaces(thread, timestamp, event);

	up_write(&thread->namespaces_lock);

	return ret;

}



struct comm *thread__comm(const struct thread *thread)

{

	if (list_empty(&thread->comm_list))
@@ -170,8 +191,8 @@ struct comm *thread__exec_comm(const struct thread *thread) 
	return last;

}



int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,

		       bool exec)

static int ____thread__set_comm(struct thread *thread, const char *str,

				u64 timestamp, bool exec)

{

	struct comm *new, *curr = thread__comm(thread);
@@ -195,6 +216,17 @@ int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp, 
	return 0;

}



int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,

		       bool exec)

{

	int ret;



	down_write(&thread->comm_lock);

	ret = ____thread__set_comm(thread, str, timestamp, exec);

	up_write(&thread->comm_lock);

	return ret;

}



int thread__set_comm_from_proc(struct thread *thread)

{

	char path[64];
@@ -212,7 +244,7 @@ int thread__set_comm_from_proc(struct thread *thread) 
	return err;

}



const char *thread__comm_str(const struct thread *thread)

static const char *__thread__comm_str(const struct thread *thread)

{

	const struct comm *comm = thread__comm(thread);
@@ -222,6 +254,17 @@ const char *thread__comm_str(const struct thread *thread) 
	return comm__str(comm);

}



const char *thread__comm_str(const struct thread *thread)

{

	const char *str;



	down_read((struct rw_semaphore *)&thread->comm_lock);

	str = __thread__comm_str(thread);

	up_read((struct rw_semaphore *)&thread->comm_lock);



	return str;

}



/* CHECKME: it should probably better return the max comm len from its comm list */

int thread__comm_len(struct thread *thread)

{

tools/perf/util/thread.h

+3 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#include "symbol.h"

#include <strlist.h>

#include <intlist.h>

#include "rwsem.h"



struct thread_stack;

struct unwind_libunwind_ops;
@@ -29,7 +30,9 @@ struct thread { 
	int			comm_len;

	bool			dead; /* if set thread has exited */

	struct list_head	namespaces_list;

	struct rw_semaphore	namespaces_lock;

	struct list_head	comm_list;

	struct rw_semaphore	comm_lock;

	u64			db_id;



	void			*priv;

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