lkml.org 
[lkml]   [2015]   [May]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 22/30] perf tools: Use atomic_t to implement thread__{get,put} refcnt
    Date
    From: Arnaldo Carvalho de Melo <acme@redhat.com>

    Fixing bugs in 'perf top' where the used thread unsafe 'struct thread'
    refcount implementation was falling apart because we really use two
    threads.

    Acked-by: David Ahern <dsahern@gmail.com>
    Cc: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Borislav Petkov <bp@suse.de>
    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-hil2hol294u5ntcuof4jhmn6@git.kernel.org
    Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
    ---
    tools/perf/util/thread.c | 6 +++---
    tools/perf/util/thread.h | 3 ++-
    2 files changed, 5 insertions(+), 4 deletions(-)

    diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
    index 1c8fbc9..1b26552 100644
    --- a/tools/perf/util/thread.c
    +++ b/tools/perf/util/thread.c
    @@ -53,7 +53,7 @@ struct thread *thread__new(pid_t pid, pid_t tid)
    goto err_thread;

    list_add(&comm->list, &thread->comm_list);
    -
    + atomic_set(&thread->refcnt, 0);
    }

    return thread;
    @@ -84,13 +84,13 @@ void thread__delete(struct thread *thread)

    struct thread *thread__get(struct thread *thread)
    {
    - ++thread->refcnt;
    + atomic_inc(&thread->refcnt);
    return thread;
    }

    void thread__put(struct thread *thread)
    {
    - if (thread && --thread->refcnt == 0) {
    + if (thread && atomic_dec_and_test(&thread->refcnt)) {
    list_del_init(&thread->node);
    thread__delete(thread);
    }
    diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
    index 9b8a54d..f33c48c 100644
    --- a/tools/perf/util/thread.h
    +++ b/tools/perf/util/thread.h
    @@ -1,6 +1,7 @@
    #ifndef __PERF_THREAD_H
    #define __PERF_THREAD_H

    +#include <linux/atomic.h>
    #include <linux/rbtree.h>
    #include <linux/list.h>
    #include <unistd.h>
    @@ -21,7 +22,7 @@ struct thread {
    pid_t tid;
    pid_t ppid;
    int cpu;
    - int refcnt;
    + atomic_t refcnt;
    char shortname[3];
    bool comm_set;
    bool dead; /* if set thread has exited */
    --
    2.1.0


    \
     
     \ /
      Last update: 2015-05-08 23:41    [W:4.225 / U:0.292 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site