Thread (1 message) 1 message, 1 author, 2014-08-15

Re: [PATCH 3/3] perf_event_open.2: document new comm_exec flag

From: Michael Kerrisk (man-pages) <hidden>
Date: 2014-08-15 19:20:36

Possibly related (same subject, not in this thread)

On 08/06/2014 08:02 PM, Vince Weaver wrote:

Linux 3.16 (more specifically, commit 82b897782d10fcc4 )
added support for differentiating between process renames
caused by exec versus those caused by other methods.
Thanks, Vince. I've applied this. One question below.
quoted hunk
Signed-off-by: Vince Weaver <redacted>
diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2
index d558379..cb15428 100644
--- a/man2/perf_event_open.2
+++ b/man2/perf_event_open.2
@@ -226,7 +226,8 @@ struct perf_event_attr {
           exclude_callchain_user   : 1,
                                 /* exclude user callchains */
           mmap2          :  1,  /* include mmap with inode data */
-          __reserved_1   : 40;
+          comm_exec      :  1,  /* flag comm events that are due to exec */
+          __reserved_1   : 39;
 
     union {
         __u32 wakeup_events;    /* wakeup every n events */
@@ -861,9 +862,16 @@ bit enables tracking of process command name as modified by the
 .BR exec (2)
 and
 .BR prctl (PR_SET_NAME)
-system calls.
-Unfortunately for tools,
-there is no way to distinguish one system call versus the other.
+system calls as well as writing to
+.IR /proc/self/comm .
+If the additional
+.I comm_exec
+flag can be set (starting with Linux 3.16)
Would that last line be better as:

    flag is set (possible since Linux 3.16)

?

Cheers,

Michael

-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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