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authorAdrian Hunter <adrian.hunter@intel.com>2014-05-28 11:45:04 +0300
committerIngo Molnar <mingo@kernel.org>2014-06-06 07:56:22 +0200
commit82b897782d10fcc4930c9d4a15b175348fdd2871 (patch)
tree82bc0bb22ef1379b901d4fce582584b6776a91ea /fs
parentec00010972a0971b2c1da4fbe4e5c7d8ed1ecb05 (diff)
downloadop-kernel-dev-82b897782d10fcc4930c9d4a15b175348fdd2871.zip
op-kernel-dev-82b897782d10fcc4930c9d4a15b175348fdd2871.tar.gz
perf: Differentiate exec() and non-exec() comm events
perf tools like 'perf report' can aggregate samples by comm strings, which generally works. However, there are other potential use-cases. For example, to pair up 'calls' with 'returns' accurately (from branch events like Intel BTS) it is necessary to identify whether the process has exec'd. Although a comm event is generated when an 'exec' happens it is also generated whenever the comm string is changed on a whim (e.g. by prctl PR_SET_NAME). This patch adds a flag to the comm event to differentiate one case from the other. In order to determine whether the kernel supports the new flag, a selection bit named 'exec' is added to struct perf_event_attr. The bit does nothing but will cause perf_event_open() to fail if the bit is set on kernels that do not have it defined. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/537D9EBE.7030806@intel.com Cc: Paul Mackerras <paulus@samba.org> Cc: Dave Jones <davej@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/exec.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/exec.c b/fs/exec.c
index a038a41..a3d33fe 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1046,13 +1046,13 @@ EXPORT_SYMBOL_GPL(get_task_comm);
* so that a new one can be started
*/
-void set_task_comm(struct task_struct *tsk, const char *buf)
+void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec)
{
task_lock(tsk);
trace_task_rename(tsk, buf);
strlcpy(tsk->comm, buf, sizeof(tsk->comm));
task_unlock(tsk);
- perf_event_comm(tsk);
+ perf_event_comm(tsk, exec);
}
int flush_old_exec(struct linux_binprm * bprm)
@@ -1111,7 +1111,7 @@ void setup_new_exec(struct linux_binprm * bprm)
set_dumpable(current->mm, suid_dumpable);
perf_event_exec();
- set_task_comm(current, kbasename(bprm->filename));
+ __set_task_comm(current, kbasename(bprm->filename), true);
/* Set the new mm task size. We have to do that late because it may
* depend on TIF_32BIT which is only updated in flush_thread() on
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