From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Kacur Subject: [PATCH 1/6] tracing: Update the comm field in the right variable in update_max_tr Date: Tue, 15 Jun 2010 00:21:22 +0200 Message-ID: <1276554087-3632-2-git-send-email-jkacur@redhat.com> References: <1276554087-3632-1-git-send-email-jkacur@redhat.com> Cc: lkml , rt-users , Clark Williams , Arnaldo Carvalho de Melo , Peter Zijlstra , Ingo Molnar To: Thomas Gleixner Return-path: In-Reply-To: <1276554087-3632-1-git-send-email-jkacur@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org From: Arnaldo Carvalho de Melo The latency output showed: # | task: -3 (uid:0 nice:0 policy:1 rt_prio:99) The comm is missing in the "task:" and it looks like a minus 3 is the output. The correct display should be: # | task: migration/0-3 (uid:0 nice:0 policy:1 rt_prio:99) The problem is that the comm is being stored in the wrong data structure. The max_tr.data[cpu] is what stores the comm, not the tr->data[cpu]. Before this patch the max_tr.data[cpu]->comm was zeroed and the /debug/trace ended up showing just the '-' sign followed by the pid. Also remove a needless initialization of max_data. Signed-off-by: Arnaldo Carvalho de Melo LKML-Reference: <1267824230-23861-1-git-send-email-acme@infradead.org> Signed-off-by: Steven Rostedt Upstream commit: 1acaa1b2d9b5904c9cce06122990a2d71046ce16 Signed-off-by: John Kacur --- kernel/trace/trace.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 9b66ee1..a1cf0ad 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -520,7 +520,7 @@ static void __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu) { struct trace_array_cpu *data = tr->data[cpu]; - struct trace_array_cpu *max_data = tr->data[cpu]; + struct trace_array_cpu *max_data; max_tr.cpu = cpu; max_tr.time_start = data->preempt_timestamp; @@ -530,7 +530,7 @@ __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu) max_data->critical_start = data->critical_start; max_data->critical_end = data->critical_end; - memcpy(data->comm, tsk->comm, TASK_COMM_LEN); + memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN); max_data->pid = tsk->pid; max_data->uid = task_uid(tsk); max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO; -- 1.6.6.1