Re: [PATCH 1/3] tracing/kprobes: Avoid perf_trace_buf_*() if ->perf_events is empty

2013-06-17 Thread Oleg Nesterov
On 06/17, zhangwei(Jovi) wrote: > > On 2013/6/17 1:21, Oleg Nesterov wrote: > > perf_trace_buf_prepare() + perf_trace_buf_submit() make no sense > > if this task/CPU has no active counters. Change kprobe_perf_func() > > and kretprobe_perf_func() to check call->perf_events beforehand > > and return

Re: [PATCH 1/3] tracing/kprobes: Avoid perf_trace_buf_*() if -perf_events is empty

2013-06-17 Thread Oleg Nesterov
On 06/17, zhangwei(Jovi) wrote: On 2013/6/17 1:21, Oleg Nesterov wrote: perf_trace_buf_prepare() + perf_trace_buf_submit() make no sense if this task/CPU has no active counters. Change kprobe_perf_func() and kretprobe_perf_func() to check call-perf_events beforehand and return if this

Re: [PATCH 1/3] tracing/kprobes: Avoid perf_trace_buf_*() if ->perf_events is empty

2013-06-16 Thread Masami Hiramatsu
(2013/06/17 2:21), Oleg Nesterov wrote: > perf_trace_buf_prepare() + perf_trace_buf_submit() make no sense > if this task/CPU has no active counters. Change kprobe_perf_func() > and kretprobe_perf_func() to check call->perf_events beforehand > and return if this list is empty. > > For example,

Re: [PATCH 1/3] tracing/kprobes: Avoid perf_trace_buf_*() if ->perf_events is empty

2013-06-16 Thread zhangwei(Jovi)
On 2013/6/17 1:21, Oleg Nesterov wrote: > perf_trace_buf_prepare() + perf_trace_buf_submit() make no sense > if this task/CPU has no active counters. Change kprobe_perf_func() > and kretprobe_perf_func() to check call->perf_events beforehand > and return if this list is empty. > > For example,

[PATCH 1/3] tracing/kprobes: Avoid perf_trace_buf_*() if ->perf_events is empty

2013-06-16 Thread Oleg Nesterov
perf_trace_buf_prepare() + perf_trace_buf_submit() make no sense if this task/CPU has no active counters. Change kprobe_perf_func() and kretprobe_perf_func() to check call->perf_events beforehand and return if this list is empty. For example, "perf record -e some_probe -p1". Only /sbin/init will

[PATCH 1/3] tracing/kprobes: Avoid perf_trace_buf_*() if -perf_events is empty

2013-06-16 Thread Oleg Nesterov
perf_trace_buf_prepare() + perf_trace_buf_submit() make no sense if this task/CPU has no active counters. Change kprobe_perf_func() and kretprobe_perf_func() to check call-perf_events beforehand and return if this list is empty. For example, perf record -e some_probe -p1. Only /sbin/init will

Re: [PATCH 1/3] tracing/kprobes: Avoid perf_trace_buf_*() if -perf_events is empty

2013-06-16 Thread zhangwei(Jovi)
On 2013/6/17 1:21, Oleg Nesterov wrote: perf_trace_buf_prepare() + perf_trace_buf_submit() make no sense if this task/CPU has no active counters. Change kprobe_perf_func() and kretprobe_perf_func() to check call-perf_events beforehand and return if this list is empty. For example, perf

Re: [PATCH 1/3] tracing/kprobes: Avoid perf_trace_buf_*() if -perf_events is empty

2013-06-16 Thread Masami Hiramatsu
(2013/06/17 2:21), Oleg Nesterov wrote: perf_trace_buf_prepare() + perf_trace_buf_submit() make no sense if this task/CPU has no active counters. Change kprobe_perf_func() and kretprobe_perf_func() to check call-perf_events beforehand and return if this list is empty. For example, perf