Messages in this thread Patch in this message | | | Date | Thu, 12 Sep 2013 12:33:47 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH]trace: fix wrong help information about snapshot |
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On Thu, 12 Sep 2013 23:04:01 +0800 Wang YanQing <udknight@gmail.com> wrote:
> > Cat snapshot give me: > " tracer: nop > > * Snapshot is freed * > > Snapshot commands: > echo 0 > snapshot : Clears and frees snapshot buffer > echo 1 > snapshot : Allocates snapshot buffer, if not already allocated. > Takes a snapshot of the main buffer. > echo 2 > snapshot : Clears snapshot buffer (but does not allocate) > (Doesn't have to be '2' works with any number that > is not a '0' or '1')" > > But after read the code, I found the right information about "echo 2 > snapshot" > should looks like below: > > " echo 2 > snapshot : Clears snapshot buffer (but does not free) > (Doesn't have to be '2' works with any number that > is not a '0' or '1')"
Actually, they both are correct:
default: if (tr->allocated_snapshot) { if (iter->cpu_file == RING_BUFFER_ALL_CPUS) tracing_reset_online_cpus(&tr->max_buffer); else tracing_reset(&tr->max_buffer, iter->cpu_file); } break; }
It does nothing if it isn't allocated.
Perhaps we need it to say "(but does not allocate or free)"
-- Steve
> > Signed-off-by: Wang YanQing <udknight@gmail.com> > --- > kernel/trace/trace.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index 7974ba2..d0da660 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -2760,7 +2760,7 @@ static void show_snapshot_main_help(struct seq_file *m) > seq_printf(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"); > seq_printf(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"); > seq_printf(m, "# Takes a snapshot of the main buffer.\n"); > - seq_printf(m, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate)\n"); > + seq_printf(m, "# echo 2 > snapshot : Clears snapshot buffer (but does not free)\n"); > seq_printf(m, "# (Doesn't have to be '2' works with any number that\n"); > seq_printf(m, "# is not a '0' or '1')\n"); > }
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