Hi Zhengjun,
On Thu, 2019-07-04 at 10:55 +0800, Zhengjun Xing wrote:
> Add "gfp_t" support in synthetic_events, then the "gfp_t" type
> parameter in some functions can be traced.
>
> Signed-off-by: Zhengjun Xing <zhengjun.x...@linux.intel.com>
> ---
> kernel/trace/trace_events_hist.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/kernel/trace/trace_events_hist.c
> b/kernel/trace/trace_events_hist.c
> index ca6b0dff60c5..0d3ab01b7cb5 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -752,6 +752,8 @@ static int synth_field_size(char *type)
> size = sizeof(unsigned long);
> else if (strcmp(type, "pid_t") == 0)
> size = sizeof(pid_t);
> + else if (strcmp(type, "gfp_t") == 0)
> + size = sizeof(gfp_t);
> else if (synth_field_is_string(type))
> size = synth_field_string_size(type);
>
> @@ -792,6 +794,8 @@ static const char *synth_field_fmt(char *type)
> fmt = "%lu";
> else if (strcmp(type, "pid_t") == 0)
> fmt = "%d";
> + else if (strcmp(type, "gfp_t") == 0)
> + fmt = "%u";
> else if (synth_field_is_string(type))
> fmt = "%s";
>
This will work, but I think it would be better to display as hex, and
also show the flags in human-readable form.
How about adding something like this on top of your patch?:
[PATCH] tracing: Add verbose gfp_flag printing to synthetic events
Add on top of 'trace:add "gfp_t" support in synthetic_events'.
Prints the gfp flags as hex in addition to the human-readable flag
string. Example output:
whoopsie-630 [000] ...1 78.969452: testevent: bar=b20 (GFP_ATOMIC|__GFP_ZERO)
rcuc/0-11 [000] ...1 81.097555: testevent: bar=a20 (GFP_ATOMIC)
rcuc/0-11 [000] ...1 81.583123: testevent: bar=a20 (GFP_ATOMIC)
Signed-off-by: Tom Zanussi <zanu...@kernel.org>
---
kernel/trace/trace_events_hist.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 0d3ab01..aeb4449 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -13,6 +13,10 @@
#include <linux/rculist.h>
#include <linux/tracefs.h>
+/* for gfp flag names */
+#include <linux/trace_events.h>
+#include <trace/events/mmflags.h>
+
#include "tracing_map.h"
#include "trace.h"
#include "trace_dynevent.h"
@@ -795,7 +799,7 @@ static const char *synth_field_fmt(char *type)
else if (strcmp(type, "pid_t") == 0)
fmt = "%d";
else if (strcmp(type, "gfp_t") == 0)
- fmt = "%u";
+ fmt = "%x";
else if (synth_field_is_string(type))
fmt = "%s";
@@ -838,9 +842,20 @@ static enum print_line_t print_synth_event(struct
trace_iterator *iter,
i == se->n_fields - 1 ? "" : " ");
n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
} else {
+ struct trace_print_flags __flags[] =
+ { __def_gfpflag_names, { -1, NULL }};
+
trace_seq_printf(s, print_fmt, se->fields[i]->name,
entry->fields[n_u64],
i == se->n_fields - 1 ? "" : " ");
+
+ if (strcmp(se->fields[i]->type, "gfp_t") == 0) {
+ trace_seq_puts(s, " (");
+ trace_print_flags_seq(s, "|",
+ entry->fields[n_u64],
+ __flags);
+ trace_seq_putc(s, ')');
+ }
n_u64++;
}
}
--
2.7.4
