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Re: [PATCH v2 4/5] perf/sdt: Delete SDT events from cache



On 10/07/2014 08:47 AM, Namhyung Kim wrote:
On Wed, 01 Oct 2014 08:18:41 +0530, Hemant Kumar wrote:
This patch adds the support to delete SDT events from the cache.
To delete an event corresponding to a file, first the cache is read into
the file_hash list. The key is calculated from the file name.
And then, the file_list for that file_hash entry is traversed to find out
the target file_list entry. Once, it is found, its contents are all freed up.

# ./perf sdt-cache --del /usr/lib64/libc-2.16.so

8 events removed for /usr/lib64/libc-2.16.so!

Signed-off-by: Hemant Kumar <hemant@linux.vnet.ibm.com>
---
  tools/perf/builtin-sdt-cache.c |   28 +++++++++++++++++++++++++++-
  tools/perf/util/parse-events.h |    1 +
  tools/perf/util/sdt.c          |   35 +++++++++++++++++++++++++++++++++++
  3 files changed, 63 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-sdt-cache.c b/tools/perf/builtin-sdt-cache.c
index 5faf8e5..12276da 100644
--- a/tools/perf/builtin-sdt-cache.c
+++ b/tools/perf/builtin-sdt-cache.c
@@ -16,6 +16,7 @@
  /* Session management structure */
  static struct {
  	bool add;
+	bool del;
  	bool dump;
  	const char *target;
  } params;
@@ -29,6 +30,15 @@ static int opt_add_sdt_events(const struct option *opt __maybe_unused,
  	return 0;
  }
+static int opt_del_sdt_events(const struct option *opt __maybe_unused,
+			      const char *str, int unset __maybe_unused)
+{
+	params.del = true;
+	params.target = str;
+
+	return 0;
+}
+
  static int opt_show_sdt_events(const struct option *opt __maybe_unused,
  			       const char *str, int unset __maybe_unused)
  {
@@ -45,13 +55,17 @@ int cmd_sdt_cache(int argc, const char **argv, const char *prefix __maybe_unused
  		OPT_CALLBACK('a', "add", NULL, "filename",
  			     "add SDT events from a file.",
  			     opt_add_sdt_events),
+		OPT_CALLBACK('d', "del", NULL, "filename",
+			     "Remove SDT events corresponding to a file from the"
+			     " sdt cache.",
+			     opt_del_sdt_events),
  		OPT_CALLBACK_NOOPT('s', "dump", NULL, "show SDT events",
  				   "Read SDT events from cache and display.",
  				   opt_show_sdt_events),
  		OPT_END()
  	};
  	const char * const sdt_cache_usage[] = {
-		"perf sdt_cache [--add filename | --dump]",
+		"perf sdt_cache [--add filename | --del filename | --dump]",
I think it'd be better split the usage into two lines:

		"perf sdt_cache [--add | --del] <filename>"
		"perf sdt_cache --dump"

Nice suggestion. Will change that.


  		NULL
  	};
@@ -63,6 +77,10 @@ int cmd_sdt_cache(int argc, const char **argv, const char *prefix __maybe_unused symbol__elf_init();
  	if (params.add) {
+		if (params.del) {
+			pr_err("Error: Don't use --del with --add\n");
+			usage_with_options(sdt_cache_usage, sdt_cache_options);
+		}
  		if (params.dump) {
  			pr_err("Error: Don't use --dump with --add\n");
  			usage_with_options(sdt_cache_usage, sdt_cache_options);
@@ -70,6 +88,14 @@ int cmd_sdt_cache(int argc, const char **argv, const char *prefix __maybe_unused
  		ret = add_sdt_events(params.target);
  		if (ret < 0)
  			pr_err("Cannot add SDT events to cache!\n");
+	} else if (params.del) {
+		if (params.dump) {
+			pr_err("Error: Don't use --dump with --del\n");
+			usage_with_options(sdt_cache_usage, sdt_cache_options);
+		}
+		ret = remove_sdt_events(params.target);
+		if (ret < 0)
+			pr_err("Cannot remove SDT events from cache!\n");
  	} else if (params.dump) {
  		if (argc == 0) {
  			ret = dump_sdt_events();
I think we need to a flag for exclusive options so that it can emit
warnings like this automatically during option parsing.

Ok.

Thanks,
Namhyung

[...]

--
Thanks,
Hemant Kumar


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