From: vincent.donnefort@arm.com
To: linux-trace-devel@vger.kernel.org
Cc: Vincent Donnefort <vincent.donnefort@arm.com>
Subject: [PATCH v2 2/2] trace-cmd: Add an option to set saved_cmdlines_size
Date: Tue, 12 Nov 2019 12:03:27 +0000 [thread overview]
Message-ID: <1573560207-52550-2-git-send-email-vincent.donnefort@arm.com> (raw)
In-Reply-To: <1573560207-52550-1-git-send-email-vincent.donnefort@arm.com>
From: Vincent Donnefort <vincent.donnefort@arm.com>
The tracing file saved_cmdlines_size allows setting the number of entries
that saved_cmdlines will contain. The latter is then dumped into the
trace.dat file to map PIDs with comm. The default value is 128.
Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com>
diff --git a/Documentation/trace-cmd-record.1.txt b/Documentation/trace-cmd-record.1.txt
index bb18e88..0d75e43 100644
--- a/Documentation/trace-cmd-record.1.txt
+++ b/Documentation/trace-cmd-record.1.txt
@@ -280,6 +280,12 @@ OPTIONS
A value of one will only show where userspace enters the kernel but not any
functions called in the kernel. The default is zero, which means no limit.
+*--cmdlines-size* 'size'::
+ Set the number of entries the kernel tracing file "saved_cmdlines" can
+ contain. This file is a circular buffer which stores the mapping between
+ cmdlines and PIDs. If full, it leads to unresolved cmdlines ("<...>") within
+ the trace. The kernel default value is 128.
+
*--module* 'module'::
Filter a module's name in function tracing. It is equivalent to adding
':mod:module' after all other functions being filtered. If no other function
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 7260d27..82556b0 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -229,6 +229,7 @@ struct common_record_context {
int topt;
int do_child;
int run_command;
+ int saved_cmdlines_size;
};
static void add_reset_file(const char *file, const char *val, int prio)
@@ -1810,6 +1811,39 @@ static void set_options(void)
}
}
+static void set_saved_cmdlines_size(struct common_record_context *ctx)
+{
+ char *path, *str;
+ int fd, len, ret;
+
+ if (!ctx->saved_cmdlines_size)
+ return;
+
+ path = tracecmd_get_tracing_file("saved_cmdlines_size");
+ if (!path)
+ goto err;
+
+ reset_save_file(path, RESET_DEFAULT_PRIO);
+
+ fd = open(path, O_WRONLY);
+ tracecmd_put_tracing_file(path);
+ if (fd < 0)
+ goto err;
+
+ len = asprintf(&str, "%d", ctx->saved_cmdlines_size);
+ if (len < 0)
+ die("%s couldn't allocate memory", __func__);
+
+ if (write(fd, str, len) > 0)
+ ret = 0;
+
+ close(fd);
+ free(str);
+err:
+ if (ret)
+ warning("Couldn't set saved_cmdlines_size");
+}
+
static int trace_check_file_exists(struct buffer_instance *instance, char *file)
{
struct stat st;
@@ -5190,6 +5224,7 @@ enum {
OPT_date = 255,
OPT_module = 256,
OPT_nofifos = 257,
+ OPT_cmdlines_size = 258,
};
void trace_stop(int argc, char **argv)
@@ -5467,6 +5502,7 @@ static void parse_record_options(int argc,
{"by-comm", no_argument, NULL, OPT_bycomm},
{"ts-offset", required_argument, NULL, OPT_tsoffset},
{"max-graph-depth", required_argument, NULL, OPT_max_graph_depth},
+ {"cmdlines-size", required_argument, NULL, OPT_cmdlines_size},
{"no-filter", no_argument, NULL, OPT_no_filter},
{"debug", no_argument, NULL, OPT_debug},
{"quiet", no_argument, NULL, OPT_quiet},
@@ -5480,7 +5516,7 @@ static void parse_record_options(int argc,
if (IS_EXTRACT(ctx))
opts = "+haf:Fp:co:O:sr:g:l:n:P:N:tb:B:ksiT";
else
- opts = "+hae:f:FA:p:cC:dDGo:O:s:r:vg:l:n:P:N:tb:R:B:ksSiTm:M:H:q";
+ opts = "+hae:f:FA:p:cC:dDGo:O:s:r:vg:l:n:P:N:tb:R:B:kK:sSiTm:M:H:qK";
c = getopt_long (argc-1, argv+1, opts, long_options, &option_index);
if (c == -1)
break;
@@ -5795,6 +5831,9 @@ static void parse_record_options(int argc,
if (!ctx->instance->max_graph_depth)
die("Could not allocate option");
break;
+ case OPT_cmdlines_size:
+ ctx->saved_cmdlines_size = atoi(optarg);
+ break;
case OPT_no_filter:
no_filter = true;
break;
@@ -5990,6 +6029,7 @@ static void record_trace(int argc, char **argv,
enable_events(instance);
}
+ set_saved_cmdlines_size(ctx);
set_buffer_size();
update_plugins(type);
set_options();
diff --git a/tracecmd/trace-usage.c b/tracecmd/trace-usage.c
index b5788f7..0080522 100644
--- a/tracecmd/trace-usage.c
+++ b/tracecmd/trace-usage.c
@@ -56,6 +56,7 @@ static struct usage_help usage_help[] = {
" --func-stack perform a stack trace for function tracer\n"
" (use with caution)\n"
" --max-graph-depth limit function_graph depth\n"
+ " --cmdlines_size change kernel saved_cmdlines_size\n"
" --no-filter include trace-cmd threads in the trace\n"
" --proc-map save the traced processes address map into the trace.dat file\n"
" --user execute the specified [command ...] as given user\n"
--
2.7.4
next prev parent reply other threads:[~2019-11-12 12:03 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-07 10:51 [PATCH 1/2] trace-cmd: Enable kptr_restrict vincent.donnefort
2019-11-07 10:51 ` [PATCH 2/2] trace-cmd: Add an option to set saved_cmdlines_size vincent.donnefort
2019-11-11 22:52 ` Steven Rostedt
2019-11-12 12:03 ` Vincent Donnefort
2019-11-12 14:40 ` Steven Rostedt
2019-11-12 19:01 ` Vincent Donnefort
2019-11-12 19:09 ` Steven Rostedt
2019-11-13 12:14 ` [PATCH v2 1/2] trace-cmd: Enable kptr_restrict vincent.donnefort
2019-11-13 12:14 ` [PATCH v2 2/2] trace-cmd: Add an option to set saved_cmdlines_size vincent.donnefort
2019-11-13 12:27 ` [PATCH " Vincent Donnefort
2019-11-13 15:08 ` Steven Rostedt
2019-11-12 12:03 ` [PATCH v2 1/2] trace-cmd: Enable kptr_restrict vincent.donnefort
2019-11-12 12:03 ` vincent.donnefort [this message]
2019-11-11 22:47 ` [PATCH " Steven Rostedt
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