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Message-ID: <20140515115352.3904ac90@gandalf.local.home>
Date: Thu, 15 May 2014 11:53:52 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Ingo Molnar <mingo@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Javi Merino <javi.merino@....com>
Subject: [for-next][PATCH] tracing: Add __bitmask() macro to trace events to
cpumasks and other bitmasks
I didn't repost the other patches that I uploaded to for-next as they
didn't change. I did rebase this patch to come after all the previous
ones. This is the final version of the added __bitmask() macro. Thanks
to Javi Merino for suggesting it (although it's been on my TODO list
for some time), but mostly for his testing of the code. I now need to
add the processing to libtraceevent. That needs a little more testing.
-- Steve
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
for-next
Head SHA1: 4449bf927b61bdb4389393c6fea6837214d1ace7
Steven Rostedt (Red Hat) (1):
tracing: Add __bitmask() macro to trace events to cpumasks and other bitmasks
----
include/linux/ftrace_event.h | 3 +++
include/linux/trace_seq.h | 10 ++++++++
include/trace/ftrace.h | 57 +++++++++++++++++++++++++++++++++++++++++++-
kernel/trace/trace_output.c | 41 +++++++++++++++++++++++++++++++
4 files changed, 110 insertions(+), 1 deletion(-)
---------------------------
commit 4449bf927b61bdb4389393c6fea6837214d1ace7
Author: Steven Rostedt (Red Hat) <rostedt@...dmis.org>
Date: Tue May 6 13:10:24 2014 -0400
tracing: Add __bitmask() macro to trace events to cpumasks and other bitmasks
Being able to show a cpumask of events can be useful as some events
may affect only some CPUs. There is no standard way to record the
cpumask and converting it to a string is rather expensive during
the trace as traces happen in hotpaths. It would be better to record
the raw event mask and be able to parse it at print time.
The following macros were added for use with the TRACE_EVENT() macro:
__bitmask()
__assign_bitmask()
__get_bitmask()
To test this, I added this to the sched_migrate_task event, which
looked like this:
TRACE_EVENT(sched_migrate_task,
TP_PROTO(struct task_struct *p, int dest_cpu, const struct cpumask *cpus),
TP_ARGS(p, dest_cpu, cpus),
TP_STRUCT__entry(
__array( char, comm, TASK_COMM_LEN )
__field( pid_t, pid )
__field( int, prio )
__field( int, orig_cpu )
__field( int, dest_cpu )
__bitmask( cpumask, num_possible_cpus() )
),
TP_fast_assign(
memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
__entry->pid = p->pid;
__entry->prio = p->prio;
__entry->orig_cpu = task_cpu(p);
__entry->dest_cpu = dest_cpu;
__assign_bitmask(cpumask, cpumask_bits(cpus), num_possible_cpus());
),
TP_printk("comm=%s pid=%d prio=%d orig_cpu=%d dest_cpu=%d cpumask=%s",
__entry->comm, __entry->pid, __entry->prio,
__entry->orig_cpu, __entry->dest_cpu,
__get_bitmask(cpumask))
);
With the output of:
ksmtuned-3613 [003] d..2 485.220508: sched_migrate_task: comm=ksmtuned pid=3615 prio=120 orig_cpu=3 dest_cpu=2 cpumask=00000000,0000000f
migration/1-13 [001] d..5 485.221202: sched_migrate_task: comm=ksmtuned pid=3614 prio=120 orig_cpu=1 dest_cpu=0 cpumask=00000000,0000000f
awk-3615 [002] d.H5 485.221747: sched_migrate_task: comm=rcu_preempt pid=7 prio=120 orig_cpu=0 dest_cpu=1 cpumask=00000000,000000ff
migration/2-18 [002] d..5 485.222062: sched_migrate_task: comm=ksmtuned pid=3615 prio=120 orig_cpu=2 dest_cpu=3 cpumask=00000000,0000000f
Link: http://lkml.kernel.org/r/1399377998-14870-6-git-send-email-javi.merino@arm.com
Link: http://lkml.kernel.org/r/20140506132238.22e136d1@gandalf.local.home
Suggested-by: Javi Merino <javi.merino@....com>
Tested-by: Javi Merino <javi.merino@....com>
Signed-off-by: Steven Rostedt <rostedt@...dmis.org>
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index d16da3e..cff3106 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -38,6 +38,9 @@ const char *ftrace_print_symbols_seq_u64(struct trace_seq *p,
*symbol_array);
#endif
+const char *ftrace_print_bitmask_seq(struct trace_seq *p, void *bitmask_ptr,
+ unsigned int bitmask_size);
+
const char *ftrace_print_hex_seq(struct trace_seq *p,
const unsigned char *buf, int len);
diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h
index a32d86e..1361169 100644
--- a/include/linux/trace_seq.h
+++ b/include/linux/trace_seq.h
@@ -46,6 +46,9 @@ extern int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
extern void *trace_seq_reserve(struct trace_seq *s, size_t len);
extern int trace_seq_path(struct trace_seq *s, const struct path *path);
+extern int trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
+ int nmaskbits);
+
#else /* CONFIG_TRACING */
static inline int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
{
@@ -57,6 +60,13 @@ trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
return 0;
}
+static inline int
+trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
+ int nmaskbits)
+{
+ return 0;
+}
+
static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s)
{
return 0;
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 0a1a4f7..9b7a989 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -53,6 +53,9 @@
#undef __string
#define __string(item, src) __dynamic_array(char, item, -1)
+#undef __bitmask
+#define __bitmask(item, nr_bits) __dynamic_array(char, item, -1)
+
#undef TP_STRUCT__entry
#define TP_STRUCT__entry(args...) args
@@ -128,6 +131,9 @@
#undef __string
#define __string(item, src) __dynamic_array(char, item, -1)
+#undef __bitmask
+#define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)
+
#undef DECLARE_EVENT_CLASS
#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print) \
struct ftrace_data_offsets_##call { \
@@ -200,6 +206,15 @@
#undef __get_str
#define __get_str(field) (char *)__get_dynamic_array(field)
+#undef __get_bitmask
+#define __get_bitmask(field) \
+ ({ \
+ void *__bitmask = __get_dynamic_array(field); \
+ unsigned int __bitmask_size; \
+ __bitmask_size = (__entry->__data_loc_##field >> 16) & 0xffff; \
+ ftrace_print_bitmask_seq(p, __bitmask, __bitmask_size); \
+ })
+
#undef __print_flags
#define __print_flags(flag, delim, flag_array...) \
({ \
@@ -322,6 +337,9 @@ static struct trace_event_functions ftrace_event_type_funcs_##call = { \
#undef __string
#define __string(item, src) __dynamic_array(char, item, -1)
+#undef __bitmask
+#define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)
+
#undef DECLARE_EVENT_CLASS
#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, func, print) \
static int notrace __init \
@@ -372,6 +390,29 @@ ftrace_define_fields_##call(struct ftrace_event_call *event_call) \
#define __string(item, src) __dynamic_array(char, item, \
strlen((src) ? (const char *)(src) : "(null)") + 1)
+/*
+ * __bitmask_size_in_bytes_raw is the number of bytes needed to hold
+ * num_possible_cpus().
+ */
+#define __bitmask_size_in_bytes_raw(nr_bits) \
+ (((nr_bits) + 7) / 8)
+
+#define __bitmask_size_in_longs(nr_bits) \
+ ((__bitmask_size_in_bytes_raw(nr_bits) + \
+ ((BITS_PER_LONG / 8) - 1)) / (BITS_PER_LONG / 8))
+
+/*
+ * __bitmask_size_in_bytes is the number of bytes needed to hold
+ * num_possible_cpus() padded out to the nearest long. This is what
+ * is saved in the buffer, just to be consistent.
+ */
+#define __bitmask_size_in_bytes(nr_bits) \
+ (__bitmask_size_in_longs(nr_bits) * (BITS_PER_LONG / 8))
+
+#undef __bitmask
+#define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, \
+ __bitmask_size_in_longs(nr_bits))
+
#undef DECLARE_EVENT_CLASS
#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print) \
static inline notrace int ftrace_get_offsets_##call( \
@@ -513,12 +554,22 @@ static inline notrace int ftrace_get_offsets_##call( \
__entry->__data_loc_##item = __data_offsets.item;
#undef __string
-#define __string(item, src) __dynamic_array(char, item, -1) \
+#define __string(item, src) __dynamic_array(char, item, -1)
#undef __assign_str
#define __assign_str(dst, src) \
strcpy(__get_str(dst), (src) ? (const char *)(src) : "(null)");
+#undef __bitmask
+#define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)
+
+#undef __get_bitmask
+#define __get_bitmask(field) (char *)__get_dynamic_array(field)
+
+#undef __assign_bitmask
+#define __assign_bitmask(dst, src, nr_bits) \
+ memcpy(__get_bitmask(dst), (src), __bitmask_size_in_bytes(nr_bits))
+
#undef TP_fast_assign
#define TP_fast_assign(args...) args
@@ -586,6 +637,7 @@ static inline void ftrace_test_probe_##call(void) \
#undef __print_hex
#undef __get_dynamic_array
#undef __get_str
+#undef __get_bitmask
#undef TP_printk
#define TP_printk(fmt, args...) "\"" fmt "\", " __stringify(args)
@@ -651,6 +703,9 @@ __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call
#undef __get_str
#define __get_str(field) (char *)__get_dynamic_array(field)
+#undef __get_bitmask
+#define __get_bitmask(field) (char *)__get_dynamic_array(field)
+
#undef __perf_addr
#define __perf_addr(a) (__addr = (a))
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index a436de1..f3dad80 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -126,6 +126,34 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
EXPORT_SYMBOL_GPL(trace_seq_printf);
/**
+ * trace_seq_bitmask - put a list of longs as a bitmask print output
+ * @s: trace sequence descriptor
+ * @maskp: points to an array of unsigned longs that represent a bitmask
+ * @nmaskbits: The number of bits that are valid in @maskp
+ *
+ * It returns 0 if the trace oversizes the buffer's free
+ * space, 1 otherwise.
+ *
+ * Writes a ASCII representation of a bitmask string into @s.
+ */
+int
+trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
+ int nmaskbits)
+{
+ int len = (PAGE_SIZE - 1) - s->len;
+ int ret;
+
+ if (s->full || !len)
+ return 0;
+
+ ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits);
+ s->len += ret;
+
+ return 1;
+}
+EXPORT_SYMBOL_GPL(trace_seq_bitmask);
+
+/**
* trace_seq_vprintf - sequence printing of trace information
* @s: trace sequence descriptor
* @fmt: printf format string
@@ -399,6 +427,19 @@ EXPORT_SYMBOL(ftrace_print_symbols_seq_u64);
#endif
const char *
+ftrace_print_bitmask_seq(struct trace_seq *p, void *bitmask_ptr,
+ unsigned int bitmask_size)
+{
+ const char *ret = p->buffer + p->len;
+
+ trace_seq_bitmask(p, bitmask_ptr, bitmask_size * 8);
+ trace_seq_putc(p, 0);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ftrace_print_bitmask_seq);
+
+const char *
ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len)
{
int i;
--
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