diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 0810f81b6db2dfedf86d11972d241bb38c21b006..404603720650dac1abd528eb76923bc89be872ed 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -407,6 +407,7 @@ enum event_trigger_type {
ETT_SNAPSHOT = (1 << 1),
ETT_STACKTRACE = (1 << 2),
ETT_EVENT_ENABLE = (1 << 3),
+ ETT_EVENT_HIST = (1 << 4),
};
extern int filter_match_preds(struct event_filter *filter, void *rec);
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index d39556fd863a9148a2d9b6af5c908a58e0d8c215..fafeaf803bd04f605dddd103f8bfc7de3ee0651e 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -538,6 +538,22 @@ config TRACING_MAP
generally used outside of that context, and is normally
selected by tracers that use it.
+config HIST_TRIGGERS
+ bool "Histogram triggers"
+ depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
+ select TRACING_MAP
+ default n
+ help
+ Hist triggers allow one or more arbitrary trace event fields
+ to be aggregated into hash tables and dumped to stdout by
+ reading a debugfs/tracefs file. They're useful for
+ gathering quick and dirty (though precise) summaries of
+ event activity as an initial guide for further investigation
+ using more advanced tools.
+
+ See Documentation/trace/events.txt.
+ If in doubt, say N.
+
config MMIOTRACE_TEST
tristate "Test module for mmiotrace"
depends on MMIOTRACE && m
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 4255c4057aaac6d7579538b75b11fe2a4bb072b8..979e7bfbde7a840dd89fa1c0b2b17a9a0021d076 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -54,6 +54,7 @@ obj-$(CONFIG_EVENT_TRACING) += trace_event_perf.o
endif
obj-$(CONFIG_EVENT_TRACING) += trace_events_filter.o
obj-$(CONFIG_EVENT_TRACING) += trace_events_trigger.o
+obj-$(CONFIG_HIST_TRIGGERS) += trace_events_hist.o
obj-$(CONFIG_BPF_EVENTS) += bpf_trace.o
obj-$(CONFIG_KPROBE_EVENT) += trace_kprobe.o
obj-$(CONFIG_TRACEPOINTS) += power-traces.o
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 0d12dbde839964a15c63537c61fb759a6a15dac4..6cf8fd03b028e99d64514f814aa177b6c5742359 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3812,6 +3812,9 @@ static const char readme_msg[] =
#endif
#ifdef CONFIG_TRACER_SNAPSHOT
"\t\t snapshot\n"
+#endif
+#ifdef CONFIG_HIST_TRIGGERS
+ "\t\t hist (see below)\n"
#endif
"\t example: echo traceoff > events/block/block_unplug/trigger\n"
"\t echo traceoff:3 > events/block/block_unplug/trigger\n"
@@ -3828,6 +3831,20 @@ static const char readme_msg[] =
"\t To remove a trigger with a count:\n"
"\t echo '!<trigger>:0 > <system>/<event>/trigger\n"
"\t Filters can be ignored when removing a trigger.\n"
+#ifdef CONFIG_HIST_TRIGGERS
+ " hist trigger\t- If set, event hits are aggregated into a hash table\n"
+ "\t Format: hist:keys=<field1>\n"
+ "\t [:size=#entries]\n"
+ "\t [if <filter>]\n\n"
+ "\t When a matching event is hit, an entry is added to a hash\n"
+ "\t table using the key named, and the value of a sum called\n"
+ "\t 'hitcount' is incremented. Keys correspond to fields in the\n"
+ "\t event's format description. Keys can be any field. The\n"
+ "\t 'size' parameter can be used to specify more or fewer than\n"
+ "\t the default 2048 entries for the hashtable size.\n\n"
+ "\t Reading the 'hist' file for the event will dump the hash\n"
+ "\t table in its entirety to stdout."
+#endif
;
static ssize_t
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 2525042760e6f4bb242742a97fe2efa0f9ae331a..505f8a45f426d5a2ef55f7339cb4442797002473 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1162,6 +1162,13 @@ extern struct mutex event_mutex;
extern struct list_head ftrace_events;
extern const struct file_operations event_trigger_fops;
+extern const struct file_operations event_hist_fops;
+
+#ifdef CONFIG_HIST_TRIGGERS
+extern int register_trigger_hist_cmd(void);
+#else
+static inline int register_trigger_hist_cmd(void) { return 0; }
+#endif
extern int register_trigger_cmds(void);
extern void clear_event_triggers(struct trace_array *tr);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index add81dff75200ba94972e511d1c0e9eab3fb77d2..e7cb983ee93c82d6a2d16e16e6c29ef3e87bfda1 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2141,6 +2141,10 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file)
trace_create_file("trigger", 0644, file->dir, file,
&event_trigger_fops);
+#ifdef CONFIG_HIST_TRIGGERS
+ trace_create_file("hist", 0444, file->dir, file,
+ &event_hist_fops);
+#endif
trace_create_file("format", 0444, file->dir, call,
&ftrace_event_format_fops);
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
new file mode 100644
index 0000000000000000000000000000000000000000..23b45e462117148029abfcf8816eddc48e7b1b64
--- /dev/null
+++ b/kernel/trace/trace_events_hist.c
@@ -0,0 +1,849 @@
+/*
+ * trace_events_hist - trace event hist triggers
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * Copyright (C) 2015 Tom Zanussi <tom.zanussi@linux.intel.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/stacktrace.h>
+
+#include "tracing_map.h"
+#include "trace.h"
+
+struct hist_field;
+
+typedef u64 (*hist_field_fn_t) (struct hist_field *field, void *event);
+
+struct hist_field {
+ struct ftrace_event_field *field;
+ unsigned long flags;
+ hist_field_fn_t fn;
+ unsigned int size;
+};
+
+static u64 hist_field_counter(struct hist_field *field, void *event)
+{
+ return 1;
+}
+
+static u64 hist_field_string(struct hist_field *hist_field, void *event)
+{
+ char *addr = (char *)(event + hist_field->field->offset);
+
+ return (u64)(unsigned long)addr;
+}
+
+#define DEFINE_HIST_FIELD_FN(type) \
+static u64 hist_field_##type(struct hist_field *hist_field, void *event)\
+{ \
+ type *addr = (type *)(event + hist_field->field->offset); \
+ \
+ return (u64)*addr; \
+}
+
+DEFINE_HIST_FIELD_FN(s64);
+DEFINE_HIST_FIELD_FN(u64);
+DEFINE_HIST_FIELD_FN(s32);
+DEFINE_HIST_FIELD_FN(u32);
+DEFINE_HIST_FIELD_FN(s16);
+DEFINE_HIST_FIELD_FN(u16);
+DEFINE_HIST_FIELD_FN(s8);
+DEFINE_HIST_FIELD_FN(u8);
+
+#define for_each_hist_field(i, hist_data) \
+ for ((i) = 0; (i) < (hist_data)->n_fields; (i)++)
+
+#define for_each_hist_val_field(i, hist_data) \
+ for ((i) = 0; (i) < (hist_data)->n_vals; (i)++)
+
+#define for_each_hist_key_field(i, hist_data) \
+ for ((i) = (hist_data)->n_vals; (i) < (hist_data)->n_fields; (i)++)
+
+#define HITCOUNT_IDX 0
+#define HIST_KEY_MAX 1
+#define HIST_KEY_SIZE_MAX MAX_FILTER_STR_VAL
+
+enum hist_field_flags {
+ HIST_FIELD_FL_HITCOUNT = 1,
+ HIST_FIELD_FL_KEY = 2,
+ HIST_FIELD_FL_STRING = 4,
+};
+
+struct hist_trigger_attrs {
+ char *keys_str;
+ unsigned int map_bits;
+};
+
+struct hist_trigger_data {
+ struct hist_field *fields[TRACING_MAP_FIELDS_MAX];
+ unsigned int n_vals;
+ unsigned int n_keys;
+ unsigned int n_fields;
+ unsigned int key_size;
+ struct tracing_map_sort_key sort_keys[TRACING_MAP_SORT_KEYS_MAX];
+ unsigned int n_sort_keys;
+ struct trace_event_file *event_file;
+ struct hist_trigger_attrs *attrs;
+ struct tracing_map *map;
+};
+
+static hist_field_fn_t select_value_fn(int field_size, int field_is_signed)
+{
+ hist_field_fn_t fn = NULL;
+
+ switch (field_size) {
+ case 8:
+ if (field_is_signed)
+ fn = hist_field_s64;
+ else
+ fn = hist_field_u64;
+ break;
+ case 4:
+ if (field_is_signed)
+ fn = hist_field_s32;
+ else
+ fn = hist_field_u32;
+ break;
+ case 2:
+ if (field_is_signed)
+ fn = hist_field_s16;
+ else
+ fn = hist_field_u16;
+ break;
+ case 1:
+ if (field_is_signed)
+ fn = hist_field_s8;
+ else
+ fn = hist_field_u8;
+ break;
+ }
+
+ return fn;
+}
+
+static int parse_map_size(char *str)
+{
+ unsigned long size, map_bits;
+ int ret;
+
+ strsep(&str, "=");
+ if (!str) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ ret = kstrtoul(str, 0, &size);
+ if (ret)
+ goto out;
+
+ map_bits = ilog2(roundup_pow_of_two(size));
+ if (map_bits < TRACING_MAP_BITS_MIN ||
+ map_bits > TRACING_MAP_BITS_MAX)
+ ret = -EINVAL;
+ else
+ ret = map_bits;
+ out:
+ return ret;
+}
+
+static void destroy_hist_trigger_attrs(struct hist_trigger_attrs *attrs)
+{
+ if (!attrs)
+ return;
+
+ kfree(attrs->keys_str);
+ kfree(attrs);
+}
+
+static struct hist_trigger_attrs *parse_hist_trigger_attrs(char *trigger_str)
+{
+ struct hist_trigger_attrs *attrs;
+ int ret = 0;
+
+ attrs = kzalloc(sizeof(*attrs), GFP_KERNEL);
+ if (!attrs)
+ return ERR_PTR(-ENOMEM);
+
+ while (trigger_str) {
+ char *str = strsep(&trigger_str, ":");
+
+ if ((strncmp(str, "key=", strlen("key=")) == 0) ||
+ (strncmp(str, "keys=", strlen("keys=")) == 0))
+ attrs->keys_str = kstrdup(str, GFP_KERNEL);
+ else if (strncmp(str, "size=", strlen("size=")) == 0) {
+ int map_bits = parse_map_size(str);
+
+ if (map_bits < 0) {
+ ret = map_bits;
+ goto free;
+ }
+ attrs->map_bits = map_bits;
+ } else {
+ ret = -EINVAL;
+ goto free;
+ }
+ }
+
+ if (!attrs->keys_str) {
+ ret = -EINVAL;
+ goto free;
+ }
+
+ return attrs;
+ free:
+ destroy_hist_trigger_attrs(attrs);
+
+ return ERR_PTR(ret);
+}
+
+static void destroy_hist_field(struct hist_field *hist_field)
+{
+ kfree(hist_field);
+}
+
+static struct hist_field *create_hist_field(struct ftrace_event_field *field,
+ unsigned long flags)
+{
+ struct hist_field *hist_field;
+
+ if (field && is_function_field(field))
+ return NULL;
+
+ hist_field = kzalloc(sizeof(struct hist_field), GFP_KERNEL);
+ if (!hist_field)
+ return NULL;
+
+ if (flags & HIST_FIELD_FL_HITCOUNT) {
+ hist_field->fn = hist_field_counter;
+ goto out;
+ }
+
+ if (is_string_field(field)) {
+ flags |= HIST_FIELD_FL_STRING;
+ hist_field->fn = hist_field_string;
+ } else {
+ hist_field->fn = select_value_fn(field->size,
+ field->is_signed);
+ if (!hist_field->fn) {
+ destroy_hist_field(hist_field);
+ return NULL;
+ }
+ }
+ out:
+ hist_field->field = field;
+ hist_field->flags = flags;
+
+ return hist_field;
+}
+
+static void destroy_hist_fields(struct hist_trigger_data *hist_data)
+{
+ unsigned int i;
+
+ for (i = 0; i < TRACING_MAP_FIELDS_MAX; i++) {
+ if (hist_data->fields[i]) {
+ destroy_hist_field(hist_data->fields[i]);
+ hist_data->fields[i] = NULL;
+ }
+ }
+}
+
+static int create_hitcount_val(struct hist_trigger_data *hist_data)
+{
+ hist_data->fields[HITCOUNT_IDX] =
+ create_hist_field(NULL, HIST_FIELD_FL_HITCOUNT);
+ if (!hist_data->fields[HITCOUNT_IDX])
+ return -ENOMEM;
+
+ hist_data->n_vals++;
+
+ if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX))
+ return -EINVAL;
+
+ return 0;
+}
+
+static int create_val_fields(struct hist_trigger_data *hist_data,
+ struct trace_event_file *file)
+{
+ int ret;
+
+ ret = create_hitcount_val(hist_data);
+
+ return ret;
+}
+
+static int create_key_field(struct hist_trigger_data *hist_data,
+ unsigned int key_idx,
+ struct trace_event_file *file,
+ char *field_str)
+{
+ struct ftrace_event_field *field = NULL;
+ unsigned long flags = 0;
+ unsigned int key_size;
+ int ret = 0;
+
+ if (WARN_ON(key_idx >= TRACING_MAP_FIELDS_MAX))
+ return -EINVAL;
+
+ flags |= HIST_FIELD_FL_KEY;
+
+ field = trace_find_event_field(file->event_call, field_str);
+ if (!field) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ key_size = field->size;
+
+ hist_data->fields[key_idx] = create_hist_field(field, flags);
+ if (!hist_data->fields[key_idx]) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ key_size = ALIGN(key_size, sizeof(u64));
+ hist_data->fields[key_idx]->size = key_size;
+ hist_data->key_size = key_size;
+ if (hist_data->key_size > HIST_KEY_SIZE_MAX) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ hist_data->n_keys++;
+
+ if (WARN_ON(hist_data->n_keys > TRACING_MAP_KEYS_MAX))
+ return -EINVAL;
+
+ ret = key_size;
+ out:
+ return ret;
+}
+
+static int create_key_fields(struct hist_trigger_data *hist_data,
+ struct trace_event_file *file)
+{
+ unsigned int i, n_vals = hist_data->n_vals;
+ char *fields_str, *field_str;
+ int ret = -EINVAL;
+
+ fields_str = hist_data->attrs->keys_str;
+ if (!fields_str)
+ goto out;
+
+ strsep(&fields_str, "=");
+ if (!fields_str)
+ goto out;
+
+ for (i = n_vals; i < n_vals + HIST_KEY_MAX; i++) {
+ field_str = strsep(&fields_str, ",");
+ if (!field_str)
+ break;
+ ret = create_key_field(hist_data, i, file, field_str);
+ if (ret < 0)
+ goto out;
+ }
+ if (fields_str) {
+ ret = -EINVAL;
+ goto out;
+ }
+ ret = 0;
+ out:
+ return ret;
+}
+
+static int create_hist_fields(struct hist_trigger_data *hist_data,
+ struct trace_event_file *file)
+{
+ int ret;
+
+ ret = create_val_fields(hist_data, file);
+ if (ret)
+ goto out;
+
+ ret = create_key_fields(hist_data, file);
+ if (ret)
+ goto out;
+
+ hist_data->n_fields = hist_data->n_vals + hist_data->n_keys;
+ out:
+ return ret;
+}
+
+static int create_sort_keys(struct hist_trigger_data *hist_data)
+{
+ int ret = 0;
+
+ hist_data->n_sort_keys = 1; /* sort_keys[0] is always hitcount */
+
+ return ret;
+}
+
+static void destroy_hist_data(struct hist_trigger_data *hist_data)
+{
+ destroy_hist_trigger_attrs(hist_data->attrs);
+ destroy_hist_fields(hist_data);
+ tracing_map_destroy(hist_data->map);
+ kfree(hist_data);
+}
+
+static int create_tracing_map_fields(struct hist_trigger_data *hist_data)
+{
+ struct tracing_map *map = hist_data->map;
+ struct ftrace_event_field *field;
+ struct hist_field *hist_field;
+ unsigned int i, idx;
+
+ for_each_hist_field(i, hist_data) {
+ hist_field = hist_data->fields[i];
+ if (hist_field->flags & HIST_FIELD_FL_KEY) {
+ tracing_map_cmp_fn_t cmp_fn;
+
+ field = hist_field->field;
+
+ if (is_string_field(field))
+ cmp_fn = tracing_map_cmp_string;
+ else
+ cmp_fn = tracing_map_cmp_num(field->size,
+ field->is_signed);
+ idx = tracing_map_add_key_field(map, 0, cmp_fn);
+ } else
+ idx = tracing_map_add_sum_field(map);
+
+ if (idx < 0)
+ return idx;
+ }
+
+ return 0;
+}
+
+static struct hist_trigger_data *
+create_hist_data(unsigned int map_bits,
+ struct hist_trigger_attrs *attrs,
+ struct trace_event_file *file)
+{
+ struct hist_trigger_data *hist_data;
+ int ret = 0;
+
+ hist_data = kzalloc(sizeof(*hist_data), GFP_KERNEL);
+ if (!hist_data)
+ return ERR_PTR(-ENOMEM);
+
+ hist_data->attrs = attrs;
+
+ ret = create_hist_fields(hist_data, file);
+ if (ret)
+ goto free;
+
+ ret = create_sort_keys(hist_data);
+ if (ret)
+ goto free;
+
+ hist_data->map = tracing_map_create(map_bits, hist_data->key_size,
+ NULL, hist_data);
+ if (IS_ERR(hist_data->map)) {
+ ret = PTR_ERR(hist_data->map);
+ hist_data->map = NULL;
+ goto free;
+ }
+
+ ret = create_tracing_map_fields(hist_data);
+ if (ret)
+ goto free;
+
+ ret = tracing_map_init(hist_data->map);
+ if (ret)
+ goto free;
+
+ hist_data->event_file = file;
+ out:
+ return hist_data;
+ free:
+ hist_data->attrs = NULL;
+
+ destroy_hist_data(hist_data);
+
+ hist_data = ERR_PTR(ret);
+
+ goto out;
+}
+
+static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
+ struct tracing_map_elt *elt,
+ void *rec)
+{
+ struct hist_field *hist_field;
+ unsigned int i;
+ u64 hist_val;
+
+ for_each_hist_val_field(i, hist_data) {
+ hist_field = hist_data->fields[i];
+ hist_val = hist_field->fn(hist_field, rec);
+ tracing_map_update_sum(elt, i, hist_val);
+ }
+}
+
+static void event_hist_trigger(struct event_trigger_data *data, void *rec)
+{
+ struct hist_trigger_data *hist_data = data->private_data;
+ struct hist_field *key_field;
+ struct tracing_map_elt *elt;
+ u64 field_contents;
+ void *key = NULL;
+ unsigned int i;
+
+ for_each_hist_key_field(i, hist_data) {
+ key_field = hist_data->fields[i];
+
+ field_contents = key_field->fn(key_field, rec);
+ if (key_field->flags & HIST_FIELD_FL_STRING)
+ key = (void *)(unsigned long)field_contents;
+ else
+ key = (void *)&field_contents;
+ }
+
+ elt = tracing_map_insert(hist_data->map, key);
+ if (elt)
+ hist_trigger_elt_update(hist_data, elt, rec);
+}
+
+static void
+hist_trigger_entry_print(struct seq_file *m,
+ struct hist_trigger_data *hist_data, void *key,
+ struct tracing_map_elt *elt)
+{
+ struct hist_field *key_field;
+ unsigned int i;
+ u64 uval;
+
+ seq_puts(m, "{ ");
+
+ for_each_hist_key_field(i, hist_data) {
+ key_field = hist_data->fields[i];
+
+ if (i > hist_data->n_vals)
+ seq_puts(m, ", ");
+
+ if (key_field->flags & HIST_FIELD_FL_STRING) {
+ seq_printf(m, "%s: %-50s", key_field->field->name,
+ (char *)key);
+ } else {
+ uval = *(u64 *)key;
+ seq_printf(m, "%s: %10llu",
+ key_field->field->name, uval);
+ }
+ }
+
+ seq_puts(m, " }");
+
+ seq_printf(m, " hitcount: %10llu",
+ tracing_map_read_sum(elt, HITCOUNT_IDX));
+
+ seq_puts(m, "\n");
+}
+
+static int print_entries(struct seq_file *m,
+ struct hist_trigger_data *hist_data)
+{
+ struct tracing_map_sort_entry **sort_entries = NULL;
+ struct tracing_map *map = hist_data->map;
+ unsigned int i, n_entries;
+
+ n_entries = tracing_map_sort_entries(map, hist_data->sort_keys,
+ hist_data->n_sort_keys,
+ &sort_entries);
+ if (n_entries < 0)
+ return n_entries;
+
+ for (i = 0; i < n_entries; i++)
+ hist_trigger_entry_print(m, hist_data,
+ sort_entries[i]->key,
+ sort_entries[i]->elt);
+
+ tracing_map_destroy_sort_entries(sort_entries, n_entries);
+
+ return n_entries;
+}
+
+static int hist_show(struct seq_file *m, void *v)
+{
+ struct event_trigger_data *test, *data = NULL;
+ struct trace_event_file *event_file;
+ struct hist_trigger_data *hist_data;
+ int n_entries, ret = 0;
+
+ mutex_lock(&event_mutex);
+
+ event_file = event_file_data(m->private);
+ if (unlikely(!event_file)) {
+ ret = -ENODEV;
+ goto out_unlock;
+ }
+
+ list_for_each_entry_rcu(test, &event_file->triggers, list) {
+ if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+ data = test;
+ break;
+ }
+ }
+ if (!data)
+ goto out_unlock;
+
+ seq_puts(m, "# event histogram\n#\n# trigger info: ");
+ data->ops->print(m, data->ops, data);
+ seq_puts(m, "\n");
+
+ hist_data = data->private_data;
+ n_entries = print_entries(m, hist_data);
+ if (n_entries < 0) {
+ ret = n_entries;
+ n_entries = 0;
+ }
+
+ seq_printf(m, "\nTotals:\n Hits: %llu\n Entries: %u\n Dropped: %llu\n",
+ (u64)atomic64_read(&hist_data->map->hits),
+ n_entries, (u64)atomic64_read(&hist_data->map->drops));
+ out_unlock:
+ mutex_unlock(&event_mutex);
+
+ return ret;
+}
+
+static int event_hist_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, hist_show, file);
+}
+
+const struct file_operations event_hist_fops = {
+ .open = event_hist_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+static void hist_field_print(struct seq_file *m, struct hist_field *hist_field)
+{
+ seq_printf(m, "%s", hist_field->field->name);
+}
+
+static int event_hist_trigger_print(struct seq_file *m,
+ struct event_trigger_ops *ops,
+ struct event_trigger_data *data)
+{
+ struct hist_trigger_data *hist_data = data->private_data;
+ struct hist_field *key_field;
+ unsigned int i;
+
+ seq_puts(m, "hist:keys=");
+
+ for_each_hist_key_field(i, hist_data) {
+ key_field = hist_data->fields[i];
+
+ if (i > hist_data->n_vals)
+ seq_puts(m, ",");
+
+ hist_field_print(m, key_field);
+ }
+
+ seq_puts(m, ":vals=");
+ seq_puts(m, "hitcount");
+
+ seq_puts(m, ":sort=");
+ seq_puts(m, "hitcount");
+
+ seq_printf(m, ":size=%u", (1 << hist_data->map->map_bits));
+
+ if (data->filter_str)
+ seq_printf(m, " if %s", data->filter_str);
+
+ seq_puts(m, " [active]");
+
+ seq_putc(m, '\n');
+
+ return 0;
+}
+
+static void event_hist_trigger_free(struct event_trigger_ops *ops,
+ struct event_trigger_data *data)
+{
+ struct hist_trigger_data *hist_data = data->private_data;
+
+ if (WARN_ON_ONCE(data->ref <= 0))
+ return;
+
+ data->ref--;
+ if (!data->ref) {
+ trigger_data_free(data);
+ destroy_hist_data(hist_data);
+ }
+}
+
+static struct event_trigger_ops event_hist_trigger_ops = {
+ .func = event_hist_trigger,
+ .print = event_hist_trigger_print,
+ .init = event_trigger_init,
+ .free = event_hist_trigger_free,
+};
+
+static struct event_trigger_ops *event_hist_get_trigger_ops(char *cmd,
+ char *param)
+{
+ return &event_hist_trigger_ops;
+}
+
+static int hist_register_trigger(char *glob, struct event_trigger_ops *ops,
+ struct event_trigger_data *data,
+ struct trace_event_file *file)
+{
+ struct event_trigger_data *test;
+ int ret = 0;
+
+ list_for_each_entry_rcu(test, &file->triggers, list) {
+ if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+ ret = -EEXIST;
+ goto out;
+ }
+ }
+
+ if (data->ops->init) {
+ ret = data->ops->init(data->ops, data);
+ if (ret < 0)
+ goto out;
+ }
+
+ list_add_rcu(&data->list, &file->triggers);
+ ret++;
+
+ update_cond_flag(file);
+ if (trace_event_trigger_enable_disable(file, 1) < 0) {
+ list_del_rcu(&data->list);
+ update_cond_flag(file);
+ ret--;
+ }
+ out:
+ return ret;
+}
+
+static int event_hist_trigger_func(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob, char *cmd, char *param)
+{
+ unsigned int hist_trigger_bits = TRACING_MAP_BITS_DEFAULT;
+ struct event_trigger_data *trigger_data;
+ struct hist_trigger_attrs *attrs;
+ struct event_trigger_ops *trigger_ops;
+ struct hist_trigger_data *hist_data;
+ char *trigger;
+ int ret = 0;
+
+ if (!param)
+ return -EINVAL;
+
+ /* separate the trigger from the filter (k:v [if filter]) */
+ trigger = strsep(¶m, " \t");
+ if (!trigger)
+ return -EINVAL;
+
+ attrs = parse_hist_trigger_attrs(trigger);
+ if (IS_ERR(attrs))
+ return PTR_ERR(attrs);
+
+ if (attrs->map_bits)
+ hist_trigger_bits = attrs->map_bits;
+
+ hist_data = create_hist_data(hist_trigger_bits, attrs, file);
+ if (IS_ERR(hist_data)) {
+ destroy_hist_trigger_attrs(attrs);
+ return PTR_ERR(hist_data);
+ }
+
+ trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
+
+ ret = -ENOMEM;
+ trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
+ if (!trigger_data)
+ goto out_free;
+
+ trigger_data->count = -1;
+ trigger_data->ops = trigger_ops;
+ trigger_data->cmd_ops = cmd_ops;
+
+ INIT_LIST_HEAD(&trigger_data->list);
+ RCU_INIT_POINTER(trigger_data->filter, NULL);
+
+ trigger_data->private_data = hist_data;
+
+ if (glob[0] == '!') {
+ cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
+ ret = 0;
+ goto out_free;
+ }
+
+ if (!param) /* if param is non-empty, it's supposed to be a filter */
+ goto out_reg;
+
+ if (!cmd_ops->set_filter)
+ goto out_reg;
+
+ ret = cmd_ops->set_filter(param, trigger_data, file);
+ if (ret < 0)
+ goto out_free;
+ out_reg:
+ ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
+ /*
+ * The above returns on success the # of triggers registered,
+ * but if it didn't register any it returns zero. Consider no
+ * triggers registered a failure too.
+ */
+ if (!ret) {
+ ret = -ENOENT;
+ goto out_free;
+ } else if (ret < 0)
+ goto out_free;
+ /* Just return zero, not the number of registered triggers */
+ ret = 0;
+ out:
+ return ret;
+ out_free:
+ if (cmd_ops->set_filter)
+ cmd_ops->set_filter(NULL, trigger_data, NULL);
+
+ kfree(trigger_data);
+
+ destroy_hist_data(hist_data);
+ goto out;
+}
+
+static struct event_command trigger_hist_cmd = {
+ .name = "hist",
+ .trigger_type = ETT_EVENT_HIST,
+ .flags = EVENT_CMD_FL_NEEDS_REC,
+ .func = event_hist_trigger_func,
+ .reg = hist_register_trigger,
+ .unreg = unregister_trigger,
+ .get_trigger_ops = event_hist_get_trigger_ops,
+ .set_filter = set_trigger_filter,
+};
+
+__init int register_trigger_hist_cmd(void)
+{
+ int ret;
+
+ ret = register_event_command(&trigger_hist_cmd);
+ WARN_ON(ret < 0);
+
+ return ret;
+}
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index d67992f3bb0ee02551487dfa9a87fc39e924a96c..d29092afe0050e38ebc01b054fd8a75582ab48e6 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -1447,6 +1447,7 @@ __init int register_trigger_cmds(void)
register_trigger_snapshot_cmd();
register_trigger_stacktrace_cmd();
register_trigger_enable_disable_cmds();
+ register_trigger_hist_cmd();
return 0;
}