Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932170AbbETVXs (ORCPT ); Wed, 20 May 2015 17:23:48 -0400 Received: from mga02.intel.com ([134.134.136.20]:45354 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754700AbbETVU2 (ORCPT ); Wed, 20 May 2015 17:20:28 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,466,1427785200"; d="scan'208";a="496256953" From: Tom Zanussi To: rostedt@goodmis.org Cc: daniel.wagner@bmw-carit.de, masami.hiramatsu.pt@hitachi.com, namhyung@kernel.org, josh@joshtriplett.org, andi@firstfloor.org, linux-kernel@vger.kernel.org, Tom Zanussi Subject: [PATCH v5 06/10] trace: Add lock-free tracing_map Date: Wed, 20 May 2015 16:19:53 -0500 Message-Id: <7c502f20907db32907ad3d2de2532c2ac3d09dd3.1432151408.git.tom.zanussi@linux.intel.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 29525 Lines: 1022 Add tracing_map, a special-purpose lock-free map for tracing. tracing_map is designed to aggregate or 'sum' one or more values associated with a specific object of type tracing_map_elt, which is associated by the map to a given key. It provides various hooks allowing per-tracer customization and is separated out into a separate file in order to allow it to be shared between multiple tracers, but isn't meant to be generally used outside of that context. The tracing_map implementation was inspired by lock-free map algorithms originated by Dr. Cliff Click: http://www.azulsystems.com/blog/cliff/2007-03-26-non-blocking-hashtable http://www.azulsystems.com/events/javaone_2007/2007_LockFreeHash.pdf Signed-off-by: Tom Zanussi --- kernel/trace/Makefile | 1 + kernel/trace/tracing_map.c | 831 +++++++++++++++++++++++++++++++++++++++++++++ kernel/trace/tracing_map.h | 133 ++++++++ 3 files changed, 965 insertions(+) create mode 100644 kernel/trace/tracing_map.c create mode 100644 kernel/trace/tracing_map.h diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index 9b1044e..3b26cfb 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -31,6 +31,7 @@ obj-$(CONFIG_TRACING) += trace_output.o obj-$(CONFIG_TRACING) += trace_seq.o obj-$(CONFIG_TRACING) += trace_stat.o obj-$(CONFIG_TRACING) += trace_printk.o +obj-$(CONFIG_TRACING) += tracing_map.o obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c new file mode 100644 index 0000000..cdbf377 --- /dev/null +++ b/kernel/trace/tracing_map.c @@ -0,0 +1,831 @@ +/* + * tracing_map - lock-free map for tracing + * + * 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 + * + * tracing_map implementation inspired by lock-free map algorithms + * originated by Dr. Cliff Click: + * + * http://www.azulsystems.com/blog/cliff/2007-03-26-non-blocking-hashtable + * http://www.azulsystems.com/events/javaone_2007/2007_LockFreeHash.pdf + */ + +#include +#include +#include + +#include "tracing_map.h" +#include "trace.h" + +/** + * tracing_map_update_sum - Add a value to a tracing_map_elt's sum + * @elt: The tracing_map_elt + * @i: The index of the given sum associated with the tracing_map_elt + * @n: The value to add to the sum + * + * Add n to sum i associated with the specified tracing_map_elt + * instance. The index i is the index returned by the call to + * tracing_map_add_sum_field() when the tracing map was set up. + */ +void tracing_map_update_sum(struct tracing_map_elt *elt, unsigned int i, u64 n) +{ + atomic64_add(n, &elt->fields[i].sum); +} + +/** + * tracing_map_read_sum - Return the value of a tracing_map_elt's sum + * @elt: The tracing_map_elt + * @i: The index of the given sum associated with the tracing_map_elt + * + * Retrieve the value of the sum i associated with the specified + * tracing_map_elt instance. The index i is the index returned by the + * call to tracing_map_add_sum_field() when the tracing map was set + * up. + * + * Return: The sum associated with field i for elt. + */ +u64 tracing_map_read_sum(struct tracing_map_elt *elt, unsigned int i) +{ + return (u64)atomic64_read(&elt->fields[i].sum); +} + +int tracing_map_cmp_string(void *val_a, void *val_b) +{ + char *a = val_a; + char *b = val_b; + + return strcmp(a, b); +} + +int tracing_map_cmp_none(void *val_a, void *val_b) +{ + return 0; +} + +static int tracing_map_cmp_atomic64(void *val_a, void *val_b) +{ + u64 a = atomic64_read((atomic64_t *)val_a); + u64 b = atomic64_read((atomic64_t *)val_b); + + return (a > b) ? 1 : ((a < b) ? -1 : 0); +} + +#define DEFINE_TRACING_MAP_CMP_FN(type) \ +static int tracing_map_cmp_##type(void *val_a, void *val_b) \ +{ \ + type a = *(type *)val_a; \ + type b = *(type *)val_b; \ + \ + return (a > b) ? 1 : ((a < b) ? -1 : 0); \ +} + +DEFINE_TRACING_MAP_CMP_FN(s64); +DEFINE_TRACING_MAP_CMP_FN(u64); +DEFINE_TRACING_MAP_CMP_FN(s32); +DEFINE_TRACING_MAP_CMP_FN(u32); +DEFINE_TRACING_MAP_CMP_FN(s16); +DEFINE_TRACING_MAP_CMP_FN(u16); +DEFINE_TRACING_MAP_CMP_FN(s8); +DEFINE_TRACING_MAP_CMP_FN(u8); + +tracing_map_cmp_fn_t tracing_map_cmp_num(int field_size, + int field_is_signed) +{ + tracing_map_cmp_fn_t fn = tracing_map_cmp_none; + + switch (field_size) { + case 8: + if (field_is_signed) + fn = tracing_map_cmp_s64; + else + fn = tracing_map_cmp_u64; + break; + case 4: + if (field_is_signed) + fn = tracing_map_cmp_s32; + else + fn = tracing_map_cmp_u32; + break; + case 2: + if (field_is_signed) + fn = tracing_map_cmp_s16; + else + fn = tracing_map_cmp_u16; + break; + case 1: + if (field_is_signed) + fn = tracing_map_cmp_s8; + else + fn = tracing_map_cmp_u8; + break; + } + + return fn; +} + +static int tracing_map_add_field(struct tracing_map *map, + tracing_map_cmp_fn_t cmp_fn) +{ + int ret = -EINVAL; + + if (map->n_fields < TRACING_MAP_FIELDS_MAX) { + ret = map->n_fields; + map->field_descr[map->n_fields++].cmp_fn = cmp_fn; + } + + return ret; +} + +/** + * tracing_map_add_sum_field - Add a field describing a tracing_map sum + * @map: The tracing_map + * + * Add a sum field to the key and return the index identifying it in + * the map and associated tracing_map_elts. This is the index used + * for instance to update a sum for a particular tracing_map_elt using + * tracing_map_update_sum() or reading it via tracing_map_read_sum(). + * + * Return: The index identifying the field in the map and associated + * tracing_map_elts. + */ +int tracing_map_add_sum_field(struct tracing_map *map) +{ + return tracing_map_add_field(map, tracing_map_cmp_atomic64); +} + +/** + * tracing_map_add_key_field - Add a field describing the tracing_map key + * @map: The tracing_map + * @cmp_fn: The comparison function that will be used to sort on the key + * + * Let the map know there is a key and that if it's used as a sort key + * to use cmp_fn. + * + * Return: The index identifying the field in the map and associated + * tracing_map_elts. + */ +int tracing_map_add_key_field(struct tracing_map *map, + tracing_map_cmp_fn_t cmp_fn) +{ + int idx = tracing_map_add_field(map, cmp_fn); + + if (idx < 0) + return idx; + + map->key_idx = idx; + + return idx; +} + +static void tracing_map_elt_clear(struct tracing_map_elt *elt) +{ + unsigned i; + + for (i = 0; i < elt->map->n_fields; i++) + atomic64_set(&elt->fields[i].sum, 0); + + if (elt->map->ops && elt->map->ops->elt_clear) + elt->map->ops->elt_clear(elt); +} + +static void tracing_map_elt_init_fields(struct tracing_map_elt *elt) +{ + unsigned int i; + + tracing_map_elt_clear(elt); + + for (i = 0; i < elt->map->n_fields; i++) + elt->fields[i].cmp_fn = elt->map->field_descr[i].cmp_fn; +} + +static void tracing_map_elt_free(struct tracing_map_elt *elt) +{ + if (!elt) + return; + + if (elt->map->ops && elt->map->ops->elt_free) + elt->map->ops->elt_free(elt); + kfree(elt->fields); + kfree(elt->key); + kfree(elt); +} + +static struct tracing_map_elt *tracing_map_elt_alloc(struct tracing_map *map) +{ + struct tracing_map_elt *elt; + int err = 0; + + elt = kzalloc(sizeof(*elt), GFP_KERNEL); + if (!elt) + return ERR_PTR(-ENOMEM); + + elt->map = map; + + elt->key = kzalloc(map->key_size, GFP_KERNEL); + if (!elt->key) { + err = -ENOMEM; + goto free; + } + + elt->fields = kcalloc(map->n_fields, sizeof(*elt->fields), GFP_KERNEL); + if (!elt->fields) { + err = -ENOMEM; + goto free; + } + + tracing_map_elt_init_fields(elt); + + if (map->ops && map->ops->elt_alloc) { + err = map->ops->elt_alloc(elt); + if (err) + goto free; + } + return elt; + free: + tracing_map_elt_free(elt); + + return ERR_PTR(err); +} + +static struct tracing_map_elt *get_free_elt(struct tracing_map *map) +{ + struct tracing_map_elt *elt = NULL; + int idx; + + idx = atomic_inc_return(&map->next_elt); + if (idx < map->max_elts) { + elt = map->elts[idx]; + if (map->ops && map->ops->elt_init) + map->ops->elt_init(elt); + } + + return elt; +} + +static void tracing_map_free_elts(struct tracing_map *map) +{ + unsigned int i; + + if (!map->elts) + return; + + for (i = 0; i < map->max_elts; i++) + tracing_map_elt_free(map->elts[i]); + + kfree(map->elts); +} + +static int tracing_map_alloc_elts(struct tracing_map *map) +{ + unsigned int i; + + map->elts = kcalloc(map->max_elts, sizeof(struct tracing_map_elt *), + GFP_KERNEL); + if (!map->elts) + return -ENOMEM; + + for (i = 0; i < map->max_elts; i++) { + map->elts[i] = tracing_map_elt_alloc(map); + if (!map->elts[i]) { + tracing_map_free_elts(map); + + return -ENOMEM; + } + } + + return 0; +} + +static inline bool keys_match(void *key, void *test_key, unsigned key_size) +{ + bool match = true; + + if (memcmp(key, test_key, key_size)) + match = false; + + return match; +} + +/** + * tracing_map_insert - Insert key and/or return associated val + * @map: The tracing_map to insert into + * @key: The key to insert + * + * Inserts a key into the map and creates and returns a new + * tracing_map_elt for it, or if the key has already been inserted by + * a previous call, returns the tracing_map_elt already associated + * with it. When the map was created, the number of elements to be + * allocated for the map was specified, and that number of + * tracing_map_elts was created by tracing_map_init(). This is the + * pre-allocated pool of tracing map element that tracing_map_insert() + * will allocate from when adding new keys. Once that pool is + * exhausted, tracing_map_insert() is useless and will return NULL to + * signal that state. + * + * This is a lock-free tracing map insertion function implementing a + * modified form of Cliff Click's basic insertion algorithm. It + * requires the table size to be a power of two. To prevent any + * possibility of an infinite loop we always make the actual table + * size double the size of the requested table size (max_size * 2). + * Likewise, we never reuse a slot or resize or delete elements - when + * we've reached map_size entries, we simply return NULL once we've + * run out of entries. Readers can at any point in time traverse the + * tracing map and safely access the key/val pairs. + * + * Return: the tracing_map_elt * val associated with the key. If this + * was a newly inserted key, the val will be a newly allocated and + * associated tracing_map_elt * val. If the key wasn't found and the + * pool of tracing_map_elts has been exhausted, NULL is returned and + * no further insertions will succeed. + */ +struct tracing_map_elt *tracing_map_insert(struct tracing_map *map, void *key) +{ + u32 idx, key_hash, test_key; + + key_hash = jhash(key, map->key_size, 0); + idx = key_hash >> (32 - (map->map_bits + 1)); + + while (1) { + idx &= (map->map_size - 1); + test_key = map->map[idx].key; + + if (test_key && test_key == key_hash && map->map[idx].val && + keys_match(key, map->map[idx].val->key, map->key_size)) + return map->map[idx].val; + + if (!test_key && !cmpxchg(&map->map[idx].key, 0, key_hash)) { + struct tracing_map_elt *elt; + + elt = get_free_elt(map); + if (!elt) + break; + memcpy(elt->key, key, map->key_size); + map->map[idx].val = elt; + + return map->map[idx].val; + } + idx++; + } + + return NULL; +} + +/** + * tracing_map_destroy - Destroy a tracing_map + * @map: The tracing_map to destroy + * + * Frees a tracing_map along with its associated array of + * tracing_map_elts. + * + * Callers should make sure there are no readers or writers actively + * reading or inserting into the map before calling this. + */ +void tracing_map_destroy(struct tracing_map *map) +{ + if (!map) + return; + + tracing_map_free_elts(map); + + kfree(map->map); + kfree(map); +} + +/** + * tracing_map_clear - Clear a tracing_map + * @map: The tracing_map to clear + * + * Resets the tracing map to a cleared or initial state. The + * tracing_map_elts are all cleared, and the array of + * tracing_map_entries are reset to an initialized state. + * + * Callers should make sure there are no writers actively inserting + * into the map before calling this. + */ +void tracing_map_clear(struct tracing_map *map) +{ + unsigned int i, size; + + atomic_set(&map->next_elt, -1); + + size = map->map_size * sizeof(struct tracing_map_entry); + memset(map->map, 0, size); + + for (i = 0; i < map->max_elts; i++) + tracing_map_elt_clear(map->elts[i]); +} + +static void set_sort_key(struct tracing_map *map, + struct tracing_map_sort_key *sort_key) +{ + map->sort_key = *sort_key; +} + +/** + * tracing_map_create - Create a lock-free map and hist element pool + * @map_bits: The size of the map (2 ** map_bits) + * @key_size: The size of the key for the map in bytes + * @ops: Optional client-defined tracing_map_ops instance + * @private_data: Client data associated with the map + * + * Creates and sets up a map to contain a max_size number of entries + * equal to a size of 2 ** map_bits. Before using, the map fields + * should be added to the map with tracing_map_add_sum_field() and + * tracing_map_add_key_field(). tracing_map_init() should then be + * called to allocate the array of tracing_map_elts, in order to avoid + * allocating anything in the map insertion path. The user-specified + * map_size reflect the max number of entries requested by the user - + * internally we double that in order to keep the table sparse and + * keep collisions manageable. + * + * A tracing_map is a special-purpose map designed to aggregate or + * 'sum' one or more values associated with a specific object of type + * tracing_map_elt, which is attached by the map to a given key. + * + * tracing_map_create() sets up the map itself, and provides + * operations for inserting tracing_map_elts, but doesn't allocate the + * tracing_map_elts themselves, or provide a means for describing the + * keys or sums associated with the tracing_map_elts. All + * tracing_map_elts for a given map have the same set of sums and + * keys, which are defined by the client using the functions + * tracing_map_add_key_field() and tracing_map_add_sum_field(). + * Currently a tracing map can only have one key field i.e. compound + * keys aren't yet supported. Once the fields are defined, the pool + * of elements allocated for the map can be created, which occurs when + * the client code calls tracing_map_init(). + * + * When tracing_map_init() returns, tracing_map_elt elements can be + * inserted into the map using tracing_map_insert(). When called, + * tracing_map_insert() grabs a free tracing_map_elt from the pool, or + * finds an existing match in the map and in either case returns it. + * The client can then use tracing_map_update_sum() and + * tracing_map_read_sum() to update or read a given sum field for the + * tracing_map_elt. + * + * The client can at any point retrieve and traverse the map and + * the set of inserted tracing_map_elts via tracing_map_sort_entries(). + * Sorting can be done on any field, including the key. + * + * See tracing_map.h for a description of tracing_map_ops. + * + * Return: the tracing_map * if successful, ERR_PTR if not. + */ +struct tracing_map *tracing_map_create(unsigned int map_bits, + unsigned int key_size, + struct tracing_map_ops *ops, + void *private_data) +{ + struct tracing_map *map; + + if (map_bits < TRACING_MAP_BITS_MIN || + map_bits > TRACING_MAP_BITS_MAX) + return ERR_PTR(-EINVAL); + + map = kzalloc(sizeof(*map), GFP_KERNEL); + if (!map) + return ERR_PTR(-ENOMEM); + + map->map_bits = map_bits; + map->max_elts = (1 << map_bits); + atomic_set(&map->next_elt, -1); + + map->map_size = (1 << (map_bits + 1)); + map->ops = ops; + + map->private_data = private_data; + + map->map = kcalloc(map->map_size, sizeof(struct tracing_map_entry), + GFP_KERNEL); + if (!map->map) + goto free; + + map->key_size = key_size; + out: + return map; + free: + tracing_map_destroy(map); + map = ERR_PTR(-ENOMEM); + + goto out; +} + +/** + * tracing_map_init - Allocate and clear a map's tracing_map_elts + * @map: The tracing_map to initialize + * + * Creates and sets up a map to contain a max_size number of entries + * equal to a size of 2 ** map_bits. Before using, the map fields + * should be added to the map with tracing_map_add_key_field() and + * tracing_map_add_key_field(). tracing_map_init() should then be + * called to allocate the array of tracing_map_elts, in order to avoid + * allocating anything in the map insertion path. The user-specified + * map_size reflect the max number of entries requested by the user - + * internally we double that in order to keep the table sparse and + * keep collisions manageable. + * + * See tracing_map.h for a description of tracing_map_ops. + * + * Return: the tracing_map * if successful, ERR_PTR if not. + */ +int tracing_map_init(struct tracing_map *map) +{ + int err; + + if (map->n_fields < 2) + return -EINVAL; /* need at least 1 key and 1 val */ + + err = tracing_map_alloc_elts(map); + if (err) + return err; + + tracing_map_clear(map); + + return err; +} + +static int cmp_entries_dup(const struct tracing_map_sort_entry **a, + const struct tracing_map_sort_entry **b) +{ + int ret = 0; + + if (memcmp((*a)->key, (*b)->key, (*a)->elt->map->key_size)) + ret = 1; + + return ret; +} + +static int cmp_entries_sum(const struct tracing_map_sort_entry **a, + const struct tracing_map_sort_entry **b) +{ + const struct tracing_map_elt *elt_a, *elt_b; + struct tracing_map_sort_key *sort_key; + struct tracing_map_field *field; + tracing_map_cmp_fn_t cmp_fn; + void *val_a, *val_b; + int ret = 0; + + elt_a = (*a)->elt; + elt_b = (*b)->elt; + + sort_key = &elt_a->map->sort_key; + + field = &elt_a->fields[sort_key->idx]; + cmp_fn = field->cmp_fn; + + val_a = &elt_a->fields[sort_key->idx].sum; + val_b = &elt_b->fields[sort_key->idx].sum; + + ret = cmp_fn(val_a, val_b); + if (sort_key->descending) + ret = -ret; + + return ret; +} + +static int cmp_entries_key(const struct tracing_map_sort_entry **a, + const struct tracing_map_sort_entry **b) +{ + const struct tracing_map_elt *elt_a, *elt_b; + struct tracing_map_sort_key *sort_key; + struct tracing_map_field *field; + tracing_map_cmp_fn_t cmp_fn; + void *val_a, *val_b; + int ret = 0; + + elt_a = (*a)->elt; + elt_b = (*b)->elt; + + sort_key = &elt_a->map->sort_key; + + field = &elt_a->fields[sort_key->idx]; + cmp_fn = field->cmp_fn; + + val_a = elt_a->key; + val_b = elt_b->key; + + ret = cmp_fn(val_a, val_b); + if (sort_key->descending) + ret = -ret; + + return ret; +} + +static void destroy_sort_entry(struct tracing_map_sort_entry *entry) +{ + if (!entry) + return; + + if (entry->elt_copied) + tracing_map_elt_free(entry->elt); + + kfree(entry); +} + +/** + * tracing_map_destroy_entries - Destroy a tracing_map_sort_entries() array + * @entries: The entries to destroy + * @n_entries: The number of entries in the array + * + * Destroy the elements returned by a tracing_map_sort_entries() call. + */ +void tracing_map_destroy_sort_entries(struct tracing_map_sort_entry **entries, + unsigned int n_entries) +{ + unsigned int i; + + for (i = 0; i < n_entries; i++) + destroy_sort_entry(entries[i]); +} + +static struct tracing_map_sort_entry * +create_sort_entry(void *key, struct tracing_map_elt *elt) +{ + struct tracing_map_sort_entry *sort_entry; + + sort_entry = kzalloc(sizeof(*sort_entry), GFP_KERNEL); + if (!sort_entry) + return NULL; + + sort_entry->key = key; + sort_entry->elt = elt; + + return sort_entry; +} + +static struct tracing_map_elt *copy_elt(struct tracing_map_elt *elt) +{ + struct tracing_map_elt *dup_elt; + unsigned int i; + + dup_elt = tracing_map_elt_alloc(elt->map); + if (!dup_elt) + return NULL; + + if (elt->map->ops && elt->map->ops->elt_copy) + elt->map->ops->elt_copy(dup_elt, elt); + + dup_elt->private_data = elt->private_data; + memcpy(dup_elt->key, elt->key, elt->map->key_size); + + for (i = 0; i < elt->map->n_fields; i++) { + atomic64_set(&dup_elt->fields[i].sum, + atomic64_read(&elt->fields[i].sum)); + dup_elt->fields[i].cmp_fn = elt->fields[i].cmp_fn; + } + + return dup_elt; +} + +static int merge_dup(struct tracing_map_sort_entry **sort_entries, + unsigned int target, unsigned int dup) +{ + struct tracing_map_elt *target_elt, *elt; + bool first_dup = (target - dup) == 1; + int i; + + if (first_dup) { + elt = sort_entries[target]->elt; + target_elt = copy_elt(elt); + if (!target_elt) + return -ENOMEM; + sort_entries[target]->elt = target_elt; + sort_entries[target]->elt_copied = true; + } else + target_elt = sort_entries[target]->elt; + + elt = sort_entries[dup]->elt; + + for (i = 0; i < elt->map->n_fields; i++) + atomic64_add(atomic64_read(&elt->fields[i].sum), + &target_elt->fields[i].sum); + + sort_entries[dup]->dup = true; + + return 0; +} + +static int merge_dups(struct tracing_map_sort_entry **sort_entries, + int n_entries, unsigned int key_size) +{ + unsigned int dups = 0, total_dups = 0; + int err, i, j; + void *key; + + if (n_entries < 2) + return total_dups; + + sort(sort_entries, n_entries, sizeof(struct tracing_map_sort_entry *), + (int (*)(const void *, const void *))cmp_entries_dup, NULL); + + key = sort_entries[0]->key; + for (i = 1; i < n_entries; i++) { + if (!memcmp(sort_entries[i]->key, key, key_size)) { + dups++; total_dups++; + err = merge_dup(sort_entries, i - dups, i); + if (err) + return err; + continue; + } + key = sort_entries[i]->key; + dups = 0; + } + + if (!total_dups) + return total_dups; + + for (i = 0, j = 0; i < n_entries; i++) { + if (!sort_entries[i]->dup) { + sort_entries[j] = sort_entries[i]; + if (j++ != i) + sort_entries[i] = NULL; + } else { + destroy_sort_entry(sort_entries[i]); + sort_entries[i] = NULL; + } + } + + return total_dups; +} + +/** + * tracing_map_sort_entries - Sort the current set of tracing_map_lts in a map + * @map: The tracing_map + * @sort_key: The sort key to use for sorting + * @sort_entries: outval: pointer to allocated and sorted array of entries + * + * tracing_map_sort_entries() sorts the current set of entries in the + * map and returns the list of tracing_map_sort_entries containing + * them to the client in the sort_entries param. + * + * The sort_key has only two fields: idx and descending. 'idx' refers + * to the index of the field added via tracing_map_add_sum_field() or + * tracing_map_add_key_field() when the tracing_map was initialized. + * 'descending' is a flag that if set reverses the sort order, which + * by default is ascending. + * + * The client should not hold on to the returned array but use it + * and call tracing_map_destroy_sort_entries() when done. + * + * Return: the number of sort_entries in the tracing_map_sort_entry + * array, negative on err + */ +int tracing_map_sort_entries(struct tracing_map *map, + struct tracing_map_sort_key *sort_key, + struct tracing_map_sort_entry ***sort_entries) +{ + int (*cmp_entries_fn)(const struct tracing_map_sort_entry **, + const struct tracing_map_sort_entry **); + struct tracing_map_sort_entry *sort_entry, **entries; + int i, j, n_entries, ret; + + set_sort_key(map, sort_key); + + entries = kcalloc(map->max_elts, sizeof(sort_entry), GFP_KERNEL); + if (!entries) + return -ENOMEM; + + for (i = 0, j = 0; i < map->map_size; i++) { + if (!map->map[i].key || !map->map[i].val) + continue; + + entries[j] = create_sort_entry(map->map[i].val->key, + map->map[i].val); + if (!entries[j++]) { + ret = -ENOMEM; + n_entries = j; + goto free; + } + } + n_entries = j; + + ret = merge_dups(entries, n_entries, map->key_size); + if (ret < 0) + goto free; + n_entries -= ret; + + if (sort_key->idx == map->key_idx) + cmp_entries_fn = cmp_entries_key; + else + cmp_entries_fn = cmp_entries_sum; + + sort(entries, n_entries, sizeof(struct hist_trigger_entry *), + (int (*)(const void *, const void *))cmp_entries_fn, NULL); + + *sort_entries = entries; + + return n_entries; + free: + tracing_map_destroy_sort_entries(entries, n_entries); + + return ret; +} diff --git a/kernel/trace/tracing_map.h b/kernel/trace/tracing_map.h new file mode 100644 index 0000000..e60e3e7 --- /dev/null +++ b/kernel/trace/tracing_map.h @@ -0,0 +1,133 @@ +#ifndef __TRACING_MAP_H +#define __TRACING_MAP_H + +#define TRACING_MAP_BITS_DEFAULT 11 +#define TRACING_MAP_BITS_MAX 17 +#define TRACING_MAP_BITS_MIN 7 + +#define TRACING_MAP_FIELDS_MAX 4 + +typedef int (*tracing_map_cmp_fn_t) (void *val_a, void *val_b); + +struct tracing_map_field { + tracing_map_cmp_fn_t cmp_fn; + atomic64_t sum; +}; + +struct tracing_map_elt { + struct tracing_map *map; + struct tracing_map_field *fields; + void *key; + void *private_data; +}; + +struct tracing_map_entry { + u32 key; + struct tracing_map_elt *val; +}; + +struct tracing_map_sort_key { + unsigned int idx; + bool descending; +}; + +struct tracing_map_sort_entry { + void *key; + struct tracing_map_elt *elt; + bool elt_copied; + bool dup; +}; + +struct tracing_map { + unsigned int key_size; + unsigned int map_bits; + unsigned int map_size; + unsigned int max_elts; + atomic_t next_elt; + struct tracing_map_elt **elts; + struct tracing_map_entry *map; + struct tracing_map_ops *ops; + void *private_data; + struct tracing_map_field field_descr[TRACING_MAP_FIELDS_MAX]; + unsigned int n_fields; + unsigned int key_idx; + struct tracing_map_sort_key sort_key; +}; + +/** + * struct tracing_map_ops - callbacks for tracing_map + * + * The methods in this structure provide per-event trigger hooks for + * various trigger operations. + * + * All the methods below are optional. + * + * @elt_alloc: When a tracing_map_elt is allocated, this function, if + * defined, will be called and gives clients the opportunity to + * allocate additional data and attach it to the element + * (tracing_map_elt->private_data is meant for that purpose). + * Element allocation occurs before tracing begins, when the + * tracing_map_init() call is made by client code. + * + * @elt_copy: At certain points in the lifetime of an element, it may + * need to be copied. The copy should include a copy of the + * client-allocated data, which can be copied into the 'to' + * element from the 'from' element. + * + * @elt_free: When a tracing_map_element is freed, this function is + * called and allows client-allocated per-element data to be + * freed. + * + * @elt_clear: This callback allows per-element client-defined data to + * be cleared, if applicable. + * + * @elt_init: This callback allows per-element client-defined data to + * be initialized when used i.e. when the element is actually + * claimed by tracing_map_insert() in the context of the map + * insertion. + */ +struct tracing_map_ops { + int (*elt_alloc)(struct tracing_map_elt *elt); + void (*elt_copy)(struct tracing_map_elt *to, + struct tracing_map_elt *from); + void (*elt_free)(struct tracing_map_elt *elt); + void (*elt_clear)(struct tracing_map_elt *elt); + void (*elt_init)(struct tracing_map_elt *elt); +}; + +extern struct tracing_map *tracing_map_create(unsigned int map_bits, + unsigned int key_size, + struct tracing_map_ops *ops, + void *private_data); +extern int tracing_map_init(struct tracing_map *map); + +extern int tracing_map_add_sum_field(struct tracing_map *map); +extern int tracing_map_add_key_field(struct tracing_map *map, + tracing_map_cmp_fn_t cmp_fn); + +extern void tracing_map_destroy(struct tracing_map *map); +extern void tracing_map_clear(struct tracing_map *map); + +extern struct tracing_map_elt * +tracing_map_insert(struct tracing_map *map, void *key); + +extern tracing_map_cmp_fn_t tracing_map_cmp_num(int field_size, + int field_is_signed); +extern int tracing_map_cmp_string(void *val_a, void *val_b); +extern int tracing_map_cmp_none(void *val_a, void *val_b); + +extern void tracing_map_update_sum(struct tracing_map_elt *elt, + unsigned int i, u64 n); +extern u64 tracing_map_read_sum(struct tracing_map_elt *elt, unsigned int i); +extern void tracing_map_set_field_descr(struct tracing_map *map, + unsigned int i, + unsigned int key_offset, + tracing_map_cmp_fn_t cmp_fn); +extern int +tracing_map_sort_entries(struct tracing_map *map, + struct tracing_map_sort_key *sort_key, + struct tracing_map_sort_entry ***sort_entries); +extern void +tracing_map_destroy_sort_entries(struct tracing_map_sort_entry **entries, + unsigned int n_entries); +#endif /* __TRACING_MAP_H */ -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/