Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752173AbbGQBfb (ORCPT ); Thu, 16 Jul 2015 21:35:31 -0400 Received: from mga03.intel.com ([134.134.136.65]:41843 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751383AbbGQBf3 (ORCPT ); Thu, 16 Jul 2015 21:35:29 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,492,1432623600"; d="scan'208";a="764216319" Message-ID: <1437096922.12633.68.camel@tzanussi-mobl.amr.corp.intel.com> Subject: Re: [PATCH v9 07/22] tracing: Add lock-free tracing_map From: Tom Zanussi To: Mathieu Desnoyers Cc: rostedt@goodmis.org, daniel.wagner@bmw-carit.de, masami.hiramatsu.pt@hitachi.com, namhyung@kernel.org, josh@joshtriplett.org, andi@firstfloor.org, linux-kernel@vger.kernel.org, Julien Desfossez Date: Thu, 16 Jul 2015 20:35:22 -0500 In-Reply-To: <1389551739.627.1437089154468.JavaMail.zimbra@efficios.com> References: <1389551739.627.1437089154468.JavaMail.zimbra@efficios.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4 (3.10.4-4.fc20) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 46406 Lines: 1292 Hi Mathieu, On Thu, 2015-07-16 at 23:25 +0000, Mathieu Desnoyers wrote: > * Tom Zanussi wrote: > >> 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 > > Hi Tom, > > First question: what is the rationale for implementing another > hash table from scratch here ? What is missing in the pre-existing > hash table implementations ? > None of the other hash tables allow for lock-free insertion (and I didn't see an easy way to add it). > Moreover, you might want to handle the case where jhash() returns > 0. AFAIU, there is a race on "insert" in this scenario. > You're right, in that case you'd accidentally overwrite an already claimed slot. Thanks for pointing that out. Tom > Thanks, > > Mathieu > > >> > >> Signed-off-by: Tom Zanussi > >> --- > >> kernel/trace/Makefile | 1 + > >> kernel/trace/tracing_map.c | 935 +++++++++++++++++++++++++++++++++++++++++++++ > >> kernel/trace/tracing_map.h | 258 +++++++++++++ > >> 3 files changed, 1194 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..a505025 > >> --- /dev/null > >> +++ b/kernel/trace/tracing_map.c > >> @@ -0,0 +1,935 @@ > >> +/* > >> + * 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" > >> + > >> +/* > >> + * NOTE: For a detailed description of the data structures used by > >> + * these functions (such as tracing_map_elt) please see the overview > >> + * of tracing_map data structures at the beginning of tracing_map.h. > >> + */ > >> + > >> +/** > >> + * tracing_map_update_sum - Add a value to a tracing_map_elt's sum field > >> + * @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 field > >> + * @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->fields[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 a tracing_map key > >> + * @map: The tracing_map > >> + * @offset: The offset within the key > >> + * @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. > >> + * > >> + * A key can be a subset of a compound key; for that purpose, the > >> + * offset param is used to describe where within the the compound key > >> + * the key referenced by this key field resides. > >> + * > >> + * Return: The index identifying the field in the map and associated > >> + * tracing_map_elts. > >> + */ > >> +int tracing_map_add_key_field(struct tracing_map *map, > >> + unsigned int offset, > >> + tracing_map_cmp_fn_t cmp_fn) > >> + > >> +{ > >> + int idx = tracing_map_add_field(map, cmp_fn); > >> + > >> + if (idx < 0) > >> + return idx; > >> + > >> + map->fields[idx].offset = offset; > >> + > >> + map->key_idx[map->n_keys++] = 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++) > >> + if (elt->fields[i].cmp_fn == tracing_map_cmp_atomic64) > >> + 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->fields[i].cmp_fn; > >> + > >> + if (elt->fields[i].cmp_fn != tracing_map_cmp_atomic64) > >> + elt->fields[i].offset = elt->map->fields[i].offset; > >> + } > >> +} > >> + > >> +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 retrieve val from a tracing_map > >> + * @map: The tracing_map to insert into > >> + * @key: The key to insert > >> + * > >> + * Inserts a key into a tracing_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 (internally maintained as > >> + * 'max_elts' in struct tracing_map), and that number of > >> + * tracing_map_elts was created by tracing_map_init(). This is the > >> + * pre-allocated pool of tracing_map_elts 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 be a power of two. To prevent any > >> + * possibility of an infinite loop we always make the internal table > >> + * size double the size of the requested table size (max_elts * 2). > >> + * Likewise, we never reuse a slot or resize or delete elements - when > >> + * we've reached max_elts 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 pointer val associated with the key. > >> + * If this was a newly inserted key, the val will be a newly allocated > >> + * and associated tracing_map_elt pointer 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 struct > >> + * tracing_map_entry is 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 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 2 ** map_bits number of > >> + * elements (internally maintained as 'max_elts' in struct > >> + * tracing_map). Before using, 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 reflects the maximum > >> + * number of elements that can be contained in the table 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(). 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 current set > >> + * of inserted tracing_map_elts in a tracing_map, via > >> + * tracing_map_sort_entries(). Sorting can be done on any field, > >> + * including keys. > >> + * > >> + * See tracing_map.h for a description of tracing_map_ops. > >> + * > >> + * Return: the tracing_map pointer 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; > >> + unsigned int i; > >> + > >> + 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; > >> + for (i = 0; i < TRACING_MAP_KEYS_MAX; i++) > >> + map->key_idx[i] = -1; > >> + 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 > >> + * > >> + * Allocates a clears a pool of tracing_map_elts equal to the > >> + * user-specified size of 2 ** map_bits (internally maintained as > >> + * 'max_elts' in struct tracing_map). 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 reflects the max number of elements 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 pointer 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->field_idx]; > >> + cmp_fn = field->cmp_fn; > >> + > >> + val_a = &elt_a->fields[sort_key->field_idx].sum; > >> + val_b = &elt_b->fields[sort_key->field_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->field_idx]; > >> + > >> + cmp_fn = field->cmp_fn; > >> + > >> + val_a = elt_a->key + field->offset; > >> + val_b = elt_b->key + field->offset; > >> + > >> + 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; > >> +} > >> + > >> +static bool is_key(struct tracing_map *map, unsigned int field_idx) > >> +{ > >> + unsigned int i; > >> + > >> + for (i = 0; i < map->n_keys; i++) > >> + if (map->key_idx[i] == field_idx) > >> + return true; > >> + return false; > >> +} > >> + > >> +static void sort_secondary(struct tracing_map *map, > >> + const struct tracing_map_sort_entry **entries, > >> + unsigned int n_entries, > >> + struct tracing_map_sort_key *primary_key, > >> + struct tracing_map_sort_key *secondary_key) > >> +{ > >> + int (*primary_fn)(const struct tracing_map_sort_entry **, > >> + const struct tracing_map_sort_entry **); > >> + int (*secondary_fn)(const struct tracing_map_sort_entry **, > >> + const struct tracing_map_sort_entry **); > >> + unsigned i, start = 0, n_sub = 1; > >> + > >> + if (is_key(map, primary_key->field_idx)) > >> + primary_fn = cmp_entries_key; > >> + else > >> + primary_fn = cmp_entries_sum; > >> + > >> + if (is_key(map, secondary_key->field_idx)) > >> + secondary_fn = cmp_entries_key; > >> + else > >> + secondary_fn = cmp_entries_sum; > >> + > >> + for (i = 0; i < n_entries - 1; i++) { > >> + const struct tracing_map_sort_entry **a = &entries[i]; > >> + const struct tracing_map_sort_entry **b = &entries[i + 1]; > >> + > >> + if (primary_fn(a, b) == 0) { > >> + n_sub++; > >> + if (i < n_entries - 2) > >> + continue; > >> + } > >> + > >> + if (n_sub < 2) { > >> + start = i + 1; > >> + n_sub = 1; > >> + continue; > >> + } > >> + > >> + set_sort_key(map, secondary_key); > >> + sort(&entries[start], n_sub, > >> + sizeof(struct tracing_map_sort_entry *), > >> + (int (*)(const void *, const void *))secondary_fn, NULL); > >> + set_sort_key(map, primary_key); > >> + > >> + start = i + 1; > >> + n_sub = 1; > >> + } > >> +} > >> + > >> +/** > >> + * tracing_map_sort_entries - Sort the current set of tracing_map_elts 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 client can > >> + * access the struct tracing_map_elt element of interest directly as > >> + * the 'elt' field of a returned struct tracing_map_sort_entry object. > >> + * > >> + * 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 should use > >> + * it and call tracing_map_destroy_sort_entries() when done. > >> + * > >> + * Return: the number of sort_entries in the struct tracing_map_sort_entry > >> + * array, negative on error > >> + */ > >> +int tracing_map_sort_entries(struct tracing_map *map, > >> + struct tracing_map_sort_key *sort_keys, > >> + unsigned int n_sort_keys, > >> + 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, n_entries, ret; > >> + > >> + entries = kcalloc(map->max_elts, sizeof(sort_entry), GFP_KERNEL); > >> + if (!entries) > >> + return -ENOMEM; > >> + > >> + for (i = 0, n_entries = 0; i < map->map_size; i++) { > >> + if (!map->map[i].key || !map->map[i].val) > >> + continue; > >> + > >> + entries[n_entries] = create_sort_entry(map->map[i].val->key, > >> + map->map[i].val); > >> + if (!entries[n_entries++]) { > >> + ret = -ENOMEM; > >> + goto free; > >> + } > >> + } > >> + > >> + if (n_entries == 0) { > >> + ret = 0; > >> + goto free; > >> + } > >> + > >> + if (n_entries == 1) { > >> + *sort_entries = entries; > >> + return 1; > >> + } > >> + > >> + ret = merge_dups(entries, n_entries, map->key_size); > >> + if (ret < 0) > >> + goto free; > >> + n_entries -= ret; > >> + > >> + if (is_key(map, sort_keys[0].field_idx)) > >> + cmp_entries_fn = cmp_entries_key; > >> + else > >> + cmp_entries_fn = cmp_entries_sum; > >> + > >> + set_sort_key(map, &sort_keys[0]); > >> + > >> + sort(entries, n_entries, sizeof(struct tracing_map_sort_entry *), > >> + (int (*)(const void *, const void *))cmp_entries_fn, NULL); > >> + > >> + if (n_sort_keys > 1) > >> + sort_secondary(map, > >> + (const struct tracing_map_sort_entry **)entries, > >> + n_entries, > >> + &sort_keys[0], > >> + &sort_keys[1]); > >> + > >> + *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..2e63c5c > >> --- /dev/null > >> +++ b/kernel/trace/tracing_map.h > >> @@ -0,0 +1,258 @@ > >> +#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 > >> +#define TRACING_MAP_KEYS_MAX 2 > >> + > >> +#define TRACING_MAP_SORT_KEYS_MAX 2 > >> + > >> +typedef int (*tracing_map_cmp_fn_t) (void *val_a, void *val_b); > >> + > >> +/* > >> + * This is an overview of the tracing_map data structures and how they > >> + * relate to the tracing_map API. The details of the algorithms > >> + * aren't discussed here - this is just a general overview of the data > >> + * structures and how they interact with the API. > >> + * > >> + * The central data structure of the tracing_map is an initially > >> + * zeroed array of struct tracing_map_entry (stored in the map field > >> + * of struct tracing_map). tracing_map_entry is a very simple data > >> + * structure containing only two fields: a 32-bit unsigned 'key' > >> + * variable and a pointer named 'val'. This array of struct > >> + * tracing_map_entry is essentially a hash table which will be > >> + * modified by a single function, tracing_map_insert(), but which can > >> + * be traversed and read by a user at any time (though the user does > >> + * this indirectly via an array of tracing_map_sort_entry - see the > >> + * explanation of that data structure in the discussion of the > >> + * sorting-related data structures below). > >> + * > >> + * The central function of the tracing_map API is > >> + * tracing_map_insert(). tracing_map_insert() hashes the > >> + * arbitrarily-sized key passed into it into a 32-bit unsigned key. > >> + * It then uses this key, truncated to the array size, as an index > >> + * into the array of tracing_map_entries. If the value of the 'key' > >> + * field of the tracing_map_entry found at that location is 0, then > >> + * that entry is considered to be free and can be claimed, by > >> + * replacing the 0 in the 'key' field of the tracing_map_entry with > >> + * the new 32-bit hashed key. Once claimed, that tracing_map_entry's > >> + * 'val' field is then used to store a unique element which will be > >> + * forever associated with that 32-bit hashed key in the > >> + * tracing_map_entry. > >> + * > >> + * That unique element now in the tracing_map_entry's 'val' field is > >> + * an instance of tracing_map_elt, where 'elt' in the latter part of > >> + * that variable name is short for 'element'. The purpose of a > >> + * tracing_map_elt is to hold values specific to the the particular > >> + * 32-bit hashed key it's assocated with. Things such as the unique > >> + * set of aggregated sums associated with the 32-bit hashed key, along > >> + * with a copy of the full key associated with the entry, and which > >> + * was used to produce the 32-bit hashed key. > >> + * > >> + * When tracing_map_create() is called to create the tracing map, the > >> + * user specifies (indirectly via the map_bits param, the details are > >> + * unimportant for this discussion) the maximum number of elements > >> + * that the map can hold (stored in the max_elts field of struct > >> + * tracing_map). This is the maximum possible number of > >> + * tracing_map_entries in the tracing_map_entry array which can be > >> + * 'claimed' as described in the above discussion, and therefore is > >> + * also the maximum number of tracing_map_elts that can be associated > >> + * with the tracing_map_entry array in the tracing_map. Because of > >> + * the way the insertion algorithm works, the size of the allocated > >> + * tracing_map_entry array is always twice the maximum number of > >> + * elements (2 * max_elts). This value is stored in the map_size > >> + * field of struct tracing_map. > >> + * > >> + * Because tracing_map_insert() needs to work from any context, > >> + * including from within the memory allocation functions themselves, > >> + * both the tracing_map_entry array and a pool of max_elts > >> + * tracing_map_elts are pre-allocated before any call is made to > >> + * tracing_map_insert(). > >> + * > >> + * The tracing_map_entry array is allocated as a single block by > >> + * tracing_map_create(). > >> + * > >> + * Because the tracing_map_elts are much larger objects and can't > >> + * generally be allocated together as a single large array without > >> + * failure, they're allocated individually, by tracing_map_init(). > >> + * > >> + * The pool of tracing_map_elts are allocated by tracing_map_init() > >> + * rather than by tracing_map_create() because at the time > >> + * tracing_map_create() is called, there isn't enough information to > >> + * create the tracing_map_elts. Specifically,the user first needs to > >> + * tell the tracing_map implementation how many fields the > >> + * tracing_map_elts contain, and which types of fields they are (key > >> + * or sum). The user does this via the tracing_map_add_sum_field() > >> + * and tracing_map_add_key_field() functions, following which the user > >> + * calls tracing_map_init() to finish up the tracing map setup. The > >> + * array holding the pointers which make up the pre-allocated pool of > >> + * tracing_map_elts is allocated as a single block and is stored in > >> + * the elts field of struct tracing_map. > >> + * > >> + * There is also a set of structures used for sorting that might > >> + * benefit from some minimal explanation. > >> + * > >> + * struct tracing_map_sort_key is used to drive the sort at any given > >> + * time. By 'any given time' we mean that a different > >> + * tracing_map_sort_key will be used at different times depending on > >> + * whether the sort currently being performed is a primary or a > >> + * secondary sort. > >> + * > >> + * The sort key is very simple, consisting of the field index of the > >> + * tracing_map_elt field to sort on (which the user saved when adding > >> + * the field), and whether the sort should be done in an ascending or > >> + * descending order. > >> + * > >> + * For the convenience of the sorting code, a tracing_map_sort_entry > >> + * is created for each tracing_map_elt, again individually allocated > >> + * to avoid failures that might be expected if allocated as a single > >> + * large array of struct tracing_map_sort_entry. > >> + * tracing_map_sort_entry instances are the objects expected by the > >> + * various internal sorting functions, and are also what the user > >> + * ultimately receives after calling tracing_map_sort_entries(). > >> + * Because it doesn't make sense for users to access an unordered and > >> + * sparsely populated tracing_map directly, the > >> + * tracing_map_sort_entries() function is provided so that users can > >> + * retrieve a sorted list of all existing elements. In addition to > >> + * the associated tracing_map_elt 'elt' field contained within the > >> + * tracing_map_sort_entry, which is the object of interest to the > >> + * user, tracing_map_sort_entry objects contain a number of additional > >> + * fields which are used for caching and internal purposes and can > >> + * safely be ignored. > >> +*/ > >> + > >> +struct tracing_map_field { > >> + tracing_map_cmp_fn_t cmp_fn; > >> + union { > >> + atomic64_t sum; > >> + unsigned int offset; > >> + }; > >> +}; > >> + > >> +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 field_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 fields[TRACING_MAP_FIELDS_MAX]; > >> + unsigned int n_fields; > >> + int key_idx[TRACING_MAP_KEYS_MAX]; > >> + unsigned int n_keys; > >> + struct tracing_map_sort_key sort_key; > >> +}; > >> + > >> +/** > >> + * struct tracing_map_ops - callbacks for tracing_map > >> + * > >> + * The methods in this structure define callback functions for various > >> + * operations on a tracing_map or objects related to a tracing_map. > >> + * > >> + * For a detailed description of tracing_map_elt objects please see > >> + * the overview of tracing_map data structures at the beginning of > >> + * this file. > >> + * > >> + * 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_elt 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, > >> + unsigned int offset, > >> + 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_keys, > >> + unsigned int n_sort_keys, > >> + 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/ > > > > -- > > Mathieu Desnoyers > > EfficiOS Inc. > > http://www.efficios.com > -- 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/