Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753783AbbGQPsO (ORCPT ); Fri, 17 Jul 2015 11:48:14 -0400 Received: from mail.efficios.com ([78.47.125.74]:46338 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753412AbbGQPsL (ORCPT ); Fri, 17 Jul 2015 11:48:11 -0400 Date: Fri, 17 Jul 2015 15:48:01 +0000 (UTC) From: Mathieu Desnoyers To: Tom Zanussi Cc: rostedt , daniel wagner , masami hiramatsu pt , namhyung@kernel.org, josh@joshtriplett.org, Andi Kleen , linux-kernel@vger.kernel.org, Julien Desfossez , Lai Jiangshan Message-ID: <1334642765.993.1437148081235.JavaMail.zimbra@efficios.com> In-Reply-To: <1437096922.12633.68.camel@tzanussi-mobl.amr.corp.intel.com> References: <1389551739.627.1437089154468.JavaMail.zimbra@efficios.com> <1437096922.12633.68.camel@tzanussi-mobl.amr.corp.intel.com> Subject: Re: [PATCH v9 07/22] tracing: Add lock-free tracing_map MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [78.47.125.74] X-Mailer: Zimbra 8.6.0_GA_1153 (ZimbraWebClient - FF39 (Linux)/8.6.0_GA_1153) Thread-Topic: tracing: Add lock-free tracing_map Thread-Index: h/uVSQNWocfNGuB/qmf8LBXLJbAg6Q== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 48540 Lines: 1315 ----- On Jul 16, 2015, at 9:35 PM, Tom Zanussi tom.zanussi@linux.intel.com wrote: > 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). This is one of the nice things about the Userspace RCU lock-free hash table we've done a few years ago: it provides lock-free add, add_unique, removal, and replace, as well as RCU wait-free lookups and traversals. Resize can be done concurrently by a worker thread. I ported it to the Linux kernel for Julien's work on latency tracker. You can find the implementation here: https://github.com/jdesfossez/latency_tracker (see rculfhash*) It is a simplified version that has the "resize" feature removed for simplicity sake. The "insert and lookup" feature you need is called "add_unique" in our API: it behaves both as a lookup and as an atomic insert if the key is not found. Thanks, Mathieu > >> 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 -- 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/