+++ /dev/null
-/*
- * lttng-tp-mempool.c
- *
- * Copyright (C) 2018 Julien Desfossez <jdesfossez@efficios.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; only
- * version 2.1 of the License.
- *
- * This library 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
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-#include <linux/slab.h>
-#include <linux/percpu.h>
-
-#include <lttng-tp-mempool.h>
-
-struct lttng_tp_buf_entry {
- int cpu; /* To make sure we return the entry to the right pool. */
- char buf[LTTNG_TP_MEMPOOL_BUF_SIZE];
- struct list_head list;
-};
-
-/*
- * No exclusive access strategy for now, this memory pool is currently only
- * used from a non-preemptible context, and the interrupt tracepoint probes do
- * not use this facility.
- */
-struct per_cpu_buf {
- struct list_head free_list; /* Free struct lttng_tp_buf_entry. */
-};
-
-static struct per_cpu_buf __percpu *pool; /* Per-cpu buffer. */
-
-int lttng_tp_mempool_init(void)
-{
- int ret, cpu;
-
- /* The pool is only supposed to be allocated once. */
- if (pool) {
- WARN_ON_ONCE(1);
- ret = -1;
- goto end;
- }
-
- pool = alloc_percpu(struct per_cpu_buf);
- if (!pool) {
- ret = -ENOMEM;
- goto end;
- }
-
- for_each_possible_cpu(cpu) {
- struct per_cpu_buf *cpu_buf = per_cpu_ptr(pool, cpu);
-
- INIT_LIST_HEAD(&cpu_buf->free_list);
- }
-
- for_each_possible_cpu(cpu) {
- int i;
- struct per_cpu_buf *cpu_buf = per_cpu_ptr(pool, cpu);
-
- for (i = 0; i < LTTNG_TP_MEMPOOL_NR_BUF_PER_CPU; i++) {
- struct lttng_tp_buf_entry *entry;
-
- entry = kzalloc_node(sizeof(struct lttng_tp_buf_entry),
- GFP_KERNEL, cpu_to_node(cpu));
- if (!entry) {
- ret = -ENOMEM;
- goto error_free_pool;
- }
- entry->cpu = cpu;
- list_add_tail(&entry->list, &cpu_buf->free_list);
- }
- }
-
- ret = 0;
- goto end;
-
-error_free_pool:
- lttng_tp_mempool_destroy();
-end:
- return ret;
-}
-
-void lttng_tp_mempool_destroy(void)
-{
- int cpu;
-
- if (!pool) {
- return;
- }
-
- for_each_possible_cpu(cpu) {
- struct per_cpu_buf *cpu_buf = per_cpu_ptr(pool, cpu);
- struct lttng_tp_buf_entry *entry, *tmp;
- int i = 0;
-
- list_for_each_entry_safe(entry, tmp, &cpu_buf->free_list, list) {
- list_del(&entry->list);
- kfree(entry);
- i++;
- }
- if (i < LTTNG_TP_MEMPOOL_NR_BUF_PER_CPU) {
- printk(KERN_WARNING "Leak detected in tp-mempool\n");
- }
- }
- free_percpu(pool);
- pool = NULL;
-}
-
-void *lttng_tp_mempool_alloc(size_t size)
-{
- void *ret;
- struct lttng_tp_buf_entry *entry;
- struct per_cpu_buf *cpu_buf;
- int cpu = smp_processor_id();
-
- if (size > LTTNG_TP_MEMPOOL_BUF_SIZE) {
- ret = NULL;
- goto end;
- }
-
- cpu_buf = per_cpu_ptr(pool, cpu);
- if (list_empty(&cpu_buf->free_list)) {
- ret = NULL;
- goto end;
- }
-
- entry = list_first_entry(&cpu_buf->free_list, struct lttng_tp_buf_entry, list);
- /* Remove the entry from the free list. */
- list_del(&entry->list);
-
- memset(entry->buf, 0, LTTNG_TP_MEMPOOL_BUF_SIZE);
-
- ret = (void *) entry->buf;
-
-end:
- return ret;
-}
-
-void lttng_tp_mempool_free(void *ptr)
-{
- struct lttng_tp_buf_entry *entry;
- struct per_cpu_buf *cpu_buf;
-
- if (!ptr) {
- goto end;
- }
-
- entry = container_of(ptr, struct lttng_tp_buf_entry, buf);
- if (!entry) {
- goto end;
- }
-
- cpu_buf = per_cpu_ptr(pool, entry->cpu);
- if (!cpu_buf) {
- goto end;
- }
- /* Add it to the free list. */
- list_add_tail(&entry->list, &cpu_buf->free_list);
-
-end:
- return;
-}