| 1 | #ifndef LTTNG_TP_MEMPOOL_H |
| 2 | #define LTTNG_TP_MEMPOOL_H |
| 3 | |
| 4 | /* |
| 5 | * lttng-tp-mempool.h |
| 6 | * |
| 7 | * Copyright (C) 2018 Julien Desfossez <jdesfossez@efficios.com> |
| 8 | * |
| 9 | * This library is free software; you can redistribute it and/or |
| 10 | * modify it under the terms of the GNU Lesser General Public |
| 11 | * License as published by the Free Software Foundation; only |
| 12 | * version 2.1 of the License. |
| 13 | * |
| 14 | * This library is distributed in the hope that it will be useful, |
| 15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 17 | * Lesser General Public License for more details. |
| 18 | * |
| 19 | * You should have received a copy of the GNU Lesser General Public |
| 20 | * License along with this library; if not, write to the Free Software |
| 21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 22 | */ |
| 23 | |
| 24 | #include <linux/percpu.h> |
| 25 | |
| 26 | #define LTTNG_TP_MEMPOOL_NR_BUF_PER_CPU 4 |
| 27 | #define LTTNG_TP_MEMPOOL_BUF_SIZE 4096 |
| 28 | |
| 29 | /* |
| 30 | * Initialize the pool, only performed once. The pool is a set of |
| 31 | * LTTNG_TP_MEMPOOL_NR_BUF_PER_CPU buffers of size LTTNG_TP_MEMPOOL_BUF_SIZE |
| 32 | * per-cpu. |
| 33 | * |
| 34 | * Returns 0 on success, a negative value on error. |
| 35 | */ |
| 36 | int lttng_tp_mempool_init(void); |
| 37 | |
| 38 | /* |
| 39 | * Destroy the pool and free all the memory allocated. |
| 40 | */ |
| 41 | void lttng_tp_mempool_destroy(void); |
| 42 | |
| 43 | /* |
| 44 | * Ask for a buffer on the current cpu. |
| 45 | * |
| 46 | * The pool is per-cpu, but there is no exclusive access guarantee on the |
| 47 | * per-cpu free-list, the caller needs to ensure it cannot get preempted or |
| 48 | * interrupted while performing the allocation. |
| 49 | * |
| 50 | * The maximum size that can be allocated is LTTNG_TP_MEMPOOL_BUF_SIZE, and the |
| 51 | * maximum number of buffers allocated simultaneously on the same CPU is |
| 52 | * LTTNG_TP_MEMPOOL_NR_BUF_PER_CPU. |
| 53 | * |
| 54 | * Return a pointer to a buffer on success, NULL on error. |
| 55 | */ |
| 56 | void *lttng_tp_mempool_alloc(size_t size); |
| 57 | |
| 58 | /* |
| 59 | * Release the memory reserved. Same concurrency limitations as the allocation. |
| 60 | */ |
| 61 | void lttng_tp_mempool_free(void *ptr); |
| 62 | |
| 63 | #endif /* LTTNG_TP_MEMPOOL_H */ |