| 1 | /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only) |
| 2 | * |
| 3 | * lttng/tp-mempool.h |
| 4 | * |
| 5 | * Copyright (C) 2018 Julien Desfossez <jdesfossez@efficios.com> |
| 6 | */ |
| 7 | |
| 8 | #ifndef LTTNG_TP_MEMPOOL_H |
| 9 | #define LTTNG_TP_MEMPOOL_H |
| 10 | |
| 11 | #include <linux/percpu.h> |
| 12 | |
| 13 | #define LTTNG_TP_MEMPOOL_NR_BUF_PER_CPU 4 |
| 14 | #define LTTNG_TP_MEMPOOL_BUF_SIZE 4096 |
| 15 | |
| 16 | /* |
| 17 | * Initialize the pool, only performed once. The pool is a set of |
| 18 | * LTTNG_TP_MEMPOOL_NR_BUF_PER_CPU buffers of size LTTNG_TP_MEMPOOL_BUF_SIZE |
| 19 | * per-cpu. |
| 20 | * |
| 21 | * Returns 0 on success, a negative value on error. |
| 22 | */ |
| 23 | int lttng_tp_mempool_init(void); |
| 24 | |
| 25 | /* |
| 26 | * Destroy the pool and free all the memory allocated. |
| 27 | */ |
| 28 | void lttng_tp_mempool_destroy(void); |
| 29 | |
| 30 | /* |
| 31 | * Ask for a buffer on the current cpu. |
| 32 | * |
| 33 | * The pool is per-cpu, but there is no exclusive access guarantee on the |
| 34 | * per-cpu free-list, the caller needs to ensure it cannot get preempted or |
| 35 | * interrupted while performing the allocation. |
| 36 | * |
| 37 | * The maximum size that can be allocated is LTTNG_TP_MEMPOOL_BUF_SIZE, and the |
| 38 | * maximum number of buffers allocated simultaneously on the same CPU is |
| 39 | * LTTNG_TP_MEMPOOL_NR_BUF_PER_CPU. |
| 40 | * |
| 41 | * Return a pointer to a buffer on success, NULL on error. |
| 42 | */ |
| 43 | void *lttng_tp_mempool_alloc(size_t size); |
| 44 | |
| 45 | /* |
| 46 | * Release the memory reserved. Same concurrency limitations as the allocation. |
| 47 | */ |
| 48 | void lttng_tp_mempool_free(void *ptr); |
| 49 | |
| 50 | #endif /* LTTNG_TP_MEMPOOL_H */ |