X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=libringbuffer%2Ffrontend_api.h;h=96f79554b3764bb3cb40d140e34b5ebcebcc725e;hb=7489fcb466935b3eeb36e99afbbb87188278cb91;hp=c112c846179aa4bc4f70d60a98cf3cad44a44925;hpb=10544ee8af31afb239e3dfa71cb2fe09d3de3771;p=lttng-ust.git diff --git a/libringbuffer/frontend_api.h b/libringbuffer/frontend_api.h index c112c846..96f79554 100644 --- a/libringbuffer/frontend_api.h +++ b/libringbuffer/frontend_api.h @@ -1,35 +1,16 @@ -#ifndef _LTTNG_RING_BUFFER_FRONTEND_API_H -#define _LTTNG_RING_BUFFER_FRONTEND_API_H - /* - * libringbuffer/frontend_api.h + * SPDX-License-Identifier: LGPL-2.1-only * * Copyright (C) 2005-2012 Mathieu Desnoyers * - * 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 - * - * Ring Buffer Library Synchronization Header (buffer write API). - * - * Author: - * Mathieu Desnoyers - * * See ring_buffer_frontend.c for more information on wait-free * algorithms. * See frontend.h for channel allocation and read-side API. */ +#ifndef _LTTNG_RING_BUFFER_FRONTEND_API_H +#define _LTTNG_RING_BUFFER_FRONTEND_API_H + #include #include @@ -37,12 +18,11 @@ #include "frontend.h" /** - * lib_ring_buffer_get_cpu - Precedes ring buffer reserve/commit. + * lib_ring_buffer_nesting_inc - Ring buffer recursive use protection. * - * Keeps a ring buffer nesting count as supplementary safety net to - * ensure tracer client code will never trigger an endless recursion. - * Returns the processor ID on success, -EPERM on failure (nesting count - * too high). + * The rint buffer buffer nesting count is a safety net to ensure tracer + * client code will never trigger an endless recursion. + * Returns 0 on success, -EPERM on failure (nesting count too high). * * asm volatile and "memory" clobber prevent the compiler from moving * instructions out of the ring buffer nesting count. This is required to ensure @@ -51,27 +31,22 @@ * section. */ static inline -int lib_ring_buffer_get_cpu(const struct lttng_ust_lib_ring_buffer_config *config) +int lib_ring_buffer_nesting_inc(const struct lttng_ust_lib_ring_buffer_config *config) { - int cpu, nesting; + int nesting; - cpu = lttng_ust_get_cpu(); nesting = ++URCU_TLS(lib_ring_buffer_nesting); cmm_barrier(); - if (caa_unlikely(nesting > 4)) { WARN_ON_ONCE(1); URCU_TLS(lib_ring_buffer_nesting)--; return -EPERM; - } else - return cpu; + } + return 0; } -/** - * lib_ring_buffer_put_cpu - Follows ring buffer reserve/commit. - */ static inline -void lib_ring_buffer_put_cpu(const struct lttng_ust_lib_ring_buffer_config *config) +void lib_ring_buffer_nesting_dec(const struct lttng_ust_lib_ring_buffer_config *config) { cmm_barrier(); URCU_TLS(lib_ring_buffer_nesting)--; /* TLS */ @@ -90,7 +65,7 @@ int lib_ring_buffer_try_reserve(const struct lttng_ust_lib_ring_buffer_config *c unsigned long *o_begin, unsigned long *o_end, unsigned long *o_old, size_t *before_hdr_pad) { - struct channel *chan = ctx->chan; + struct lttng_ust_lib_ring_buffer_channel *chan = ctx->chan; struct lttng_ust_lib_ring_buffer *buf = ctx->buf; *o_begin = v_read(config, &buf->offset); *o_old = *o_begin; @@ -158,7 +133,7 @@ int lib_ring_buffer_reserve(const struct lttng_ust_lib_ring_buffer_config *confi struct lttng_ust_lib_ring_buffer_ctx *ctx, void *client_ctx) { - struct channel *chan = ctx->chan; + struct lttng_ust_lib_ring_buffer_channel *chan = ctx->chan; struct lttng_ust_shm_handle *handle = ctx->handle; struct lttng_ust_lib_ring_buffer *buf; unsigned long o_begin, o_end, o_old; @@ -167,10 +142,12 @@ int lib_ring_buffer_reserve(const struct lttng_ust_lib_ring_buffer_config *confi if (caa_unlikely(uatomic_read(&chan->record_disabled))) return -EAGAIN; - if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) - buf = shmp(handle, chan->backend.buf[ctx->cpu].shmp); - else + if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { + ctx->reserve_cpu = lttng_ust_get_cpu(); + buf = shmp(handle, chan->backend.buf[ctx->reserve_cpu].shmp); + } else { buf = shmp(handle, chan->backend.buf[0].shmp); + } if (caa_unlikely(!buf)) return -EIO; if (caa_unlikely(uatomic_read(&buf->record_disabled))) @@ -250,7 +227,7 @@ static inline void lib_ring_buffer_commit(const struct lttng_ust_lib_ring_buffer_config *config, const struct lttng_ust_lib_ring_buffer_ctx *ctx) { - struct channel *chan = ctx->chan; + struct lttng_ust_lib_ring_buffer_channel *chan = ctx->chan; struct lttng_ust_shm_handle *handle = ctx->handle; struct lttng_ust_lib_ring_buffer *buf = ctx->buf; unsigned long offset_end = ctx->buf_offset; @@ -345,14 +322,14 @@ int lib_ring_buffer_try_discard_reserve(const struct lttng_ust_lib_ring_buffer_c static inline void channel_record_disable(const struct lttng_ust_lib_ring_buffer_config *config, - struct channel *chan) + struct lttng_ust_lib_ring_buffer_channel *chan) { uatomic_inc(&chan->record_disabled); } static inline void channel_record_enable(const struct lttng_ust_lib_ring_buffer_config *config, - struct channel *chan) + struct lttng_ust_lib_ring_buffer_channel *chan) { uatomic_dec(&chan->record_disabled); }