X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=libringbuffer%2Fbackend_internal.h;h=e597cf4dd42be43d344b29dc31c89b8b90fea83c;hb=1e1782558131e5669466639d7f28e2f08b0d026d;hp=ba0497f9f089f3cb6714f2e59603524eab5c725b;hpb=4746ae29409b78e96543a3b207c91a3c510c6476;p=lttng-ust.git diff --git a/libringbuffer/backend_internal.h b/libringbuffer/backend_internal.h index ba0497f9..e597cf4d 100644 --- a/libringbuffer/backend_internal.h +++ b/libringbuffer/backend_internal.h @@ -1,20 +1,32 @@ -#ifndef _LINUX_RING_BUFFER_BACKEND_INTERNAL_H -#define _LINUX_RING_BUFFER_BACKEND_INTERNAL_H +#ifndef _LTTNG_RING_BUFFER_BACKEND_INTERNAL_H +#define _LTTNG_RING_BUFFER_BACKEND_INTERNAL_H /* - * linux/ringbuffer/backend_internal.h - * - * Copyright (C) 2008-2010 - Mathieu Desnoyers + * libringbuffer/backend_internal.h * * Ring buffer backend (internal helpers). * - * Dual LGPL v2.1/GPL v2 license. + * 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 */ #include #include -#include +#include #include "backend_types.h" #include "frontend_types.h" #include "shm.h" @@ -23,28 +35,29 @@ /* Ring buffer and channel backend create/free */ -int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend *bufb, +int lib_ring_buffer_backend_create(struct lttng_ust_lib_ring_buffer_backend *bufb, struct channel_backend *chan, int cpu, - struct shm_handle *handle, + struct lttng_ust_shm_handle *handle, struct shm_object *shmobj); void channel_backend_unregister_notifiers(struct channel_backend *chanb); -void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend *bufb); +void lib_ring_buffer_backend_free(struct lttng_ust_lib_ring_buffer_backend *bufb); int channel_backend_init(struct channel_backend *chanb, const char *name, - const struct lib_ring_buffer_config *config, - void *priv, size_t subbuf_size, - size_t num_subbuf, struct shm_handle *handle); + const struct lttng_ust_lib_ring_buffer_config *config, + size_t subbuf_size, + size_t num_subbuf, struct lttng_ust_shm_handle *handle, + const int *stream_fds); void channel_backend_free(struct channel_backend *chanb, - struct shm_handle *handle); + struct lttng_ust_shm_handle *handle); -void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend *bufb, - struct shm_handle *handle); +void lib_ring_buffer_backend_reset(struct lttng_ust_lib_ring_buffer_backend *bufb, + struct lttng_ust_shm_handle *handle); void channel_backend_reset(struct channel_backend *chanb); int lib_ring_buffer_backend_init(void); void lib_ring_buffer_backend_exit(void); -extern void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb, +extern void _lib_ring_buffer_write(struct lttng_ust_lib_ring_buffer_backend *bufb, size_t offset, const void *src, size_t len, ssize_t pagecpy); @@ -86,7 +99,7 @@ extern void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb, * mode). */ static inline -unsigned long subbuffer_id(const struct lib_ring_buffer_config *config, +unsigned long subbuffer_id(const struct lttng_ust_lib_ring_buffer_config *config, unsigned long offset, unsigned long noref, unsigned long index) { @@ -103,14 +116,14 @@ unsigned long subbuffer_id(const struct lib_ring_buffer_config *config, * bits are identical, else 0. */ static inline -int subbuffer_id_compare_offset(const struct lib_ring_buffer_config *config, +int subbuffer_id_compare_offset(const struct lttng_ust_lib_ring_buffer_config *config, unsigned long id, unsigned long offset) { return (id & SB_ID_OFFSET_MASK) == (offset << SB_ID_OFFSET_SHIFT); } static inline -unsigned long subbuffer_id_get_index(const struct lib_ring_buffer_config *config, +unsigned long subbuffer_id_get_index(const struct lttng_ust_lib_ring_buffer_config *config, unsigned long id) { if (config->mode == RING_BUFFER_OVERWRITE) @@ -120,7 +133,7 @@ unsigned long subbuffer_id_get_index(const struct lib_ring_buffer_config *config } static inline -unsigned long subbuffer_id_is_noref(const struct lib_ring_buffer_config *config, +unsigned long subbuffer_id_is_noref(const struct lttng_ust_lib_ring_buffer_config *config, unsigned long id) { if (config->mode == RING_BUFFER_OVERWRITE) @@ -134,7 +147,7 @@ unsigned long subbuffer_id_is_noref(const struct lib_ring_buffer_config *config, * needed. */ static inline -void subbuffer_id_set_noref(const struct lib_ring_buffer_config *config, +void subbuffer_id_set_noref(const struct lttng_ust_lib_ring_buffer_config *config, unsigned long *id) { if (config->mode == RING_BUFFER_OVERWRITE) @@ -142,7 +155,7 @@ void subbuffer_id_set_noref(const struct lib_ring_buffer_config *config, } static inline -void subbuffer_id_set_noref_offset(const struct lib_ring_buffer_config *config, +void subbuffer_id_set_noref_offset(const struct lttng_ust_lib_ring_buffer_config *config, unsigned long *id, unsigned long offset) { unsigned long tmp; @@ -159,7 +172,7 @@ void subbuffer_id_set_noref_offset(const struct lib_ring_buffer_config *config, /* No volatile access, since already used locally */ static inline -void subbuffer_id_clear_noref(const struct lib_ring_buffer_config *config, +void subbuffer_id_clear_noref(const struct lttng_ust_lib_ring_buffer_config *config, unsigned long *id) { if (config->mode == RING_BUFFER_OVERWRITE) @@ -174,7 +187,7 @@ void subbuffer_id_clear_noref(const struct lib_ring_buffer_config *config, * -EPERM on failure. */ static inline -int subbuffer_id_check_index(const struct lib_ring_buffer_config *config, +int subbuffer_id_check_index(const struct lttng_ust_lib_ring_buffer_config *config, unsigned long num_subbuf) { if (config->mode == RING_BUFFER_OVERWRITE) @@ -184,116 +197,255 @@ int subbuffer_id_check_index(const struct lib_ring_buffer_config *config, } static inline -void subbuffer_count_record(const struct lib_ring_buffer_config *config, - struct lib_ring_buffer_backend *bufb, - unsigned long idx, struct shm_handle *handle) +int lib_ring_buffer_backend_get_pages(const struct lttng_ust_lib_ring_buffer_config *config, + struct lttng_ust_lib_ring_buffer_ctx *ctx, + struct lttng_ust_lib_ring_buffer_backend_pages **backend_pages) { - unsigned long sb_bindex; + struct lttng_ust_lib_ring_buffer_backend *bufb = &ctx->buf->backend; + struct channel_backend *chanb = &ctx->chan->backend; + struct lttng_ust_shm_handle *handle = ctx->handle; + size_t sbidx; + size_t offset = ctx->buf_offset; + struct lttng_ust_lib_ring_buffer_backend_subbuffer *wsb; + struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; + unsigned long sb_bindex, id; + struct lttng_ust_lib_ring_buffer_backend_pages *_backend_pages; + + offset &= chanb->buf_size - 1; + sbidx = offset >> chanb->subbuf_size_order; + wsb = shmp_index(handle, bufb->buf_wsb, sbidx); + if (caa_unlikely(!wsb)) + return -1; + id = wsb->id; + sb_bindex = subbuffer_id_get_index(config, id); + rpages = shmp_index(handle, bufb->array, sb_bindex); + if (caa_unlikely(!rpages)) + return -1; + CHAN_WARN_ON(ctx->chan, + config->mode == RING_BUFFER_OVERWRITE + && subbuffer_id_is_noref(config, id)); + _backend_pages = shmp(handle, rpages->shmp); + if (caa_unlikely(!_backend_pages)) + return -1; + *backend_pages = _backend_pages; + return 0; +} - sb_bindex = subbuffer_id_get_index(config, shmp_index(handle, bufb->buf_wsb, idx)->id); - v_inc(config, &shmp(handle, shmp_index(handle, bufb->array, sb_bindex)->shmp)->records_commit); +/* Get backend pages from cache. */ +static inline +struct lttng_ust_lib_ring_buffer_backend_pages * + lib_ring_buffer_get_backend_pages_from_ctx(const struct lttng_ust_lib_ring_buffer_config *config, + struct lttng_ust_lib_ring_buffer_ctx *ctx) +{ + if (caa_unlikely(ctx->ctx_len + < sizeof(struct lttng_ust_lib_ring_buffer_ctx))) + return NULL; + return ctx->backend_pages; +} + +/* + * The ring buffer can count events recorded and overwritten per buffer, + * but it is disabled by default due to its performance overhead. + */ +#ifdef LTTNG_RING_BUFFER_COUNT_EVENTS +static inline +void subbuffer_count_record(const struct lttng_ust_lib_ring_buffer_config *config, + const struct lttng_ust_lib_ring_buffer_ctx *ctx, + struct lttng_ust_lib_ring_buffer_backend *bufb, + unsigned long idx, struct lttng_ust_shm_handle *handle) +{ + struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; + + backend_pages = lib_ring_buffer_get_backend_pages_from_ctx(config, ctx); + if (caa_unlikely(!backend_pages)) { + if (lib_ring_buffer_backend_get_pages(config, ctx, &backend_pages)) + return; + } + v_inc(config, &backend_pages->records_commit); +} +#else /* LTTNG_RING_BUFFER_COUNT_EVENTS */ +static inline +void subbuffer_count_record(const struct lttng_ust_lib_ring_buffer_config *config, + const struct lttng_ust_lib_ring_buffer_ctx *ctx, + struct lttng_ust_lib_ring_buffer_backend *bufb, + unsigned long idx, struct lttng_ust_shm_handle *handle) +{ } +#endif /* #else LTTNG_RING_BUFFER_COUNT_EVENTS */ /* * Reader has exclusive subbuffer access for record consumption. No need to * perform the decrement atomically. */ static inline -void subbuffer_consume_record(const struct lib_ring_buffer_config *config, - struct lib_ring_buffer_backend *bufb, - struct shm_handle *handle) +void subbuffer_consume_record(const struct lttng_ust_lib_ring_buffer_config *config, + struct lttng_ust_lib_ring_buffer_backend *bufb, + struct lttng_ust_shm_handle *handle) { unsigned long sb_bindex; + struct channel *chan; + struct lttng_ust_lib_ring_buffer_backend_pages_shmp *pages_shmp; + struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; sb_bindex = subbuffer_id_get_index(config, bufb->buf_rsb.id); - CHAN_WARN_ON(shmp(handle, bufb->chan), - !v_read(config, &shmp(handle, shmp_index(handle, bufb->array, sb_bindex)->shmp)->records_unread)); + chan = shmp(handle, bufb->chan); + if (!chan) + return; + pages_shmp = shmp_index(handle, bufb->array, sb_bindex); + if (!pages_shmp) + return; + backend_pages = shmp(handle, pages_shmp->shmp); + if (!backend_pages) + return; + CHAN_WARN_ON(chan, !v_read(config, &backend_pages->records_unread)); /* Non-atomic decrement protected by exclusive subbuffer access */ - _v_dec(config, &shmp(handle, shmp_index(handle, bufb->array, sb_bindex)->shmp)->records_unread); + _v_dec(config, &backend_pages->records_unread); v_inc(config, &bufb->records_read); } static inline unsigned long subbuffer_get_records_count( - const struct lib_ring_buffer_config *config, - struct lib_ring_buffer_backend *bufb, + const struct lttng_ust_lib_ring_buffer_config *config, + struct lttng_ust_lib_ring_buffer_backend *bufb, unsigned long idx, - struct shm_handle *handle) + struct lttng_ust_shm_handle *handle) { unsigned long sb_bindex; + struct lttng_ust_lib_ring_buffer_backend_subbuffer *wsb; + struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; + struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; - sb_bindex = subbuffer_id_get_index(config, shmp_index(handle, bufb->buf_wsb, idx)->id); - return v_read(config, &shmp(handle, shmp_index(handle, bufb->array, sb_bindex)->shmp)->records_commit); + wsb = shmp_index(handle, bufb->buf_wsb, idx); + if (!wsb) + return 0; + sb_bindex = subbuffer_id_get_index(config, wsb->id); + rpages = shmp_index(handle, bufb->array, sb_bindex); + if (!rpages) + return 0; + backend_pages = shmp(handle, rpages->shmp); + if (!backend_pages) + return 0; + return v_read(config, &backend_pages->records_commit); } /* * Must be executed at subbuffer delivery when the writer has _exclusive_ - * subbuffer access. See ring_buffer_check_deliver() for details. - * ring_buffer_get_records_count() must be called to get the records count - * before this function, because it resets the records_commit count. + * subbuffer access. See lib_ring_buffer_check_deliver() for details. + * lib_ring_buffer_get_records_count() must be called to get the records + * count before this function, because it resets the records_commit + * count. */ static inline unsigned long subbuffer_count_records_overrun( - const struct lib_ring_buffer_config *config, - struct lib_ring_buffer_backend *bufb, + const struct lttng_ust_lib_ring_buffer_config *config, + struct lttng_ust_lib_ring_buffer_backend *bufb, unsigned long idx, - struct shm_handle *handle) + struct lttng_ust_shm_handle *handle) { - struct lib_ring_buffer_backend_pages_shmp *pages; unsigned long overruns, sb_bindex; + struct lttng_ust_lib_ring_buffer_backend_subbuffer *wsb; + struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; + struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; - sb_bindex = subbuffer_id_get_index(config, shmp_index(handle, bufb->buf_wsb, idx)->id); - pages = shmp_index(handle, bufb->array, sb_bindex); - overruns = v_read(config, &shmp(handle, pages->shmp)->records_unread); - v_set(config, &shmp(handle, pages->shmp)->records_unread, - v_read(config, &shmp(handle, pages->shmp)->records_commit)); - v_set(config, &shmp(handle, pages->shmp)->records_commit, 0); + wsb = shmp_index(handle, bufb->buf_wsb, idx); + if (!wsb) + return 0; + sb_bindex = subbuffer_id_get_index(config, wsb->id); + rpages = shmp_index(handle, bufb->array, sb_bindex); + if (!rpages) + return 0; + backend_pages = shmp(handle, rpages->shmp); + if (!backend_pages) + return 0; + overruns = v_read(config, &backend_pages->records_unread); + v_set(config, &backend_pages->records_unread, + v_read(config, &backend_pages->records_commit)); + v_set(config, &backend_pages->records_commit, 0); return overruns; } static inline -void subbuffer_set_data_size(const struct lib_ring_buffer_config *config, - struct lib_ring_buffer_backend *bufb, +void subbuffer_set_data_size(const struct lttng_ust_lib_ring_buffer_config *config, + struct lttng_ust_lib_ring_buffer_backend *bufb, unsigned long idx, unsigned long data_size, - struct shm_handle *handle) + struct lttng_ust_shm_handle *handle) { - struct lib_ring_buffer_backend_pages_shmp *pages; unsigned long sb_bindex; + struct lttng_ust_lib_ring_buffer_backend_subbuffer *wsb; + struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; + struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; - sb_bindex = subbuffer_id_get_index(config, shmp_index(handle, bufb->buf_wsb, idx)->id); - pages = shmp_index(handle, bufb->array, sb_bindex); - shmp(handle, pages->shmp)->data_size = data_size; + wsb = shmp_index(handle, bufb->buf_wsb, idx); + if (!wsb) + return; + sb_bindex = subbuffer_id_get_index(config, wsb->id); + rpages = shmp_index(handle, bufb->array, sb_bindex); + if (!rpages) + return; + backend_pages = shmp(handle, rpages->shmp); + if (!backend_pages) + return; + backend_pages->data_size = data_size; } static inline unsigned long subbuffer_get_read_data_size( - const struct lib_ring_buffer_config *config, - struct lib_ring_buffer_backend *bufb, - struct shm_handle *handle) + const struct lttng_ust_lib_ring_buffer_config *config, + struct lttng_ust_lib_ring_buffer_backend *bufb, + struct lttng_ust_shm_handle *handle) { - struct lib_ring_buffer_backend_pages_shmp *pages; unsigned long sb_bindex; + struct lttng_ust_lib_ring_buffer_backend_pages_shmp *pages_shmp; + struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; sb_bindex = subbuffer_id_get_index(config, bufb->buf_rsb.id); - pages = shmp_index(handle, bufb->array, sb_bindex); - return shmp(handle, pages->shmp)->data_size; + pages_shmp = shmp_index(handle, bufb->array, sb_bindex); + if (!pages_shmp) + return 0; + backend_pages = shmp(handle, pages_shmp->shmp); + if (!backend_pages) + return 0; + return backend_pages->data_size; } static inline unsigned long subbuffer_get_data_size( - const struct lib_ring_buffer_config *config, - struct lib_ring_buffer_backend *bufb, + const struct lttng_ust_lib_ring_buffer_config *config, + struct lttng_ust_lib_ring_buffer_backend *bufb, unsigned long idx, - struct shm_handle *handle) + struct lttng_ust_shm_handle *handle) { - struct lib_ring_buffer_backend_pages_shmp *pages; unsigned long sb_bindex; + struct lttng_ust_lib_ring_buffer_backend_subbuffer *wsb; + struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; + struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; + + wsb = shmp_index(handle, bufb->buf_wsb, idx); + if (!wsb) + return 0; + sb_bindex = subbuffer_id_get_index(config, wsb->id); + rpages = shmp_index(handle, bufb->array, sb_bindex); + if (!rpages) + return 0; + backend_pages = shmp(handle, rpages->shmp); + if (!backend_pages) + return 0; + return backend_pages->data_size; +} - sb_bindex = subbuffer_id_get_index(config, shmp_index(handle, bufb->buf_wsb, idx)->id); - pages = shmp_index(handle, bufb->array, sb_bindex); - return shmp(handle, pages->shmp)->data_size; +static inline +void subbuffer_inc_packet_count(const struct lttng_ust_lib_ring_buffer_config *config, + struct lttng_ust_lib_ring_buffer_backend *bufb, + unsigned long idx, struct lttng_ust_shm_handle *handle) +{ + struct lttng_ust_lib_ring_buffer_backend_counts *counts; + + counts = shmp_index(handle, bufb->buf_cnt, idx); + if (!counts) + return; + counts->seq_cnt++; } /** @@ -301,12 +453,13 @@ unsigned long subbuffer_get_data_size( * writer. */ static inline -void lib_ring_buffer_clear_noref(const struct lib_ring_buffer_config *config, - struct lib_ring_buffer_backend *bufb, +void lib_ring_buffer_clear_noref(const struct lttng_ust_lib_ring_buffer_config *config, + struct lttng_ust_lib_ring_buffer_backend *bufb, unsigned long idx, - struct shm_handle *handle) + struct lttng_ust_shm_handle *handle) { unsigned long id, new_id; + struct lttng_ust_lib_ring_buffer_backend_subbuffer *wsb; if (config->mode != RING_BUFFER_OVERWRITE) return; @@ -315,10 +468,13 @@ void lib_ring_buffer_clear_noref(const struct lib_ring_buffer_config *config, * Performing a volatile access to read the sb_pages, because we want to * read a coherent version of the pointer and the associated noref flag. */ - id = CMM_ACCESS_ONCE(shmp_index(handle, bufb->buf_wsb, idx)->id); + wsb = shmp_index(handle, bufb->buf_wsb, idx); + if (!wsb) + return; + id = CMM_ACCESS_ONCE(wsb->id); for (;;) { /* This check is called on the fast path for each record. */ - if (likely(!subbuffer_id_is_noref(config, id))) { + if (caa_likely(!subbuffer_id_is_noref(config, id))) { /* * Store after load dependency ordering the writes to * the subbuffer after load and test of the noref flag @@ -329,8 +485,8 @@ void lib_ring_buffer_clear_noref(const struct lib_ring_buffer_config *config, } new_id = id; subbuffer_id_clear_noref(config, &new_id); - new_id = uatomic_cmpxchg(&shmp_index(handle, bufb->buf_wsb, idx)->id, id, new_id); - if (likely(new_id == id)) + new_id = uatomic_cmpxchg(&wsb->id, id, new_id); + if (caa_likely(new_id == id)) break; id = new_id; } @@ -341,14 +497,20 @@ void lib_ring_buffer_clear_noref(const struct lib_ring_buffer_config *config, * called by writer. */ static inline -void lib_ring_buffer_set_noref_offset(const struct lib_ring_buffer_config *config, - struct lib_ring_buffer_backend *bufb, +void lib_ring_buffer_set_noref_offset(const struct lttng_ust_lib_ring_buffer_config *config, + struct lttng_ust_lib_ring_buffer_backend *bufb, unsigned long idx, unsigned long offset, - struct shm_handle *handle) + struct lttng_ust_shm_handle *handle) { + struct lttng_ust_lib_ring_buffer_backend_subbuffer *wsb; + struct channel *chan; + if (config->mode != RING_BUFFER_OVERWRITE) return; + wsb = shmp_index(handle, bufb->buf_wsb, idx); + if (!wsb) + return; /* * Because ring_buffer_set_noref() is only called by a single thread * (the one which updated the cc_sb value), there are no concurrent @@ -360,62 +522,98 @@ void lib_ring_buffer_set_noref_offset(const struct lib_ring_buffer_config *confi * subbuffer_set_noref() uses a volatile store to deal with concurrent * readers of the noref flag. */ - CHAN_WARN_ON(shmp(handle, bufb->chan), - subbuffer_id_is_noref(config, shmp_index(handle, bufb->buf_wsb, idx)->id)); + chan = shmp(handle, bufb->chan); + if (!chan) + return; + CHAN_WARN_ON(chan, subbuffer_id_is_noref(config, wsb->id)); /* * Memory barrier that ensures counter stores are ordered before set * noref and offset. */ cmm_smp_mb(); - subbuffer_id_set_noref_offset(config, &shmp_index(handle, bufb->buf_wsb, idx)->id, offset); + subbuffer_id_set_noref_offset(config, &wsb->id, offset); } /** * update_read_sb_index - Read-side subbuffer index update. */ static inline -int update_read_sb_index(const struct lib_ring_buffer_config *config, - struct lib_ring_buffer_backend *bufb, +int update_read_sb_index(const struct lttng_ust_lib_ring_buffer_config *config, + struct lttng_ust_lib_ring_buffer_backend *bufb, struct channel_backend *chanb, unsigned long consumed_idx, unsigned long consumed_count, - struct shm_handle *handle) + struct lttng_ust_shm_handle *handle) { + struct lttng_ust_lib_ring_buffer_backend_subbuffer *wsb; unsigned long old_id, new_id; + wsb = shmp_index(handle, bufb->buf_wsb, consumed_idx); + if (caa_unlikely(!wsb)) + return -EPERM; + if (config->mode == RING_BUFFER_OVERWRITE) { + struct channel *chan; + /* * Exchange the target writer subbuffer with our own unused * subbuffer. No need to use CMM_ACCESS_ONCE() here to read the * old_wpage, because the value read will be confirmed by the * following cmpxchg(). */ - old_id = shmp_index(handle, bufb->buf_wsb, consumed_idx)->id; - if (unlikely(!subbuffer_id_is_noref(config, old_id))) + old_id = wsb->id; + if (caa_unlikely(!subbuffer_id_is_noref(config, old_id))) return -EAGAIN; /* * Make sure the offset count we are expecting matches the one * indicated by the writer. */ - if (unlikely(!subbuffer_id_compare_offset(config, old_id, + if (caa_unlikely(!subbuffer_id_compare_offset(config, old_id, consumed_count))) return -EAGAIN; - CHAN_WARN_ON(shmp(handle, bufb->chan), - !subbuffer_id_is_noref(config, bufb->buf_rsb.id)); + chan = shmp(handle, bufb->chan); + if (caa_unlikely(!chan)) + return -EPERM; + CHAN_WARN_ON(chan, !subbuffer_id_is_noref(config, bufb->buf_rsb.id)); subbuffer_id_set_noref_offset(config, &bufb->buf_rsb.id, consumed_count); - new_id = uatomic_cmpxchg(&shmp_index(handle, bufb->buf_wsb, consumed_idx)->id, old_id, - bufb->buf_rsb.id); - if (unlikely(old_id != new_id)) + new_id = uatomic_cmpxchg(&wsb->id, old_id, bufb->buf_rsb.id); + if (caa_unlikely(old_id != new_id)) return -EAGAIN; bufb->buf_rsb.id = new_id; } else { /* No page exchange, use the writer page directly */ - bufb->buf_rsb.id = shmp_index(handle, bufb->buf_wsb, consumed_idx)->id; + bufb->buf_rsb.id = wsb->id; } return 0; } +#ifndef inline_memcpy +#define inline_memcpy(dest, src, n) memcpy(dest, src, n) +#endif + +static inline __attribute__((always_inline)) +void lttng_inline_memcpy(void *dest, const void *src, + unsigned long len) +{ + switch (len) { + case 1: + *(uint8_t *) dest = *(const uint8_t *) src; + break; + case 2: + *(uint16_t *) dest = *(const uint16_t *) src; + break; + case 4: + *(uint32_t *) dest = *(const uint32_t *) src; + break; + case 8: + *(uint64_t *) dest = *(const uint64_t *) src; + break; + default: + inline_memcpy(dest, src, len); + } +} + /* * Use the architecture-specific memcpy implementation for constant-sized * inputs, but rely on an inline memcpy for length statically unknown. @@ -427,7 +625,60 @@ do { \ if (__builtin_constant_p(len)) \ memcpy(dest, src, __len); \ else \ - inline_memcpy(dest, src, __len); \ + lttng_inline_memcpy(dest, src, __len); \ } while (0) -#endif /* _LINUX_RING_BUFFER_BACKEND_INTERNAL_H */ +/* + * write len bytes to dest with c + */ +static inline +void lib_ring_buffer_do_memset(char *dest, int c, unsigned long len) +{ + unsigned long i; + + for (i = 0; i < len; i++) + dest[i] = c; +} + +/* arch-agnostic implementation */ + +static inline int lttng_ust_fls(unsigned int x) +{ + int r = 32; + + if (!x) + return 0; + if (!(x & 0xFFFF0000U)) { + x <<= 16; + r -= 16; + } + if (!(x & 0xFF000000U)) { + x <<= 8; + r -= 8; + } + if (!(x & 0xF0000000U)) { + x <<= 4; + r -= 4; + } + if (!(x & 0xC0000000U)) { + x <<= 2; + r -= 2; + } + if (!(x & 0x80000000U)) { + /* No need to bit shift on last operation */ + r -= 1; + } + return r; +} + +static inline int get_count_order(unsigned int count) +{ + int order; + + order = lttng_ust_fls(count) - 1; + if (count & (count - 1)) + order++; + return order; +} + +#endif /* _LTTNG_RING_BUFFER_BACKEND_INTERNAL_H */