X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=libringbuffer%2Fbackend_internal.h;h=fe8f6eb611ebb5b11e59d3611e2b20956652bf97;hb=fb31eb73d8a4a6d9784ed5c335b7fa3b9684108c;hp=df3617cacd76dccdd756d870cf56d0e477b8f387;hpb=1ff31389b273bb27a619a794ce414c65e73cb6ea;p=lttng-ust.git diff --git a/libringbuffer/backend_internal.h b/libringbuffer/backend_internal.h index df3617ca..fe8f6eb6 100644 --- a/libringbuffer/backend_internal.h +++ b/libringbuffer/backend_internal.h @@ -23,6 +23,8 @@ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ +#include +#include #include #include @@ -196,16 +198,82 @@ int subbuffer_id_check_index(const struct lttng_ust_lib_ring_buffer_config *conf return 0; } +static inline +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) +{ + 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; +} + +/* 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) { - unsigned long sb_bindex; + 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); - v_inc(config, &shmp(handle, shmp_index(handle, bufb->array, sb_bindex)->shmp)->records_commit); + 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 @@ -217,12 +285,23 @@ void subbuffer_consume_record(const struct lttng_ust_lib_ring_buffer_config *con 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); } @@ -234,9 +313,21 @@ unsigned long subbuffer_get_records_count( 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); } /* @@ -253,15 +344,25 @@ unsigned long subbuffer_count_records_overrun( unsigned long idx, struct lttng_ust_shm_handle *handle) { - struct lttng_ust_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; } @@ -273,12 +374,22 @@ void subbuffer_set_data_size(const struct lttng_ust_lib_ring_buffer_config *conf unsigned long data_size, struct lttng_ust_shm_handle *handle) { - struct lttng_ust_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 @@ -287,12 +398,18 @@ unsigned long subbuffer_get_read_data_size( struct lttng_ust_lib_ring_buffer_backend *bufb, struct lttng_ust_shm_handle *handle) { - struct lttng_ust_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 @@ -302,12 +419,22 @@ unsigned long subbuffer_get_data_size( unsigned long idx, struct lttng_ust_shm_handle *handle) { - struct lttng_ust_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); - return shmp(handle, pages->shmp)->data_size; + 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; } static inline @@ -315,7 +442,12 @@ void subbuffer_inc_packet_count(const struct lttng_ust_lib_ring_buffer_config *c struct lttng_ust_lib_ring_buffer_backend *bufb, unsigned long idx, struct lttng_ust_shm_handle *handle) { - shmp_index(handle, bufb->buf_cnt, idx)->seq_cnt++; + struct lttng_ust_lib_ring_buffer_backend_counts *counts; + + counts = shmp_index(handle, bufb->buf_cnt, idx); + if (!counts) + return; + counts->seq_cnt++; } /** @@ -329,6 +461,7 @@ void lib_ring_buffer_clear_noref(const struct lttng_ust_lib_ring_buffer_config * 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; @@ -337,7 +470,10 @@ void lib_ring_buffer_clear_noref(const struct lttng_ust_lib_ring_buffer_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 (caa_likely(!subbuffer_id_is_noref(config, id))) { @@ -351,7 +487,7 @@ void lib_ring_buffer_clear_noref(const struct lttng_ust_lib_ring_buffer_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); + new_id = uatomic_cmpxchg(&wsb->id, id, new_id); if (caa_likely(new_id == id)) break; id = new_id; @@ -368,9 +504,15 @@ void lib_ring_buffer_set_noref_offset(const struct lttng_ust_lib_ring_buffer_con unsigned long idx, unsigned long offset, 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 @@ -382,14 +524,16 @@ void lib_ring_buffer_set_noref_offset(const struct lttng_ust_lib_ring_buffer_con * 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); } /** @@ -403,16 +547,23 @@ int update_read_sb_index(const struct lttng_ust_lib_ring_buffer_config *config, unsigned long consumed_count, 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; + old_id = wsb->id; if (caa_unlikely(!subbuffer_id_is_noref(config, old_id))) return -EAGAIN; /* @@ -422,18 +573,19 @@ int update_read_sb_index(const struct lttng_ust_lib_ring_buffer_config *config, 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); + 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; } @@ -442,6 +594,28 @@ int update_read_sb_index(const struct lttng_ust_lib_ring_buffer_config *config, #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. @@ -453,7 +627,7 @@ do { \ if (__builtin_constant_p(len)) \ memcpy(dest, src, __len); \ else \ - inline_memcpy(dest, src, __len); \ + lttng_inline_memcpy(dest, src, __len); \ } while (0) /*