X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=libringbuffer%2Ffrontend_api.h;h=5ddb8ac460951f0bae59a3f098cf6bca510a3799;hb=f52a5702dbeb8125ca373ba363b29cbff3042cc1;hp=6a06bba2c2393ba139bc506a8f88bb4027b59ea9;hpb=9501d22f55b3a23f382f631c99b2325d1419b5da;p=lttng-ust.git diff --git a/libringbuffer/frontend_api.h b/libringbuffer/frontend_api.h index 6a06bba2..5ddb8ac4 100644 --- a/libringbuffer/frontend_api.h +++ b/libringbuffer/frontend_api.h @@ -37,10 +37,10 @@ /** * lib_ring_buffer_get_cpu - Precedes ring buffer reserve/commit. * - * Grabs RCU read-side lock and 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). + * 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). * * asm volatile and "memory" clobber prevent the compiler from moving * instructions out of the ring buffer nesting count. This is required to ensure @@ -53,15 +53,13 @@ int lib_ring_buffer_get_cpu(const struct lttng_ust_lib_ring_buffer_config *confi { int cpu, nesting; - rcu_read_lock(); cpu = lttng_ust_get_cpu(); - nesting = ++lib_ring_buffer_nesting; /* TLS */ + nesting = ++URCU_TLS(lib_ring_buffer_nesting); cmm_barrier(); if (caa_unlikely(nesting > 4)) { WARN_ON_ONCE(1); - lib_ring_buffer_nesting--; /* TLS */ - rcu_read_unlock(); + URCU_TLS(lib_ring_buffer_nesting)--; return -EPERM; } else return cpu; @@ -74,8 +72,7 @@ static inline void lib_ring_buffer_put_cpu(const struct lttng_ust_lib_ring_buffer_config *config) { cmm_barrier(); - lib_ring_buffer_nesting--; /* TLS */ - rcu_read_unlock(); + URCU_TLS(lib_ring_buffer_nesting)--; /* TLS */ } /* @@ -163,14 +160,14 @@ int lib_ring_buffer_reserve(const struct lttng_ust_lib_ring_buffer_config *confi unsigned long o_begin, o_end, o_old; size_t before_hdr_pad = 0; - if (uatomic_read(&chan->record_disabled)) + 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 buf = shmp(handle, chan->backend.buf[0].shmp); - if (uatomic_read(&buf->record_disabled)) + if (caa_unlikely(uatomic_read(&buf->record_disabled))) return -EAGAIN; ctx->buf = buf; @@ -288,14 +285,13 @@ void lib_ring_buffer_commit(const struct lttng_ust_lib_ring_buffer_config *confi commit_count = v_read(config, &shmp_index(handle, buf->commit_hot, endidx)->cc); lib_ring_buffer_check_deliver(config, buf, chan, offset_end - 1, - commit_count, endidx, handle); + commit_count, endidx, handle, ctx->tsc); /* * Update used size at each commit. It's needed only for extracting * ring_buffer buffers from vmcore, after crash. */ lib_ring_buffer_write_commit_counter(config, buf, chan, endidx, - ctx->buf_offset, commit_count, - ctx->slot_size, handle); + offset_end, commit_count, handle); } /**