#ifndef _LTTNG_RING_BUFFER_FRONTEND_TYPES_H #define _LTTNG_RING_BUFFER_FRONTEND_TYPES_H /* * libringbuffer/frontend_types.h * * Ring Buffer Library Synchronization Header (types). * * 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 * * Author: * Mathieu Desnoyers * * See ring_buffer_frontend.c for more information on wait-free algorithms. */ #include #include /* for timer_t */ #include #include #include #include #include "backend_types.h" #include "shm_internal.h" #include "shm_types.h" #include "vatomic.h" /* * A switch is done during tracing or as a final flush after tracing (so it * won't write in the new sub-buffer). */ enum switch_mode { SWITCH_ACTIVE, SWITCH_FLUSH }; /* channel: collection of per-cpu ring buffers. */ #define RB_CHANNEL_PADDING 32 struct channel { int record_disabled; unsigned long commit_count_mask; /* * Commit count mask, removing * the MSBs corresponding to * bits used to represent the * subbuffer index. */ unsigned long switch_timer_interval; /* Buffer flush (us) */ timer_t switch_timer; int switch_timer_enabled; unsigned long read_timer_interval; /* Reader wakeup (us) */ timer_t read_timer; int read_timer_enabled; int finalized; /* Has channel been finalized */ size_t priv_data_offset; unsigned int nr_streams; /* Number of streams */ struct lttng_ust_shm_handle *handle; char padding[RB_CHANNEL_PADDING]; /* * Associated backend contains a variable-length array. Needs to * be last member. */ struct channel_backend backend; /* Associated backend */ } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); /* Per-subbuffer commit counters used on the hot path */ #define RB_COMMIT_COUNT_HOT_PADDING 16 struct commit_counters_hot { union v_atomic cc; /* Commit counter */ union v_atomic seq; /* Consecutive commits */ char padding[RB_COMMIT_COUNT_HOT_PADDING]; } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); /* Per-subbuffer commit counters used only on cold paths */ #define RB_COMMIT_COUNT_COLD_PADDING 24 struct commit_counters_cold { union v_atomic cc_sb; /* Incremented _once_ at sb switch */ char padding[RB_COMMIT_COUNT_COLD_PADDING]; } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); /* ring buffer state */ #define RB_CRASH_DUMP_ABI_LEN 256 #define RB_RING_BUFFER_PADDING 60 #define RB_CRASH_DUMP_ABI_MAGIC_LEN 16 /* * The 128-bit magic number is xor'd in the process data so it does not * cause a false positive when searching for buffers by scanning memory. * The actual magic number is: * 0x17, 0x7B, 0xF1, 0x77, 0xBF, 0x17, 0x7B, 0xF1, * 0x77, 0xBF, 0x17, 0x7B, 0xF1, 0x77, 0xBF, 0x17, */ #define RB_CRASH_DUMP_ABI_MAGIC_XOR \ { \ 0x17 ^ 0xFF, 0x7B ^ 0xFF, 0xF1 ^ 0xFF, 0x77 ^ 0xFF, \ 0xBF ^ 0xFF, 0x17 ^ 0xFF, 0x7B ^ 0xFF, 0xF1 ^ 0xFF, \ 0x77 ^ 0xFF, 0xBF ^ 0xFF, 0x17 ^ 0xFF, 0x7B ^ 0xFF, \ 0xF1 ^ 0xFF, 0x77 ^ 0xFF, 0xBF ^ 0xFF, 0x17 ^ 0xFF, \ } #define RB_CRASH_ENDIAN 0x1234 #define RB_CRASH_DUMP_ABI_MAJOR 0 #define RB_CRASH_DUMP_ABI_MINOR 0 enum lttng_crash_type { LTTNG_CRASH_TYPE_UST = 0, LTTNG_CRASH_TYPE_KERNEL = 1, }; struct lttng_crash_abi { uint8_t magic[RB_CRASH_DUMP_ABI_MAGIC_LEN]; uint64_t mmap_length; /* Overall lenght of crash record */ uint16_t endian; /* * { 0x12, 0x34 }: big endian * { 0x34, 0x12 }: little endian */ uint16_t major; /* Major number. */ uint16_t minor; /* Minor number. */ uint8_t word_size; /* Word size (bytes). */ uint8_t layout_type; /* enum lttng_crash_type */ struct { uint32_t prod_offset; uint32_t consumed_offset; uint32_t commit_hot_array; uint32_t commit_hot_seq; uint32_t buf_wsb_array; uint32_t buf_wsb_id; uint32_t sb_array; uint32_t sb_array_shmp_offset; uint32_t sb_backend_p_offset; uint32_t content_size; uint32_t packet_size; } __attribute__((packed)) offset; struct { uint8_t prod_offset; uint8_t consumed_offset; uint8_t commit_hot_seq; uint8_t buf_wsb_id; uint8_t sb_array_shmp_offset; uint8_t sb_backend_p_offset; uint8_t content_size; uint8_t packet_size; } __attribute__((packed)) length; struct { uint32_t commit_hot_array; uint32_t buf_wsb_array; uint32_t sb_array; } __attribute__((packed)) stride; uint64_t buf_size; /* Size of the buffer */ uint64_t subbuf_size; /* Sub-buffer size */ uint64_t num_subbuf; /* Number of sub-buffers for writer */ uint32_t mode; /* Buffer mode: 0: overwrite, 1: discard */ } __attribute__((packed)); struct lttng_ust_lib_ring_buffer { /* First 32 bytes are for the buffer crash dump ABI */ struct lttng_crash_abi crash_abi; /* 32 bytes cache-hot cacheline */ union v_atomic __attribute__((aligned(32))) offset; /* Current offset in the buffer */ DECLARE_SHMP(struct commit_counters_hot, commit_hot); /* Commit count per sub-buffer */ long consumed; /* * Current offset in the buffer * standard atomic access (shared) */ int record_disabled; /* End of cache-hot 32 bytes cacheline */ union v_atomic last_tsc; /* * Last timestamp written in the buffer. */ struct lttng_ust_lib_ring_buffer_backend backend; /* Associated backend */ DECLARE_SHMP(struct commit_counters_cold, commit_cold); /* Commit count per sub-buffer */ long active_readers; /* * Active readers count * standard atomic access (shared) */ /* Dropped records */ union v_atomic records_lost_full; /* Buffer full */ union v_atomic records_lost_wrap; /* Nested wrap-around */ union v_atomic records_lost_big; /* Events too big */ union v_atomic records_count; /* Number of records written */ union v_atomic records_overrun; /* Number of overwritten records */ //wait_queue_head_t read_wait; /* reader buffer-level wait queue */ int finalized; /* buffer has been finalized */ unsigned long get_subbuf_consumed; /* Read-side consumed */ unsigned long prod_snapshot; /* Producer count snapshot */ unsigned long cons_snapshot; /* Consumer count snapshot */ unsigned int get_subbuf:1; /* Sub-buffer being held by reader */ /* shmp pointer to self */ DECLARE_SHMP(struct lttng_ust_lib_ring_buffer, self); char padding[RB_RING_BUFFER_PADDING]; } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); static inline void *channel_get_private(struct channel *chan) { return ((char *) chan) + chan->priv_data_offset; } #ifndef __rb_same_type #define __rb_same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b)) #endif /* * Issue warnings and disable channels upon internal error. * Can receive struct lttng_ust_lib_ring_buffer or struct lttng_ust_lib_ring_buffer_backend * parameters. */ #define CHAN_WARN_ON(c, cond) \ ({ \ struct channel *__chan; \ int _____ret = caa_unlikely(cond); \ if (_____ret) { \ if (__rb_same_type(*(c), struct channel_backend)) \ __chan = caa_container_of((void *) (c), \ struct channel, \ backend); \ else if (__rb_same_type(*(c), struct channel)) \ __chan = (void *) (c); \ else \ BUG_ON(1); \ uatomic_inc(&__chan->record_disabled); \ WARN_ON(1); \ } \ _____ret = _____ret; /* For clang "unused result". */ \ }) #endif /* _LTTNG_RING_BUFFER_FRONTEND_TYPES_H */