1 #ifndef _LINUX_RING_BUFFER_FRONTEND_TYPES_H
2 #define _LINUX_RING_BUFFER_FRONTEND_TYPES_H
5 * linux/ringbuffer/frontend_types.h
7 * (C) Copyright 2005-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
9 * Ring Buffer Library Synchronization Header (types).
12 * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
14 * See ring_buffer_frontend.c for more information on wait-free algorithms.
16 * Dual LGPL v2.1/GPL v2 license.
21 #include <urcu/list.h>
22 #include <urcu/uatomic.h>
26 #include <ust/usterr-signal-safe.h>
27 #include <ust/ringbuffer-config.h>
28 #include "backend_types.h"
29 #include "shm_internal.h"
32 * A switch is done during tracing or as a final flush after tracing (so it
33 * won't write in the new sub-buffer).
35 enum switch_mode
{ SWITCH_ACTIVE
, SWITCH_FLUSH
};
37 /* channel: collection of per-cpu ring buffers. */
40 unsigned long commit_count_mask
; /*
41 * Commit count mask, removing
42 * the MSBs corresponding to
43 * bits used to represent the
47 struct channel_backend backend
; /* Associated backend */
49 unsigned long switch_timer_interval
; /* Buffer flush (jiffies) */
50 unsigned long read_timer_interval
; /* Reader wakeup (jiffies) */
51 //wait_queue_head_t read_wait; /* reader wait queue */
52 int finalized
; /* Has channel been finalized */
53 } ____cacheline_aligned
;
55 /* Per-subbuffer commit counters used on the hot path */
56 struct commit_counters_hot
{
57 union v_atomic cc
; /* Commit counter */
58 union v_atomic seq
; /* Consecutive commits */
59 } ____cacheline_aligned
;
61 /* Per-subbuffer commit counters used only on cold paths */
62 struct commit_counters_cold
{
63 union v_atomic cc_sb
; /* Incremented _once_ at sb switch */
64 } ____cacheline_aligned
;
66 /* ring buffer state */
67 struct lib_ring_buffer
{
68 /* First 32 bytes cache-hot cacheline */
69 union v_atomic offset
; /* Current offset in the buffer */
70 DECLARE_SHMP(struct commit_counters_hot
, commit_hot
);
71 /* Commit count per sub-buffer */
73 * Current offset in the buffer
74 * standard atomic access (shared)
77 /* End of first 32 bytes cacheline */
78 union v_atomic last_tsc
; /*
79 * Last timestamp written in the buffer.
82 struct lib_ring_buffer_backend backend
; /* Associated backend */
84 DECLARE_SHMP(struct commit_counters_cold
, commit_cold
);
85 /* Commit count per sub-buffer */
86 long active_readers
; /*
87 * Active readers count
88 * standard atomic access (shared)
91 union v_atomic records_lost_full
; /* Buffer full */
92 union v_atomic records_lost_wrap
; /* Nested wrap-around */
93 union v_atomic records_lost_big
; /* Events too big */
94 union v_atomic records_count
; /* Number of records written */
95 union v_atomic records_overrun
; /* Number of overwritten records */
96 //wait_queue_head_t read_wait; /* reader buffer-level wait queue */
97 int finalized
; /* buffer has been finalized */
98 //struct timer_list switch_timer; /* timer for periodical switch */
99 //struct timer_list read_timer; /* timer for read poll */
100 unsigned long get_subbuf_consumed
; /* Read-side consumed */
101 unsigned long prod_snapshot
; /* Producer count snapshot */
102 unsigned long cons_snapshot
; /* Consumer count snapshot */
103 int get_subbuf
:1; /* Sub-buffer being held by reader */
104 int switch_timer_enabled
:1; /* Protected by ring_buffer_nohz_lock */
105 int read_timer_enabled
:1; /* Protected by ring_buffer_nohz_lock */
106 } ____cacheline_aligned
;
109 void *channel_get_private(struct channel
*chan
)
111 return chan
->backend
.priv
;
115 * Issue warnings and disable channels upon internal error.
116 * Can receive struct lib_ring_buffer or struct lib_ring_buffer_backend
119 #define CHAN_WARN_ON(c, cond) \
121 struct channel *__chan; \
122 int _____ret = unlikely(cond); \
124 if (__same_type(*(c), struct channel_backend)) \
125 __chan = caa_container_of((void *) (c), \
128 else if (__same_type(*(c), struct channel)) \
129 __chan = (void *) (c); \
132 uatomic_inc(&__chan->record_disabled); \
138 #endif /* _LINUX_RING_BUFFER_FRONTEND_TYPES_H */