aboutsummaryrefslogtreecommitdiffhomepage
path: root/src/core/lib/iomgr/pollset_posix.h
blob: f53ef8855c5f691baaca44b9b4a1849664a212d1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
/*
 *
 * Copyright 2015, Google Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#ifndef GRPC_CORE_LIB_IOMGR_POLLSET_POSIX_H
#define GRPC_CORE_LIB_IOMGR_POLLSET_POSIX_H

#include <poll.h>

#include <grpc/support/sync.h>

#include "src/core/lib/iomgr/exec_ctx.h"
#include "src/core/lib/iomgr/iomgr.h"
#include "src/core/lib/iomgr/pollset.h"
#include "src/core/lib/iomgr/wakeup_fd_posix.h"

typedef struct grpc_pollset_vtable grpc_pollset_vtable;

/* forward declare only in this file to avoid leaking impl details via
   pollset.h; real users of grpc_fd should always include 'fd_posix.h' and not
   use the struct tag */
struct grpc_fd;

typedef struct grpc_cached_wakeup_fd {
  grpc_wakeup_fd fd;
  struct grpc_cached_wakeup_fd *next;
} grpc_cached_wakeup_fd;

struct grpc_pollset_worker {
  grpc_cached_wakeup_fd *wakeup_fd;
  int reevaluate_polling_on_wakeup;
  int kicked_specifically;
  struct grpc_pollset_worker *next;
  struct grpc_pollset_worker *prev;
};

struct grpc_pollset {
  /* pollsets under posix can mutate representation as fds are added and
     removed.
     For example, we may choose a poll() based implementation on linux for
     few fds, and an epoll() based implementation for many fds */
  const grpc_pollset_vtable *vtable;
  gpr_mu mu;
  grpc_pollset_worker root_worker;
  int in_flight_cbs;
  int shutting_down;
  int called_shutdown;
  int kicked_without_pollers;
  grpc_closure *shutdown_done;
  grpc_closure_list idle_jobs;
  union {
    int fd;
    void *ptr;
  } data;
  /* Local cache of eventfds for workers */
  grpc_cached_wakeup_fd *local_wakeup_cache;
};

struct grpc_pollset_vtable {
  void (*add_fd)(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
                 struct grpc_fd *fd, int and_unlock_pollset);
  void (*maybe_work_and_unlock)(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
                                grpc_pollset_worker *worker,
                                gpr_timespec deadline, gpr_timespec now);
  void (*finish_shutdown)(grpc_pollset *pollset);
  void (*destroy)(grpc_pollset *pollset);
};

/* Add an fd to a pollset */
void grpc_pollset_add_fd(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
                         struct grpc_fd *fd);

/* Returns the fd to listen on for kicks */
int grpc_kick_read_fd(grpc_pollset *p);
/* Call after polling has been kicked to leave the kicked state */
void grpc_kick_drain(grpc_pollset *p);

/* Convert a timespec to milliseconds:
   - very small or negative poll times are clamped to zero to do a
     non-blocking poll (which becomes spin polling)
   - other small values are rounded up to one millisecond
   - longer than a millisecond polls are rounded up to the next nearest
     millisecond to avoid spinning
   - infinite timeouts are converted to -1 */
int grpc_poll_deadline_to_millis_timeout(gpr_timespec deadline,
                                         gpr_timespec now);

/* Allow kick to wakeup the currently polling worker */
#define GRPC_POLLSET_CAN_KICK_SELF 1
/* Force the wakee to repoll when awoken */
#define GRPC_POLLSET_REEVALUATE_POLLING_ON_WAKEUP 2
/* As per grpc_pollset_kick, with an extended set of flags (defined above)
   -- mostly for fd_posix's use. */
void grpc_pollset_kick_ext(grpc_pollset *p,
                           grpc_pollset_worker *specific_worker,
                           uint32_t flags);

/* turn a pollset into a multipoller: platform specific */
typedef void (*grpc_platform_become_multipoller_type)(grpc_exec_ctx *exec_ctx,
                                                      grpc_pollset *pollset,
                                                      struct grpc_fd **fds,
                                                      size_t fd_count);
extern grpc_platform_become_multipoller_type grpc_platform_become_multipoller;

void grpc_poll_become_multipoller(grpc_exec_ctx *exec_ctx,
                                  grpc_pollset *pollset, struct grpc_fd **fds,
                                  size_t fd_count);

/* Return 1 if the pollset has active threads in grpc_pollset_work (pollset must
 * be locked) */
int grpc_pollset_has_workers(grpc_pollset *pollset);

void grpc_remove_fd_from_all_epoll_sets(int fd);

/* override to allow tests to hook poll() usage */
/* NOTE: Any changes to grpc_poll_function must take place when the gRPC
   is certainly not doing any polling anywhere.
   Otherwise, there might be a race between changing the variable and actually
   doing a polling operation */
typedef int (*grpc_poll_function_type)(struct pollfd *, nfds_t, int);
extern grpc_poll_function_type grpc_poll_function;
extern grpc_wakeup_fd grpc_global_wakeup_fd;

#endif /* GRPC_CORE_LIB_IOMGR_POLLSET_POSIX_H */