Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * aio_init.c
4 : * AIO - Subsystem Initialization
5 : *
6 : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : * IDENTIFICATION
10 : * src/backend/storage/aio/aio_init.c
11 : *
12 : *-------------------------------------------------------------------------
13 : */
14 :
15 : #include "postgres.h"
16 :
17 : #include "miscadmin.h"
18 : #include "storage/aio.h"
19 : #include "storage/aio_internal.h"
20 : #include "storage/aio_subsys.h"
21 : #include "storage/bufmgr.h"
22 : #include "storage/io_worker.h"
23 : #include "storage/ipc.h"
24 : #include "storage/proc.h"
25 : #include "storage/shmem.h"
26 : #include "utils/guc.h"
27 :
28 :
29 :
30 : static Size
31 4407 : AioCtlShmemSize(void)
32 : {
33 : /* pgaio_ctl itself */
34 4407 : return sizeof(PgAioCtl);
35 : }
36 :
37 : static uint32
38 185636 : AioProcs(void)
39 : {
40 : /*
41 : * While AIO workers don't need their own AIO context, we can't currently
42 : * guarantee that nothing gets assigned to an IO worker's ProcNumber if we
43 : * just subtracted MAX_IO_WORKERS.
44 : */
45 185636 : return MaxBackends + NUM_AUXILIARY_PROCS;
46 : }
47 :
48 : static Size
49 3267 : AioBackendShmemSize(void)
50 : {
51 3267 : return mul_size(AioProcs(), sizeof(PgAioBackend));
52 : }
53 :
54 : static Size
55 3267 : AioHandleShmemSize(void)
56 : {
57 : Size sz;
58 :
59 : /* verify AioChooseMaxConcurrency() did its thing */
60 : Assert(io_max_concurrency > 0);
61 :
62 : /* io handles */
63 3267 : sz = mul_size(AioProcs(),
64 : mul_size(io_max_concurrency, sizeof(PgAioHandle)));
65 :
66 3267 : return sz;
67 : }
68 :
69 : static Size
70 3267 : AioHandleIOVShmemSize(void)
71 : {
72 : /* each IO handle can have up to io_max_combine_limit iovec objects */
73 3267 : return mul_size(sizeof(struct iovec),
74 3267 : mul_size(mul_size(io_max_combine_limit, AioProcs()),
75 : io_max_concurrency));
76 : }
77 :
78 : static Size
79 3267 : AioHandleDataShmemSize(void)
80 : {
81 : /* each buffer referenced by an iovec can have associated data */
82 3267 : return mul_size(sizeof(uint64),
83 3267 : mul_size(mul_size(io_max_combine_limit, AioProcs()),
84 : io_max_concurrency));
85 : }
86 :
87 : /*
88 : * Choose a suitable value for io_max_concurrency.
89 : *
90 : * It's unlikely that we could have more IOs in flight than buffers that we
91 : * would be allowed to pin.
92 : *
93 : * On the upper end, apply a cap too - just because shared_buffers is large,
94 : * it doesn't make sense have millions of buffers undergo IO concurrently.
95 : */
96 : static int
97 1137 : AioChooseMaxConcurrency(void)
98 : {
99 : uint32 max_backends;
100 : int max_proportional_pins;
101 :
102 : /* Similar logic to LimitAdditionalPins() */
103 1137 : max_backends = MaxBackends + NUM_AUXILIARY_PROCS;
104 1137 : max_proportional_pins = NBuffers / max_backends;
105 :
106 1137 : max_proportional_pins = Max(max_proportional_pins, 1);
107 :
108 : /* apply upper limit */
109 1137 : return Min(max_proportional_pins, 64);
110 : }
111 :
112 : Size
113 2127 : AioShmemSize(void)
114 : {
115 2127 : Size sz = 0;
116 :
117 : /*
118 : * We prefer to report this value's source as PGC_S_DYNAMIC_DEFAULT.
119 : * However, if the DBA explicitly set io_max_concurrency = -1 in the
120 : * config file, then PGC_S_DYNAMIC_DEFAULT will fail to override that and
121 : * we must force the matter with PGC_S_OVERRIDE.
122 : */
123 2127 : if (io_max_concurrency == -1)
124 : {
125 : char buf[32];
126 :
127 1137 : snprintf(buf, sizeof(buf), "%d", AioChooseMaxConcurrency());
128 1137 : SetConfigOption("io_max_concurrency", buf, PGC_POSTMASTER,
129 : PGC_S_DYNAMIC_DEFAULT);
130 1137 : if (io_max_concurrency == -1) /* failed to apply it? */
131 0 : SetConfigOption("io_max_concurrency", buf, PGC_POSTMASTER,
132 : PGC_S_OVERRIDE);
133 : }
134 :
135 2127 : sz = add_size(sz, AioCtlShmemSize());
136 2127 : sz = add_size(sz, AioBackendShmemSize());
137 2127 : sz = add_size(sz, AioHandleShmemSize());
138 2127 : sz = add_size(sz, AioHandleIOVShmemSize());
139 2127 : sz = add_size(sz, AioHandleDataShmemSize());
140 :
141 : /* Reserve space for method specific resources. */
142 2127 : if (pgaio_method_ops->shmem_size)
143 2120 : sz = add_size(sz, pgaio_method_ops->shmem_size());
144 :
145 2127 : return sz;
146 : }
147 :
148 : void
149 1140 : AioShmemInit(void)
150 : {
151 : bool found;
152 1140 : uint32 io_handle_off = 0;
153 1140 : uint32 iovec_off = 0;
154 1140 : uint32 per_backend_iovecs = io_max_concurrency * io_max_combine_limit;
155 :
156 1140 : pgaio_ctl = (PgAioCtl *)
157 1140 : ShmemInitStruct("AioCtl", AioCtlShmemSize(), &found);
158 :
159 1140 : if (found)
160 0 : goto out;
161 :
162 1140 : memset(pgaio_ctl, 0, AioCtlShmemSize());
163 :
164 1140 : pgaio_ctl->io_handle_count = AioProcs() * io_max_concurrency;
165 1140 : pgaio_ctl->iovec_count = AioProcs() * per_backend_iovecs;
166 :
167 2280 : pgaio_ctl->backend_state = (PgAioBackend *)
168 1140 : ShmemInitStruct("AioBackend", AioBackendShmemSize(), &found);
169 :
170 2280 : pgaio_ctl->io_handles = (PgAioHandle *)
171 1140 : ShmemInitStruct("AioHandle", AioHandleShmemSize(), &found);
172 :
173 2280 : pgaio_ctl->iovecs = (struct iovec *)
174 1140 : ShmemInitStruct("AioHandleIOV", AioHandleIOVShmemSize(), &found);
175 2280 : pgaio_ctl->handle_data = (uint64 *)
176 1140 : ShmemInitStruct("AioHandleData", AioHandleDataShmemSize(), &found);
177 :
178 149060 : for (int procno = 0; procno < AioProcs(); procno++)
179 : {
180 147920 : PgAioBackend *bs = &pgaio_ctl->backend_state[procno];
181 :
182 147920 : bs->io_handle_off = io_handle_off;
183 147920 : io_handle_off += io_max_concurrency;
184 :
185 147920 : dclist_init(&bs->idle_ios);
186 147920 : memset(bs->staged_ios, 0, sizeof(PgAioHandle *) * PGAIO_SUBMIT_BATCH_SIZE);
187 147920 : dclist_init(&bs->in_flight_ios);
188 :
189 : /* initialize per-backend IOs */
190 7070923 : for (int i = 0; i < io_max_concurrency; i++)
191 : {
192 6923003 : PgAioHandle *ioh = &pgaio_ctl->io_handles[bs->io_handle_off + i];
193 :
194 6923003 : ioh->generation = 1;
195 6923003 : ioh->owner_procno = procno;
196 6923003 : ioh->iovec_off = iovec_off;
197 6923003 : ioh->handle_data_len = 0;
198 6923003 : ioh->report_return = NULL;
199 6923003 : ioh->resowner = NULL;
200 6923003 : ioh->num_callbacks = 0;
201 6923003 : ioh->distilled_result.status = PGAIO_RS_UNKNOWN;
202 6923003 : ioh->flags = 0;
203 :
204 6923003 : ConditionVariableInit(&ioh->cv);
205 :
206 6923003 : dclist_push_tail(&bs->idle_ios, &ioh->node);
207 6923003 : iovec_off += io_max_combine_limit;
208 : }
209 : }
210 :
211 1140 : out:
212 : /* Initialize IO method specific resources. */
213 1140 : if (pgaio_method_ops->shmem_init)
214 1135 : pgaio_method_ops->shmem_init(!found);
215 1140 : }
216 :
217 : void
218 22974 : pgaio_init_backend(void)
219 : {
220 : /* shouldn't be initialized twice */
221 : Assert(!pgaio_my_backend);
222 :
223 22974 : if (MyBackendType == B_IO_WORKER)
224 1746 : return;
225 :
226 21228 : if (MyProc == NULL || MyProcNumber >= AioProcs())
227 0 : elog(ERROR, "aio requires a normal PGPROC");
228 :
229 21228 : pgaio_my_backend = &pgaio_ctl->backend_state[MyProcNumber];
230 :
231 21228 : if (pgaio_method_ops->init_backend)
232 0 : pgaio_method_ops->init_backend();
233 :
234 21228 : before_shmem_exit(pgaio_shutdown, 0);
235 : }
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