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1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * buf_internals.h
4 : : * Internal definitions for buffer manager and the buffer replacement
5 : : * strategy.
6 : : *
7 : : *
8 : : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
9 : : * Portions Copyright (c) 1994, Regents of the University of California
10 : : *
11 : : * src/include/storage/buf_internals.h
12 : : *
13 : : *-------------------------------------------------------------------------
14 : : */
15 : : #ifndef BUFMGR_INTERNALS_H
16 : : #define BUFMGR_INTERNALS_H
17 : :
18 : : #include "pgstat.h"
19 : : #include "port/atomics.h"
20 : : #include "storage/aio_types.h"
21 : : #include "storage/buf.h"
22 : : #include "storage/bufmgr.h"
23 : : #include "storage/condition_variable.h"
24 : : #include "storage/lwlock.h"
25 : : #include "storage/procnumber.h"
26 : : #include "storage/proclist_types.h"
27 : : #include "storage/shmem.h"
28 : : #include "storage/smgr.h"
29 : : #include "storage/spin.h"
30 : : #include "utils/relcache.h"
31 : : #include "utils/resowner.h"
32 : :
33 : : /*
34 : : * Buffer state is a single 64-bit variable where following data is combined.
35 : : *
36 : : * State of the buffer itself (in order):
37 : : * - 18 bits refcount
38 : : * - 4 bits usage count
39 : : * - 12 bits of flags
40 : : * - 18 bits share-lock count
41 : : * - 1 bit share-exclusive locked
42 : : * - 1 bit exclusive locked
43 : : *
44 : : * Combining these values allows to perform some operations without locking
45 : : * the buffer header, by modifying them together with a CAS loop.
46 : : *
47 : : * The definition of buffer state components is below.
48 : : */
49 : : #define BUF_REFCOUNT_BITS 18
50 : : #define BUF_USAGECOUNT_BITS 4
51 : : #define BUF_FLAG_BITS 12
52 : : #define BUF_LOCK_BITS (18+2)
53 : :
54 : : StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS + BUF_LOCK_BITS <= 64,
55 : : "parts of buffer state space need to be <= 64");
56 : :
57 : : /* refcount related definitions */
58 : : #define BUF_REFCOUNT_ONE 1
59 : : #define BUF_REFCOUNT_MASK \
60 : : ((UINT64CONST(1) << BUF_REFCOUNT_BITS) - 1)
61 : :
62 : : /* usage count related definitions */
63 : : #define BUF_USAGECOUNT_SHIFT \
64 : : BUF_REFCOUNT_BITS
65 : : #define BUF_USAGECOUNT_MASK \
66 : : (((UINT64CONST(1) << BUF_USAGECOUNT_BITS) - 1) << (BUF_USAGECOUNT_SHIFT))
67 : : #define BUF_USAGECOUNT_ONE \
68 : : (UINT64CONST(1) << BUF_REFCOUNT_BITS)
69 : :
70 : : /* flags related definitions */
71 : : #define BUF_FLAG_SHIFT \
72 : : (BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS)
73 : : #define BUF_FLAG_MASK \
74 : : (((UINT64CONST(1) << BUF_FLAG_BITS) - 1) << BUF_FLAG_SHIFT)
75 : :
76 : : /* lock state related definitions */
77 : : #define BM_LOCK_SHIFT \
78 : : (BUF_FLAG_SHIFT + BUF_FLAG_BITS)
79 : : #define BM_LOCK_VAL_SHARED \
80 : : (UINT64CONST(1) << (BM_LOCK_SHIFT))
81 : : #define BM_LOCK_VAL_SHARE_EXCLUSIVE \
82 : : (UINT64CONST(1) << (BM_LOCK_SHIFT + MAX_BACKENDS_BITS))
83 : : #define BM_LOCK_VAL_EXCLUSIVE \
84 : : (UINT64CONST(1) << (BM_LOCK_SHIFT + MAX_BACKENDS_BITS + 1))
85 : : #define BM_LOCK_MASK \
86 : : ((((uint64) MAX_BACKENDS) << BM_LOCK_SHIFT) | BM_LOCK_VAL_SHARE_EXCLUSIVE | BM_LOCK_VAL_EXCLUSIVE)
87 : :
88 : :
89 : : /* Get refcount and usagecount from buffer state */
90 : : #define BUF_STATE_GET_REFCOUNT(state) \
91 : : ((uint32)((state) & BUF_REFCOUNT_MASK))
92 : : #define BUF_STATE_GET_USAGECOUNT(state) \
93 : : ((uint32)(((state) & BUF_USAGECOUNT_MASK) >> BUF_USAGECOUNT_SHIFT))
94 : :
95 : : /*
96 : : * Flags for buffer descriptors
97 : : *
98 : : * Note: BM_TAG_VALID essentially means that there is a buffer hashtable
99 : : * entry associated with the buffer's tag.
100 : : */
101 : :
102 : : #define BUF_DEFINE_FLAG(flagno) \
103 : : (UINT64CONST(1) << (BUF_FLAG_SHIFT + (flagno)))
104 : :
105 : : /* buffer header is locked */
106 : : #define BM_LOCKED BUF_DEFINE_FLAG( 0)
107 : : /* data needs writing */
108 : : #define BM_DIRTY BUF_DEFINE_FLAG( 1)
109 : : /* data is valid */
110 : : #define BM_VALID BUF_DEFINE_FLAG( 2)
111 : : /* tag is assigned */
112 : : #define BM_TAG_VALID BUF_DEFINE_FLAG( 3)
113 : : /* read or write in progress */
114 : : #define BM_IO_IN_PROGRESS BUF_DEFINE_FLAG( 4)
115 : : /* previous I/O failed */
116 : : #define BM_IO_ERROR BUF_DEFINE_FLAG( 5)
117 : : /* dirtied since write started */
118 : : #define BM_JUST_DIRTIED BUF_DEFINE_FLAG( 6)
119 : : /* have waiter for sole pin */
120 : : #define BM_PIN_COUNT_WAITER BUF_DEFINE_FLAG( 7)
121 : : /* must write for checkpoint */
122 : : #define BM_CHECKPOINT_NEEDED BUF_DEFINE_FLAG( 8)
123 : : /* permanent buffer (not unlogged, or init fork) */
124 : : #define BM_PERMANENT BUF_DEFINE_FLAG( 9)
125 : : /* content lock has waiters */
126 : : #define BM_LOCK_HAS_WAITERS BUF_DEFINE_FLAG(10)
127 : : /* waiter for content lock has been signalled but not yet run */
128 : : #define BM_LOCK_WAKE_IN_PROGRESS BUF_DEFINE_FLAG(11)
129 : :
130 : :
131 : : StaticAssertDecl(MAX_BACKENDS_BITS <= BUF_REFCOUNT_BITS,
132 : : "MAX_BACKENDS_BITS needs to be <= BUF_REFCOUNT_BITS");
133 : : StaticAssertDecl(MAX_BACKENDS_BITS <= (BUF_LOCK_BITS - 2),
134 : : "MAX_BACKENDS_BITS needs to be <= BUF_LOCK_BITS - 2");
135 : :
136 : :
137 : : /*
138 : : * The maximum allowed value of usage_count represents a tradeoff between
139 : : * accuracy and speed of the clock-sweep buffer management algorithm. A
140 : : * large value (comparable to NBuffers) would approximate LRU semantics.
141 : : * But it can take as many as BM_MAX_USAGE_COUNT+1 complete cycles of the
142 : : * clock-sweep hand to find a free buffer, so in practice we don't want the
143 : : * value to be very large.
144 : : */
145 : : #define BM_MAX_USAGE_COUNT 5
146 : :
147 : : StaticAssertDecl(BM_MAX_USAGE_COUNT < (UINT64CONST(1) << BUF_USAGECOUNT_BITS),
148 : : "BM_MAX_USAGE_COUNT doesn't fit in BUF_USAGECOUNT_BITS bits");
149 : :
150 : : /*
151 : : * Buffer tag identifies which disk block the buffer contains.
152 : : *
153 : : * Note: the BufferTag data must be sufficient to determine where to write the
154 : : * block, without reference to pg_class or pg_tablespace entries. It's
155 : : * possible that the backend flushing the buffer doesn't even believe the
156 : : * relation is visible yet (its xact may have started before the xact that
157 : : * created the rel). The storage manager must be able to cope anyway.
158 : : *
159 : : * Note: if there's any pad bytes in the struct, InitBufferTag will have
160 : : * to be fixed to zero them, since this struct is used as a hash key.
161 : : */
162 : : typedef struct buftag
163 : : {
164 : : Oid spcOid; /* tablespace oid */
165 : : Oid dbOid; /* database oid */
166 : : RelFileNumber relNumber; /* relation file number */
167 : : ForkNumber forkNum; /* fork number */
168 : : BlockNumber blockNum; /* blknum relative to begin of reln */
169 : : } BufferTag;
170 : :
171 : : static inline RelFileNumber
172 : 65840574 : BufTagGetRelNumber(const BufferTag *tag)
173 : : {
174 : 65840574 : return tag->relNumber;
175 : : }
176 : :
177 : : static inline ForkNumber
178 : 3491567 : BufTagGetForkNum(const BufferTag *tag)
179 : : {
180 : 3491567 : return tag->forkNum;
181 : : }
182 : :
183 : : static inline void
184 : 11834686 : BufTagSetRelForkDetails(BufferTag *tag, RelFileNumber relnumber,
185 : : ForkNumber forknum)
186 : : {
187 : 11834686 : tag->relNumber = relnumber;
188 : 11834686 : tag->forkNum = forknum;
189 : 11834686 : }
190 : :
191 : : static inline RelFileLocator
192 : 3082011 : BufTagGetRelFileLocator(const BufferTag *tag)
193 : : {
194 : : RelFileLocator rlocator;
195 : :
196 : 3082011 : rlocator.spcOid = tag->spcOid;
197 : 3082011 : rlocator.dbOid = tag->dbOid;
198 : 3082011 : rlocator.relNumber = BufTagGetRelNumber(tag);
199 : :
200 : 3082011 : return rlocator;
201 : : }
202 : :
203 : : static inline void
204 : 110802 : ClearBufferTag(BufferTag *tag)
205 : : {
206 : 110802 : tag->spcOid = InvalidOid;
207 : 110802 : tag->dbOid = InvalidOid;
208 : 110802 : BufTagSetRelForkDetails(tag, InvalidRelFileNumber, InvalidForkNumber);
209 : 110802 : tag->blockNum = InvalidBlockNumber;
210 : 110802 : }
211 : :
212 : : static inline void
213 : 11723884 : InitBufferTag(BufferTag *tag, const RelFileLocator *rlocator,
214 : : ForkNumber forkNum, BlockNumber blockNum)
215 : : {
216 : 11723884 : tag->spcOid = rlocator->spcOid;
217 : 11723884 : tag->dbOid = rlocator->dbOid;
218 : 11723884 : BufTagSetRelForkDetails(tag, rlocator->relNumber, forkNum);
219 : 11723884 : tag->blockNum = blockNum;
220 : 11723884 : }
221 : :
222 : : static inline bool
223 : 371850 : BufferTagsEqual(const BufferTag *tag1, const BufferTag *tag2)
224 : : {
225 [ + - ]: 743700 : return (tag1->spcOid == tag2->spcOid) &&
226 [ + - ]: 371850 : (tag1->dbOid == tag2->dbOid) &&
227 [ + - ]: 371850 : (tag1->relNumber == tag2->relNumber) &&
228 [ - + ]: 371850 : (tag1->blockNum == tag2->blockNum) &&
229 : 371850 : (tag1->forkNum == tag2->forkNum);
230 : : }
231 : :
232 : : static inline bool
233 : 115547010 : BufTagMatchesRelFileLocator(const BufferTag *tag,
234 : : const RelFileLocator *rlocator)
235 : : {
236 [ + + ]: 182703448 : return (tag->spcOid == rlocator->spcOid) &&
237 [ + + ]: 67156438 : (tag->dbOid == rlocator->dbOid) &&
238 : 62753333 : (BufTagGetRelNumber(tag) == rlocator->relNumber);
239 : : }
240 : :
241 : :
242 : : /*
243 : : * The shared buffer mapping table is partitioned to reduce contention.
244 : : * To determine which partition lock a given tag requires, compute the tag's
245 : : * hash code with BufTableHashCode(), then apply BufMappingPartitionLock().
246 : : * NB: NUM_BUFFER_PARTITIONS must be a power of 2!
247 : : */
248 : : static inline uint32
249 : 11386660 : BufTableHashPartition(uint32 hashcode)
250 : : {
251 : 11386660 : return hashcode % NUM_BUFFER_PARTITIONS;
252 : : }
253 : :
254 : : static inline LWLock *
255 : 11386660 : BufMappingPartitionLock(uint32 hashcode)
256 : : {
257 : 22773320 : return &MainLWLockArray[BUFFER_MAPPING_LWLOCK_OFFSET +
258 : 11386660 : BufTableHashPartition(hashcode)].lock;
259 : : }
260 : :
261 : : static inline LWLock *
262 : : BufMappingPartitionLockByIndex(uint32 index)
263 : : {
264 : : return &MainLWLockArray[BUFFER_MAPPING_LWLOCK_OFFSET + index].lock;
265 : : }
266 : :
267 : : /*
268 : : * BufferDesc -- shared descriptor/state data for a single shared buffer.
269 : : *
270 : : * The state of the buffer is controlled by the, drumroll, state variable. It
271 : : * only may be modified using atomic operations. The state variable combines
272 : : * various flags, the buffer's refcount and usage count. See comment above
273 : : * BUF_REFCOUNT_BITS for details about the division. This layout allow us to
274 : : * do some operations in a single atomic operation, without actually acquiring
275 : : * and releasing the spinlock; for instance, increasing or decreasing the
276 : : * refcount.
277 : : *
278 : : * One of the aforementioned flags is BM_LOCKED, used to implement the buffer
279 : : * header lock. See the following paragraphs, as well as the documentation for
280 : : * individual fields, for more details.
281 : : *
282 : : * The identity of the buffer (BufferDesc.tag) can only be changed by the
283 : : * backend holding the buffer header lock.
284 : : *
285 : : * If the lock is held by another backend, neither additional buffer pins may
286 : : * be established (we would like to relax this eventually), nor can flags be
287 : : * set/cleared. These operations either need to acquire the buffer header
288 : : * spinlock, or need to use a CAS loop, waiting for the lock to be released if
289 : : * it is held. However, existing buffer pins may be released while the buffer
290 : : * header spinlock is held, using an atomic subtraction.
291 : : *
292 : : * If we have the buffer pinned, its tag can't change underneath us, so we can
293 : : * examine the tag without locking the buffer header. Also, in places we do
294 : : * one-time reads of the flags without bothering to lock the buffer header;
295 : : * this is generally for situations where we don't expect the flag bit being
296 : : * tested to be changing.
297 : : *
298 : : * We can't physically remove items from a disk page if another backend has
299 : : * the buffer pinned. Hence, a backend may need to wait for all other pins
300 : : * to go away. This is signaled by storing its own pgprocno into
301 : : * wait_backend_pgprocno and setting flag bit BM_PIN_COUNT_WAITER. At present,
302 : : * there can be only one such waiter per buffer.
303 : : *
304 : : * The content of buffers is protected via the buffer content lock,
305 : : * implemented as part of the buffer state. Note that the buffer header lock
306 : : * is *not* used to control access to the data in the buffer! We used to use
307 : : * an LWLock to implement the content lock, but having a dedicated
308 : : * implementation of content locks allows us to implement some otherwise hard
309 : : * things (e.g. race-freely checking if AIO is in progress before locking a
310 : : * buffer exclusively) and enables otherwise impossible optimizations
311 : : * (e.g. unlocking and unpinning a buffer in one atomic operation).
312 : : *
313 : : * We use this same struct for local buffer headers, but the locks are not
314 : : * used and not all of the flag bits are useful either. To avoid unnecessary
315 : : * overhead, manipulations of the state field should be done without actual
316 : : * atomic operations (i.e. only pg_atomic_read_u64() and
317 : : * pg_atomic_unlocked_write_u64()).
318 : : *
319 : : * Be careful to avoid increasing the size of the struct when adding or
320 : : * reordering members. Keeping it below 64 bytes (the most common CPU
321 : : * cache line size) is fairly important for performance.
322 : : *
323 : : * Per-buffer I/O condition variables are currently kept outside this struct in
324 : : * a separate array. They could be moved in here and still fit within that
325 : : * limit on common systems, but for now that is not done.
326 : : */
327 : : typedef struct BufferDesc
328 : : {
329 : : /*
330 : : * ID of page contained in buffer. The buffer header spinlock needs to be
331 : : * held to modify this field.
332 : : */
333 : : BufferTag tag;
334 : :
335 : : /*
336 : : * Buffer's index number (from 0). The field never changes after
337 : : * initialization, so does not need locking.
338 : : */
339 : : int buf_id;
340 : :
341 : : /*
342 : : * State of the buffer, containing flags, refcount and usagecount. See
343 : : * BUF_* and BM_* defines at the top of this file.
344 : : */
345 : : pg_atomic_uint64 state;
346 : :
347 : : /*
348 : : * Backend of pin-count waiter. The buffer header spinlock needs to be
349 : : * held to modify this field.
350 : : */
351 : : int wait_backend_pgprocno;
352 : :
353 : : PgAioWaitRef io_wref; /* set iff AIO is in progress */
354 : :
355 : : /*
356 : : * List of PGPROCs waiting for the buffer content lock. Protected by the
357 : : * buffer header spinlock.
358 : : */
359 : : proclist_head lock_waiters;
360 : : } BufferDesc;
361 : :
362 : : /*
363 : : * Concurrent access to buffer headers has proven to be more efficient if
364 : : * they're cache line aligned. So we force the start of the BufferDescriptors
365 : : * array to be on a cache line boundary and force the elements to be cache
366 : : * line sized.
367 : : *
368 : : * XXX: As this is primarily matters in highly concurrent workloads which
369 : : * probably all are 64bit these days, and the space wastage would be a bit
370 : : * more noticeable on 32bit systems, we don't force the stride to be cache
371 : : * line sized on those. If somebody does actual performance testing, we can
372 : : * reevaluate.
373 : : *
374 : : * Note that local buffer descriptors aren't forced to be aligned - as there's
375 : : * no concurrent access to those it's unlikely to be beneficial.
376 : : *
377 : : * We use a 64-byte cache line size here, because that's the most common
378 : : * size. Making it bigger would be a waste of memory. Even if running on a
379 : : * platform with either 32 or 128 byte line sizes, it's good to align to
380 : : * boundaries and avoid false sharing.
381 : : */
382 : : #define BUFFERDESC_PAD_TO_SIZE (SIZEOF_VOID_P == 8 ? 64 : 1)
383 : :
384 : : typedef union BufferDescPadded
385 : : {
386 : : BufferDesc bufferdesc;
387 : : char pad[BUFFERDESC_PAD_TO_SIZE];
388 : : } BufferDescPadded;
389 : :
390 : : /*
391 : : * The PendingWriteback & WritebackContext structure are used to keep
392 : : * information about pending flush requests to be issued to the OS.
393 : : */
394 : : typedef struct PendingWriteback
395 : : {
396 : : /* could store different types of pending flushes here */
397 : : BufferTag tag;
398 : : } PendingWriteback;
399 : :
400 : : /* struct forward declared in bufmgr.h */
401 : : typedef struct WritebackContext
402 : : {
403 : : /* pointer to the max number of writeback requests to coalesce */
404 : : int *max_pending;
405 : :
406 : : /* current number of pending writeback requests */
407 : : int nr_pending;
408 : :
409 : : /* pending requests */
410 : : PendingWriteback pending_writebacks[WRITEBACK_MAX_PENDING_FLUSHES];
411 : : } WritebackContext;
412 : :
413 : : /* in buf_init.c */
414 : : extern PGDLLIMPORT BufferDescPadded *BufferDescriptors;
415 : : extern PGDLLIMPORT ConditionVariableMinimallyPadded *BufferIOCVArray;
416 : : extern PGDLLIMPORT WritebackContext BackendWritebackContext;
417 : :
418 : : /* in localbuf.c */
419 : : extern PGDLLIMPORT BufferDesc *LocalBufferDescriptors;
420 : :
421 : :
422 : : static inline BufferDesc *
423 : 169063499 : GetBufferDescriptor(uint32 id)
424 : : {
425 : 169063499 : return &(BufferDescriptors[id]).bufferdesc;
426 : : }
427 : :
428 : : static inline BufferDesc *
429 : 3803408 : GetLocalBufferDescriptor(uint32 id)
430 : : {
431 : 3803408 : return &LocalBufferDescriptors[id];
432 : : }
433 : :
434 : : static inline Buffer
435 : 73679211 : BufferDescriptorGetBuffer(const BufferDesc *bdesc)
436 : : {
437 : 73679211 : return (Buffer) (bdesc->buf_id + 1);
438 : : }
439 : :
440 : : static inline ConditionVariable *
441 : 128979 : BufferDescriptorGetIOCV(const BufferDesc *bdesc)
442 : : {
443 : 128979 : return &(BufferIOCVArray[bdesc->buf_id]).cv;
444 : : }
445 : :
446 : : /*
447 : : * Functions for acquiring/releasing a shared buffer header's spinlock. Do
448 : : * not apply these to local buffers!
449 : : */
450 : : extern uint64 LockBufHdr(BufferDesc *desc);
451 : :
452 : : /*
453 : : * Unlock the buffer header.
454 : : *
455 : : * This can only be used if the caller did not modify BufferDesc.state. To
456 : : * set/unset flag bits or change the refcount use UnlockBufHdrExt().
457 : : */
458 : : static inline void
459 : 982220 : UnlockBufHdr(BufferDesc *desc)
460 : : {
461 [ + - ]: 982220 : Assert(pg_atomic_read_u64(&desc->state) & BM_LOCKED);
462 : :
463 : 982220 : pg_atomic_fetch_sub_u64(&desc->state, BM_LOCKED);
464 : 982220 : }
465 : :
466 : : /*
467 : : * Unlock the buffer header, while atomically adding the flags in set_bits,
468 : : * unsetting the ones in unset_bits and changing the refcount by
469 : : * refcount_change.
470 : : *
471 : : * Note that this approach would not work for usagecount, since we need to cap
472 : : * the usagecount at BM_MAX_USAGE_COUNT.
473 : : */
474 : : static inline uint64
475 : 295431 : UnlockBufHdrExt(BufferDesc *desc, uint64 old_buf_state,
476 : : uint64 set_bits, uint64 unset_bits,
477 : : int refcount_change)
478 : : {
479 : 295431 : for (;;)
480 : : {
481 : 295431 : uint64 buf_state = old_buf_state;
482 : :
483 [ + - ]: 295431 : Assert(buf_state & BM_LOCKED);
484 : :
485 : 295431 : buf_state |= set_bits;
486 : 295431 : buf_state &= ~unset_bits;
487 : 295431 : buf_state &= ~BM_LOCKED;
488 : :
489 [ + + ]: 295431 : if (refcount_change != 0)
490 : 22283 : buf_state += BUF_REFCOUNT_ONE * refcount_change;
491 : :
492 [ + - + - ]: 590862 : if (pg_atomic_compare_exchange_u64(&desc->state, &old_buf_state,
493 : 295431 : buf_state))
494 : : {
495 : 295431 : return old_buf_state;
496 : : }
497 [ - - + ]: 295431 : }
498 : 295431 : }
499 : :
500 : : extern uint64 WaitBufHdrUnlocked(BufferDesc *buf);
501 : :
502 : : /* in bufmgr.c */
503 : :
504 : : /*
505 : : * Structure to sort buffers per file on checkpoints.
506 : : *
507 : : * This structure is allocated per buffer in shared memory, so it should be
508 : : * kept as small as possible.
509 : : */
510 : : typedef struct CkptSortItem
511 : : {
512 : : Oid tsId;
513 : : RelFileNumber relNumber;
514 : : ForkNumber forkNum;
515 : : BlockNumber blockNum;
516 : : int buf_id;
517 : : } CkptSortItem;
518 : :
519 : : extern PGDLLIMPORT CkptSortItem *CkptBufferIds;
520 : :
521 : : /* ResourceOwner callbacks to hold buffer I/Os and pins */
522 : : extern PGDLLIMPORT const ResourceOwnerDesc buffer_io_resowner_desc;
523 : : extern PGDLLIMPORT const ResourceOwnerDesc buffer_resowner_desc;
524 : :
525 : : /* Convenience wrappers over ResourceOwnerRemember/Forget */
526 : : static inline void
527 : 14141001 : ResourceOwnerRememberBuffer(ResourceOwner owner, Buffer buffer)
528 : : {
529 : 14141001 : ResourceOwnerRemember(owner, Int32GetDatum(buffer), &buffer_resowner_desc);
530 : 14141001 : }
531 : : static inline void
532 : 14138790 : ResourceOwnerForgetBuffer(ResourceOwner owner, Buffer buffer)
533 : : {
534 : 14138790 : ResourceOwnerForget(owner, Int32GetDatum(buffer), &buffer_resowner_desc);
535 : 14138790 : }
536 : : static inline void
537 : 47535 : ResourceOwnerRememberBufferIO(ResourceOwner owner, Buffer buffer)
538 : : {
539 : 47535 : ResourceOwnerRemember(owner, Int32GetDatum(buffer), &buffer_io_resowner_desc);
540 : 47535 : }
541 : : static inline void
542 : 47535 : ResourceOwnerForgetBufferIO(ResourceOwner owner, Buffer buffer)
543 : : {
544 : 47535 : ResourceOwnerForget(owner, Int32GetDatum(buffer), &buffer_io_resowner_desc);
545 : 47535 : }
546 : :
547 : : /*
548 : : * Internal buffer management routines
549 : : */
550 : : /* bufmgr.c */
551 : : extern void WritebackContextInit(WritebackContext *context, int *max_pending);
552 : : extern void IssuePendingWritebacks(WritebackContext *wb_context, IOContext io_context);
553 : : extern void ScheduleBufferTagForWriteback(WritebackContext *wb_context,
554 : : IOContext io_context, BufferTag *tag);
555 : :
556 : : extern void TrackNewBufferPin(Buffer buf);
557 : :
558 : : /* solely to make it easier to write tests */
559 : : extern bool StartBufferIO(BufferDesc *buf, bool forInput, bool nowait);
560 : : extern void TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint64 set_flag_bits,
561 : : bool forget_owner, bool release_aio);
562 : :
563 : :
564 : : /* freelist.c */
565 : : extern IOContext IOContextForStrategy(BufferAccessStrategy strategy);
566 : : extern BufferDesc *StrategyGetBuffer(BufferAccessStrategy strategy,
567 : : uint64 *buf_state, bool *from_ring);
568 : : extern bool StrategyRejectBuffer(BufferAccessStrategy strategy,
569 : : BufferDesc *buf, bool from_ring);
570 : :
571 : : extern int StrategySyncStart(uint32 *complete_passes, uint32 *num_buf_alloc);
572 : : extern void StrategyNotifyBgWriter(int bgwprocno);
573 : :
574 : : extern Size StrategyShmemSize(void);
575 : : extern void StrategyInitialize(bool init);
576 : :
577 : : /* buf_table.c */
578 : : extern Size BufTableShmemSize(int size);
579 : : extern void InitBufTable(int size);
580 : : extern uint32 BufTableHashCode(BufferTag *tagPtr);
581 : : extern int BufTableLookup(BufferTag *tagPtr, uint32 hashcode);
582 : : extern int BufTableInsert(BufferTag *tagPtr, uint32 hashcode, int buf_id);
583 : : extern void BufTableDelete(BufferTag *tagPtr, uint32 hashcode);
584 : :
585 : : /* localbuf.c */
586 : : extern bool PinLocalBuffer(BufferDesc *buf_hdr, bool adjust_usagecount);
587 : : extern void UnpinLocalBuffer(Buffer buffer);
588 : : extern void UnpinLocalBufferNoOwner(Buffer buffer);
589 : : extern PrefetchBufferResult PrefetchLocalBuffer(SMgrRelation smgr,
590 : : ForkNumber forkNum,
591 : : BlockNumber blockNum);
592 : : extern BufferDesc *LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum,
593 : : BlockNumber blockNum, bool *foundPtr);
594 : : extern BlockNumber ExtendBufferedRelLocal(BufferManagerRelation bmr,
595 : : ForkNumber fork,
596 : : uint32 flags,
597 : : uint32 extend_by,
598 : : BlockNumber extend_upto,
599 : : Buffer *buffers,
600 : : uint32 *extended_by);
601 : : extern void MarkLocalBufferDirty(Buffer buffer);
602 : : extern void TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty,
603 : : uint64 set_flag_bits, bool release_aio);
604 : : extern bool StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait);
605 : : extern void FlushLocalBuffer(BufferDesc *bufHdr, SMgrRelation reln);
606 : : extern void InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced);
607 : : extern void DropRelationLocalBuffers(RelFileLocator rlocator,
608 : : ForkNumber *forkNum, int nforks,
609 : : BlockNumber *firstDelBlock);
610 : : extern void DropRelationAllLocalBuffers(RelFileLocator rlocator);
611 : : extern void AtEOXact_LocalBuffers(bool isCommit);
612 : :
613 : : #endif /* BUFMGR_INTERNALS_H */
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