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cpython-source-deps/dbinc/mp.h
2017-09-04 13:40:25 -05:00

650 lines
22 KiB
C

/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1996,2008 Oracle. All rights reserved.
*
* $Id: mp.h 63573 2008-05-23 21:43:21Z trent.nelson $
*/
#ifndef _DB_MP_H_
#define _DB_MP_H_
#if defined(__cplusplus)
extern "C" {
#endif
struct __bh; typedef struct __bh BH;
struct __bh_frozen_p; typedef struct __bh_frozen_p BH_FROZEN_PAGE;
struct __bh_frozen_a; typedef struct __bh_frozen_a BH_FROZEN_ALLOC;
struct __db_mpool_hash; typedef struct __db_mpool_hash DB_MPOOL_HASH;
struct __db_mpreg; typedef struct __db_mpreg DB_MPREG;
struct __mpool; typedef struct __mpool MPOOL;
/* We require at least 20KB of cache. */
#define DB_CACHESIZE_MIN (20 * 1024)
/*
* DB_MPOOLFILE initialization methods cannot be called after open is called,
* other methods cannot be called before open is called
*/
#define MPF_ILLEGAL_AFTER_OPEN(dbmfp, name) \
if (F_ISSET(dbmfp, MP_OPEN_CALLED)) \
return (__db_mi_open((dbmfp)->env, name, 1));
#define MPF_ILLEGAL_BEFORE_OPEN(dbmfp, name) \
if (!F_ISSET(dbmfp, MP_OPEN_CALLED)) \
return (__db_mi_open((dbmfp)->env, name, 0));
/*
* Cache flush operations, plus modifiers.
*/
#define DB_SYNC_ALLOC 0x0001 /* Flush for allocation. */
#define DB_SYNC_CACHE 0x0002 /* Flush entire cache. */
#define DB_SYNC_CHECKPOINT 0x0004 /* Checkpoint. */
#define DB_SYNC_FILE 0x0008 /* Flush file. */
#define DB_SYNC_INTERRUPT_OK 0x0010 /* Allow interrupt and return OK. */
#define DB_SYNC_QUEUE_EXTENT 0x0020 /* Flush a queue file with extents. */
#define DB_SYNC_SUPPRESS_WRITE 0x0040 /* Ignore max-write configuration. */
#define DB_SYNC_TRICKLE 0x0080 /* Trickle sync. */
/*
* DB_MPOOL --
* Per-process memory pool structure.
*/
struct __db_mpool {
/* These fields need to be protected for multi-threaded support. */
db_mutex_t mutex; /* Thread mutex. */
/*
* DB_MPREG structure for the DB pgin/pgout routines.
*
* Linked list of application-specified pgin/pgout routines.
*/
DB_MPREG *pg_inout;
LIST_HEAD(__db_mpregh, __db_mpreg) dbregq;
/* List of DB_MPOOLFILE's. */
TAILQ_HEAD(__db_mpoolfileh, __db_mpoolfile) dbmfq;
/*
* The env and reginfo fields are not thread protected, as they are
* initialized during mpool creation, and not modified again.
*/
ENV *env; /* Enclosing environment. */
REGINFO *reginfo; /* Underlying cache regions. */
};
/*
* DB_MPREG --
* DB_MPOOL registry of pgin/pgout functions.
*/
struct __db_mpreg {
LIST_ENTRY(__db_mpreg) q; /* Linked list. */
int32_t ftype; /* File type. */
/* Pgin, pgout routines. */
int (*pgin) __P((DB_ENV *, db_pgno_t, void *, DBT *));
int (*pgout) __P((DB_ENV *, db_pgno_t, void *, DBT *));
};
/*
* File hashing --
* We hash each file to hash bucket based on its fileid
* or, in the case of in memory files, its name.
*/
/* Number of file hash buckets, a small prime number */
#define MPOOL_FILE_BUCKETS 17
#define FHASH(id, len) __ham_func5(NULL, id, (u_int32_t)(len))
#define FNBUCKET(id, len) \
(FHASH(id, len) % MPOOL_FILE_BUCKETS)
/* Macros to lock/unlock the mpool region as a whole. */
#define MPOOL_SYSTEM_LOCK(env) \
MUTEX_LOCK(env, ((MPOOL *) \
(env)->mp_handle->reginfo[0].primary)->mtx_region)
#define MPOOL_SYSTEM_UNLOCK(env) \
MUTEX_UNLOCK(env, ((MPOOL *) \
(env)->mp_handle->reginfo[0].primary)->mtx_region)
/* Macros to lock/unlock a specific mpool region. */
#define MPOOL_REGION_LOCK(env, infop) \
MUTEX_LOCK(env, ((MPOOL *)(infop)->primary)->mtx_region)
#define MPOOL_REGION_UNLOCK(env, infop) \
MUTEX_UNLOCK(env, ((MPOOL *)(infop)->primary)->mtx_region)
/*
* MPOOL --
* Shared memory pool region.
*/
struct __mpool {
/*
* The memory pool can be broken up into individual pieces/files.
* There are two reasons for this: firstly, on Solaris you can allocate
* only a little more than 2GB of memory in a contiguous chunk,
* and I expect to see more systems with similar issues. Secondly,
* applications can add / remove pieces to dynamically resize the
* cache.
*
* While this structure is duplicated in each piece of the cache,
* the first of these pieces/files describes the entire pool, the
* second only describe a piece of the cache.
*/
db_mutex_t mtx_region; /* Region mutex. */
db_mutex_t mtx_resize; /* Resizing mutex. */
/*
* The lsn field and list of underlying MPOOLFILEs are thread protected
* by the region lock.
*/
DB_LSN lsn; /* Maximum checkpoint LSN. */
/* Configuration information: protected by the region lock. */
u_int32_t max_nreg; /* Maximum number of regions. */
size_t mp_mmapsize; /* Maximum file size for mmap. */
int mp_maxopenfd; /* Maximum open file descriptors. */
int mp_maxwrite; /* Maximum buffers to write. */
db_timeout_t mp_maxwrite_sleep; /* Sleep after writing max buffers. */
/*
* The number of regions and the total number of hash buckets across
* all regions.
* These fields are not protected by a mutex because we assume that we
* can read a 32-bit value atomically. They are only modified by cache
* resizing which holds the mpool resizing mutex to ensure that
* resizing is single-threaded. See the comment in mp_resize.c for
* more information.
*/
u_int32_t nreg; /* Number of underlying REGIONS. */
u_int32_t nbuckets; /* Total number of hash buckets. */
/*
* The regid field is protected by the resize mutex.
*/
roff_t regids; /* Array of underlying REGION Ids. */
roff_t ftab; /* Hash table of files. */
/*
* The following fields describe the per-cache portion of the region.
*
* The htab and htab_buckets fields are not thread protected as they
* are initialized during mpool creation, and not modified again.
*
* The last_checked and lru_count fields are thread protected by
* the region lock.
*/
roff_t htab; /* Hash table offset. */
u_int32_t htab_buckets; /* Number of hash table entries. */
u_int32_t last_checked; /* Last bucket checked for free. */
u_int32_t lru_count; /* Counter for buffer LRU. */
int32_t lru_reset; /* Hash bucket lru reset point. */
/*
* The stat fields are generally not thread protected, and cannot be
* trusted. Note that st_pages is an exception, and is always updated
* inside a region lock (although it is sometimes read outside of the
* region lock).
*/
DB_MPOOL_STAT stat; /* Per-cache mpool statistics. */
/*
* We track page puts so that we can decide when allocation is never
* going to succeed. We don't lock the field, all we care about is
* if it changes.
*/
u_int32_t put_counter; /* Count of page put calls. */
/*
* Cache flush operations take a long time...
*
* Some cache flush operations want to ignore the app's configured
* max-write parameters (they are trying to quickly shut down an
* environment, for example). We can't specify that as an argument
* to the cache region functions, because we may decide to ignore
* the max-write configuration after the cache operation has begun.
* If the variable suppress_maxwrite is set, ignore the application
* max-write config.
*
* We may want to interrupt cache flush operations in high-availability
* configurations.
*/
#define DB_MEMP_SUPPRESS_WRITE 0x01
#define DB_MEMP_SYNC_INTERRUPT 0x02
u_int32_t config_flags;
/* Free frozen buffer headers, protected by the region lock. */
SH_TAILQ_HEAD(__free_frozen) free_frozen;
/* Allocated blocks of frozen buffer headers. */
SH_TAILQ_HEAD(__alloc_frozen) alloc_frozen;
};
/*
* NREGION --
* Select a cache region given the bucket number.
*/
#define NREGION(mp, bucket) \
((bucket) / (mp)->htab_buckets)
/*
* MP_HASH --
* We make the assumption that early pages of the file are more likely
* to be retrieved than the later pages, which means the top bits will
* be more interesting for hashing as they're less likely to collide.
* That said, as 512 8K pages represents a 4MB file, so only reasonably
* large files will have page numbers with any other than the bottom 9
* bits set. We XOR in the MPOOL offset of the MPOOLFILE that backs the
* page, since that should also be unique for the page. We don't want
* to do anything very fancy -- speed is more important to us than using
* good hashing.
*
* Since moving to a dynamic hash, which boils down to using some of the
* least significant bits of the hash value, we no longer want to use a
* simple shift here, because it's likely with a bit shift that mf_offset
* will be ignored, and pages from different files end up in the same
* hash bucket. Use a nearby prime instead.
*/
#define MP_HASH(mf_offset, pgno) \
((((pgno) << 8) ^ (pgno)) ^ ((mf_offset) * 509))
/*
* Inline the calculation of the mask, since we can't reliably store the mask
* with the number of buckets in the region.
*
* This is equivalent to:
* mask = (1 << __db_log2(nbuckets)) - 1;
*/
#define MP_MASK(nbuckets, mask) do { \
for (mask = 1; mask < (nbuckets); mask = (mask << 1) | 1) \
; \
} while (0)
#define MP_HASH_BUCKET(hash, nbuckets, mask, bucket) do { \
(bucket) = (hash) & (mask); \
if ((bucket) >= (nbuckets)) \
(bucket) &= ((mask) >> 1); \
} while (0)
#define MP_BUCKET(mf_offset, pgno, nbuckets, bucket) do { \
u_int32_t __mask; \
MP_MASK(nbuckets, __mask); \
MP_HASH_BUCKET(MP_HASH(mf_offset, pgno), nbuckets, \
__mask, bucket); \
} while (0)
/*
* MP_GET_REGION --
* Select the region for a given page.
*/
#define MP_GET_REGION(dbmfp, pgno, infopp, ret) do { \
DB_MPOOL *__t_dbmp; \
MPOOL *__t_mp; \
\
__t_dbmp = dbmfp->env->mp_handle; \
__t_mp = __t_dbmp->reginfo[0].primary; \
if (__t_mp->max_nreg == 1) { \
*(infopp) = &__t_dbmp->reginfo[0]; \
} else \
ret = __memp_get_bucket((dbmfp)->env, \
(dbmfp)->mfp, (pgno), (infopp), NULL); \
} while (0)
/*
* MP_GET_BUCKET --
* Select and lock the bucket for a given page.
*/
#define MP_GET_BUCKET(env, mfp, pgno, infopp, hp, ret) do { \
DB_MPOOL *__t_dbmp; \
MPOOL *__t_mp; \
roff_t __t_mf_offset; \
u_int32_t __t_bucket; \
\
__t_dbmp = (env)->mp_handle; \
__t_mp = __t_dbmp->reginfo[0].primary; \
if (__t_mp->max_nreg == 1) { \
*(infopp) = &__t_dbmp->reginfo[0]; \
__t_mf_offset = R_OFFSET(*(infopp), (mfp)); \
MP_BUCKET(__t_mf_offset, \
(pgno), __t_mp->nbuckets, __t_bucket); \
(hp) = R_ADDR(*(infopp), __t_mp->htab); \
(hp) = &(hp)[__t_bucket]; \
MUTEX_LOCK(env, (hp)->mtx_hash); \
ret = 0; \
} else \
ret = __memp_get_bucket((env), \
(mfp), (pgno), (infopp), &(hp)); \
} while (0)
struct __db_mpool_hash {
db_mutex_t mtx_hash; /* Per-bucket mutex. */
db_mutex_t mtx_io; /* Buffer I/O mutex. */
DB_HASHTAB hash_bucket; /* Head of bucket. */
u_int32_t hash_page_dirty;/* Count of dirty pages. */
#ifndef __TEST_DB_NO_STATISTICS
u_int32_t hash_io_wait; /* Count of I/O waits. */
u_int32_t hash_frozen; /* Count of frozen buffers. */
u_int32_t hash_thawed; /* Count of thawed buffers. */
u_int32_t hash_frozen_freed;/* Count of freed frozen buffers. */
#endif
DB_LSN old_reader; /* Oldest snapshot reader (cached). */
#define IO_WAITER 0x001 /* Thread is waiting on page. */
u_int32_t flags;
};
/*
* The base mpool priority is 1/4th of the name space, or just under 2^30.
* When the LRU counter wraps, we shift everybody down to a base-relative
* value.
*/
#define MPOOL_BASE_DECREMENT (UINT32_MAX - (UINT32_MAX / 4))
/*
* Mpool priorities from low to high. Defined in terms of fractions of the
* buffers in the pool.
*/
#define MPOOL_PRI_VERY_LOW -1 /* Dead duck. Check and set to 0. */
#define MPOOL_PRI_LOW -2 /* Low. */
#define MPOOL_PRI_DEFAULT 0 /* No adjustment -- special case.*/
#define MPOOL_PRI_HIGH 10 /* With the dirty buffers. */
#define MPOOL_PRI_DIRTY 10 /* Dirty gets a 10% boost. */
#define MPOOL_PRI_VERY_HIGH 1 /* Add number of buffers in pool. */
/*
* MPOOLFILE --
* Shared DB_MPOOLFILE information.
*/
struct __mpoolfile {
db_mutex_t mutex; /* MPOOLFILE mutex. */
/* Protected by MPOOLFILE mutex. */
u_int32_t mpf_cnt; /* Ref count: DB_MPOOLFILEs. */
u_int32_t block_cnt; /* Ref count: blocks in cache. */
db_pgno_t last_pgno; /* Last page in the file. */
db_pgno_t last_flushed_pgno; /* Last page flushed to disk. */
db_pgno_t orig_last_pgno; /* Original last page in the file. */
db_pgno_t maxpgno; /* Maximum page number. */
roff_t path_off; /* File name location. */
/* Protected by hash bucket mutex. */
SH_TAILQ_ENTRY q; /* List of MPOOLFILEs */
/*
* The following are used for file compaction processing.
* They are only used when a thread is in the process
* of trying to move free pages to the end of the file.
* Other threads may look here when freeing a page.
* Protected by a lock on the metapage.
*/
u_int32_t free_ref; /* Refcount to freelist. */
u_int32_t free_cnt; /* Count of free pages. */
size_t free_size; /* Allocated size of free list. */
roff_t free_list; /* Offset to free list. */
/*
* We normally don't lock the deadfile field when we read it since we
* only care if the field is zero or non-zero. We do lock on read when
* searching for a matching MPOOLFILE -- see that code for more detail.
*/
int32_t deadfile; /* Dirty pages can be discarded. */
u_int32_t bucket; /* hash bucket for this file. */
/*
* None of the following fields are thread protected.
*
* There are potential races with the ftype field because it's read
* without holding a lock. However, it has to be set before adding
* any buffers to the cache that depend on it being set, so there
* would need to be incorrect operation ordering to have a problem.
*/
int32_t ftype; /* File type. */
/*
* There are potential races with the priority field because it's read
* without holding a lock. However, a collision is unlikely and if it
* happens is of little consequence.
*/
int32_t priority; /* Priority when unpinning buffer. */
/*
* There are potential races with the file_written field (many threads
* may be writing blocks at the same time), and with no_backing_file
* and unlink_on_close fields, as they may be set while other threads
* are reading them. However, we only care if the field value is zero
* or non-zero, so don't lock the memory.
*
* !!!
* Theoretically, a 64-bit architecture could put two of these fields
* in a single memory operation and we could race. I have never seen
* an architecture where that's a problem, and I believe Java requires
* that to never be the case.
*
* File_written is set whenever a buffer is marked dirty in the cache.
* It can be cleared in some cases, after all dirty buffers have been
* written AND the file has been flushed to disk.
*/
int32_t file_written; /* File was written. */
int32_t no_backing_file; /* Never open a backing file. */
int32_t unlink_on_close; /* Unlink file on last close. */
int32_t multiversion; /* Number of DB_MULTIVERSION handles. */
/*
* We do not protect the statistics in "stat" because of the cost of
* the mutex in the get/put routines. There is a chance that a count
* will get lost.
*/
DB_MPOOL_FSTAT stat; /* Per-file mpool statistics. */
/*
* The remaining fields are initialized at open and never subsequently
* modified.
*/
int32_t lsn_off; /* Page's LSN offset. */
u_int32_t clear_len; /* Bytes to clear on page create. */
roff_t fileid_off; /* File ID string location. */
roff_t pgcookie_len; /* Pgin/pgout cookie length. */
roff_t pgcookie_off; /* Pgin/pgout cookie location. */
/*
* The flags are initialized at open and never subsequently modified.
*/
#define MP_CAN_MMAP 0x001 /* If the file can be mmap'd. */
#define MP_DIRECT 0x002 /* No OS buffering. */
#define MP_DURABLE_UNKNOWN 0x004 /* We don't care about durability. */
#define MP_EXTENT 0x008 /* Extent file. */
#define MP_FAKE_DEADFILE 0x010 /* Deadfile field: fake flag. */
#define MP_FAKE_FILEWRITTEN 0x020 /* File_written field: fake flag. */
#define MP_FAKE_NB 0x040 /* No_backing_file field: fake flag. */
#define MP_FAKE_UOC 0x080 /* Unlink_on_close field: fake flag. */
#define MP_NOT_DURABLE 0x100 /* File is not durable. */
#define MP_TEMP 0x200 /* Backing file is a temporary. */
u_int32_t flags;
};
/*
* Flags to __memp_bh_free.
*/
#define BH_FREE_FREEMEM 0x01
#define BH_FREE_REUSE 0x02
#define BH_FREE_UNLOCKED 0x04
/*
* BH --
* Buffer header.
*/
struct __bh {
u_int16_t ref; /* Reference count. */
u_int16_t ref_sync; /* Sync wait-for reference count. */
#define BH_CALLPGIN 0x001 /* Convert the page before use. */
#define BH_DIRTY 0x002 /* Page is modified. */
#define BH_DIRTY_CREATE 0x004 /* Page is modified. */
#define BH_DISCARD 0x008 /* Page is useless. */
#define BH_FREED 0x010 /* Page was freed. */
#define BH_FROZEN 0x020 /* Frozen buffer: allocate & re-read. */
#define BH_LOCKED 0x040 /* Page is locked (I/O in progress). */
#define BH_TRASH 0x080 /* Page is garbage. */
#define BH_THAWED 0x100 /* Page was thawed. */
u_int16_t flags;
u_int32_t priority; /* Priority. */
SH_TAILQ_ENTRY hq; /* MPOOL hash bucket queue. */
db_pgno_t pgno; /* Underlying MPOOLFILE page number. */
roff_t mf_offset; /* Associated MPOOLFILE offset. */
roff_t td_off; /* MVCC: creating TXN_DETAIL offset. */
SH_CHAIN_ENTRY vc; /* MVCC: version chain. */
#ifdef DIAG_MVCC
u_int16_t align_off; /* Alignment offset for diagnostics.*/
#endif
/*
* !!!
* This array must be at least size_t aligned -- the DB access methods
* put PAGE and other structures into it, and then access them directly.
* (We guarantee size_t alignment to applications in the documentation,
* too.)
*/
u_int8_t buf[1]; /* Variable length data. */
};
/*
* BH_FROZEN_PAGE --
* Data used to find a frozen buffer header.
*/
struct __bh_frozen_p {
BH header;
db_pgno_t spgno; /* Page number in freezer file. */
};
/*
* BH_FROZEN_ALLOC --
* Frozen buffer headers are allocated a page at a time in general. This
* structure is allocated at the beginning of the page so that the
* allocation chunks can be tracked and freed (for private environments).
*/
struct __bh_frozen_a {
SH_TAILQ_ENTRY links;
};
#define MULTIVERSION(dbp) ((dbp)->mpf->mfp->multiversion)
#define IS_DIRTY(p) \
F_ISSET((BH *)((u_int8_t *)(p) - SSZA(BH, buf)), BH_DIRTY)
#define BH_OWNER(env, bhp) \
((TXN_DETAIL *)R_ADDR(&env->tx_handle->reginfo, bhp->td_off))
#define BH_OWNED_BY(env, bhp, txn) ((txn) != NULL && \
(bhp)->td_off != INVALID_ROFF && \
(txn)->td == BH_OWNER(env, bhp))
#define BH_PRIORITY(bhp) \
(SH_CHAIN_SINGLETON(bhp, vc) ? (bhp)->priority : \
__memp_bh_priority(bhp))
#define VISIBLE_LSN(env, bhp) \
(&BH_OWNER(env, bhp)->visible_lsn)
/*
* Make a copy of the buffer's visible LSN, one field at a time. We rely on the
* 32-bit operations being atomic. The visible_lsn starts at MAX_LSN and is
* set during commit or abort to the current LSN.
*
* If we race with a commit / abort, we may see either the file or the offset
* still at UINT32_MAX, so vlsn is guaranteed to be in the future. That's OK,
* since we had to take the log region lock to allocate the read LSN so we were
* never going to see this buffer anyway.
*/
#define BH_VISIBLE(env, bhp, read_lsnp, vlsn) \
(bhp->td_off == INVALID_ROFF || \
((vlsn).file = VISIBLE_LSN(env, bhp)->file, \
(vlsn).offset = VISIBLE_LSN(env, bhp)->offset, \
LOG_COMPARE((read_lsnp), &(vlsn)) >= 0))
#define BH_OBSOLETE(bhp, old_lsn, vlsn) (SH_CHAIN_HASNEXT(bhp, vc) ? \
BH_VISIBLE(env, SH_CHAIN_NEXTP(bhp, vc, __bh), &(old_lsn), vlsn) :\
BH_VISIBLE(env, bhp, &(old_lsn), vlsn))
#define MVCC_SKIP_CURADJ(dbc, pgno) \
(dbc->txn != NULL && F_ISSET(dbc->txn, TXN_SNAPSHOT) && \
dbc->txn->td != NULL && __memp_skip_curadj(dbc, pgno))
#if defined(DIAG_MVCC) && defined(HAVE_MPROTECT)
#define VM_PAGESIZE 4096
#define MVCC_BHSIZE(mfp, sz) do { \
sz += VM_PAGESIZE + sizeof(BH); \
if (mfp->stat.st_pagesize < VM_PAGESIZE) \
sz += VM_PAGESIZE - mfp->stat.st_pagesize; \
} while (0)
#define MVCC_BHALIGN(mfp, p) do { \
if (mfp != NULL) { \
BH *__bhp; \
void *__orig = (p); \
p = ALIGNP_INC(p, VM_PAGESIZE); \
if ((u_int8_t *)p < (u_int8_t *)__orig + sizeof(BH)) \
p = (u_int8_t *)p + VM_PAGESIZE; \
__bhp = (BH *)((u_int8_t *)p - SSZA(BH, buf)); \
DB_ASSERT(env, \
((uintptr_t)__bhp->buf & (VM_PAGESIZE - 1)) == 0); \
DB_ASSERT(env, \
(u_int8_t *)__bhp >= (u_int8_t *)__orig); \
DB_ASSERT(env, (u_int8_t *)p + mfp->stat.st_pagesize <\
(u_int8_t *)__orig + len); \
__bhp->align_off = \
(u_int16_t)((u_int8_t *)__bhp - (u_int8_t *)__orig);\
p = __bhp; \
} \
} while (0)
#define MVCC_BHUNALIGN(mfp, p) do { \
if ((mfp) != NULL) { \
BH *bhp = (BH *)(p); \
(p) = ((u_int8_t *)bhp - bhp->align_off); \
} \
} while (0)
#ifdef linux
#define MVCC_MPROTECT(buf, sz, mode) do { \
int __ret = mprotect((buf), (sz), (mode)); \
DB_ASSERT(env, __ret == 0); \
} while (0)
#else
#define MVCC_MPROTECT(buf, sz, mode) do { \
if (!F_ISSET(env, ENV_PRIVATE | ENV_SYSTEM_MEM)) { \
int __ret = mprotect((buf), (sz), (mode)); \
DB_ASSERT(env, __ret == 0); \
} \
} while (0)
#endif /* linux */
#else /* defined(DIAG_MVCC) && defined(HAVE_MPROTECT) */
#define MVCC_BHSIZE(mfp, sz) do {} while (0)
#define MVCC_BHALIGN(mfp, p) do {} while (0)
#define MVCC_BHUNALIGN(mfp, p) do {} while (0)
#define MVCC_MPROTECT(buf, size, mode) do {} while (0)
#endif
/*
* Flags to __memp_ftruncate.
*/
#define MP_TRUNC_RECOVER 0x01
#if defined(__cplusplus)
}
#endif
#include "dbinc_auto/mp_ext.h"
#endif /* !_DB_MP_H_ */