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Diffstat (limited to 'db2/include/mp.h')
| -rw-r--r-- | db2/include/mp.h | 266 |
1 files changed, 266 insertions, 0 deletions
diff --git a/db2/include/mp.h b/db2/include/mp.h new file mode 100644 index 0000000000..4872596f83 --- /dev/null +++ b/db2/include/mp.h @@ -0,0 +1,266 @@ +/*- + * See the file LICENSE for redistribution information. + * + * Copyright (c) 1996, 1997 + * Sleepycat Software. All rights reserved. + * + * @(#)mp.h 10.14 (Sleepycat) 8/18/97 + */ + +struct __bh; typedef struct __bh BH; +struct __db_mpreg; typedef struct __db_mpreg DB_MPREG; +struct __mpool; typedef struct __mpool MPOOL; +struct __mpoolfile; typedef struct __mpoolfile MPOOLFILE; + + /* Default mpool name. */ +#define DB_DEFAULT_MPOOL_FILE "__db_mpool.share" + +/* + * We default to 128K (16 8K pages) if the user doesn't specify, and + * require a minimum of 20K. + */ +#define DB_CACHESIZE_DEF (128 * 1024) +#define DB_CACHESIZE_MIN ( 20 * 1024) + +/* Macro to return per-process address, offsets. */ +#define ADDR(base, offset) ((void *)((u_int8_t *)((base)->addr) + offset)) +#define OFFSET(base, p) ((u_int8_t *)(p) - (u_int8_t *)(base)->addr) + +#define INVALID 0 /* Invalid shared memory offset. */ +#define TEMPORARY "<tmp>" /* Temporary file name. */ + +/* + * There are two kinds of locks in the mpool code. The first is the region + * lock, used to serialize modifications to all data structures. The second + * is a per-buffer header lock. The locking order is as follows: + * + * Process searching for a buffer: + * Acquire the region lock. + * Find the buffer header. + * Increment the reference count (guarantee the buffer stays). + * If the BH_LOCKED flag is set: + * Release the region lock. + * Acquire the buffer lock. + * Release the buffer lock. + * Acquire the region lock. + * Return the buffer. + * + * Process reading/writing a buffer: + * Acquire the region lock. + * Find/create the buffer header. + * If reading, increment the reference count (guarantee the buffer stays). + * Set the BH_LOCKED flag. + * Acquire the buffer lock (guaranteed not to block). + * Release the region lock. + * Do the I/O and/or initialize buffer contents. + * Acquire the region lock. + * Clear the BH_LOCKED flag. + * Release the region lock. + * Release the buffer lock. + * If reading, return the buffer. + * + * Pointers to DB_MPOOL, MPOOL, DB_MPOOLFILE and MPOOLFILE structures are not + * reacquired when a region lock is reacquired because they couldn't have been + * closed/discarded and because they never move in memory. + */ +#define LOCKINIT(dbmp, mutexp) \ + if (F_ISSET(dbmp, MP_LOCKHANDLE | MP_LOCKREGION)) \ + (void)__db_mutex_init(mutexp, (dbmp)->fd) + +#define LOCKHANDLE(dbmp, mutexp) \ + if (F_ISSET(dbmp, MP_LOCKHANDLE)) \ + (void)__db_mutex_lock(mutexp, (dbmp)->fd, \ + (dbmp)->dbenv == NULL ? NULL : (dbmp)->dbenv->db_yield) +#define UNLOCKHANDLE(dbmp, mutexp) \ + if (F_ISSET(dbmp, MP_LOCKHANDLE)) \ + (void)__db_mutex_unlock(mutexp, (dbmp)->fd) + +#define LOCKREGION(dbmp) \ + if (F_ISSET(dbmp, MP_LOCKREGION)) \ + (void)__db_mutex_lock(&((RLAYOUT *)(dbmp)->mp)->lock, \ + (dbmp)->fd, \ + (dbmp)->dbenv == NULL ? NULL : (dbmp)->dbenv->db_yield) +#define UNLOCKREGION(dbmp) \ + if (F_ISSET(dbmp, MP_LOCKREGION)) \ + (void)__db_mutex_unlock(&((RLAYOUT *)(dbmp)->mp)->lock, \ + (dbmp)->fd) + +#define LOCKBUFFER(dbmp, bhp) \ + if (F_ISSET(dbmp, MP_LOCKREGION)) \ + (void)__db_mutex_lock(&(bhp)->mutex, (dbmp)->fd, \ + (dbmp)->dbenv == NULL ? NULL : (dbmp)->dbenv->db_yield) +#define UNLOCKBUFFER(dbmp, bhp) \ + if (F_ISSET(dbmp, MP_LOCKREGION)) \ + (void)__db_mutex_unlock(&(bhp)->mutex, (dbmp)->fd) + +/* + * DB_MPOOL -- + * Per-process memory pool structure. + */ +struct __db_mpool { +/* These fields need to be protected for multi-threaded support. */ + db_mutex_t mutex; /* Structure lock. */ + + /* List of pgin/pgout routines. */ + LIST_HEAD(__db_mpregh, __db_mpreg) dbregq; + + /* List of DB_MPOOLFILE's. */ + TAILQ_HEAD(__db_mpoolfileh, __db_mpoolfile) dbmfq; + +/* These fields are not protected. */ + DB_ENV *dbenv; /* Reference to error information. */ + + MPOOL *mp; /* Address of the shared MPOOL. */ + + void *maddr; /* Address of mmap'd region. */ + void *addr; /* Address of shalloc() region. */ + + DB_HASHTAB *htab; /* Hash table of bucket headers. */ + + int fd; /* Underlying mmap'd fd. */ + + +#define MP_ISPRIVATE 0x01 /* Private, so local memory. */ +#define MP_LOCKHANDLE 0x02 /* Threaded, lock handles and region. */ +#define MP_LOCKREGION 0x04 /* Concurrent access, lock region. */ + u_int32_t flags; +}; + +/* + * DB_MPREG -- + * DB_MPOOL registry of pgin/pgout functions. + */ +struct __db_mpreg { + LIST_ENTRY(__db_mpreg) q; /* Linked list. */ + + int ftype; /* File type. */ + /* Pgin, pgout routines. */ + int (*pgin) __P((db_pgno_t, void *, DBT *)); + int (*pgout) __P((db_pgno_t, void *, DBT *)); +}; + +/* + * DB_MPOOLFILE -- + * Per-process DB_MPOOLFILE information. + */ +struct __db_mpoolfile { +/* These fields need to be protected for multi-threaded support. */ + db_mutex_t mutex; /* Structure lock. */ + + int fd; /* Underlying file descriptor. */ + + u_int32_t pinref; /* Pinned block reference count. */ + +/* These fields are not protected. */ + TAILQ_ENTRY(__db_mpoolfile) q; /* Linked list of DB_MPOOLFILE's. */ + + char *path; /* Initial file path. */ + DB_MPOOL *dbmp; /* Overlying DB_MPOOL. */ + MPOOLFILE *mfp; /* Underlying MPOOLFILE. */ + + void *addr; /* Address of mmap'd region. */ + size_t len; /* Length of mmap'd region. */ + +#define MP_PATH_ALLOC 0x01 /* Path is allocated memory. */ +#define MP_PATH_TEMP 0x02 /* Backing file is a temporary. */ +#define MP_READONLY 0x04 /* File is readonly. */ + u_int32_t flags; +}; + +/* + * MPOOL -- + * Shared memory pool region. One of these is allocated in shared + * memory, and describes the pool. + */ +struct __mpool { + RLAYOUT rlayout; /* General region information. */ + + SH_TAILQ_HEAD(__bhq) bhq; /* LRU list of buckets. */ + SH_TAILQ_HEAD(__bhfq) bhfq; /* Free buckets. */ + SH_TAILQ_HEAD(__mpfq) mpfq; /* List of MPOOLFILEs. */ + + /* + * We make the assumption that the early pages of the file are far + * more likely to be retrieved than the later pages, which means + * that the top bits are more interesting for hashing since they're + * less likely to collide. On the other hand, since 512 4K pages + * represents a 2MB file, only the bottom 9 bits of the page number + * are likely to be set. We XOR in the offset in the MPOOL of the + * MPOOLFILE that backs this particular page, since that should also + * be unique for the page. + */ +#define BUCKET(mp, mf_offset, pgno) \ + (((pgno) ^ ((mf_offset) << 9)) % (mp)->htab_buckets) + + size_t htab; /* Hash table offset. */ + size_t htab_buckets; /* Number of hash table entries. */ + + DB_LSN lsn; /* Maximum checkpoint LSN. */ + int lsn_cnt; /* Checkpoint buffers left to write. */ + + DB_MPOOL_STAT stat; /* Global mpool statistics. */ + +#define MP_LSN_RETRY 0x01 /* Retry all BH_WRITE buffers. */ + u_int32_t flags; +}; + +/* + * MPOOLFILE -- + * Shared DB_MPOOLFILE information. + */ +struct __mpoolfile { + SH_TAILQ_ENTRY q; /* List of MPOOLFILEs */ + + u_int32_t ref; /* Reference count. */ + + int ftype; /* File type. */ + int can_mmap; /* If the file can be mmap'd. */ + + int lsn_off; /* Page's LSN offset. */ + + size_t path_off; /* File name location. */ + + size_t fileid_off; /* File identification location. */ + + size_t pgcookie_len; /* Pgin/pgout cookie length. */ + size_t pgcookie_off; /* Pgin/pgout cookie location. */ + + int lsn_cnt; /* Checkpoint buffers left to write. */ + + DB_MPOOL_FSTAT stat; /* Per-file mpool statistics. */ +}; + +/* + * BH -- + * Buffer header. + */ +struct __bh { + db_mutex_t mutex; /* Structure lock. */ + + u_int16_t ref; /* Reference count. */ + +#define BH_CALLPGIN 0x001 /* Page needs to be reworked... */ +#define BH_DIRTY 0x002 /* Page was modified. */ +#define BH_DISCARD 0x004 /* Page is useless. */ +#define BH_LOCKED 0x008 /* Page is locked (I/O in progress). */ +#define BH_TRASH 0x010 /* Page is garbage. */ +#define BH_WRITE 0x020 /* Page scheduled for writing. */ + u_int16_t flags; + + SH_TAILQ_ENTRY q; /* LRU list of bucket headers. */ + SH_TAILQ_ENTRY mq; /* MPOOLFILE list of bucket headers. */ + + db_pgno_t pgno; /* Underlying MPOOLFILE page number. */ + size_t mf_offset; /* Associated MPOOLFILE offset. */ + + /* + * !!! + * This array must be size_t aligned -- the DB access methods put PAGE + * and other structures into it, and expect to be able to access them + * directly. (We guarantee size_t alignment in the db_mpool(3) manual + * page as well.) + */ + u_int8_t buf[1]; /* Variable length data. */ +}; + +#include "mp_ext.h" |