/*- * See the file LICENSE for redistribution information. * * Copyright (c) 1996, 1997, 1998, 1999 * Sleepycat Software. All rights reserved. * * @(#)mp.h 11.3 (Sleepycat) 10/6/99 */ struct __bh; typedef struct __bh BH; struct __db_mpool; typedef struct __db_mpool DB_MPOOL; struct __db_mpreg; typedef struct __db_mpreg DB_MPREG; struct __mcache; typedef struct __mcache MCACHE; struct __mpool; typedef struct __mpool MPOOL; struct __mpoolfile; typedef struct __mpoolfile MPOOLFILE; /* We require at least 20K of cache. */ #define DB_CACHESIZE_MIN ( 20 * 1024) /* * By default, environments have room for 500 files. */ #define DB_MPOOLFILE_DEF 500 /* * DB_MPOOL -- * Per-process memory pool structure. */ struct __db_mpool { /* These fields need to be protected for multi-threaded support. */ MUTEX *mutexp; /* Structure thread 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 thread-protected. */ DB_ENV *dbenv; /* Reference to error information. */ REGINFO reginfo; /* Main shared region. */ int nc_reg; /* N underlying cache regions. */ REGINFO *c_reginfo; /* Underlying cache regions. */ }; /* * 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. */ MUTEX *mutexp; /* Structure thread lock. */ DB_FH fh; /* Underlying file handle. */ u_int32_t ref; /* Reference count. */ /* * !!! * This field is a special case -- it's protected by the region lock * NOT the thread lock. The reason for this is that we always have * the region lock immediately before or after we modify the field, * and we don't want to use the structure lock to protect it because * then I/O (which is done with the structure lock held because of * the race between the seek and write of the file descriptor) will * block any other put/get calls using this DB_MPOOLFILE structure. */ u_int32_t pinref; /* Pinned block reference count. */ /* * !!! * This field is a special case -- it's protected by the region lock * since it's manipulated only when new files are added to the list. */ TAILQ_ENTRY(__db_mpoolfile) q; /* Linked list of DB_MPOOLFILE's. */ /* These fields are not thread-protected. */ 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. */ /* These fields need to be protected for multi-threaded support. */ #define MP_READONLY 0x01 /* File is readonly. */ #define MP_UPGRADE 0x02 /* File descriptor is readwrite. */ #define MP_UPGRADE_FAIL 0x04 /* Upgrade wasn't possible. */ u_int32_t flags; }; /* * NCACHE -- * Select a cache based on the page number. This assumes accesses are * uniform across pages, which is probably OK -- what we really want to * avoid is anything that puts all the pages for any single file in the * same cache, as we expect that file access will be bursty. */ #define NCACHE(mp, pgno) \ ((pgno) % ((MPOOL *)mp)->nc_reg) /* * NBUCKET -- * 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. */ #define NBUCKET(mc, mf_offset, pgno) \ (((pgno) ^ ((mf_offset) << 9)) % (mc)->htab_buckets) /* * MPOOL -- * Shared memory pool region. One of these is allocated in shared * memory, and describes the entire pool. */ struct __mpool { SH_TAILQ_HEAD(__mpfq) mpfq; /* List of MPOOLFILEs. */ /* * We single-thread memp_sync and memp_fsync calls. * * This mutex is intended *only* to single-thread access to the call, * it is not used to protect the lsn and lsn_cnt fields, the region * lock is used to protect them. */ MUTEX sync_mutex; /* Checkpoint lock. */ DB_LSN lsn; /* Maximum checkpoint LSN. */ u_int32_t lsn_cnt; /* Checkpoint buffers left to write. */ u_int32_t nc_reg; /* Number of underlying REGIONS. */ roff_t c_regids; /* Array of underlying REGION Ids. */ #define MP_LSN_RETRY 0x01 /* Retry all BH_WRITE buffers. */ u_int32_t flags; }; /* * MCACHE -- * The memory pool may be broken up into individual pieces/files. Not * what we would have liked, but on Solaris you can allocate only a * little more than 2GB of memory in a single contiguous chunk, and I * expect to see more systems with similar issues. An MCACHE structure * describes a backing piece of memory used as a cache. */ struct __mcache { SH_TAILQ_HEAD(__bhq) bhq; /* LRU list of buffer headers. */ int htab_buckets; /* Number of hash table entries. */ roff_t htab; /* Hash table offset. */ DB_MPOOL_STAT stat; /* Per-cache mpool statistics. */ }; /* * MPOOLFILE -- * Shared DB_MPOOLFILE information. */ struct __mpoolfile { SH_TAILQ_ENTRY q; /* List of MPOOLFILEs */ int ftype; /* File type. */ int32_t lsn_off; /* Page's LSN offset. */ u_int32_t clear_len; /* Bytes to clear on page create. */ roff_t path_off; /* File name location. */ roff_t fileid_off; /* File identification location. */ roff_t pgcookie_len; /* Pgin/pgout cookie length. */ roff_t pgcookie_off; /* Pgin/pgout cookie location. */ u_int32_t lsn_cnt; /* Checkpoint buffers left to write. */ db_pgno_t last_pgno; /* Last page in the file. */ db_pgno_t orig_last_pgno; /* Original last page in the file. */ #define MP_CAN_MMAP 0x01 /* If the file can be mmap'd. */ #define MP_REMOVED 0x02 /* Backing file has been removed. */ #define MP_TEMP 0x04 /* Backing file is a temporary. */ u_int32_t flags; DB_MPOOL_FSTAT stat; /* Per-file mpool statistics. */ }; /* * BH_TO_CACHE -- * Return the cache where we can find the specified buffer header. */ #define BH_TO_CACHE(dbmp, bhp) \ (dbmp)->c_reginfo[NCACHE((dbmp)->reginfo.primary, (bhp)->pgno)].primary /* * BH -- * Buffer header. */ struct __bh { MUTEX mutex; /* Buffer thread/process 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 queue. */ SH_TAILQ_ENTRY hq; /* MPOOL hash bucket queue. */ db_pgno_t pgno; /* Underlying MPOOLFILE page number. */ roff_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 documentation too.) */ u_int8_t buf[1]; /* Variable length data. */ }; #include "mp_ext.h"