/*- * See the file LICENSE for redistribution information. * * Copyright (c) 1996-2001 * Sleepycat Software. All rights reserved. * * $Id: mp.h,v 11.27 2001/10/29 19:10:46 ubell Exp $ */ #ifndef _DB_MP_H_ #define _DB_MP_H_ struct __bh; typedef struct __bh BH; struct __db_mpreg; typedef struct __db_mpreg DB_MPREG; struct __mpool; typedef struct __mpool MPOOL; /* We require at least 20K of cache. */ #define DB_CACHESIZE_MIN (20 * 1024) /* * DB_MPOOL -- * Per-process memory pool structure. */ struct __db_mpool { /* These fields need to be protected for multi-threaded support. */ DB_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. */ u_int32_t nreg; /* N underlying cache regions. */ REGINFO *reginfo; /* Underlying cache regions. */ int extents; /* Extent files opened by bhwrite. */ /* Once set it's never cleared. */ }; /* * 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_ENV *, db_pgno_t, void *, DBT *)); int (*pgout) __P((DB_ENV *, db_pgno_t, void *, DBT *)); }; /* * 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)->nreg) /* * 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. */ struct __mpool { /* * The memory pool can 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 contiguous chunk, * and I expect to see more systems with similar issues. * * The first of these pieces/files describes the entire pool, all * subsequent ones only describe a part of the cache. */ /* * We single-thread memp_sync and memp_fsync calls. * * This mutex is intended *only* to single-thread access to the call, */ DB_MUTEX sync_mutex; /* Checkpoint lock. */ /* * The lsn and lsn_cnt fields, and the list of underlying MPOOLFILEs * are thread-protected, by the region lock. */ DB_LSN lsn; /* Maximum checkpoint LSN. */ u_int32_t lsn_cnt; /* Checkpoint buffers left to write. */ SH_TAILQ_HEAD(__mpfq) mpfq; /* List of MPOOLFILEs. */ /* * The nreg, regids and maint_off fields are not thread protected, * as they are initialized during mpool creation, and not modified * again. */ u_int32_t nreg; /* Number of underlying REGIONS. */ roff_t regids; /* Array of underlying REGION Ids. */ #ifdef MUTEX_SYSTEM_RESOURCES roff_t maint_off; /* Maintenance information offset */ #endif /* The flags field is thread-protected, by the region lock. */ #define MP_LSN_RETRY 0x01 /* Retry all BH_WRITE buffers. */ u_int32_t flags; /* * The following structure fields only describe the cache portion of * the region. The bhq and stat files are thread-protected, by the * region lock. The htab fields are not thread-protected, as they are * initialized during mpool creation, and not modified again. */ 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 */ u_int32_t mpf_cnt; /* Ref count: DB_MPOOLFILEs. */ u_int32_t block_cnt; /* Ref count: blocks in cache. */ u_int32_t lsn_cnt; /* Checkpoint buffers left to write. */ 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. */ db_pgno_t last_pgno; /* Last page in the file. */ db_pgno_t orig_last_pgno; /* Original last page in the file. */ DB_MPOOL_FSTAT stat; /* Per-file mpool statistics. */ #define MP_CAN_MMAP 0x01 /* If the file can be mmap'd. */ #define MP_DEADFILE 0x02 /* Dirty pages can simply be trashed. */ #define MP_EXTENT 0x04 /* Extent file. */ #define MP_TEMP 0x08 /* Backing file is a temporary. */ #define MP_UNLINK 0x10 /* Unlink file on last close. */ u_int32_t flags; }; /* * BH_TO_CACHE -- * Return the cache where we can find the specified buffer header. */ #define BH_TO_CACHE(dbmp, bhp) \ (dbmp)->reginfo[NCACHE((dbmp)->reginfo[0].primary, (bhp)->pgno)].primary /* * BH -- * Buffer header. */ struct __bh { DB_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_DIRTY_CREATE 0x004 /* Page created, must be written. */ #define BH_DISCARD 0x008 /* Page is useless. */ #define BH_LOCKED 0x010 /* Page is locked (I/O in progress). */ #define BH_SYNC 0x020 /* memp sync: write the page */ #define BH_SYNC_LOGFLSH 0x040 /* memp sync: also flush the log */ #define BH_TRASH 0x080 /* Page is garbage. */ 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 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. */ }; #include "mp_ext.h" #endif /* !_DB_MP_H_ */