245 lines
7.8 KiB
C
245 lines
7.8 KiB
C
/*-
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* See the file LICENSE for redistribution information.
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*
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* Copyright (c) 1996, 1997, 1998, 1999, 2000
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* Sleepycat Software. All rights reserved.
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*
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* $Id: mp.h,v 11.16 2001/01/10 04:50:53 ubell Exp $
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*/
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struct __bh; typedef struct __bh BH;
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struct __db_mpool; typedef struct __db_mpool DB_MPOOL;
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struct __db_mpreg; typedef struct __db_mpreg DB_MPREG;
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struct __mpool; typedef struct __mpool MPOOL;
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struct __mpoolfile; typedef struct __mpoolfile MPOOLFILE;
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/* We require at least 40K of cache. */
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#define DB_CACHESIZE_MIN (20 * 1024)
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/*
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* DB_MPOOL --
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* Per-process memory pool structure.
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*/
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struct __db_mpool {
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/* These fields need to be protected for multi-threaded support. */
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MUTEX *mutexp; /* Structure thread lock. */
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/* List of pgin/pgout routines. */
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LIST_HEAD(__db_mpregh, __db_mpreg) dbregq;
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/* List of DB_MPOOLFILE's. */
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TAILQ_HEAD(__db_mpoolfileh, __db_mpoolfile) dbmfq;
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/* These fields are not thread-protected. */
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DB_ENV *dbenv; /* Reference to error information. */
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u_int32_t nreg; /* N underlying cache regions. */
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REGINFO *reginfo; /* Underlying cache regions. */
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};
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/*
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* DB_MPREG --
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* DB_MPOOL registry of pgin/pgout functions.
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*/
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struct __db_mpreg {
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LIST_ENTRY(__db_mpreg) q; /* Linked list. */
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int ftype; /* File type. */
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/* Pgin, pgout routines. */
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int (*pgin) __P((DB_ENV *, db_pgno_t, void *, DBT *));
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int (*pgout) __P((DB_ENV *, db_pgno_t, void *, DBT *));
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};
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/*
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* DB_MPOOLFILE --
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* Per-process DB_MPOOLFILE information.
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*/
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struct __db_mpoolfile {
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/* These fields need to be protected for multi-threaded support. */
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MUTEX *mutexp; /* Structure thread lock. */
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DB_FH fh; /* Underlying file handle. */
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u_int32_t ref; /* Reference count. */
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/*
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* !!!
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* This field is a special case -- it's protected by the region lock
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* NOT the thread lock. The reason for this is that we always have
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* the region lock immediately before or after we modify the field,
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* and we don't want to use the structure lock to protect it because
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* then I/O (which is done with the structure lock held because of
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* the race between the seek and write of the file descriptor) will
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* block any other put/get calls using this DB_MPOOLFILE structure.
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*/
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u_int32_t pinref; /* Pinned block reference count. */
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/*
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* !!!
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* This field is a special case -- it's protected by the region lock
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* since it's manipulated only when new files are added to the list.
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*/
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TAILQ_ENTRY(__db_mpoolfile) q; /* Linked list of DB_MPOOLFILE's. */
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/* These fields are not thread-protected. */
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DB_MPOOL *dbmp; /* Overlying DB_MPOOL. */
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MPOOLFILE *mfp; /* Underlying MPOOLFILE. */
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void *addr; /* Address of mmap'd region. */
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size_t len; /* Length of mmap'd region. */
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/* These fields need to be protected for multi-threaded support. */
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#define MP_READONLY 0x01 /* File is readonly. */
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#define MP_UPGRADE 0x02 /* File descriptor is readwrite. */
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#define MP_UPGRADE_FAIL 0x04 /* Upgrade wasn't possible. */
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u_int32_t flags;
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};
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/*
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* NCACHE --
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* Select a cache based on the page number. This assumes accesses are
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* uniform across pages, which is probably OK -- what we really want to
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* avoid is anything that puts all the pages for any single file in the
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* same cache, as we expect that file access will be bursty.
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*/
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#define NCACHE(mp, pgno) \
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((pgno) % ((MPOOL *)mp)->nreg)
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/*
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* NBUCKET --
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* We make the assumption that early pages of the file are more likely
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* to be retrieved than the later pages, which means the top bits will
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* be more interesting for hashing as they're less likely to collide.
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* That said, as 512 8K pages represents a 4MB file, so only reasonably
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* large files will have page numbers with any other than the bottom 9
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* bits set. We XOR in the MPOOL offset of the MPOOLFILE that backs the
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* page, since that should also be unique for the page. We don't want
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* to do anything very fancy -- speed is more important to us than using
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* good hashing.
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*/
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#define NBUCKET(mc, mf_offset, pgno) \
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(((pgno) ^ ((mf_offset) << 9)) % (mc)->htab_buckets)
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/*
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* MPOOL --
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* Shared memory pool region.
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*/
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struct __mpool {
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/*
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* The memory pool can be broken up into individual pieces/files.
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* Not what we would have liked, but on Solaris you can allocate
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* only a little more than 2GB of memory in a contiguous chunk,
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* and I expect to see more systems with similar issues.
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*
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* The first of these pieces/files describes the entire pool, all
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* subsequent ones only describe a part of the cache.
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*
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* We single-thread memp_sync and memp_fsync calls.
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*
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* This mutex is intended *only* to single-thread access to the call,
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* it is not used to protect the lsn and lsn_cnt fields, the region
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* lock is used to protect them.
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*/
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MUTEX sync_mutex; /* Checkpoint lock. */
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DB_LSN lsn; /* Maximum checkpoint LSN. */
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u_int32_t lsn_cnt; /* Checkpoint buffers left to write. */
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SH_TAILQ_HEAD(__mpfq) mpfq; /* List of MPOOLFILEs. */
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u_int32_t nreg; /* Number of underlying REGIONS. */
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roff_t regids; /* Array of underlying REGION Ids. */
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#define MP_LSN_RETRY 0x01 /* Retry all BH_WRITE buffers. */
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u_int32_t flags;
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/*
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* The following structure fields only describe the cache portion of
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* the region.
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*/
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SH_TAILQ_HEAD(__bhq) bhq; /* LRU list of buffer headers. */
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int htab_buckets; /* Number of hash table entries. */
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roff_t htab; /* Hash table offset. */
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DB_MPOOL_STAT stat; /* Per-cache mpool statistics. */
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#ifdef MUTEX_SYSTEM_RESOURCES
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roff_t maint_off; /* Maintenance information offset */
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#endif
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};
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/*
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* MPOOLFILE --
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* Shared DB_MPOOLFILE information.
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*/
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struct __mpoolfile {
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SH_TAILQ_ENTRY q; /* List of MPOOLFILEs */
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db_pgno_t mpf_cnt; /* Ref count: DB_MPOOLFILEs. */
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db_pgno_t block_cnt; /* Ref count: blocks in cache. */
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db_pgno_t lsn_cnt; /* Checkpoint buffers left to write. */
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int ftype; /* File type. */
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int32_t lsn_off; /* Page's LSN offset. */
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u_int32_t clear_len; /* Bytes to clear on page create. */
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roff_t path_off; /* File name location. */
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roff_t fileid_off; /* File identification location. */
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roff_t pgcookie_len; /* Pgin/pgout cookie length. */
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roff_t pgcookie_off; /* Pgin/pgout cookie location. */
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db_pgno_t last_pgno; /* Last page in the file. */
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db_pgno_t orig_last_pgno; /* Original last page in the file. */
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DB_MPOOL_FSTAT stat; /* Per-file mpool statistics. */
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#define MP_CAN_MMAP 0x01 /* If the file can be mmap'd. */
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#define MP_DEADFILE 0x02 /* Dirty pages can simply be trashed. */
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#define MP_TEMP 0x04 /* Backing file is a temporary. */
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#define MP_UNLINK 0x08 /* Unlink file on last close. */
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u_int32_t flags;
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};
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/*
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* BH_TO_CACHE --
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* Return the cache where we can find the specified buffer header.
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*/
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#define BH_TO_CACHE(dbmp, bhp) \
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(dbmp)->reginfo[NCACHE((dbmp)->reginfo[0].primary, (bhp)->pgno)].primary
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/*
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* BH --
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* Buffer header.
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*/
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struct __bh {
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MUTEX mutex; /* Buffer thread/process lock. */
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u_int16_t ref; /* Reference count. */
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#define BH_CALLPGIN 0x001 /* Page needs to be reworked... */
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#define BH_DIRTY 0x002 /* Page was modified. */
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#define BH_DISCARD 0x004 /* Page is useless. */
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#define BH_LOCKED 0x008 /* Page is locked (I/O in progress). */
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#define BH_SYNC 0x010 /* memp sync: write the page */
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#define BH_SYNC_LOGFLSH 0x020 /* memp sync: also flush the log */
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#define BH_TRASH 0x040 /* Page is garbage. */
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u_int16_t flags;
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SH_TAILQ_ENTRY q; /* LRU queue. */
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SH_TAILQ_ENTRY hq; /* MPOOL hash bucket queue. */
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db_pgno_t pgno; /* Underlying MPOOLFILE page number. */
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roff_t mf_offset; /* Associated MPOOLFILE offset. */
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/*
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* !!!
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* This array must be at least size_t aligned -- the DB access methods
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* put PAGE and other structures into it, and then access them directly.
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* (We guarantee size_t alignment to applications in the documentation,
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* too.)
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*/
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u_int8_t buf[1]; /* Variable length data. */
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};
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#include "mp_ext.h"
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