diff options
Diffstat (limited to 'src/include/access/slru.h')
| -rw-r--r-- | src/include/access/slru.h | 35 |
1 files changed, 19 insertions, 16 deletions
diff --git a/src/include/access/slru.h b/src/include/access/slru.h index 851dfd865d3..fec968e7a20 100644 --- a/src/include/access/slru.h +++ b/src/include/access/slru.h @@ -6,7 +6,7 @@ * Portions Copyright (c) 2003, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/access/slru.h,v 1.4 2003/11/29 22:40:55 pgsql Exp $ + * $PostgreSQL: pgsql/src/include/access/slru.h,v 1.5 2004/05/28 05:13:17 tgl Exp $ */ #ifndef SLRU_H #define SLRU_H @@ -16,35 +16,38 @@ /* exported because lwlock.c needs it */ #define NUM_CLOG_BUFFERS 8 +/* + * Note: the separation between SlruLockData and SlruSharedData is purely + * historical; the structs could be combined. + */ typedef struct SlruLockData { LWLockId ControlLock; -/* - * BufferLocks is set during CLOGShmemInit and does not change thereafter. - * The value is automatically inherited by backends via fork, and - * doesn't need to be in shared memory. - */ LWLockId BufferLocks[NUM_CLOG_BUFFERS]; /* Per-buffer I/O locks */ } SlruLockData; typedef SlruLockData *SlruLock; +/* + * SlruCtlData is an unshared structure that points to the active information + * in shared memory. + */ typedef struct SlruCtlData { void *shared; /* pointer to SlruSharedData */ SlruLock locks; -/* - * Dir is set during SimpleLruShmemInit and does not change thereafter. - * The value is automatically inherited by backends via fork, and - * doesn't need to be in shared memory. - */ + /* + * Dir is set during SimpleLruShmemInit and does not change thereafter. + * The value is automatically inherited by backends via fork, and + * doesn't need to be in shared memory. + */ char Dir[MAXPGPATH]; -/* - * Decide which of two page numbers is "older" for truncation purposes. - * We need to use comparison of TransactionIds here in order to do the right - * thing with wraparound XID arithmetic. - */ + /* + * Decide which of two page numbers is "older" for truncation purposes. + * We need to use comparison of TransactionIds here in order to do the + * right thing with wraparound XID arithmetic. + */ bool (*PagePrecedes) (int, int); } SlruCtlData; |