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Remove SB_PAD. Compute padding at compile time.

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This commit is contained in:
Bruce Momjian
1997-01-23 18:15:29 +00:00
parent f0ff9ac0c2
commit fa937b5e6b
3 changed files with 36 additions and 21 deletions
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34
src/include/storage/buf_internals.h
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@@ -6,7 +6,7 @@
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: buf_internals.h,v 1.9 1997/01/20 04:06:13 vadim Exp $
* $Id: buf_internals.h,v 1.10 1997/01/23 18:15:29 momjian Exp $
*
* NOTE
* If BUFFERPAGE0 is defined, then 0 will be used as a
@@ -100,6 +100,30 @@ struct buftag{
* to put the buffer, for all storage managers.
*/
#define PADDED_SBUFDESC_SIZE 128
/* DO NOT CHANGE THIS NEXT STRUCTURE:
It is used only to get padding information for the real sbufdesc structure
It should match the sbufdesc structure exactly except for a missing sb_pad
*/
struct sbufdesc_unpadded {
Buffer freeNext;
Buffer freePrev;
SHMEM_OFFSET data;
BufferTag tag;
int buf_id;
BufFlags flags;
int16 bufsmgr;
unsigned refcount;
char sb_dbname[NAMEDATALEN+1];
char sb_relname[NAMEDATALEN+1];
#ifdef HAS_TEST_AND_SET
slock_t io_in_progress_lock;
#endif /* HAS_TEST_AND_SET */
/* NOTE NO sb_pad HERE */
};
/* THE REAL STRUCTURE - the structure above must match it, minus sb_pad */
struct sbufdesc {
Buffer freeNext; /* link for freelist chain */
Buffer freePrev;
@@ -121,7 +145,7 @@ struct sbufdesc {
#endif /* HAS_TEST_AND_SET */
/*
* I padded this structure to a power of 2 (128 bytes on a MIPS) because
* I padded this structure to a power of 2 (PADDED_SBUFDESC_SIZE) because
* BufferDescriptorGetBuffer is called a billion times and it does an
* C pointer subtraction (i.e., "x - y" -> array index of x relative
* to y, which is calculated using division by struct size). Integer
@@ -131,11 +155,7 @@ struct sbufdesc {
* going to make some of these types bigger soon anyway... -pma 1/2/93
*/
/*
* NOTE: This is now defined in the ..../include/config.h file!
*/
char sb_pad[SB_PAD];
char sb_pad[PADDED_SBUFDESC_SIZE-sizeof(struct sbufdesc_unpadded)];
};
/*