David Gould writes:
> Michael Meskes:
> > It seems this patch is incomplete. The file has 20 #if's but only 19
> > #endif's.
>
> Hmmm, I just checked my file, and the patch I got back from the list and
> I don't see this. Could you send me a copy of your patched file so I can see
> maybe what is the problem?
I wasn't precise enough. I didn't apply the patch but cvsup'ed the latest
file. Anyway, here is my s_lock.h:
/*-------------------------------------------------------------------------
*
* s_lock.h--
* This file contains the implementation (if any) for spinlocks.
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /usr/local/cvsroot/pgsql/src/include/storage/s_lock.h,v 1.30 1998/04/29 12:40:56 scrappy Exp $
*
*-------------------------------------------------------------------------
*/
/*
* DESCRIPTION
* The public functions that must be provided are:
*
* void S_INIT_LOCK(slock_t *lock)
*
* void S_LOCK(slock_t *lock)
*
* void S_UNLOCK(slock_t *lock)
*
* int S_LOCK_FREE(slock_t *lock)
* Tests if the lock is free. Returns non-zero if free, 0 if locked.
*
* The S_LOCK() function (in s_lock.c) implements a primitive but
* still useful random backoff to avoid hordes of busywaiting lockers
* chewing CPU.
*
* void
* S_LOCK(slock_t *lock)
* {
* while (TAS(lock))
* {
* // back off the cpu for a semi-random short time
* }
* }
*
* This implementation takes advantage of a tas function written
* (in assembly language) on machines that have a native test-and-set
* instruction. Alternative mutex implementations may also be used.
* This function is hidden under the TAS macro to allow substitutions.
*
* #define TAS(lock) tas(lock)
* int tas(slock_t *lock) // True if lock already set
*
* If none of this can be done, POSTGRES will default to using
* System V semaphores (and take a large performance hit -- around 40%
* of its time on a DS5000/240 is spent in semop(3)...).
*
* NOTES
* AIX has a test-and-set but the recommended interface is the cs(3)
* system call. This provides an 8-instruction (plus system call
* overhead) uninterruptible compare-and-set operation. True
* spinlocks might be faster but using cs(3) still speeds up the
* regression test suite by about 25%. I don't have an assembler
* manual for POWER in any case.
*
* There are default implementations for all these macros at the bottom
* of this file. Check if your platform can use these or needs to
* override them.
*
*/
#ifndef S_LOCK_H
#define S_LOCK_H
#include "storage/ipc.h"
#if defined(HAS_TEST_AND_SET)
#if defined(linux)
/***************************************************************************
* All Linux
*/
#if defined(__alpha__)
#define S_UNLOCK(lock) { __asm__("mb"); *(lock) = 0; }
#endif /* defined(__alpha__) && defined(linux) */
#else /* defined(linux) */
/***************************************************************************
* All non Linux
*/
#if defined (nextstep)
/*
* NEXTSTEP (mach)
* slock_t is defined as a struct mutex.
*/
#define S_LOCK(lock) mutex_lock(lock)
#define S_UNLOCK(lock) mutex_unlock(lock)
#define S_INIT_LOCK(lock) mutex_init(lock)
/* For Mach, we have to delve inside the entrails of `struct mutex'. Ick! */
#define S_LOCK_FREE(alock) ((alock)->lock == 0)
#endif /* nextstep */
#if defined(__sgi)
/*
* SGI IRIX 5
* slock_t is defined as a struct abilock_t, which has a single unsigned long
* member.
*
* This stuff may be supplemented in the future with Masato Kataoka's MIPS-II
* assembly from his NECEWS SVR4 port, but we probably ought to retain this
* for the R3000 chips out there.
*/
#define S_LOCK(lock) do \
{ \
while (!acquire_lock(lock)) \
; \
} while (0)
#define S_UNLOCK(lock) release_lock(lock)
#define S_INIT_LOCK(lock) init_lock(lock)
/* S_LOCK_FREE should return 1 if lock is free; 0 if lock is locked */
#define S_LOCK_FREE(lock) (stat_lock(lock) == UNLOCKED)
#endif /* __sgi */
/*
* OSF/1 (Alpha AXP)
*
* Note that slock_t on the Alpha AXP is msemaphore instead of char
* (see storage/ipc.h).
*/
#if defined(__alpha) && !defined(linux)
#define S_LOCK(lock) do \
{ \
while (msem_lock((lock), MSEM_IF_NOWAIT) < 0) \
; \
} while (0)
#define S_UNLOCK(lock) msem_unlock((lock), 0)
#define S_INIT_LOCK(lock) msem_init((lock), MSEM_UNLOCKED)
#define S_LOCK_FREE(lock) (!(lock)->msem_state)
#endif /* alpha */
/*
* Solaris 2
*/
#if (defined(__i386__) || defined(__sparc__)) && defined(__sun__)
/* for xxxxx_solaris, this is defined in port/.../tas.s */
static int tas(slock_t *lock);
#define S_LOCK(lock) do \
{ \
while (tas(lock)) \
; \
} while (0)
#define S_UNLOCK(lock) (*(lock) = 0)
#define S_INIT_LOCK(lock) S_UNLOCK(lock)
#endif /* i86pc_solaris || sparc_solaris */
/*
* AIX (POWER)
*
* Note that slock_t on POWER/POWER2/PowerPC is int instead of char
* (see storage/ipc.h).
*/
#if defined(_AIX)
#define S_LOCK(lock) do \
{ \
while (cs((int *) (lock), 0, 1)) \
; \
} while (0)
#define S_UNLOCK(lock) (*(lock) = 0)
#define S_INIT_LOCK(lock) S_UNLOCK(lock)
#endif /* _AIX */
/*
* HP-UX (PA-RISC)
*
* Note that slock_t on PA-RISC is a structure instead of char
* (see storage/ipc.h).
*/
#if defined(__hpux)
/*
* a "set" slock_t has a single word cleared. a "clear" slock_t has
* all words set to non-zero.
*/
static slock_t clear_lock = {-1, -1, -1, -1};
static int tas(slock_t *lock);
#define S_LOCK(lock) do \
{ \
while (tas(lock)) \
; \
} while (0)
#define S_UNLOCK(lock) (*(lock) = clear_lock) /* struct assignment */
#define S_INIT_LOCK(lock) S_UNLOCK(lock)
#define S_LOCK_FREE(lock) ( *(int *) (((long) (lock) + 15) & ~15) != 0)
#endif /* __hpux */
/*
* sun3
*/
#if defined(sun3)
static int tas(slock_t *lock);
#define S_LOCK(lock) do \
{ \
while (tas(lock)) \
; \
} while (0)
#define S_UNLOCK(lock) (*(lock) = 0)
#define S_INIT_LOCK(lock) S_UNLOCK(lock)
static int
tas_dummy()
{
asm("LLA0:");
asm(" .data");
asm(" .text");
asm("|#PROC# 04");
asm(" .globl _tas");
asm("_tas:");
asm("|#PROLOGUE# 1");
asm(" movel sp@(0x4),a0");
asm(" tas a0@");
asm(" beq LLA1");
asm(" moveq #-128,d0");
asm(" rts");
asm("LLA1:");
asm(" moveq #0,d0");
asm(" rts");
asm(" .data");
}
#endif /* sun3 */
/*
* sparc machines
*/
#if defined(NEED_SPARC_TAS_ASM)
/* if we're using -ansi w/ gcc, use __asm__ instead of asm */
#if defined(__STRICT_ANSI__)
#define asm(x) __asm__(x)
#endif
static int tas(slock_t *lock);
static void
tas_dummy()
{
asm(".seg \"data\"");
asm(".seg \"text\"");
asm("_tas:");
/*
* Sparc atomic test and set (sparc calls it "atomic load-store")
*/
asm("ldstub [%r8], %r8");
/*
* Did test and set actually do the set?
*/
asm("tst %r8");
asm("be,a ReturnZero");
/*
* otherwise, just return.
*/
asm("clr %r8");
asm("mov 0x1, %r8");
asm("ReturnZero:");
asm("retl");
asm("nop");
}
#define S_LOCK(addr) do \
{ \
while (tas(addr)) \
; \
} while (0)
/*
* addr should be as in the above S_LOCK routine
*/
#define S_UNLOCK(addr) (*(addr) = 0)
#define S_INIT_LOCK(addr) (*(addr) = 0)
#endif /* NEED_SPARC_TAS_ASM */
/*
* VAXen -- even multiprocessor ones
*/
#if defined(NEED_VAX_TAS_ASM)
#define S_LOCK(addr) __asm__("1: bbssi $0,(%0),1b": :"r"(addr))
#define S_UNLOCK(addr) (*(addr) = 0)
#define S_INIT_LOCK(addr) (*(addr) = 0)
#endif /* NEED_VAX_TAS_ASM */
/*
* i386 based things
*/
#if defined(NEED_I386_TAS_ASM)
#if defined(USE_UNIVEL_CC)
asm void
S_LOCK(char *lval)
{
% lab again;
/* Upon entry, %eax will contain the pointer to the lock byte */
pushl %ebx
xchgl %eax, %ebx
movb $255, %al
again:
lock
xchgb %al, (%ebx)
cmpb $0, %al
jne again
popl %ebx
}
#else
#define S_LOCK(lock) do \
{ \
slock_t _res; \
do \
{ \
__asm__("lock; xchgb %0,%1": "=q"(_res), "=m"(*lock):"0"(0x1)); \
} while (_res != 0); \
} while (0)
#endif
#define S_UNLOCK(lock) (*(lock) = 0)
#define S_INIT_LOCK(lock) S_UNLOCK(lock)
#endif /* NEED_I386_TAS_ASM */
#if defined(__alpha) && defined(linux)
void S_LOCK(slock_t *lock);
#define S_UNLOCK(lock) { __asm__("mb"); *(lock) = 0; }
#define S_INIT_LOCK(lock) S_UNLOCK(lock)
#endif /* defined(__alpha) && defined(linux) */
#if defined(linux) && defined(sparc)
#define S_LOCK(lock) do \
{ \
slock_t _res; \
slock_t *tmplock = lock ; \
do \
{ \
__asm__("ldstub [%1], %0" \
: "=&r"(_res), "=r"(tmplock) \
: "1"(tmplock)); \
} while (_res != 0); \
} while (0)
#define S_UNLOCK(lock) (*(lock) = 0)
#define S_INIT_LOCK(lock) S_UNLOCK(lock)
#endif /* defined(linux) && defined(sparc) */
#if defined(linux) && defined(PPC)
static int
tas_dummy()
{
__asm__(" \n\
tas: \n\
lwarx 5,0,3 \n\
cmpwi 5,0 \n\
bne fail \n\
addi 5,5,1 \n\
stwcx. 5,0,3 \n\
beq success \n\
fail: li 3,1 \n\
blr \n\
success: \n\
li 3,0 \n\
blr \n\
");
}
#define S_LOCK(lock) do \
{ \
while (tas(lock)) \
; \
} while (0)
#define S_UNLOCK(lock) (*(lock) = 0)
#define S_INIT_LOCK(lock) S_UNLOCK(lock)
#endif /* defined(linux) && defined(PPC) */
#ifndef S_LOCK_FREE /* for those who have not already defined
* it */
#define S_LOCK_FREE(lock) ((*lock) == 0)
#endif
#endif /* HAS_TEST_AND_SET */
#endif /* S_LOCK_H */
Michael
--
Dr. Michael Meskes, Project-Manager | topsystem Systemhaus GmbH
meskes@topsystem.de | Europark A2, Adenauerstr. 20
meskes@debian.org | 52146 Wuerselen
Go SF49ers! Go Rhein Fire! | Tel: (+49) 2405/4670-44
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