diff options
Diffstat (limited to 'db2/mutex')
| -rw-r--r-- | db2/mutex/alpha.dec | 25 | ||||
| -rw-r--r-- | db2/mutex/alpha.gcc | 52 | ||||
| -rw-r--r-- | db2/mutex/mutex.c | 49 | ||||
| -rw-r--r-- | db2/mutex/parisc.hp | 29 | ||||
| -rw-r--r-- | db2/mutex/uts4_cc.s (renamed from db2/mutex/uts4.cc.s) | 0 |
5 files changed, 30 insertions, 125 deletions
diff --git a/db2/mutex/alpha.dec b/db2/mutex/alpha.dec deleted file mode 100644 index 83ed371136..0000000000 --- a/db2/mutex/alpha.dec +++ /dev/null @@ -1,25 +0,0 @@ -/* - * @(#)alpha.dec 8.3 (Sleepycat Software) 1/18/97 - * - * The DEC C asm acts as a pseudo-call. The first argument is the assembly - * code, and the remaining arguments are assigned as in a procedure call, to - * r16, r17, etc. (represented in asm as %a0, %a1, and so forth). - * - * From: Dave Butenhof. - */ - -#include <c_asm.h> - -#define TSL_SET(tsl) (asm ("mb; \ - 10: ldl_l %v0,(%a0) ; \ - bne %v0,30f ; \ - or %v0,1,%r1 ; \ - stl_c %r1,(%a0) ; \ - beq %r1,20f ; \ - mb ; \ - br %r31,30f ; \ - 20: br %r31,10b ; \ - 30: ", (tsl))) - -THIS WAS NOT CONVERTED TO TAKE A POINTER AS AN ARGUMENT... -#define TSL_UNSET(tsl) (asm ("mb"), *(tsl) = 0) diff --git a/db2/mutex/alpha.gcc b/db2/mutex/alpha.gcc deleted file mode 100644 index 247d04cf31..0000000000 --- a/db2/mutex/alpha.gcc +++ /dev/null @@ -1,52 +0,0 @@ -/* - * @(#)alpha.gcc 10.1 (Sleepycat) 4/12/97 - * - * The code appearing below is taken from Richard L. Sites, ed. "Alpha - * Architecture Reference Manual", Digital Press, 1992, page 5-7 and 5-8. - * There are 2 modifications: - * - * 1. The jump from blbs __r1,30f to !__r1, which is dictated by the way the - * TSL_SET macro is used. The code suggested in Sites includes the main loop - * of the spin lock, whereas in this code the rest the loop is specified in C. - * The generated code might be suboptimal if the compiler generates a forward - * branch for the usual case in which the mutex is uncontested. - * - * 2. At label 20, Sites suggests including code for testing for an excessive - * number of _processor_ lock conflicts. (The seq_c instruction stores its - * first argument provided that no other processor has written to a byte range - * including its memory-location argument.) Absent such checking the code - * below could conceivably stall silently on a multiprocessor alpha, depending - * on how often processor/processor conflicts occur in a particular byte range. - * - * Note that the mb ("memory-barrier") instruction in TSL_UNSET is critical to - * correct operation in a multiprocessor alpha (as is, of course, the mb in - * the TSL_SET macro). Without the mb, changes to shared memory that occurred - * inside the critical section (before the TSL_UNSET) might reach shared memory - * _after_ the change of tsl to 0, thereby permitting another processor to see - * an inconsistent view of the data protected by the mutex. - * - * For gcc/alpha, 0 is clear, 1 is set. - */ -#define TSL_SET(tsl) ({ \ - register tsl_t *__l = (tsl); \ - register tsl_t __r1, __r2; \ - __asm__ volatile(" \n\ - 10: ldq_l %0,(%2) \n\ - blbs %0,30f \n\ - or %0,1,%1 \n\ - stq_c %1,(%2) \n\ - beq %1,20f \n\ - mb \n\ - br 30f \n\ - 20: br 10b \n\ - 30: " \ - : "=&r" (__r1), "=&r" (__r2) \ - : "r" (__l)); \ - !__r1; \ -}) - -#define TSL_UNSET(tsl) ({ \ - register tsl_t *__l = (tsl); \ - __asm__ volatile("mb; stq $31,(%0);" : : "r" (__l)); \ -}) -#define TSL_INIT(tsl) TSL_UNSET(tsl) diff --git a/db2/mutex/mutex.c b/db2/mutex/mutex.c index de0d0e23fe..acc6aa07c9 100644 --- a/db2/mutex/mutex.c +++ b/db2/mutex/mutex.c @@ -8,7 +8,7 @@ #include "config.h" #ifndef lint -static const char sccsid[] = "@(#)mutex.c 10.48 (Sleepycat) 5/23/98"; +static const char sccsid[] = "@(#)mutex.c 10.52 (Sleepycat) 11/8/98"; #endif /* not lint */ #ifndef NO_SYSTEM_INCLUDES @@ -37,9 +37,12 @@ static const char sccsid[] = "@(#)mutex.c 10.48 (Sleepycat) 5/23/98"; #if defined(HAVE_FUNC_MSEM) /* - * XXX - * Should we not use MSEM_IF_NOWAIT and let the system block for us? - * I've no idea if this will block all threads in the process or not. + * !!! + * Do not remove the MSEM_IF_NOWAIT flag. The problem is that if a single + * process makes two msem_lock() calls in a row, the second one returns an + * error. We depend on the fact that we can lock against ourselves in the + * locking subsystem, where we set up a mutex so that we can block ourselves. + * Tested on OSF1 v4.0. */ #define TSL_INIT(x) (msem_init(x, MSEM_UNLOCKED) == NULL) #define TSL_INIT_ERROR 1 @@ -74,6 +77,17 @@ static const char sccsid[] = "@(#)mutex.c 10.48 (Sleepycat) 5/23/98"; #define TSL_UNSET(x) _lock_clear(x) #endif +#ifdef HAVE_FUNC_VMS +#include <builtins.h> +#ifdef __ALPHA +#define TSL_SET(tsl) (!__TESTBITSSI(tsl, 0)) +#else /* __VAX */ +#define TSL_SET(tsl) (!(int)_BBSSI(0, tsl)) +#endif +#define TSL_UNSET(tsl) (*(tsl) = 0) +#define TSL_INIT(tsl) TSL_UNSET(tsl) +#endif + #ifdef HAVE_ASSEM_PARISC_GCC #include "parisc.gcc" #endif @@ -181,7 +195,7 @@ __db_mutex_lock(mp, fd) #ifdef HAVE_SPINLOCKS COMPQUIET(fd, 0); - for (usecs = MS(10);;) { + for (usecs = MS(1);;) { /* Try and acquire the uncontested resource lock for N spins. */ for (nspins = mp->spins; nspins > 0; --nspins) if (TSL_SET(&mp->tsl_resource)) { @@ -193,19 +207,17 @@ __db_mutex_lock(mp, fd) } mp->pid = getpid(); #endif - if (usecs == MS(10)) + if (usecs == MS(1)) ++mp->mutex_set_nowait; else ++mp->mutex_set_wait; return (0); } - /* Yield the processor; wait 10ms initially, up to 1 second. */ - if (__db_yield == NULL || __db_yield() != 0) { - (void)__db_sleep(0, usecs); - if ((usecs <<= 1) > SECOND) - usecs = SECOND; - } + /* Yield the processor; wait 1ms initially, up to 1 second. */ + __os_yield(usecs); + if ((usecs <<= 1) > SECOND) + usecs = SECOND; } /* NOTREACHED */ @@ -218,15 +230,14 @@ __db_mutex_lock(mp, fd) for (locked = 0, mypid = getpid();;) { /* - * Wait for the lock to become available; wait 10ms initially, + * Wait for the lock to become available; wait 1ms initially, * up to 1 second. */ - for (usecs = MS(10); mp->pid != 0;) - if (__db_yield == NULL || __db_yield() != 0) { - (void)__db_sleep(0, usecs); - if ((usecs <<= 1) > SECOND) - usecs = SECOND; - } + for (usecs = MS(1); mp->pid != 0;) { + __os_yield(usecs); + if ((usecs <<= 1) > SECOND) + usecs = SECOND; + } /* Acquire an exclusive kernel lock. */ k_lock.l_type = F_WRLCK; diff --git a/db2/mutex/parisc.hp b/db2/mutex/parisc.hp deleted file mode 100644 index bd0e37fc78..0000000000 --- a/db2/mutex/parisc.hp +++ /dev/null @@ -1,29 +0,0 @@ -/* - * @(#)parisc.hp 8.6 (Sleepycat) 6/2/98 - * - * Copyright (c) 1996-1997, The University of Utah and the Computer Systems - * Laboratory at the University of Utah (CSL). All rights reserved. - * - * Permission to use, copy, modify and distribute this software is hereby - * granted provided that (1) source code retains these copyright, permission, - * and disclaimer notices, and (2) redistributions including binaries - * reproduce the notices in supporting documentation, and (3) all advertising - * materials mentioning features or use of this software display the following - * acknowledgement: ``This product includes software developed by the Computer - * Systems Laboratory at the University of Utah.'' - * - * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS - * IS" CONDITION. THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF - * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. - * - * CSL requests users of this software to return to csl-dist@cs.utah.edu any - * improvements that they make and grant CSL redistribution rights. - */ - -/* - * The PA-RISC has a "load and clear" instead of a "test and set" instruction. - * The 32-bit word used by that instruction must be 16-byte aligned hence we - * allocate 16 bytes for a tsl_t and use the word that is properly aligned. - */ -#define TSL_SET(tsl) tsl_set(tsl) -#define TSL_UNSET(tsl) tsl_unset(tsl) diff --git a/db2/mutex/uts4.cc.s b/db2/mutex/uts4_cc.s index ee5f4143bd..ee5f4143bd 100644 --- a/db2/mutex/uts4.cc.s +++ b/db2/mutex/uts4_cc.s |