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Move s_lock.c and spin.c into lmgr subdirectory, which seems a much

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more reasonable location for them.
This commit is contained in:
Tom Lane
2001-09-27 19:10:02 +00:00
parent 3d59ad00e8
commit 90aebf7f52
5 changed files with 14 additions and 15 deletions
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5
src/backend/storage/ipc/Makefile
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@@ -1,7 +1,7 @@
#
# Makefile for storage/ipc
#
# $Header: /cvsroot/pgsql/src/backend/storage/ipc/Makefile,v 1.15 2000/10/20 21:03:47 petere Exp $
# $Header: /cvsroot/pgsql/src/backend/storage/ipc/Makefile,v 1.16 2001/09/27 19:10:02 tgl Exp $
#
subdir = src/backend/storage/ipc
@@ -15,8 +15,7 @@ override CFLAGS+= -fno-inline
endif
endif
OBJS = ipc.o ipci.o shmem.o shmqueue.o sinval.o \
sinvaladt.o spin.o
OBJS = ipc.o ipci.o shmem.o shmqueue.o sinval.o sinvaladt.o
all: SUBSYS.o

397
src/backend/storage/ipc/spin.c
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@@ -1,397 +0,0 @@
/*-------------------------------------------------------------------------
*
* spin.c
* routines for managing spin locks
*
* POSTGRES has two kinds of locks: semaphores (which put the
* process to sleep) and spinlocks (which are supposed to be
* short term locks). Spinlocks are implemented via test-and-set (TAS)
* instructions if possible, else via semaphores. The semaphore method
* is too slow to be useful :-(
*
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/ipc/Attic/spin.c,v 1.33 2001/06/27 23:31:39 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <errno.h>
#if !defined(HAS_TEST_AND_SET) && defined(HAVE_SYS_SEM_H)
#include <sys/sem.h>
#endif
#include "miscadmin.h"
#include "storage/proc.h"
#include "storage/s_lock.h"
/* Probably should move these to an appropriate header file */
extern SPINLOCK BufMgrLock;
extern SPINLOCK OidGenLockId;
extern SPINLOCK XidGenLockId;
extern SPINLOCK ControlFileLockId;
extern SPINLOCK ShmemLock;
extern SPINLOCK ShmemIndexLock;
extern SPINLOCK LockMgrLock;
extern SPINLOCK SInvalLock;
extern SPINLOCK ProcStructLock;
extern SPINLOCK FreeSpaceLock;
#ifdef STABLE_MEMORY_STORAGE
extern SPINLOCK MMCacheLock;
#endif
/*
* Initialize identifiers for permanent spinlocks during startup
*
* The same identifiers are used for both TAS and semaphore implementations,
* although in one case they are indexes into a shmem array and in the other
* they are semaphore numbers.
*/
static void
InitSpinLockIDs(void)
{
BufMgrLock = (SPINLOCK) BUFMGRLOCKID;
OidGenLockId = (SPINLOCK) OIDGENLOCKID;
XidGenLockId = (SPINLOCK) XIDGENLOCKID;
ControlFileLockId = (SPINLOCK) CNTLFILELOCKID;
ShmemLock = (SPINLOCK) SHMEMLOCKID;
ShmemIndexLock = (SPINLOCK) SHMEMINDEXLOCKID;
LockMgrLock = (SPINLOCK) LOCKMGRLOCKID;
SInvalLock = (SPINLOCK) SINVALLOCKID;
ProcStructLock = (SPINLOCK) PROCSTRUCTLOCKID;
FreeSpaceLock = (SPINLOCK) FREESPACELOCKID;
#ifdef STABLE_MEMORY_STORAGE
MMCacheLock = (SPINLOCK) MMCACHELOCKID;
#endif
}
#ifdef HAS_TEST_AND_SET
/* real spin lock implementation */
typedef struct slock
{
slock_t shlock;
} SLock;
#ifdef LOCK_DEBUG
bool Trace_spinlocks = false;
inline static void
PRINT_SLDEBUG(const char *where, SPINLOCK lockid, const SLock *lock)
{
if (Trace_spinlocks)
elog(DEBUG, "%s: id=%d", where, lockid);
}
#else /* not LOCK_DEBUG */
#define PRINT_SLDEBUG(a,b,c)
#endif /* not LOCK_DEBUG */
static SLock *SLockArray = NULL;
#define SLOCKMEMORYSIZE ((int) MAX_SPINS * sizeof(SLock))
/*
* SLockShmemSize --- return shared-memory space needed
*/
int
SLockShmemSize(void)
{
return MAXALIGN(SLOCKMEMORYSIZE);
}
/*
* CreateSpinlocks --- create and initialize spinlocks during startup
*/
void
CreateSpinlocks(PGShmemHeader *seghdr)
{
int id;
/*
* We must allocate the space "by hand" because shmem.c isn't up yet
*/
SLockArray = (SLock *) (((char *) seghdr) + seghdr->freeoffset);
seghdr->freeoffset += MAXALIGN(SLOCKMEMORYSIZE);
Assert(seghdr->freeoffset <= seghdr->totalsize);
/*
* Initialize all spinlocks to "unlocked" state
*/
for (id = 0; id < (int) MAX_SPINS; id++)
{
SLock *slckP = &(SLockArray[id]);
S_INIT_LOCK(&(slckP->shlock));
}
/*
* Assign indexes for fixed spinlocks
*/
InitSpinLockIDs();
}
void
SpinAcquire(SPINLOCK lockid)
{
SLock *slckP = &(SLockArray[lockid]);
PRINT_SLDEBUG("SpinAcquire", lockid, slckP);
/*
* Acquire the lock, then record that we have done so (for recovery in
* case of elog(ERROR) while holding the lock). Note we assume here
* that S_LOCK will not accept cancel/die interrupts once it has
* acquired the lock. However, interrupts should be accepted while
* waiting, if InterruptHoldoffCount is zero.
*/
S_LOCK(&(slckP->shlock));
PROC_INCR_SLOCK(lockid);
/*
* Lock out cancel/die interrupts until we exit the code section
* protected by the spinlock. This ensures that interrupts will not
* interfere with manipulations of data structures in shared memory.
*/
HOLD_INTERRUPTS();
PRINT_SLDEBUG("SpinAcquire/done", lockid, slckP);
}
void
SpinRelease(SPINLOCK lockid)
{
SLock *slckP = &(SLockArray[lockid]);
PRINT_SLDEBUG("SpinRelease", lockid, slckP);
/*
* Check that we are actually holding the lock we are releasing. This
* can be done only after MyProc has been initialized.
*/
Assert(!MyProc || MyProc->sLocks[lockid] > 0);
/*
* Record that we no longer hold the spinlock, and release it.
*/
PROC_DECR_SLOCK(lockid);
S_UNLOCK(&(slckP->shlock));
/*
* Exit the interrupt holdoff entered in SpinAcquire().
*/
RESUME_INTERRUPTS();
PRINT_SLDEBUG("SpinRelease/done", lockid, slckP);
}
#else /* !HAS_TEST_AND_SET */
/*
* No TAS, so spinlocks are implemented using SysV semaphores.
*
* We support two slightly different APIs here: SpinAcquire/SpinRelease
* work with SPINLOCK integer indexes for the permanent spinlocks, which
* are all assumed to live in the first spinlock semaphore set. There
* is also an emulation of the s_lock.h TAS-spinlock macros; for that case,
* typedef slock_t stores the semId and sem number of the sema to use.
* The semas needed are created by CreateSpinlocks and doled out by
* s_init_lock_sema.
*
* Since many systems have a rather small SEMMSL limit on semas per set,
* we allocate the semaphores required in sets of SPINLOCKS_PER_SET semas.
* This value is deliberately made equal to PROC_NSEMS_PER_SET so that all
* sema sets allocated by Postgres will be the same size; that eases the
* semaphore-recycling logic in IpcSemaphoreCreate().
*
* Note that the SpinLockIds array is not in shared memory; it is filled
* by the postmaster and then inherited through fork() by backends. This
* is OK because its contents do not change after shmem initialization.
*/
#define SPINLOCKS_PER_SET PROC_NSEMS_PER_SET
static IpcSemaphoreId *SpinLockIds = NULL;
static int numSpinSets = 0; /* number of sema sets used */
static int numSpinLocks = 0; /* total number of semas allocated */
static int nextSpinLock = 0; /* next free spinlock index */
static void SpinFreeAllSemaphores(void);
/*
* SLockShmemSize --- return shared-memory space needed
*/
int
SLockShmemSize(void)
{
return 0;
}
/*
* CreateSpinlocks --- create and initialize spinlocks during startup
*/
void
CreateSpinlocks(PGShmemHeader *seghdr)
{
int i;
if (SpinLockIds == NULL)
{
/*
* Compute number of spinlocks needed. If this logic gets any
* more complicated, it should be distributed into the affected
* modules, similar to the way shmem space estimation is handled.
*
* For now, though, we just need the fixed spinlocks (MAX_SPINS), two
* spinlocks per shared disk buffer, and four spinlocks for XLOG.
*/
numSpinLocks = (int) MAX_SPINS + 2 * NBuffers + 4;
/* might as well round up to a multiple of SPINLOCKS_PER_SET */
numSpinSets = (numSpinLocks - 1) / SPINLOCKS_PER_SET + 1;
numSpinLocks = numSpinSets * SPINLOCKS_PER_SET;
SpinLockIds = (IpcSemaphoreId *)
malloc(numSpinSets * sizeof(IpcSemaphoreId));
Assert(SpinLockIds != NULL);
}
for (i = 0; i < numSpinSets; i++)
SpinLockIds[i] = -1;
/*
* Arrange to delete semas on exit --- set this up now so that we will
* clean up if allocation fails. We use our own freeproc, rather than
* IpcSemaphoreCreate's removeOnExit option, because we don't want to
* fill up the on_shmem_exit list with a separate entry for each
* semaphore set.
*/
on_shmem_exit(SpinFreeAllSemaphores, 0);
/* Create sema sets and set all semas to count 1 */
for (i = 0; i < numSpinSets; i++)
{
SpinLockIds[i] = IpcSemaphoreCreate(SPINLOCKS_PER_SET,
IPCProtection,
1,
false);
}
/*
* Assign indexes for fixed spinlocks
*/
Assert(MAX_SPINS <= SPINLOCKS_PER_SET);
InitSpinLockIDs();
/* Init counter for allocating dynamic spinlocks */
nextSpinLock = MAX_SPINS;
}
/*
* SpinFreeAllSemaphores -
* called at shmem_exit time, ie when exiting the postmaster or
* destroying shared state for a failed set of backends.
* Free up all the semaphores allocated for spinlocks.
*/
static void
SpinFreeAllSemaphores(void)
{
int i;
for (i = 0; i < numSpinSets; i++)
{
if (SpinLockIds[i] >= 0)
IpcSemaphoreKill(SpinLockIds[i]);
}
free(SpinLockIds);
SpinLockIds = NULL;
}
/*
* SpinAcquire -- grab a fixed spinlock
*
* FAILS if the semaphore is corrupted.
*/
void
SpinAcquire(SPINLOCK lock)
{
/*
* See the TAS() version of this routine for primary commentary.
*
* NOTE we must pass interruptOK = false to IpcSemaphoreLock, to ensure
* that a cancel/die interrupt cannot prevent us from recording
* ownership of a lock we have just acquired.
*/
IpcSemaphoreLock(SpinLockIds[0], lock, false);
PROC_INCR_SLOCK(lock);
HOLD_INTERRUPTS();
}
/*
* SpinRelease -- release a fixed spin lock
*
* FAILS if the semaphore is corrupted
*/
void
SpinRelease(SPINLOCK lock)
{
/* See the TAS() version of this routine for commentary */
#ifdef USE_ASSERT_CHECKING
/* Check it's locked */
int semval;
semval = IpcSemaphoreGetValue(SpinLockIds[0], lock);
Assert(semval < 1);
#endif
Assert(!MyProc || MyProc->sLocks[lockid] > 0);
PROC_DECR_SLOCK(lock);
IpcSemaphoreUnlock(SpinLockIds[0], lock);
RESUME_INTERRUPTS();
}
/*
* s_lock.h hardware-spinlock emulation
*/
void
s_init_lock_sema(volatile slock_t *lock)
{
if (nextSpinLock >= numSpinLocks)
elog(FATAL, "s_init_lock_sema: not enough semaphores");
lock->semId = SpinLockIds[nextSpinLock / SPINLOCKS_PER_SET];
lock->sem = nextSpinLock % SPINLOCKS_PER_SET;
nextSpinLock++;
}
void
s_unlock_sema(volatile slock_t *lock)
{
IpcSemaphoreUnlock(lock->semId, lock->sem);
}
bool
s_lock_free_sema(volatile slock_t *lock)
{
return IpcSemaphoreGetValue(lock->semId, lock->sem) > 0;
}
int
tas_sema(volatile slock_t *lock)
{
/* Note that TAS macros return 0 if *success* */
return !IpcSemaphoreTryLock(lock->semId, lock->sem);
}
#endif /* !HAS_TEST_AND_SET */