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Code Activity

Get rid of the SpinLockAcquire/SpinLockAcquire_NoHoldoff distinction

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in favor of having just one set of macros that don't do HOLD/RESUME_INTERRUPTS
(hence, these correspond to the old SpinLockAcquire_NoHoldoff case).
Given our coding rules for spinlock use, there is no reason to allow
CHECK_FOR_INTERRUPTS to be done while holding a spinlock, and also there
is no situation where ImmediateInterruptOK will be true while holding a
spinlock.  Therefore doing HOLD/RESUME_INTERRUPTS while taking/releasing a
spinlock is just a waste of cycles.  Qingqing Zhou and Tom Lane.
This commit is contained in:
Tom Lane
2005-12-29 18:08:05 +00:00
parent e135d9631b
commit 195f164228
6 changed files with 80 additions and 112 deletions
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19
src/backend/storage/lmgr/lwlock.c
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@@ -15,7 +15,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/storage/lmgr/lwlock.c,v 1.36 2005/12/11 21:02:18 tgl Exp $
* $PostgreSQL: pgsql/src/backend/storage/lmgr/lwlock.c,v 1.37 2005/12/29 18:08:05 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -24,6 +24,7 @@
#include "access/clog.h"
#include "access/multixact.h"
#include "access/subtrans.h"
#include "miscadmin.h"
#include "storage/lwlock.h"
#include "storage/proc.h"
#include "storage/spin.h"
@@ -301,7 +302,7 @@ LWLockAcquire(LWLockId lockid, LWLockMode mode)
bool mustwait;
/* Acquire mutex. Time spent holding mutex should be short! */
SpinLockAcquire_NoHoldoff(&lock->mutex);
SpinLockAcquire(&lock->mutex);
/* If retrying, allow LWLockRelease to release waiters again */
if (retry)
@@ -340,7 +341,7 @@ LWLockAcquire(LWLockId lockid, LWLockMode mode)
* memory initialization.
*/
if (proc == NULL)
elog(FATAL, "cannot wait without a PGPROC structure");
elog(PANIC, "cannot wait without a PGPROC structure");
proc->lwWaiting = true;
proc->lwExclusive = (mode == LW_EXCLUSIVE);
@@ -352,7 +353,7 @@ LWLockAcquire(LWLockId lockid, LWLockMode mode)
lock->tail = proc;
/* Can release the mutex now */
SpinLockRelease_NoHoldoff(&lock->mutex);
SpinLockRelease(&lock->mutex);
/*
* Wait until awakened.
@@ -384,7 +385,7 @@ LWLockAcquire(LWLockId lockid, LWLockMode mode)
}
/* We are done updating shared state of the lock itself. */
SpinLockRelease_NoHoldoff(&lock->mutex);
SpinLockRelease(&lock->mutex);
/* Add lock to list of locks held by this backend */
held_lwlocks[num_held_lwlocks++] = lockid;
@@ -423,7 +424,7 @@ LWLockConditionalAcquire(LWLockId lockid, LWLockMode mode)
HOLD_INTERRUPTS();
/* Acquire mutex. Time spent holding mutex should be short! */
SpinLockAcquire_NoHoldoff(&lock->mutex);
SpinLockAcquire(&lock->mutex);
/* If I can get the lock, do so quickly. */
if (mode == LW_EXCLUSIVE)
@@ -448,7 +449,7 @@ LWLockConditionalAcquire(LWLockId lockid, LWLockMode mode)
}
/* We are done updating shared state of the lock itself. */
SpinLockRelease_NoHoldoff(&lock->mutex);
SpinLockRelease(&lock->mutex);
if (mustwait)
{
@@ -494,7 +495,7 @@ LWLockRelease(LWLockId lockid)
held_lwlocks[i] = held_lwlocks[i + 1];
/* Acquire mutex. Time spent holding mutex should be short! */
SpinLockAcquire_NoHoldoff(&lock->mutex);
SpinLockAcquire(&lock->mutex);
/* Release my hold on lock */
if (lock->exclusive > 0)
@@ -542,7 +543,7 @@ LWLockRelease(LWLockId lockid)
}
/* We are done updating shared state of the lock itself. */
SpinLockRelease_NoHoldoff(&lock->mutex);
SpinLockRelease(&lock->mutex);
/*
* Awaken any waiters I removed from the queue.