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Remove volatile qualifiers from dynahash.c, shmem.c, and sinvaladt.c

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Prior to commit 0709b7ee72, access to
variables within a spinlock-protected critical section had to be done
through a volatile pointer, but that should no longer be necessary.

Thomas Munro
This commit is contained in:
Robert Haas
2015-10-16 14:12:20 -04:00
parent 78652a3332
commit 430008b5a7
3 changed files with 37 additions and 55 deletions
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11
src/backend/storage/ipc/shmem.c
View File

@@ -170,29 +170,26 @@ ShmemAlloc(Size size)
Size newFree;
void *newSpace;
/* use volatile pointer to prevent code rearrangement */
volatile PGShmemHeader *shmemseghdr = ShmemSegHdr;
/*
* ensure all space is adequately aligned.
*/
size = MAXALIGN(size);
Assert(shmemseghdr != NULL);
Assert(ShmemSegHdr != NULL);
SpinLockAcquire(ShmemLock);
newStart = shmemseghdr->freeoffset;
newStart = ShmemSegHdr->freeoffset;
/* extra alignment for large requests, since they are probably buffers */
if (size >= BLCKSZ)
newStart = BUFFERALIGN(newStart);
newFree = newStart + size;
if (newFree <= shmemseghdr->totalsize)
if (newFree <= ShmemSegHdr->totalsize)
{
newSpace = (void *) ((char *) ShmemBase + newStart);
shmemseghdr->freeoffset = newFree;
ShmemSegHdr->freeoffset = newFree;
}
else
newSpace = NULL;

22
src/backend/storage/ipc/sinvaladt.c
View File

@@ -485,14 +485,9 @@ SIInsertDataEntries(const SharedInvalidationMessage *data, int n)
}
/* Update current value of maxMsgNum using spinlock */
{
/* use volatile pointer to prevent code rearrangement */
volatile SISeg *vsegP = segP;
SpinLockAcquire(&vsegP->msgnumLock);
vsegP->maxMsgNum = max;
SpinLockRelease(&vsegP->msgnumLock);
}
SpinLockAcquire(&segP->msgnumLock);
segP->maxMsgNum = max;
SpinLockRelease(&segP->msgnumLock);
/*
* Now that the maxMsgNum change is globally visible, we give everyone
@@ -579,14 +574,9 @@ SIGetDataEntries(SharedInvalidationMessage *data, int datasize)
stateP->hasMessages = false;
/* Fetch current value of maxMsgNum using spinlock */
{
/* use volatile pointer to prevent code rearrangement */
volatile SISeg *vsegP = segP;
SpinLockAcquire(&vsegP->msgnumLock);
max = vsegP->maxMsgNum;
SpinLockRelease(&vsegP->msgnumLock);
}
SpinLockAcquire(&segP->msgnumLock);
max = segP->maxMsgNum;
SpinLockRelease(&segP->msgnumLock);
if (stateP->resetState)
{