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Implement new 'lightweight lock manager' that's intermediate between

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existing lock manager and spinlocks: it understands exclusive vs shared
lock but has few other fancy features.  Replace most uses of spinlocks
with lightweight locks.  All remaining uses of spinlocks have very short
lock hold times (a few dozen instructions), so tweak spinlock backoff
code to work efficiently given this assumption.  All per my proposal on
pghackers 26-Sep-01.
This commit is contained in:
Tom Lane
2001-09-29 04:02:27 +00:00
parent 818fb55ac4
commit 499abb0c0f
46 changed files with 1595 additions and 1355 deletions
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24
src/backend/storage/buffer/buf_init.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/buf_init.c,v 1.43 2001/07/06 21:04:25 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/buf_init.c,v 1.44 2001/09/29 04:02:22 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -28,10 +28,9 @@
#include "storage/fd.h"
#include "storage/ipc.h"
#include "storage/lmgr.h"
#include "storage/s_lock.h"
#include "storage/shmem.h"
#include "storage/smgr.h"
#include "storage/spin.h"
#include "storage/lwlock.h"
#include "utils/builtins.h"
#include "utils/hsearch.h"
#include "utils/memutils.h"
@ -117,8 +116,6 @@ bool *BufferDirtiedByMe; /* T if buf has been dirtied in cur xact */
*
*/
SPINLOCK BufMgrLock;
long int ReadBufferCount;
long int ReadLocalBufferCount;
long int BufferHitCount;
@ -151,7 +148,7 @@ InitBufferPool(void)
* anyone else attached to the shmem at this point, we've got
* problems.
*/
SpinAcquire(BufMgrLock);
LWLockAcquire(BufMgrLock, LW_EXCLUSIVE);
#ifdef BMTRACE
CurTraceBuf = (long *) ShmemInitStruct("Buffer trace",
@ -186,8 +183,8 @@ InitBufferPool(void)
/*
* link the buffers into a circular, doubly-linked list to
* initialize free list. Still don't know anything about
* replacement strategy in this file.
* initialize free list, and initialize the buffer headers.
* Still don't know anything about replacement strategy in this file.
*/
for (i = 0; i < Data_Descriptors; block += BLCKSZ, buf++, i++)
{
@ -197,12 +194,15 @@ InitBufferPool(void)
buf->freePrev = i - 1;
CLEAR_BUFFERTAG(&(buf->tag));
buf->buf_id = i;
buf->data = MAKE_OFFSET(block);
buf->flags = (BM_DELETED | BM_FREE | BM_VALID);
buf->refcount = 0;
buf->buf_id = i;
S_INIT_LOCK(&(buf->io_in_progress_lock));
S_INIT_LOCK(&(buf->cntx_lock));
buf->io_in_progress_lock = LWLockAssign();
buf->cntx_lock = LWLockAssign();
buf->cntxDirty = false;
buf->wait_backend_id = 0;
}
/* close the circular queue */
@ -214,7 +214,7 @@ InitBufferPool(void)
InitBufTable();
InitFreeList(!foundDescs);
SpinRelease(BufMgrLock);
LWLockRelease(BufMgrLock);
}
/*