diff options
Diffstat (limited to 'src/backend/access/transam/xlog.c')
| -rw-r--r-- | src/backend/access/transam/xlog.c | 78 |
1 files changed, 51 insertions, 27 deletions
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index b1ea722674e..46e3470ae38 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.84 2001/12/23 07:25:39 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.85 2001/12/28 18:16:41 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -617,10 +617,15 @@ begin:; START_CRIT_SECTION(); /* update LogwrtResult before doing cache fill check */ - SpinLockAcquire_NoHoldoff(&XLogCtl->info_lck); - LogwrtRqst = XLogCtl->LogwrtRqst; - LogwrtResult = XLogCtl->LogwrtResult; - SpinLockRelease_NoHoldoff(&XLogCtl->info_lck); + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire_NoHoldoff(&xlogctl->info_lck); + LogwrtRqst = xlogctl->LogwrtRqst; + LogwrtResult = xlogctl->LogwrtResult; + SpinLockRelease_NoHoldoff(&xlogctl->info_lck); + } /* * If cache is half filled then try to acquire write lock and do @@ -838,16 +843,20 @@ begin:; if (updrqst) { - SpinLockAcquire_NoHoldoff(&XLogCtl->info_lck); + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire_NoHoldoff(&xlogctl->info_lck); /* advance global request to include new block(s) */ - if (XLByteLT(XLogCtl->LogwrtRqst.Write, WriteRqst)) - XLogCtl->LogwrtRqst.Write = WriteRqst; + if (XLByteLT(xlogctl->LogwrtRqst.Write, WriteRqst)) + xlogctl->LogwrtRqst.Write = WriteRqst; /* update local result copy while I have the chance */ - LogwrtResult = XLogCtl->LogwrtResult; - SpinLockRelease_NoHoldoff(&XLogCtl->info_lck); + LogwrtResult = xlogctl->LogwrtResult; + SpinLockRelease_NoHoldoff(&xlogctl->info_lck); } END_CRIT_SECTION(); + return (RecPtr); } @@ -892,11 +901,16 @@ AdvanceXLInsertBuffer(void) FinishedPageRqstPtr = XLogCtl->xlblocks[Insert->curridx]; /* Before waiting, get info_lck and update LogwrtResult */ - SpinLockAcquire_NoHoldoff(&XLogCtl->info_lck); - if (XLByteLT(XLogCtl->LogwrtRqst.Write, FinishedPageRqstPtr)) - XLogCtl->LogwrtRqst.Write = FinishedPageRqstPtr; - LogwrtResult = XLogCtl->LogwrtResult; - SpinLockRelease_NoHoldoff(&XLogCtl->info_lck); + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire_NoHoldoff(&xlogctl->info_lck); + if (XLByteLT(xlogctl->LogwrtRqst.Write, FinishedPageRqstPtr)) + xlogctl->LogwrtRqst.Write = FinishedPageRqstPtr; + LogwrtResult = xlogctl->LogwrtResult; + SpinLockRelease_NoHoldoff(&xlogctl->info_lck); + } update_needed = false; /* Did the shared-request update */ @@ -1149,13 +1163,18 @@ XLogWrite(XLogwrtRqst WriteRqst) * 'result' values. This is not absolutely essential, but it saves * some code in a couple of places. */ - SpinLockAcquire_NoHoldoff(&XLogCtl->info_lck); - XLogCtl->LogwrtResult = LogwrtResult; - if (XLByteLT(XLogCtl->LogwrtRqst.Write, LogwrtResult.Write)) - XLogCtl->LogwrtRqst.Write = LogwrtResult.Write; - if (XLByteLT(XLogCtl->LogwrtRqst.Flush, LogwrtResult.Flush)) - XLogCtl->LogwrtRqst.Flush = LogwrtResult.Flush; - SpinLockRelease_NoHoldoff(&XLogCtl->info_lck); + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire_NoHoldoff(&xlogctl->info_lck); + xlogctl->LogwrtResult = LogwrtResult; + if (XLByteLT(xlogctl->LogwrtRqst.Write, LogwrtResult.Write)) + xlogctl->LogwrtRqst.Write = LogwrtResult.Write; + if (XLByteLT(xlogctl->LogwrtRqst.Flush, LogwrtResult.Flush)) + xlogctl->LogwrtRqst.Flush = LogwrtResult.Flush; + SpinLockRelease_NoHoldoff(&xlogctl->info_lck); + } Write->LogwrtResult = LogwrtResult; } @@ -1206,11 +1225,16 @@ XLogFlush(XLogRecPtr record) WriteRqstPtr = record; /* read LogwrtResult and update local state */ - SpinLockAcquire_NoHoldoff(&XLogCtl->info_lck); - if (XLByteLT(WriteRqstPtr, XLogCtl->LogwrtRqst.Write)) - WriteRqstPtr = XLogCtl->LogwrtRqst.Write; - LogwrtResult = XLogCtl->LogwrtResult; - SpinLockRelease_NoHoldoff(&XLogCtl->info_lck); + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire_NoHoldoff(&xlogctl->info_lck); + if (XLByteLT(WriteRqstPtr, xlogctl->LogwrtRqst.Write)) + WriteRqstPtr = xlogctl->LogwrtRqst.Write; + LogwrtResult = xlogctl->LogwrtResult; + SpinLockRelease_NoHoldoff(&xlogctl->info_lck); + } /* done already? */ if (!XLByteLE(record, LogwrtResult.Flush)) |