From 8b07fadf865dc65083f6f54d61e0368e72e590d3 Mon Sep 17 00:00:00 2001 From: Nathan Bossart Date: Wed, 22 Jul 2026 11:32:05 -0400 Subject: [PATCH v2 4/9] use Buffer instead of buffer ID for startup's buffer pin wait --- src/backend/storage/buffer/bufmgr.c | 16 ++++++++-------- src/backend/storage/lmgr/proc.c | 20 ++++++++++---------- src/include/storage/proc.h | 9 +++++---- 3 files changed, 23 insertions(+), 22 deletions(-) diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c index 3908529872a..a85547fa492 100644 --- a/src/backend/storage/buffer/bufmgr.c +++ b/src/backend/storage/buffer/bufmgr.c @@ -6806,12 +6806,12 @@ LockBufferForCleanup(Buffer buffer) if (log_recovery_conflict_waits && waitStart == 0) waitStart = GetCurrentTimestamp(); - /* Publish the bufid that Startup process waits on */ - SetStartupBufferPinWaitBufId(buffer - 1); + /* Publish the buffer that Startup process waits on */ + SetStartupBufferPinWaitBuf(buffer); /* Set alarm and then wait to be signaled by UnpinBuffer() */ ResolveRecoveryConflictWithBufferPin(); - /* Reset the published bufid */ - SetStartupBufferPinWaitBufId(-1); + /* Reset the published buffer */ + SetStartupBufferPinWaitBuf(InvalidBuffer); } else ProcWaitForSignal(WAIT_EVENT_BUFFER_CLEANUP); @@ -6865,18 +6865,18 @@ cleanup_lock_acquired: bool HoldingBufferPinThatDelaysRecovery(void) { - int bufid = GetStartupBufferPinWaitBufId(); + Buffer buffer = GetStartupBufferPinWaitBuf(); /* * If we get woken slowly then it's possible that the Startup process was * already woken by other backends before we got here. Also possible that * we get here by multiple interrupts or interrupts at inappropriate - * times, so make sure we do nothing if the bufid is not set. + * times, so make sure we do nothing if the buffer is not set. */ - if (bufid < 0) + if (buffer == InvalidBuffer) return false; - if (GetPrivateRefCount(bufid + 1) > 0) + if (GetPrivateRefCount(buffer) > 0) return true; return false; diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 9d6e69175a5..f973494abb1 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -239,7 +239,7 @@ ProcGlobalShmemInit(void *arg) dlist_init(&ProcGlobal->autovacFreeProcs); dlist_init(&ProcGlobal->bgworkerFreeProcs); dlist_init(&ProcGlobal->walsenderFreeProcs); - ProcGlobal->startupBufferPinWaitBufId = -1; + ProcGlobal->startupBufferPinWaitBuf = InvalidBuffer; pg_atomic_init_u32(&ProcGlobal->avLauncherProc, INVALID_PROC_NUMBER); pg_atomic_init_u32(&ProcGlobal->walwriterProc, INVALID_PROC_NUMBER); pg_atomic_init_u32(&ProcGlobal->checkpointerProc, INVALID_PROC_NUMBER); @@ -760,30 +760,30 @@ InitAuxiliaryProcess(void) /* * Used from bufmgr to share the value of the buffer that Startup waits on, - * or to reset the value to "not waiting" (-1). This allows processing - * of recovery conflicts for buffer pins. Set is made before backends look - * at this value, so locking not required, especially since the set is - * an atomic integer set operation. + * or to reset the value to "not waiting" (InvalidBuffer). This allows + * processing of recovery conflicts for buffer pins. Set is made before + * backends look at this value, so locking not required, especially since + * the set is an atomic integer set operation. */ void -SetStartupBufferPinWaitBufId(int bufid) +SetStartupBufferPinWaitBuf(Buffer buffer) { /* use volatile pointer to prevent code rearrangement */ volatile PROC_HDR *procglobal = ProcGlobal; - procglobal->startupBufferPinWaitBufId = bufid; + procglobal->startupBufferPinWaitBuf = buffer; } /* * Used by backends when they receive a request to check for buffer pin waits. */ -int -GetStartupBufferPinWaitBufId(void) +Buffer +GetStartupBufferPinWaitBuf(void) { /* use volatile pointer to prevent code rearrangement */ volatile PROC_HDR *procglobal = ProcGlobal; - return procglobal->startupBufferPinWaitBufId; + return procglobal->startupBufferPinWaitBuf; } /* diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h index 03a1a466fa8..4c3f431b4eb 100644 --- a/src/include/storage/proc.h +++ b/src/include/storage/proc.h @@ -17,6 +17,7 @@ #include "access/xlogdefs.h" #include "lib/ilist.h" #include "miscadmin.h" +#include "storage/buf.h" #include "storage/latch.h" #include "storage/lock.h" #include "storage/pg_sema.h" @@ -498,8 +499,8 @@ typedef struct PROC_HDR /* Current shared estimate of appropriate spins_per_delay value */ int spins_per_delay; - /* Buffer id of the buffer that Startup process waits for pin on, or -1 */ - int startupBufferPinWaitBufId; + /* Buffer that Startup process waits for pin on, or InvalidBuffer */ + Buffer startupBufferPinWaitBuf; } PROC_HDR; extern PGDLLIMPORT PROC_HDR *ProcGlobal; @@ -558,8 +559,8 @@ extern void InitProcess(void); extern void InitProcessPhase2(void); extern void InitAuxiliaryProcess(void); -extern void SetStartupBufferPinWaitBufId(int bufid); -extern int GetStartupBufferPinWaitBufId(void); +extern void SetStartupBufferPinWaitBuf(Buffer buffer); +extern Buffer GetStartupBufferPinWaitBuf(void); extern bool HaveNFreeProcs(int n, int *nfree); extern void ProcReleaseLocks(bool isCommit); -- 2.50.1 (Apple Git-155)