From b319356f0e94a6482c726cf4af96597c211d8d6e Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Fri, 29 Jan 2016 08:10:47 -0500
Subject: [PATCH] Migrate PGPROC's backendLock into PGPROC itself, using a new
tranche.
Previously, each PGPROC's backendLock was part of the main tranche,
and the PGPROC just contained a pointer. Now, the actual LWLock is
part of the PGPROC.
As with previous, similar patches, this makes it significantly easier
to identify these lwlocks in LWLOCK_STATS or Trace_lwlocks output
and improves modularity.
Author: Ildus Kurbangaliev
Reviewed-by: Amit Kapila, Robert Haas
---
src/backend/storage/ipc/procarray.c | 10 +++++
src/backend/storage/lmgr/lock.c | 58 ++++++++++++++---------------
src/backend/storage/lmgr/lwlock.c | 3 --
src/backend/storage/lmgr/proc.c | 2 +-
src/include/storage/lwlock.h | 1 +
src/include/storage/proc.h | 2 +-
6 files changed, 42 insertions(+), 34 deletions(-)
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index bd0c96124e3..6ded0f0f126 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -106,6 +106,9 @@ static TransactionId *KnownAssignedXids;
static bool *KnownAssignedXidsValid;
static TransactionId latestObservedXid = InvalidTransactionId;
+/* LWLock tranche for backend locks */
+static LWLockTranche ProcLWLockTranche;
+
/*
* If we're in STANDBY_SNAPSHOT_PENDING state, standbySnapshotPendingXmin is
* the highest xid that might still be running that we don't have in
@@ -261,6 +264,13 @@ CreateSharedProcArray(void)
mul_size(sizeof(bool), TOTAL_MAX_CACHED_SUBXIDS),
&found);
}
+
+ /* Register and initialize fields of ProcLWLockTranche */
+ ProcLWLockTranche.name = "proc";
+ ProcLWLockTranche.array_base = (char *) (ProcGlobal->allProcs) +
+ offsetof(PGPROC, backendLock);
+ ProcLWLockTranche.array_stride = sizeof(PGPROC);
+ LWLockRegisterTranche(LWTRANCHE_PROC, &ProcLWLockTranche);
}
/*
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 9c2e49cc849..269fe143019 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -825,13 +825,13 @@ LockAcquireExtended(const LOCKTAG *locktag,
* FastPathStrongRelationLocks->counts becomes visible after we test
* it has yet to begin to transfer fast-path locks.
*/
- LWLockAcquire(MyProc->backendLock, LW_EXCLUSIVE);
+ LWLockAcquire(&MyProc->backendLock, LW_EXCLUSIVE);
if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
acquired = false;
else
acquired = FastPathGrantRelationLock(locktag->locktag_field2,
lockmode);
- LWLockRelease(MyProc->backendLock);
+ LWLockRelease(&MyProc->backendLock);
if (acquired)
{
/*
@@ -1838,10 +1838,10 @@ LockRelease(const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock)
* We might not find the lock here, even if we originally entered it
* here. Another backend may have moved it to the main table.
*/
- LWLockAcquire(MyProc->backendLock, LW_EXCLUSIVE);
+ LWLockAcquire(&MyProc->backendLock, LW_EXCLUSIVE);
released = FastPathUnGrantRelationLock(locktag->locktag_field2,
lockmode);
- LWLockRelease(MyProc->backendLock);
+ LWLockRelease(&MyProc->backendLock);
if (released)
{
RemoveLocalLock(locallock);
@@ -2044,7 +2044,7 @@ LockReleaseAll(LOCKMETHODID lockmethodid, bool allLocks)
*/
if (!have_fast_path_lwlock)
{
- LWLockAcquire(MyProc->backendLock, LW_EXCLUSIVE);
+ LWLockAcquire(&MyProc->backendLock, LW_EXCLUSIVE);
have_fast_path_lwlock = true;
}
@@ -2061,7 +2061,7 @@ LockReleaseAll(LOCKMETHODID lockmethodid, bool allLocks)
* transferred to the main lock table. That's going to require
* some extra work, so release our fast-path lock before starting.
*/
- LWLockRelease(MyProc->backendLock);
+ LWLockRelease(&MyProc->backendLock);
have_fast_path_lwlock = false;
/*
@@ -2087,7 +2087,7 @@ LockReleaseAll(LOCKMETHODID lockmethodid, bool allLocks)
/* Done with the fast-path data structures */
if (have_fast_path_lwlock)
- LWLockRelease(MyProc->backendLock);
+ LWLockRelease(&MyProc->backendLock);
/*
* Now, scan each lock partition separately.
@@ -2490,7 +2490,7 @@ FastPathTransferRelationLocks(LockMethod lockMethodTable, const LOCKTAG *locktag
PGPROC *proc = &ProcGlobal->allProcs[i];
uint32 f;
- LWLockAcquire(proc->backendLock, LW_EXCLUSIVE);
+ LWLockAcquire(&proc->backendLock, LW_EXCLUSIVE);
/*
* If the target backend isn't referencing the same database as the
@@ -2499,7 +2499,7 @@ FastPathTransferRelationLocks(LockMethod lockMethodTable, const LOCKTAG *locktag
*
* proc->databaseId is set at backend startup time and never changes
* thereafter, so it might be safe to perform this test before
- * acquiring proc->backendLock. In particular, it's certainly safe to
+ * acquiring &proc->backendLock. In particular, it's certainly safe to
* assume that if the target backend holds any fast-path locks, it
* must have performed a memory-fencing operation (in particular, an
* LWLock acquisition) since setting proc->databaseId. However, it's
@@ -2509,7 +2509,7 @@ FastPathTransferRelationLocks(LockMethod lockMethodTable, const LOCKTAG *locktag
*/
if (proc->databaseId != locktag->locktag_field1)
{
- LWLockRelease(proc->backendLock);
+ LWLockRelease(&proc->backendLock);
continue;
}
@@ -2536,7 +2536,7 @@ FastPathTransferRelationLocks(LockMethod lockMethodTable, const LOCKTAG *locktag
if (!proclock)
{
LWLockRelease(partitionLock);
- LWLockRelease(proc->backendLock);
+ LWLockRelease(&proc->backendLock);
return false;
}
GrantLock(proclock->tag.myLock, proclock, lockmode);
@@ -2547,7 +2547,7 @@ FastPathTransferRelationLocks(LockMethod lockMethodTable, const LOCKTAG *locktag
/* No need to examine remaining slots. */
break;
}
- LWLockRelease(proc->backendLock);
+ LWLockRelease(&proc->backendLock);
}
return true;
}
@@ -2569,7 +2569,7 @@ FastPathGetRelationLockEntry(LOCALLOCK *locallock)
Oid relid = locktag->locktag_field2;
uint32 f;
- LWLockAcquire(MyProc->backendLock, LW_EXCLUSIVE);
+ LWLockAcquire(&MyProc->backendLock, LW_EXCLUSIVE);
for (f = 0; f < FP_LOCK_SLOTS_PER_BACKEND; f++)
{
@@ -2592,7 +2592,7 @@ FastPathGetRelationLockEntry(LOCALLOCK *locallock)
if (!proclock)
{
LWLockRelease(partitionLock);
- LWLockRelease(MyProc->backendLock);
+ LWLockRelease(&MyProc->backendLock);
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of shared memory"),
@@ -2607,7 +2607,7 @@ FastPathGetRelationLockEntry(LOCALLOCK *locallock)
break;
}
- LWLockRelease(MyProc->backendLock);
+ LWLockRelease(&MyProc->backendLock);
/* Lock may have already been transferred by some other backend. */
if (proclock == NULL)
@@ -2732,7 +2732,7 @@ GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode)
if (proc == MyProc)
continue;
- LWLockAcquire(proc->backendLock, LW_SHARED);
+ LWLockAcquire(&proc->backendLock, LW_SHARED);
/*
* If the target backend isn't referencing the same database as
@@ -2744,7 +2744,7 @@ GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode)
*/
if (proc->databaseId != locktag->locktag_field1)
{
- LWLockRelease(proc->backendLock);
+ LWLockRelease(&proc->backendLock);
continue;
}
@@ -2782,7 +2782,7 @@ GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode)
break;
}
- LWLockRelease(proc->backendLock);
+ LWLockRelease(&proc->backendLock);
}
}
@@ -3332,7 +3332,7 @@ GetLockStatusData(void)
PGPROC *proc = &ProcGlobal->allProcs[i];
uint32 f;
- LWLockAcquire(proc->backendLock, LW_SHARED);
+ LWLockAcquire(&proc->backendLock, LW_SHARED);
for (f = 0; f < FP_LOCK_SLOTS_PER_BACKEND; ++f)
{
@@ -3390,7 +3390,7 @@ GetLockStatusData(void)
el++;
}
- LWLockRelease(proc->backendLock);
+ LWLockRelease(&proc->backendLock);
}
/*
@@ -3930,7 +3930,7 @@ VirtualXactLockTableInsert(VirtualTransactionId vxid)
{
Assert(VirtualTransactionIdIsValid(vxid));
- LWLockAcquire(MyProc->backendLock, LW_EXCLUSIVE);
+ LWLockAcquire(&MyProc->backendLock, LW_EXCLUSIVE);
Assert(MyProc->backendId == vxid.backendId);
Assert(MyProc->fpLocalTransactionId == InvalidLocalTransactionId);
@@ -3939,7 +3939,7 @@ VirtualXactLockTableInsert(VirtualTransactionId vxid)
MyProc->fpVXIDLock = true;
MyProc->fpLocalTransactionId = vxid.localTransactionId;
- LWLockRelease(MyProc->backendLock);
+ LWLockRelease(&MyProc->backendLock);
}
/*
@@ -3959,14 +3959,14 @@ VirtualXactLockTableCleanup(void)
/*
* Clean up shared memory state.
*/
- LWLockAcquire(MyProc->backendLock, LW_EXCLUSIVE);
+ LWLockAcquire(&MyProc->backendLock, LW_EXCLUSIVE);
fastpath = MyProc->fpVXIDLock;
lxid = MyProc->fpLocalTransactionId;
MyProc->fpVXIDLock = false;
MyProc->fpLocalTransactionId = InvalidLocalTransactionId;
- LWLockRelease(MyProc->backendLock);
+ LWLockRelease(&MyProc->backendLock);
/*
* If fpVXIDLock has been cleared without touching fpLocalTransactionId,
@@ -4022,13 +4022,13 @@ VirtualXactLock(VirtualTransactionId vxid, bool wait)
* against the ones we're waiting for. The target backend will only set
* or clear lxid while holding this lock.
*/
- LWLockAcquire(proc->backendLock, LW_EXCLUSIVE);
+ LWLockAcquire(&proc->backendLock, LW_EXCLUSIVE);
/* If the transaction has ended, our work here is done. */
if (proc->backendId != vxid.backendId
|| proc->fpLocalTransactionId != vxid.localTransactionId)
{
- LWLockRelease(proc->backendLock);
+ LWLockRelease(&proc->backendLock);
return true;
}
@@ -4038,7 +4038,7 @@ VirtualXactLock(VirtualTransactionId vxid, bool wait)
*/
if (!wait)
{
- LWLockRelease(proc->backendLock);
+ LWLockRelease(&proc->backendLock);
return false;
}
@@ -4063,7 +4063,7 @@ VirtualXactLock(VirtualTransactionId vxid, bool wait)
if (!proclock)
{
LWLockRelease(partitionLock);
- LWLockRelease(proc->backendLock);
+ LWLockRelease(&proc->backendLock);
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of shared memory"),
@@ -4077,7 +4077,7 @@ VirtualXactLock(VirtualTransactionId vxid, bool wait)
}
/* Done with proc->fpLockBits */
- LWLockRelease(proc->backendLock);
+ LWLockRelease(&proc->backendLock);
/* Time to wait. */
(void) LockAcquire(&tag, ShareLock, false, false);
diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c
index ac61be2789c..5e276a08da3 100644
--- a/src/backend/storage/lmgr/lwlock.c
+++ b/src/backend/storage/lmgr/lwlock.c
@@ -353,9 +353,6 @@ NumLWLocks(void)
/* Predefined LWLocks */
numLocks = NUM_FIXED_LWLOCKS;
- /* proc.c needs one for each backend or auxiliary process */
- numLocks += MaxBackends + NUM_AUXILIARY_PROCS;
-
/* slot.c needs one for each slot */
numLocks += max_replication_slots;
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 0d5e23ac4d6..3690753d648 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -226,7 +226,7 @@ InitProcGlobal(void)
{
PGSemaphoreCreate(&(procs[i].sem));
InitSharedLatch(&(procs[i].procLatch));
- procs[i].backendLock = LWLockAssign();
+ LWLockInitialize(&(procs[i].backendLock), LWTRANCHE_PROC);
}
procs[i].pgprocno = i;
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index 5e8825ebeab..3f1da5155ef 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -213,6 +213,7 @@ typedef enum BuiltinTrancheIds
LWTRANCHE_WAL_INSERT,
LWTRANCHE_BUFFER_CONTENT,
LWTRANCHE_BUFFER_IO_IN_PROGRESS,
+ LWTRANCHE_PROC,
LWTRANCHE_FIRST_USER_DEFINED
} BuiltinTrancheIds;
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 38943a17671..3441288dd06 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -147,7 +147,7 @@ struct PGPROC
TransactionId backendLatestXid;
/* Per-backend LWLock. Protects fields below. */
- LWLock *backendLock; /* protects the fields below */
+ LWLock backendLock;
/* Lock manager data, recording fast-path locks taken by this backend. */
uint64 fpLockBits; /* lock modes held for each fast-path slot */
--
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