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-rw-r--r--src/backend/storage/aio/method_io_uring.c210
-rw-r--r--src/backend/storage/ipc/standby.c4
-rw-r--r--src/backend/storage/lmgr/lock.c20
-rw-r--r--src/backend/storage/lmgr/predicate.c11
4 files changed, 222 insertions, 23 deletions
diff --git a/src/backend/storage/aio/method_io_uring.c b/src/backend/storage/aio/method_io_uring.c
index b78048328e1..0a8c054162f 100644
--- a/src/backend/storage/aio/method_io_uring.c
+++ b/src/backend/storage/aio/method_io_uring.c
@@ -29,6 +29,9 @@
#ifdef IOMETHOD_IO_URING_ENABLED
+#include <sys/mman.h>
+#include <unistd.h>
+
#include <liburing.h>
#include "miscadmin.h"
@@ -94,12 +97,32 @@ PgAioUringContext
struct io_uring io_uring_ring;
} PgAioUringContext;
+/*
+ * Information about the capabilities that io_uring has.
+ *
+ * Depending on liburing and kernel version different features are
+ * supported. At least for the kernel a kernel version check does not suffice
+ * as various vendors do backport features to older kernels :(.
+ */
+typedef struct PgAioUringCaps
+{
+ bool checked;
+ /* -1 if io_uring_queue_init_mem() is unsupported */
+ int mem_init_size;
+} PgAioUringCaps;
+
+
/* PgAioUringContexts for all backends */
static PgAioUringContext *pgaio_uring_contexts;
/* the current backend's context */
static PgAioUringContext *pgaio_my_uring_context;
+static PgAioUringCaps pgaio_uring_caps =
+{
+ .checked = false,
+ .mem_init_size = -1,
+};
static uint32
pgaio_uring_procs(void)
@@ -111,16 +134,145 @@ pgaio_uring_procs(void)
return MaxBackends + NUM_AUXILIARY_PROCS - MAX_IO_WORKERS;
}
-static Size
+/*
+ * Initializes pgaio_uring_caps, unless that's already done.
+ */
+static void
+pgaio_uring_check_capabilities(void)
+{
+ if (pgaio_uring_caps.checked)
+ return;
+
+ /*
+ * By default io_uring creates a shared memory mapping for each io_uring
+ * instance, leading to a large number of memory mappings. Unfortunately a
+ * large number of memory mappings slows things down, backend exit is
+ * particularly affected. To address that, newer kernels (6.5) support
+ * using user-provided memory for the memory, by putting the relevant
+ * memory into shared memory we don't need any additional mappings.
+ *
+ * To know whether this is supported, we unfortunately need to probe the
+ * kernel by trying to create a ring with userspace-provided memory. This
+ * also has a secondary benefit: We can determine precisely how much
+ * memory we need for each io_uring instance.
+ */
+#if defined(HAVE_LIBURING_QUEUE_INIT_MEM) && defined(IORING_SETUP_NO_MMAP)
+ {
+ struct io_uring test_ring;
+ size_t ring_size;
+ void *ring_ptr;
+ struct io_uring_params p = {0};
+ int ret;
+
+ /*
+ * Liburing does not yet provide an API to query how much memory a
+ * ring will need. So we over-estimate it here. As the memory is freed
+ * just below that's small temporary waste of memory.
+ *
+ * 1MB is more than enough for rings within io_max_concurrency's
+ * range.
+ */
+ ring_size = 1024 * 1024;
+
+ /*
+ * Hard to believe a system exists where 1MB would not be a multiple
+ * of the page size. But it's cheap to ensure...
+ */
+ ring_size -= ring_size % sysconf(_SC_PAGESIZE);
+
+ ring_ptr = mmap(NULL, ring_size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+ if (ring_ptr == MAP_FAILED)
+ elog(ERROR,
+ "mmap(%zu) to determine io_uring_queue_init_mem() support failed: %m",
+ ring_size);
+
+ ret = io_uring_queue_init_mem(io_max_concurrency, &test_ring, &p, ring_ptr, ring_size);
+ if (ret > 0)
+ {
+ pgaio_uring_caps.mem_init_size = ret;
+
+ elog(DEBUG1,
+ "can use combined memory mapping for io_uring, each ring needs %d bytes",
+ ret);
+
+ /* clean up the created ring, it was just for a test */
+ io_uring_queue_exit(&test_ring);
+ }
+ else
+ {
+ /*
+ * There are different reasons for ring creation to fail, but it's
+ * ok to treat that just as io_uring_queue_init_mem() not being
+ * supported. We'll report a more detailed error in
+ * pgaio_uring_shmem_init().
+ */
+ errno = -ret;
+ elog(DEBUG1,
+ "cannot use combined memory mapping for io_uring, ring creation failed: %m");
+
+ }
+
+ if (munmap(ring_ptr, ring_size) != 0)
+ elog(ERROR, "munmap() failed: %m");
+ }
+#else
+ {
+ elog(DEBUG1,
+ "can't use combined memory mapping for io_uring, kernel or liburing too old");
+ }
+#endif
+
+ pgaio_uring_caps.checked = true;
+}
+
+/*
+ * Memory for all PgAioUringContext instances
+ */
+static size_t
pgaio_uring_context_shmem_size(void)
{
return mul_size(pgaio_uring_procs(), sizeof(PgAioUringContext));
}
+/*
+ * Memory for the combined memory used by io_uring instances. Returns 0 if
+ * that is not supported by kernel/liburing.
+ */
+static size_t
+pgaio_uring_ring_shmem_size(void)
+{
+ size_t sz = 0;
+
+ if (pgaio_uring_caps.mem_init_size > 0)
+ {
+ /*
+ * Memory for rings needs to be allocated to the page boundary,
+ * reserve space. Luckily it does not need to be aligned to hugepage
+ * boundaries, even if huge pages are used.
+ */
+ sz = add_size(sz, sysconf(_SC_PAGESIZE));
+ sz = add_size(sz, mul_size(pgaio_uring_procs(),
+ pgaio_uring_caps.mem_init_size));
+ }
+
+ return sz;
+}
+
static size_t
pgaio_uring_shmem_size(void)
{
- return pgaio_uring_context_shmem_size();
+ size_t sz;
+
+ /*
+ * Kernel and liburing support for various features influences how much
+ * shmem we need, perform the necessary checks.
+ */
+ pgaio_uring_check_capabilities();
+
+ sz = pgaio_uring_context_shmem_size();
+ sz = add_size(sz, pgaio_uring_ring_shmem_size());
+
+ return sz;
}
static void
@@ -128,13 +280,38 @@ pgaio_uring_shmem_init(bool first_time)
{
int TotalProcs = pgaio_uring_procs();
bool found;
+ char *shmem;
+ size_t ring_mem_remain = 0;
+ char *ring_mem_next = 0;
- pgaio_uring_contexts = (PgAioUringContext *)
- ShmemInitStruct("AioUring", pgaio_uring_shmem_size(), &found);
-
+ /*
+ * We allocate memory for all PgAioUringContext instances and, if
+ * supported, the memory required for each of the io_uring instances, in
+ * one ShmemInitStruct().
+ */
+ shmem = ShmemInitStruct("AioUringContext", pgaio_uring_shmem_size(), &found);
if (found)
return;
+ pgaio_uring_contexts = (PgAioUringContext *) shmem;
+ shmem += pgaio_uring_context_shmem_size();
+
+ /* if supported, handle memory alignment / sizing for io_uring memory */
+ if (pgaio_uring_caps.mem_init_size > 0)
+ {
+ ring_mem_remain = pgaio_uring_ring_shmem_size();
+ ring_mem_next = (char *) shmem;
+
+ /* align to page boundary, see also pgaio_uring_ring_shmem_size() */
+ ring_mem_next = (char *) TYPEALIGN(sysconf(_SC_PAGESIZE), ring_mem_next);
+
+ /* account for alignment */
+ ring_mem_remain -= ring_mem_next - shmem;
+ shmem += ring_mem_next - shmem;
+
+ shmem += ring_mem_remain;
+ }
+
for (int contextno = 0; contextno < TotalProcs; contextno++)
{
PgAioUringContext *context = &pgaio_uring_contexts[contextno];
@@ -158,7 +335,28 @@ pgaio_uring_shmem_init(bool first_time)
* be worth using that - also need to evaluate if that causes
* noticeable additional contention?
*/
- ret = io_uring_queue_init(io_max_concurrency, &context->io_uring_ring, 0);
+
+ /*
+ * If supported (c.f. pgaio_uring_check_capabilities()), create ring
+ * with its data in shared memory. Otherwise fall back io_uring
+ * creating a memory mapping for each ring.
+ */
+#if defined(HAVE_LIBURING_QUEUE_INIT_MEM) && defined(IORING_SETUP_NO_MMAP)
+ if (pgaio_uring_caps.mem_init_size > 0)
+ {
+ struct io_uring_params p = {0};
+
+ ret = io_uring_queue_init_mem(io_max_concurrency, &context->io_uring_ring, &p, ring_mem_next, ring_mem_remain);
+
+ ring_mem_remain -= ret;
+ ring_mem_next += ret;
+ }
+ else
+#endif
+ {
+ ret = io_uring_queue_init(io_max_concurrency, &context->io_uring_ring, 0);
+ }
+
if (ret < 0)
{
char *hint = NULL;
diff --git a/src/backend/storage/ipc/standby.c b/src/backend/storage/ipc/standby.c
index 7fa8d9247e0..4222bdab078 100644
--- a/src/backend/storage/ipc/standby.c
+++ b/src/backend/storage/ipc/standby.c
@@ -1376,7 +1376,7 @@ LogCurrentRunningXacts(RunningTransactions CurrRunningXacts)
if (xlrec.subxid_overflow)
elog(DEBUG2,
- "snapshot of %d running transactions overflowed (lsn %X/%X oldest xid %u latest complete %u next xid %u)",
+ "snapshot of %d running transactions overflowed (lsn %X/%08X oldest xid %u latest complete %u next xid %u)",
CurrRunningXacts->xcnt,
LSN_FORMAT_ARGS(recptr),
CurrRunningXacts->oldestRunningXid,
@@ -1384,7 +1384,7 @@ LogCurrentRunningXacts(RunningTransactions CurrRunningXacts)
CurrRunningXacts->nextXid);
else
elog(DEBUG2,
- "snapshot of %d+%d running transaction ids (lsn %X/%X oldest xid %u latest complete %u next xid %u)",
+ "snapshot of %d+%d running transaction ids (lsn %X/%08X oldest xid %u latest complete %u next xid %u)",
CurrRunningXacts->xcnt, CurrRunningXacts->subxcnt,
LSN_FORMAT_ARGS(recptr),
CurrRunningXacts->oldestRunningXid,
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 2776ceb295b..62f3471448e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -3539,9 +3539,9 @@ AtPrepare_Locks(void)
* but that probably costs more cycles.
*/
void
-PostPrepare_Locks(TransactionId xid)
+PostPrepare_Locks(FullTransactionId fxid)
{
- PGPROC *newproc = TwoPhaseGetDummyProc(xid, false);
+ PGPROC *newproc = TwoPhaseGetDummyProc(fxid, false);
HASH_SEQ_STATUS status;
LOCALLOCK *locallock;
LOCK *lock;
@@ -4324,11 +4324,11 @@ DumpAllLocks(void)
* and PANIC anyway.
*/
void
-lock_twophase_recover(TransactionId xid, uint16 info,
+lock_twophase_recover(FullTransactionId fxid, uint16 info,
void *recdata, uint32 len)
{
TwoPhaseLockRecord *rec = (TwoPhaseLockRecord *) recdata;
- PGPROC *proc = TwoPhaseGetDummyProc(xid, false);
+ PGPROC *proc = TwoPhaseGetDummyProc(fxid, false);
LOCKTAG *locktag;
LOCKMODE lockmode;
LOCKMETHODID lockmethodid;
@@ -4505,7 +4505,7 @@ lock_twophase_recover(TransactionId xid, uint16 info,
* starting up into hot standby mode.
*/
void
-lock_twophase_standby_recover(TransactionId xid, uint16 info,
+lock_twophase_standby_recover(FullTransactionId fxid, uint16 info,
void *recdata, uint32 len)
{
TwoPhaseLockRecord *rec = (TwoPhaseLockRecord *) recdata;
@@ -4524,7 +4524,7 @@ lock_twophase_standby_recover(TransactionId xid, uint16 info,
if (lockmode == AccessExclusiveLock &&
locktag->locktag_type == LOCKTAG_RELATION)
{
- StandbyAcquireAccessExclusiveLock(xid,
+ StandbyAcquireAccessExclusiveLock(XidFromFullTransactionId(fxid),
locktag->locktag_field1 /* dboid */ ,
locktag->locktag_field2 /* reloid */ );
}
@@ -4537,11 +4537,11 @@ lock_twophase_standby_recover(TransactionId xid, uint16 info,
* Find and release the lock indicated by the 2PC record.
*/
void
-lock_twophase_postcommit(TransactionId xid, uint16 info,
+lock_twophase_postcommit(FullTransactionId fxid, uint16 info,
void *recdata, uint32 len)
{
TwoPhaseLockRecord *rec = (TwoPhaseLockRecord *) recdata;
- PGPROC *proc = TwoPhaseGetDummyProc(xid, true);
+ PGPROC *proc = TwoPhaseGetDummyProc(fxid, true);
LOCKTAG *locktag;
LOCKMETHODID lockmethodid;
LockMethod lockMethodTable;
@@ -4563,10 +4563,10 @@ lock_twophase_postcommit(TransactionId xid, uint16 info,
* This is actually just the same as the COMMIT case.
*/
void
-lock_twophase_postabort(TransactionId xid, uint16 info,
+lock_twophase_postabort(FullTransactionId fxid, uint16 info,
void *recdata, uint32 len)
{
- lock_twophase_postcommit(xid, info, recdata, len);
+ lock_twophase_postcommit(fxid, info, recdata, len);
}
/*
diff --git a/src/backend/storage/lmgr/predicate.c b/src/backend/storage/lmgr/predicate.c
index d82114ffca1..c07fb588355 100644
--- a/src/backend/storage/lmgr/predicate.c
+++ b/src/backend/storage/lmgr/predicate.c
@@ -191,7 +191,7 @@
* AtPrepare_PredicateLocks(void);
* PostPrepare_PredicateLocks(TransactionId xid);
* PredicateLockTwoPhaseFinish(TransactionId xid, bool isCommit);
- * predicatelock_twophase_recover(TransactionId xid, uint16 info,
+ * predicatelock_twophase_recover(FullTransactionId fxid, uint16 info,
* void *recdata, uint32 len);
*/
@@ -4856,7 +4856,7 @@ AtPrepare_PredicateLocks(void)
* anyway. We only need to clean up our local state.
*/
void
-PostPrepare_PredicateLocks(TransactionId xid)
+PostPrepare_PredicateLocks(FullTransactionId fxid)
{
if (MySerializableXact == InvalidSerializableXact)
return;
@@ -4879,12 +4879,12 @@ PostPrepare_PredicateLocks(TransactionId xid)
* commits or aborts.
*/
void
-PredicateLockTwoPhaseFinish(TransactionId xid, bool isCommit)
+PredicateLockTwoPhaseFinish(FullTransactionId fxid, bool isCommit)
{
SERIALIZABLEXID *sxid;
SERIALIZABLEXIDTAG sxidtag;
- sxidtag.xid = xid;
+ sxidtag.xid = XidFromFullTransactionId(fxid);
LWLockAcquire(SerializableXactHashLock, LW_SHARED);
sxid = (SERIALIZABLEXID *)
@@ -4906,10 +4906,11 @@ PredicateLockTwoPhaseFinish(TransactionId xid, bool isCommit)
* Re-acquire a predicate lock belonging to a transaction that was prepared.
*/
void
-predicatelock_twophase_recover(TransactionId xid, uint16 info,
+predicatelock_twophase_recover(FullTransactionId fxid, uint16 info,
void *recdata, uint32 len)
{
TwoPhasePredicateRecord *record;
+ TransactionId xid = XidFromFullTransactionId(fxid);
Assert(len == sizeof(TwoPhasePredicateRecord));
generated by cgit v1.2.3 (git 2.39.1) at 2025-07-08 15:43:28 +0000