Merge branch 'rickard/proc-lock-queues/OTP-10163' into maint

* rickard/proc-lock-queues/OTP-10163:
  Use static allocation of process lock queues

4 files changed, 39 insertions, 137 deletions

diff --git a/erts/emulator/beam/erl_alloc.types b/erts/emulator/beam/erl_alloc.types
index d4ef9cc553..4aa8fa82fb 100644
--- a/erts/emulator/beam/erl_alloc.types
+++ b/erts/emulator/beam/erl_alloc.types
@@ -291,7 +291,6 @@ type	PORT_LOCK	STANDARD	SYSTEM		port_lock
 type	DRIVER_LOCK	STANDARD	SYSTEM		driver_lock
 type	XPORTS_LIST	SHORT_LIVED	SYSTEM		extra_port_list
 type	PROC_LCK_WTR	LONG_LIVED	SYSTEM		proc_lock_waiter
-type	PROC_LCK_QS	LONG_LIVED	SYSTEM		proc_lock_queues
 type	RUNQ_BLNS	LONG_LIVED	SYSTEM		run_queue_balancing
 type	THR_PRGR_IDATA	LONG_LIVED	SYSTEM		thr_prgr_internal_data
 type	THR_PRGR_DATA	LONG_LIVED	SYSTEM		thr_prgr_data
diff --git a/erts/emulator/beam/erl_lock_check.c b/erts/emulator/beam/erl_lock_check.c
index a0f744be9d..b545ec07c0 100644
--- a/erts/emulator/beam/erl_lock_check.c
+++ b/erts/emulator/beam/erl_lock_check.c
@@ -175,9 +175,6 @@ static erts_lc_lock_order_t erts_lock_order[] = {
     {	"sched_stat",				NULL			},
 #endif
     {	"async_init_mtx",			NULL			},
-#ifdef ERTS_SMP
-    {	"proc_lck_qs_alloc",			NULL 			},
-#endif
 #ifdef __WIN32__
 #ifdef DEBUG
     {   "save_ops_lock",                        NULL                    },
diff --git a/erts/emulator/beam/erl_process_lock.c b/erts/emulator/beam/erl_process_lock.c
index b3b4601a31..34d591df40 100644
--- a/erts/emulator/beam/erl_process_lock.c
+++ b/erts/emulator/beam/erl_process_lock.c
@@ -90,16 +90,6 @@ static void check_queue(erts_proc_lock_t *lck);
 #error "The size of the 'uflgs' field of the erts_tse_t type is too small"
 #endif
 
-struct erts_proc_lock_queues_t_ {
-    erts_proc_lock_queues_t *next;
-    erts_tse_t *queue[ERTS_PROC_LOCK_MAX_BIT+1];
-};
-
-static erts_proc_lock_queues_t zeroqs = {0};
-
-static erts_smp_spinlock_t qs_lock;
-static erts_proc_lock_queues_t *queue_free_list;
-
 #ifdef ERTS_ENABLE_LOCK_CHECK
 static struct {
     Sint16 proc_lock_main;
@@ -120,7 +110,6 @@ void
 erts_init_proc_lock(int cpus)
 {
     int i;
-    erts_smp_spinlock_init(&qs_lock, "proc_lck_qs_alloc");
     for (i = 0; i < ERTS_NO_OF_PIX_LOCKS; i++) {
 #ifdef ERTS_ENABLE_LOCK_COUNT
 	erts_mtx_init_x(&erts_pix_locks[i].u.mtx,
@@ -129,7 +118,6 @@ erts_init_proc_lock(int cpus)
 	erts_mtx_init(&erts_pix_locks[i].u.mtx, "pix_lock");
 #endif
     }
-    queue_free_list = NULL;
     erts_thr_install_exit_handler(cleanup_tse);
 #ifdef ERTS_ENABLE_LOCK_CHECK
     lc_id.proc_lock_main	= erts_lc_get_lock_order_id("proc_main");
@@ -156,16 +144,7 @@ erts_init_proc_lock(int cpus)
 }
 
 #ifdef ERTS_ENABLE_LOCK_CHECK
-static void
-check_unused_tse(erts_tse_t *wtr)
-{
-    int i;
-    erts_proc_lock_queues_t *queues = wtr->udata;
-    ERTS_LC_ASSERT(wtr->uflgs == 0);
-    for (i = 0; i <= ERTS_PROC_LOCK_MAX_BIT; i++)
-	ERTS_LC_ASSERT(!queues->queue[i]);
-}
-#define CHECK_UNUSED_TSE(W) check_unused_tse((W))
+#define CHECK_UNUSED_TSE(W) ERTS_LC_ASSERT((W)->uflgs == 0)
 #else
 #define CHECK_UNUSED_TSE(W)
 #endif
@@ -174,56 +153,21 @@ static ERTS_INLINE erts_tse_t *
 tse_fetch(erts_pix_lock_t *pix_lock)
 {
     erts_tse_t *tse = erts_tse_fetch();
-    if (!tse->udata) {
-	erts_proc_lock_queues_t *qs;
-#if ERTS_PROC_LOCK_SPINLOCK_IMPL && !ERTS_PROC_LOCK_ATOMIC_IMPL
-	if (pix_lock)
-	    erts_pix_unlock(pix_lock);
-#endif
-	erts_smp_spin_lock(&qs_lock);
-	qs = queue_free_list;
-	if (qs) {
-	    queue_free_list = queue_free_list->next;
-	    erts_smp_spin_unlock(&qs_lock);
-	}
-	else {
-	    erts_smp_spin_unlock(&qs_lock);
-	    qs = erts_alloc(ERTS_ALC_T_PROC_LCK_QS,
-			    sizeof(erts_proc_lock_queues_t));
-	    sys_memcpy((void *) qs,
-		       (void *) &zeroqs,
-		       sizeof(erts_proc_lock_queues_t));
-	}
-	tse->udata = qs;
-#if ERTS_PROC_LOCK_SPINLOCK_IMPL && !ERTS_PROC_LOCK_ATOMIC_IMPL
-	if (pix_lock)
-	    erts_pix_lock(pix_lock);
-#endif
-    }
     tse->uflgs = 0;
     return tse;
 }
 
 static ERTS_INLINE void
-tse_return(erts_tse_t *tse, int force_free_q)
+tse_return(erts_tse_t *tse)
 {
     CHECK_UNUSED_TSE(tse);
-    if (force_free_q || erts_tse_is_tmp(tse)) {
-	erts_proc_lock_queues_t *qs = tse->udata;
-	ASSERT(qs);
-	erts_smp_spin_lock(&qs_lock);
-	qs->next = queue_free_list;
-	queue_free_list = qs;
-	erts_smp_spin_unlock(&qs_lock);
-	tse->udata = NULL;
-    }
     erts_tse_return(tse);
 }
 
 void
 erts_proc_lock_prepare_proc_lock_waiter(void)
 {
-    tse_return(tse_fetch(NULL), 0);
+    tse_return(tse_fetch(NULL));
 }
 
 
@@ -231,55 +175,49 @@ static void
 cleanup_tse(void)
 {
     erts_tse_t *tse = erts_tse_fetch();
-    if (tse) {
-	if (tse->udata)
-	    tse_return(tse, 1);
-	else
-	    erts_tse_return(tse);
-    }
+    if (tse)
+	erts_tse_return(tse);
 }
 
 
 /*
  * Waiters are queued in a circular double linked list;
- * where qs->queue[lock_ix] is the first waiter in queue, and
- * qs->queue[lock_ix]->prev is the last waiter in queue.
+ * where lck->queue[lock_ix] is the first waiter in queue, and
+ * lck->queue[lock_ix]->prev is the last waiter in queue.
  */
 
 static ERTS_INLINE void
-enqueue_waiter(erts_proc_lock_queues_t *qs,
-	       int ix,
-	       erts_tse_t *wtr)
+enqueue_waiter(erts_proc_lock_t *lck, int ix, erts_tse_t *wtr)
 {
-    if (!qs->queue[ix]) {
-	qs->queue[ix] = wtr;
+    if (!lck->queue[ix]) {
+	lck->queue[ix] = wtr;
 	wtr->next = wtr;
 	wtr->prev = wtr;
     }
     else {
-	ERTS_LC_ASSERT(qs->queue[ix]->next && qs->queue[ix]->prev);
-	wtr->next = qs->queue[ix];
-	wtr->prev = qs->queue[ix]->prev;
+	ERTS_LC_ASSERT(lck->queue[ix]->next && lck->queue[ix]->prev);
+	wtr->next = lck->queue[ix];
+	wtr->prev = lck->queue[ix]->prev;
 	wtr->prev->next = wtr;
-	qs->queue[ix]->prev = wtr;
+	lck->queue[ix]->prev = wtr;
     }
 }
 
 static erts_tse_t *
-dequeue_waiter(erts_proc_lock_queues_t *qs, int ix)
+dequeue_waiter(erts_proc_lock_t *lck, int ix)
 {
-    erts_tse_t *wtr = qs->queue[ix];
-    ERTS_LC_ASSERT(qs->queue[ix]);
+    erts_tse_t *wtr = lck->queue[ix];
+    ERTS_LC_ASSERT(lck->queue[ix]);
     if (wtr->next == wtr) {
-	ERTS_LC_ASSERT(qs->queue[ix]->prev == wtr);
-	qs->queue[ix] = NULL;
+	ERTS_LC_ASSERT(lck->queue[ix]->prev == wtr);
+	lck->queue[ix] = NULL;
     }
     else {
 	ERTS_LC_ASSERT(wtr->next != wtr);
 	ERTS_LC_ASSERT(wtr->prev != wtr);
 	wtr->next->prev = wtr->prev;
 	wtr->prev->next = wtr->next;
-	qs->queue[ix] = wtr->next;
+	lck->queue[ix] = wtr->next;
     }
     return wtr;
 }
@@ -300,19 +238,18 @@ try_aquire(erts_proc_lock_t *lck, erts_tse_t *wtr)
     ErtsProcLocks locks = wtr->uflgs;
     int lock_no;
 
-    ERTS_LC_ASSERT(lck->queues);
     ERTS_LC_ASSERT(got_locks != locks);
 
     for (lock_no = 0; lock_no <= ERTS_PROC_LOCK_MAX_BIT; lock_no++) {
 	ErtsProcLocks lock = ((ErtsProcLocks) 1) << lock_no;
 	if (locks & lock) {
 	    ErtsProcLocks wflg, old_lflgs;
-	    if (lck->queues->queue[lock_no]) {
+	    if (lck->queue[lock_no]) {
 		/* Others already waiting */
 	    enqueue:
 		ERTS_LC_ASSERT(ERTS_PROC_LOCK_FLGS_READ_(lck)
 			       & (lock << ERTS_PROC_LOCK_WAITER_SHIFT));
-		enqueue_waiter(lck->queues, lock_no, wtr);
+		enqueue_waiter(lck, lock_no, wtr);
 		break;
 	    }
 	    wflg = lock << ERTS_PROC_LOCK_WAITER_SHIFT;
@@ -364,7 +301,6 @@ transfer_locks(Process *p,
     for (lock_no = 0; tlocks && lock_no <= ERTS_PROC_LOCK_MAX_BIT; lock_no++) {
 	ErtsProcLocks lock = ((ErtsProcLocks) 1) << lock_no;
 	if (tlocks & lock) {
-	    erts_proc_lock_queues_t *qs = p->lock.queues;
 	    /* Transfer lock */
 #ifdef ERTS_ENABLE_LOCK_CHECK
 	    tlocks &= ~lock;
@@ -372,9 +308,9 @@ transfer_locks(Process *p,
 	    ERTS_LC_ASSERT(ERTS_PROC_LOCK_FLGS_READ_(&p->lock)
 			   & (lock << ERTS_PROC_LOCK_WAITER_SHIFT));
 	    transferred++;
-	    wtr = dequeue_waiter(qs, lock_no);
+	    wtr = dequeue_waiter(&p->lock, lock_no);
 	    ERTS_LC_ASSERT(wtr);
-	    if (!qs->queue[lock_no])
+	    if (!p->lock.queue[lock_no])
 		unset_waiter |= lock;
 	    ERTS_LC_ASSERT(wtr->uflgs & lock);
 	    wtr->uflgs &= ~lock;
@@ -463,7 +399,6 @@ wait_for_locks(Process *p,
 {
     erts_pix_lock_t *pix_lock = pixlck ? pixlck : ERTS_PID2PIXLOCK(p->id);
     erts_tse_t *wtr;
-    erts_proc_lock_queues_t *qs;
 
     /* Acquire a waiter object on which this thread can wait. */
     wtr = tse_fetch(pix_lock);
@@ -479,18 +414,6 @@ wait_for_locks(Process *p,
 
     ERTS_LC_ASSERT(erts_lc_pix_lock_is_locked(pix_lock));
 
-    qs = wtr->udata;
-    ASSERT(qs);
-    /* Provide the process with waiter queues, if it doesn't have one. */
-    if (!p->lock.queues) {
-	qs->next = NULL;
-	p->lock.queues = qs;
-    }
-    else {
-	qs->next = p->lock.queues->next;
-	p->lock.queues->next = qs;
-    }
-
 #ifdef ERTS_PROC_LOCK_HARD_DEBUG
     check_queue(&p->lock);
 #endif
@@ -504,7 +427,9 @@ wait_for_locks(Process *p,
     check_queue(&p->lock);
 #endif
 
-    if (wtr->uflgs) {
+    if (wtr->uflgs == 0)
+	erts_pix_unlock(pix_lock);
+    else {
 	/* We didn't get them all; need to wait... */
 
 	ASSERT((wtr->uflgs & ~ERTS_PROC_LOCKS_ALL) == 0);
@@ -529,28 +454,12 @@ wait_for_locks(Process *p,
 	    } while (res != 0);
 	}
 
-	erts_pix_lock(pix_lock);
-
 	ASSERT(wtr->uflgs == 0);
     }
 
-    /* Recover some queues to store in the waiter. */
-    ERTS_LC_ASSERT(p->lock.queues);
-    if (p->lock.queues->next) {
-	qs = p->lock.queues->next;
-	p->lock.queues->next = qs->next;
-    }
-    else {
-	qs = p->lock.queues;
-	p->lock.queues = NULL;
-    }
-    wtr->udata = qs;
-
-    erts_pix_unlock(pix_lock);
-
     ERTS_LC_ASSERT(locks == (ERTS_PROC_LOCK_FLGS_READ_(&p->lock) & locks));
 
-    tse_return(wtr, 0);
+    tse_return(wtr);
 }
 
 /*
@@ -971,6 +880,7 @@ erts_pid2proc_safelock(Process *c_p,
 void
 erts_proc_lock_init(Process *p)
 {
+    int i;
     /* We always start with all locks locked */
 #if ERTS_PROC_LOCK_ATOMIC_IMPL
     erts_smp_atomic32_init_nob(&p->lock.flags,
@@ -978,7 +888,8 @@ erts_proc_lock_init(Process *p)
 #else
     p->lock.flags = ERTS_PROC_LOCKS_ALL;
 #endif
-    p->lock.queues = NULL;
+    for (i = 0; i <= ERTS_PROC_LOCK_MAX_BIT; i++)
+	p->lock.queue[i] = NULL;
     p->lock.refc = 1;
 #ifdef ERTS_ENABLE_LOCK_COUNT
     erts_lcnt_proc_lock_init(p);
@@ -990,11 +901,8 @@ erts_proc_lock_init(Process *p)
     erts_proc_lc_trylock(p, ERTS_PROC_LOCKS_ALL, 1);
 #endif
 #ifdef ERTS_PROC_LOCK_DEBUG
-    {
-	int i;
-	for (i = 0; i <= ERTS_PROC_LOCK_MAX_BIT; i++)
-	    erts_smp_atomic32_init_nob(&p->lock.locked[i], (erts_aint32_t) 1);
-    }
+    for (i = 0; i <= ERTS_PROC_LOCK_MAX_BIT; i++)
+	erts_smp_atomic32_init_nob(&p->lock.locked[i], (erts_aint32_t) 1);
 #endif
 }
 
@@ -1463,21 +1371,21 @@ check_queue(erts_proc_lock_t *lck)
 	if (lflgs & wtr) {
 	    int n;
 	    erts_tse_t *wtr;
-	    ERTS_LC_ASSERT(lck->queues && lck->queues->queue[lock_no]);
-	    wtr = lck->queues->queue[lock_no];
+	    ERTS_LC_ASSERT(lck->queue[lock_no]);
+	    wtr = lck->queue[lock_no];
 	    n = 0;
 	    do {
 		wtr = wtr->next;
 		n++;
-	    } while (wtr != lck->queues->queue[lock_no]);
+	    } while (wtr != lck->queue[lock_no]);
 	    do {
 		wtr = wtr->prev;
 		n--;
-	    } while (wtr != lck->queues->queue[lock_no]);
+	    } while (wtr != lck->queue[lock_no]);
 	    ERTS_LC_ASSERT(n == 0);
 	}
 	else {
-	    ERTS_LC_ASSERT(!lck->queues || !lck->queues->queue[lock_no]);
+	    ERTS_LC_ASSERT(!lck->queue[lock_no]);
 	}
     }
 }
diff --git a/erts/emulator/beam/erl_process_lock.h b/erts/emulator/beam/erl_process_lock.h
index 413c45480c..290084d8ca 100644
--- a/erts/emulator/beam/erl_process_lock.h
+++ b/erts/emulator/beam/erl_process_lock.h
@@ -56,15 +56,13 @@
 
 typedef erts_aint32_t ErtsProcLocks;
 
-typedef struct erts_proc_lock_queues_t_ erts_proc_lock_queues_t;
-
 typedef struct erts_proc_lock_t_ {
 #if ERTS_PROC_LOCK_ATOMIC_IMPL
     erts_smp_atomic32_t flags;
 #else
     ErtsProcLocks flags;
 #endif
-    erts_proc_lock_queues_t *queues;
+    erts_tse_t *queue[ERTS_PROC_LOCK_MAX_BIT+1];
     Sint32 refc;
 #ifdef ERTS_PROC_LOCK_DEBUG
     erts_smp_atomic32_t locked[ERTS_PROC_LOCK_MAX_BIT+1];