* (d) release the locks on the TVars, writing updates to them in the case of a
* commit, (e) unlock the STM.
*
- * Queues of waiting threads hang off the first_watch_queue_entry field of each
- * TVar. This may only be manipulated when holding that TVar's lock. In
- * particular, when a thread is putting itself to sleep, it mustn't release
- * the TVar's lock until it has added itself to the wait queue and marked its
- * TSO as BlockedOnSTM -- this makes sure that other threads will know to wake it.
+ * Queues of waiting threads hang off the first_watch_queue_entry
+ * field of each TVar. This may only be manipulated when holding that
+ * TVar's lock. In particular, when a thread is putting itself to
+ * sleep, it mustn't release the TVar's lock until it has added itself
+ * to the wait queue and marked its TSO as BlockedOnSTM -- this makes
+ * sure that other threads will know to wake it.
*
* ---------------------------------------------------------------------------*/
#include "PosixSource.h"
#include "Rts.h"
-#include "RtsFlags.h"
+
#include "RtsUtils.h"
-#include "Storage.h"
#include "Schedule.h"
-#include "SMP.h"
#include "STM.h"
#include "Trace.h"
+#include "Threads.h"
-#include <stdlib.h>
#include <stdio.h>
#define TRUE 1
do {
do {
result = s -> current_value;
- } while (GET_INFO(result) == &stg_TREC_HEADER_info);
+ } while (GET_INFO(UNTAG_CLOSURE(result)) == &stg_TREC_HEADER_info);
} while (cas((void *)&(s -> current_value),
(StgWord)result, (StgWord)trec) != (StgWord)result);
return result;
static StgBool watcher_is_invariant(StgTVarWatchQueue *q) {
StgClosure *c = q -> closure;
- StgInfoTable *info = get_itbl(c);
- return (info -> type) == ATOMIC_INVARIANT;
+ return (c->header.info == &stg_ATOMIC_INVARIANT_info);
}
/*......................................................................*/
lockTSO(tso);
if (tso -> why_blocked == BlockedOnSTM) {
TRACE("unpark_tso on tso=%p", tso);
- unblockOne(cap,tso);
+ tryWakeupThread(cap,tso);
} else {
TRACE("spurious unpark_tso on tso=%p", tso);
}
static void unpark_waiters_on(Capability *cap, StgTVar *s) {
StgTVarWatchQueue *q;
+ StgTVarWatchQueue *trail;
TRACE("unpark_waiters_on tvar=%p", s);
- for (q = s -> first_watch_queue_entry;
- q != END_STM_WATCH_QUEUE;
+ // unblock TSOs in reverse order, to be a bit fairer (#2319)
+ for (q = s -> first_watch_queue_entry, trail = q;
+ q != END_STM_WATCH_QUEUE;
q = q -> next_queue_entry) {
+ trail = q;
+ }
+ q = trail;
+ for (;
+ q != END_STM_WATCH_QUEUE;
+ q = q -> prev_queue_entry) {
if (watcher_is_tso(q)) {
unpark_tso(cap, (StgTSO *)(q -> closure));
}
static StgInvariantCheckQueue *new_stg_invariant_check_queue(Capability *cap,
StgAtomicInvariant *invariant) {
StgInvariantCheckQueue *result;
- result = (StgInvariantCheckQueue *)allocateLocal(cap, sizeofW(StgInvariantCheckQueue));
+ result = (StgInvariantCheckQueue *)allocate(cap, sizeofW(StgInvariantCheckQueue));
SET_HDR (result, &stg_INVARIANT_CHECK_QUEUE_info, CCS_SYSTEM);
result -> invariant = invariant;
result -> my_execution = NO_TREC;
static StgTVarWatchQueue *new_stg_tvar_watch_queue(Capability *cap,
StgClosure *closure) {
StgTVarWatchQueue *result;
- result = (StgTVarWatchQueue *)allocateLocal(cap, sizeofW(StgTVarWatchQueue));
+ result = (StgTVarWatchQueue *)allocate(cap, sizeofW(StgTVarWatchQueue));
SET_HDR (result, &stg_TVAR_WATCH_QUEUE_info, CCS_SYSTEM);
result -> closure = closure;
return result;
static StgTRecChunk *new_stg_trec_chunk(Capability *cap) {
StgTRecChunk *result;
- result = (StgTRecChunk *)allocateLocal(cap, sizeofW(StgTRecChunk));
+ result = (StgTRecChunk *)allocate(cap, sizeofW(StgTRecChunk));
SET_HDR (result, &stg_TREC_CHUNK_info, CCS_SYSTEM);
result -> prev_chunk = END_STM_CHUNK_LIST;
result -> next_entry_idx = 0;
static StgTRecHeader *new_stg_trec_header(Capability *cap,
StgTRecHeader *enclosing_trec) {
StgTRecHeader *result;
- result = (StgTRecHeader *) allocateLocal(cap, sizeofW(StgTRecHeader));
+ result = (StgTRecHeader *) allocate(cap, sizeofW(StgTRecHeader));
SET_HDR (result, &stg_TREC_HEADER_info, CCS_SYSTEM);
result -> enclosing_trec = enclosing_trec;
StgTVarWatchQueue *pq;
StgTVarWatchQueue *nq;
StgTVarWatchQueue *q;
+ StgClosure *saw;
s = e -> tvar;
- StgClosure *saw = lock_tvar(trec, s);
+ saw = lock_tvar(trec, s);
q = (StgTVarWatchQueue *) (e -> new_value);
TRACE("%p : removing tso=%p from watch queue for tvar=%p",
trec,
/************************************************************************/
-void stmPreGCHook() {
- nat i;
-
+void stmPreGCHook (Capability *cap) {
lock_stm(NO_TREC);
TRACE("stmPreGCHook");
- for (i = 0; i < n_capabilities; i ++) {
- Capability *cap = &capabilities[i];
- cap -> free_tvar_watch_queues = END_STM_WATCH_QUEUE;
- cap -> free_trec_chunks = END_STM_CHUNK_LIST;
- cap -> free_trec_headers = NO_TREC;
- }
+ cap->free_tvar_watch_queues = END_STM_WATCH_QUEUE;
+ cap->free_trec_chunks = END_STM_CHUNK_LIST;
+ cap->free_trec_headers = NO_TREC;
unlock_stm(NO_TREC);
}
void stmAbortTransaction(Capability *cap,
StgTRecHeader *trec) {
+ StgTRecHeader *et;
TRACE("%p : stmAbortTransaction", trec);
ASSERT (trec != NO_TREC);
ASSERT ((trec -> state == TREC_ACTIVE) ||
lock_stm(trec);
- StgTRecHeader *et = trec -> enclosing_trec;
+ et = trec -> enclosing_trec;
if (et == NO_TREC) {
// We're a top-level transaction: remove any watch queue entries that
// we may have.
/*......................................................................*/
-StgTRecHeader *stmGetEnclosingTRec(StgTRecHeader *trec) {
- StgTRecHeader *outer;
- TRACE("%p : stmGetEnclosingTRec", trec);
- outer = trec -> enclosing_trec;
- TRACE("%p : stmGetEnclosingTRec()=%p", trec, outer);
- return outer;
-}
-
-/*......................................................................*/
-
StgBool stmValidateNestOfTransactions(StgTRecHeader *trec) {
StgTRecHeader *t;
StgBool result;
void stmAddInvariantToCheck(Capability *cap,
StgTRecHeader *trec,
StgClosure *code) {
+ StgAtomicInvariant *invariant;
+ StgInvariantCheckQueue *q;
TRACE("%p : stmAddInvariantToCheck closure=%p", trec, code);
ASSERT(trec != NO_TREC);
ASSERT(trec -> state == TREC_ACTIVE ||
trec -> state == TREC_CONDEMNED);
- StgAtomicInvariant *invariant;
- StgInvariantCheckQueue *q;
// 1. Allocate an StgAtomicInvariant, set last_execution to NO_TREC
// to signal that this is a new invariant in the current atomic block
- invariant = (StgAtomicInvariant *) allocateLocal(cap, sizeofW(StgAtomicInvariant));
+ invariant = (StgAtomicInvariant *) allocate(cap, sizeofW(StgAtomicInvariant));
TRACE("%p : stmAddInvariantToCheck allocated invariant=%p", trec, invariant);
SET_HDR (invariant, &stg_ATOMIC_INVARIANT_info, CCS_SYSTEM);
invariant -> code = code;
invariant -> last_execution = NO_TREC;
+ invariant -> lock = 0;
// 2. Allocate an StgInvariantCheckQueue entry, link it to the current trec
*/
StgInvariantCheckQueue *stmGetInvariantsToCheck(Capability *cap, StgTRecHeader *trec) {
+ StgTRecChunk *c;
TRACE("%p : stmGetInvariantsToCheck, head was %p",
trec,
trec -> invariants_to_check);
ASSERT(trec -> enclosing_trec == NO_TREC);
lock_stm(trec);
- StgTRecChunk *c = trec -> current_chunk;
+ c = trec -> current_chunk;
while (c != END_STM_CHUNK_LIST) {
unsigned int i;
for (i = 0; i < c -> next_entry_idx; i ++) {
// Pick up any invariants on the TVar being updated
// by entry "e"
- TRACE("%p : checking for invariants on %p", trec, s);
StgTVarWatchQueue *q;
+ TRACE("%p : checking for invariants on %p", trec, s);
for (q = s -> first_watch_queue_entry;
q != END_STM_WATCH_QUEUE;
q = q -> next_queue_entry) {
if (watcher_is_invariant(q)) {
- TRACE("%p : Touching invariant %p", trec, q -> closure);
StgBool found = FALSE;
StgInvariantCheckQueue *q2;
+ TRACE("%p : Touching invariant %p", trec, q -> closure);
for (q2 = trec -> invariants_to_check;
q2 != END_INVARIANT_CHECK_QUEUE;
q2 = q2 -> next_queue_entry) {
}
if (!found) {
- TRACE("%p : Not already found %p", trec, q -> closure);
StgInvariantCheckQueue *q3;
+ TRACE("%p : Not already found %p", trec, q -> closure);
q3 = alloc_stg_invariant_check_queue(cap,
(StgAtomicInvariant*) q -> closure);
q3 -> next_queue_entry = trec -> invariants_to_check;
StgBool stmCommitTransaction(Capability *cap, StgTRecHeader *trec) {
int result;
StgInt64 max_commits_at_start = max_commits;
+ StgBool touched_invariants;
+ StgBool use_read_phase;
TRACE("%p : stmCommitTransaction()", trec);
ASSERT (trec != NO_TREC);
// touched_invariants is true if we've written to a TVar with invariants
// attached to it, or if we're trying to add a new invariant to the system.
- StgBool touched_invariants = (trec -> invariants_to_check != END_INVARIANT_CHECK_QUEUE);
+ touched_invariants = (trec -> invariants_to_check != END_INVARIANT_CHECK_QUEUE);
// If we have touched invariants then (i) lock the invariant, and (ii) add
// the invariant's read set to our own. Step (i) is needed to serialize
// invariant from both tvars).
if (touched_invariants) {
- TRACE("%p : locking invariants", trec);
StgInvariantCheckQueue *q = trec -> invariants_to_check;
+ TRACE("%p : locking invariants", trec);
while (q != END_INVARIANT_CHECK_QUEUE) {
+ StgTRecHeader *inv_old_trec;
+ StgAtomicInvariant *inv;
TRACE("%p : locking invariant %p", trec, q -> invariant);
- StgAtomicInvariant *inv = q -> invariant;
+ inv = q -> invariant;
if (!lock_inv(inv)) {
TRACE("%p : failed to lock %p", trec, inv);
trec -> state = TREC_CONDEMNED;
break;
}
- StgTRecHeader *inv_old_trec = inv -> last_execution;
+ inv_old_trec = inv -> last_execution;
if (inv_old_trec != NO_TREC) {
StgTRecChunk *c = inv_old_trec -> current_chunk;
while (c != END_STM_CHUNK_LIST) {
// invariants and TVars are managed by the TVar watch queues which are
// protected by the TVar's locks.
- StgBool use_read_phase = ((config_use_read_phase) && (!touched_invariants));
+ use_read_phase = ((config_use_read_phase) && (!touched_invariants));
result = validate_and_acquire_ownership(trec, (!use_read_phase), TRUE);
if (result) {
ASSERT (trec -> state == TREC_ACTIVE);
if (use_read_phase) {
+ StgInt64 max_commits_at_end;
+ StgInt64 max_concurrent_commits;
TRACE("%p : doing read check", trec);
result = check_read_only(trec);
TRACE("%p : read-check %s", trec, result ? "succeeded" : "failed");
- StgInt64 max_commits_at_end = max_commits;
- StgInt64 max_concurrent_commits;
+ max_commits_at_end = max_commits;
max_concurrent_commits = ((max_commits_at_end - max_commits_at_start) +
(n_capabilities * TOKEN_BATCH_SIZE));
if (((max_concurrent_commits >> 32) > 0) || shake()) {
result = tvar -> current_value;
#if defined(STM_FG_LOCKS)
- while (GET_INFO(result) == &stg_TREC_HEADER_info) {
+ while (GET_INFO(UNTAG_CLOSURE(result)) == &stg_TREC_HEADER_info) {
TRACE("%p : read_current_value(%p) saw %p", trec, tvar, result);
result = tvar -> current_value;
}
StgClosure *stmReadTVar(Capability *cap,
StgTRecHeader *trec,
StgTVar *tvar) {
- StgTRecHeader *entry_in;
+ StgTRecHeader *entry_in = NULL;
StgClosure *result = NULL;
TRecEntry *entry = NULL;
TRACE("%p : stmReadTVar(%p)", trec, tvar);
StgTVar *tvar,
StgClosure *new_value) {
- StgTRecHeader *entry_in;
+ StgTRecHeader *entry_in = NULL;
TRecEntry *entry = NULL;
TRACE("%p : stmWriteTVar(%p, %p)", trec, tvar, new_value);
ASSERT (trec != NO_TREC);
StgTVar *stmNewTVar(Capability *cap,
StgClosure *new_value) {
StgTVar *result;
- result = (StgTVar *)allocateLocal(cap, sizeofW(StgTVar));
+ result = (StgTVar *)allocate(cap, sizeofW(StgTVar));
SET_HDR (result, &stg_TVAR_info, CCS_SYSTEM);
result -> current_value = new_value;
result -> first_watch_queue_entry = END_STM_WATCH_QUEUE;