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| author | Ben Gamari <ben@smart-cactus.org> | 2021-01-01 20:56:02 -0500 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2021-01-09 21:21:37 -0500 |
| commit | 83ac5594d101440f72dc0ead97f0d1583056c07d (patch) | |
| tree | eefd71c530bab1cd245c13dadf9bffd6dbc13729 | |
| parent | 3d15d8d008307a19314c23eeb65b8ead448f0b37 (diff) | |
| download | haskell-83ac5594d101440f72dc0ead97f0d1583056c07d.tar.gz | |
rts: Use SEQ_CST accesses when touching `wakeup`
These are the two remaining non-atomic accesses to `wakeup` which were
missed by the original TSAN patch.
| -rw-r--r-- | rts/hooks/LongGCSync.c | 2 | ||||
| -rw-r--r-- | rts/sm/GC.c | 4 | ||||
| -rw-r--r-- | rts/sm/GCThread.h | 2 |
3 files changed, 4 insertions, 4 deletions
diff --git a/rts/hooks/LongGCSync.c b/rts/hooks/LongGCSync.c index 351406df98..58ee52fa3d 100644 --- a/rts/hooks/LongGCSync.c +++ b/rts/hooks/LongGCSync.c @@ -21,7 +21,7 @@ void LongGCSync (uint32_t me USED_IF_THREADS, Time t STG_UNUSED) { uint32_t i; for (i=0; i < n_capabilities; i++) { - if (i != me && gc_threads[i]->wakeup != GC_THREAD_STANDING_BY) { + if (i != me && SEQ_CST_LOAD(&gc_threads[i]->wakeup) == GC_THREAD_STANDING_BY) { debugBelch("Warning: slow GC sync: still waiting for cap %d\n", i); } diff --git a/rts/sm/GC.c b/rts/sm/GC.c index d8ce3a1377..4c46e82200 100644 --- a/rts/sm/GC.c +++ b/rts/sm/GC.c @@ -1055,7 +1055,7 @@ new_gc_thread (uint32_t n, gc_thread *t) initSpinLock(&t->mut_spin); ACQUIRE_SPIN_LOCK(&t->gc_spin); ACQUIRE_SPIN_LOCK(&t->mut_spin); - t->wakeup = GC_THREAD_INACTIVE; // starts true, so we can wait for the + SEQ_CST_STORE(&t->wakeup, GC_THREAD_INACTIVE); // starts true, so we can wait for the // thread to start up, see wakeup_gc_threads #endif @@ -1300,7 +1300,7 @@ gcWorkerThread (Capability *cap) // measurements more accurate on Linux, perhaps because it syncs // the CPU time across the multiple cores. Without this, CPU time // is heavily skewed towards GC rather than MUT. - gct->wakeup = GC_THREAD_STANDING_BY; + SEQ_CST_STORE(&gct->wakeup, GC_THREAD_STANDING_BY); debugTrace(DEBUG_gc, "GC thread %d standing by...", gct->thread_index); ACQUIRE_SPIN_LOCK(&gct->gc_spin); diff --git a/rts/sm/GCThread.h b/rts/sm/GCThread.h index 723bb00bf1..d15189988d 100644 --- a/rts/sm/GCThread.h +++ b/rts/sm/GCThread.h @@ -127,7 +127,7 @@ typedef struct gc_thread_ { OSThreadId id; // The OS thread that this struct belongs to SpinLock gc_spin; SpinLock mut_spin; - volatile StgWord wakeup; // NB not StgWord8; only StgWord is guaranteed atomic + StgWord wakeup; // This should only be accessed via atomic accesses #endif uint32_t thread_index; // a zero based index identifying the thread |