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authorRickard Green <[email protected]>2015-11-19 17:07:06 +0100
committerRickard Green <[email protected]>2015-12-08 14:47:46 +0100
commita5dd6499d53ed596e2f8aa17ee35ff87cd32fe60 (patch)
tree26d671ac23cc2934706981318b0f7d6fee5affd4 /erts/emulator/beam
parentcc3cc025f43a00281d2f836e12c2e1627cd50145 (diff)
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Distinguish between GC disabled by BIFs and other disabled GC
Processes remember heap fragments that are known to be fully live due to creation in a just called BIF that yields in the live_hf_end field. This field must not be used if we have not disabled GC in a BIF. F_DELAY_GC has been introduced in order to distinguish between to two different scenarios. - F_DISABLE_GC should *only* be used by BIFs. This when the BIF needs to yield while preventig a GC. - F_DELAY_GC should only be used when GC is temporarily disabled while the process is scheduled. A process must not be scheduled out while F_DELAY_GC is set.
Diffstat (limited to 'erts/emulator/beam')
-rw-r--r--erts/emulator/beam/beam_emu.c14
-rw-r--r--erts/emulator/beam/erl_gc.c15
-rw-r--r--erts/emulator/beam/erl_process.c2
-rw-r--r--erts/emulator/beam/erl_process.h14
4 files changed, 34 insertions, 11 deletions
diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c
index 208a16dfd0..95a22e6c54 100644
--- a/erts/emulator/beam/beam_emu.c
+++ b/erts/emulator/beam/beam_emu.c
@@ -1843,8 +1843,8 @@ void process_main(void)
* in the queue. This since messages with data outside
* the heap will be corrupted by a GC.
*/
- ASSERT(!(c_p->flags & F_DISABLE_GC));
- c_p->flags |= F_DISABLE_GC;
+ ASSERT(!(c_p->flags & F_DELAY_GC));
+ c_p->flags |= F_DELAY_GC;
loop_rec__:
PROCESS_MAIN_CHK_LOCKS(c_p);
@@ -1858,7 +1858,7 @@ void process_main(void)
if (ERTS_PROC_PENDING_EXIT(c_p)) {
erts_smp_proc_unlock(c_p, ERTS_PROC_LOCKS_MSG_RECEIVE);
SWAPOUT;
- c_p->flags &= ~F_DISABLE_GC;
+ c_p->flags &= ~F_DELAY_GC;
goto do_schedule; /* Will be rescheduled for exit */
}
ERTS_SMP_MSGQ_MV_INQ2PRIVQ(c_p);
@@ -1868,7 +1868,7 @@ void process_main(void)
else
#endif
{
- c_p->flags &= ~F_DISABLE_GC;
+ c_p->flags &= ~F_DELAY_GC;
SET_I((BeamInstr *) Arg(0));
Goto(*I); /* Jump to a wait or wait_timeout instruction */
}
@@ -1997,7 +1997,7 @@ void process_main(void)
CANCEL_TIMER(c_p);
erts_save_message_in_proc(c_p, msgp);
- c_p->flags &= ~F_DISABLE_GC;
+ c_p->flags &= ~F_DELAY_GC;
if (ERTS_IS_GC_DESIRED_INTERNAL(c_p, HTOP, E)) {
/*
@@ -2019,7 +2019,7 @@ void process_main(void)
*/
OpCase(loop_rec_end_f): {
- ASSERT(c_p->flags & F_DISABLE_GC);
+ ASSERT(c_p->flags & F_DELAY_GC);
SET_I((BeamInstr *) Arg(0));
SAVE_MESSAGE(c_p);
@@ -2028,7 +2028,7 @@ void process_main(void)
goto loop_rec__;
}
- c_p->flags &= ~F_DISABLE_GC;
+ c_p->flags &= ~F_DELAY_GC;
c_p->i = I;
SWAPOUT;
c_p->arity = 0;
diff --git a/erts/emulator/beam/erl_gc.c b/erts/emulator/beam/erl_gc.c
index 3bb1f601aa..3784367195 100644
--- a/erts/emulator/beam/erl_gc.c
+++ b/erts/emulator/beam/erl_gc.c
@@ -440,8 +440,15 @@ delay_garbage_collection(Process *p, ErlHeapFragment *live_hf_end, int need)
ERTS_HOLE_CHECK(p);
- if (p->live_hf_end == ERTS_INVALID_HFRAG_PTR)
+ if ((p->flags & F_DISABLE_GC)
+ && p->live_hf_end == ERTS_INVALID_HFRAG_PTR) {
+ /*
+ * A BIF yielded with disabled GC. Remember
+ * heap fragments created by the BIF until we
+ * do next GC.
+ */
p->live_hf_end = live_hf_end;
+ }
if (need == 0)
return 1;
@@ -564,10 +571,12 @@ garbage_collect(Process* p, ErlHeapFragment *live_hf_end,
DTRACE_CHARBUF(pidbuf, DTRACE_TERM_BUF_SIZE);
#endif
- if (p->flags & F_DISABLE_GC)
+ if (p->flags & (F_DISABLE_GC|F_DELAY_GC))
return delay_garbage_collection(p, live_hf_end, need);
- if (p->live_hf_end != ERTS_INVALID_HFRAG_PTR)
+ if (p->abandoned_heap)
+ live_hf_end = ERTS_INVALID_HFRAG_PTR;
+ else if (p->live_hf_end != ERTS_INVALID_HFRAG_PTR)
live_hf_end = p->live_hf_end;
esdp = erts_get_scheduler_data();
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index ebe9361b8d..d17355207b 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -9262,6 +9262,8 @@ Process *schedule(Process *p, int calls)
} else {
sched_out_proc:
+ ASSERT(!(p->flags & F_DELAY_GC));
+
#ifdef ERTS_SMP
ERTS_SMP_CHK_HAVE_ONLY_MAIN_PROC_LOCK(p);
esdp = p->scheduler_data;
diff --git a/erts/emulator/beam/erl_process.h b/erts/emulator/beam/erl_process.h
index b80aa12872..41b367435d 100644
--- a/erts/emulator/beam/erl_process.h
+++ b/erts/emulator/beam/erl_process.h
@@ -1288,10 +1288,22 @@ extern struct erts_system_profile_flags_t erts_system_profile_flags;
#define F_HAVE_BLCKD_MSCHED (1 << 8) /* Process has blocked multi-scheduling */
#define F_P2PNR_RESCHED (1 << 9) /* Process has been rescheduled via erts_pid2proc_not_running() */
#define F_FORCE_GC (1 << 10) /* Force gc at process in-scheduling */
-#define F_DISABLE_GC (1 << 11) /* Disable GC */
+#define F_DISABLE_GC (1 << 11) /* Disable GC (see below) */
#define F_OFF_HEAP_MSGQ (1 << 12) /* Off heap msg queue */
#define F_OFF_HEAP_MSGQ_CHNG (1 << 13) /* Off heap msg queue changing */
#define F_ABANDONED_HEAP_USE (1 << 14) /* Have usage of abandoned heap */
+#define F_DELAY_GC (1 << 15) /* Similar to disable GC (see below) */
+
+/*
+ * F_DISABLE_GC and F_DELAY_GC are similar. Both will prevent
+ * GC of the process, but it is important to use the right
+ * one:
+ * - F_DISABLE_GC should *only* be used by BIFs. This when
+ * the BIF needs to yield while preventig a GC.
+ * - F_DELAY_GC should only be used when GC is temporarily
+ * disabled while the process is scheduled. A process must
+ * not be scheduled out while F_DELAY_GC is set.
+ */
/* process trace_flags */
#define F_SENSITIVE (1 << 0)