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authorRickard Green <[email protected]>2010-11-26 13:37:23 +0100
committerRickard Green <[email protected]>2010-12-01 11:18:24 +0100
commit7136d5ed3f68414ad122ef39cb51fe4c80011be8 (patch)
treeaa0813e40917c12e8803e32c4f6089ba12e69e9d /erts
parent17224a3d31d25ce6daa4de63b52b26bee9564bcd (diff)
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Prevent wrapping of values used during load balancing
Some integer values used during load balancing could under rare circumstances wrap causing a load unbalance between schedulers.
Diffstat (limited to 'erts')
-rw-r--r--erts/emulator/beam/erl_process.c28
1 files changed, 18 insertions, 10 deletions
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index 901167a315..6a647848a2 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -1886,6 +1886,9 @@ do { \
static void
check_balance(ErtsRunQueue *c_rq)
{
+#if ERTS_MAX_PROCESSES >= (1 << 27)
+# error check_balance() assumes ERTS_MAX_PROCESS < (1 << 27)
+#endif
ErtsRunQueueBalance avg = {0};
Sint64 scheds_reds, full_scheds_reds;
int forced, active, current_active, oowc, half_full_scheds, full_scheds,
@@ -2009,12 +2012,14 @@ check_balance(ErtsRunQueue *c_rq)
run_queue_info[qix].prio[pix].avail = 0;
}
else {
- int xreds = 0;
- int procreds = treds;
- procreds -= run_queue_info[qix].prio[ERTS_PORT_PRIO_LEVEL].reds;
+ Sint64 xreds = 0;
+ Sint64 procreds = treds;
+ procreds -=
+ ((Sint64)
+ run_queue_info[qix].prio[ERTS_PORT_PRIO_LEVEL].reds);
for (pix = 0; pix < ERTS_NO_PROC_PRIO_LEVELS; pix++) {
- int av;
+ Sint64 av;
if (xreds == 0)
av = 100;
@@ -2025,9 +2030,10 @@ check_balance(ErtsRunQueue *c_rq)
if (av == 0)
av = 1;
}
- run_queue_info[qix].prio[pix].avail = av;
+ run_queue_info[qix].prio[pix].avail = (int) av;
+ ASSERT(run_queue_info[qix].prio[pix].avail >= 0);
if (pix < PRIORITY_NORMAL) /* ie., max or high */
- xreds += run_queue_info[qix].prio[pix].reds;
+ xreds += (Sint64) run_queue_info[qix].prio[pix].reds;
}
run_queue_info[qix].prio[ERTS_PORT_PRIO_LEVEL].avail = 100;
}
@@ -2132,7 +2138,8 @@ check_balance(ErtsRunQueue *c_rq)
if (max_len != 0) {
int avail = avg.prio[pix].avail;
if (avail != 0) {
- max_len = ((100*max_len - 1) / avail) + 1;
+ max_len = (int) ((100*((Sint64) max_len) - 1)
+ / ((Sint64) avail)) + 1;
avg.prio[pix].max_len = max_len;
ASSERT(max_len >= 0);
}
@@ -2149,9 +2156,10 @@ check_balance(ErtsRunQueue *c_rq)
|| run_queue_info[qix].prio[pix].avail == 0)
limit = 0;
else
- limit = (((avg.prio[pix].max_len
- * run_queue_info[qix].prio[pix].avail) - 1)
- / 100 + 1);
+ limit = (int) (((((Sint64) avg.prio[pix].max_len)
+ * ((Sint64) run_queue_info[qix].prio[pix].avail))
+ - 1)
+ / 100 + 1);
run_queue_info[qix].prio[pix].migration_limit = limit;
}
}