[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH 2/4] trace: Direct access of atomics is verboten, us
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH 2/4] trace: Direct access of atomics is verboten, use the API |
Date: |
Wed, 6 Feb 2013 16:30:15 +0100 |
From: Markus Armbruster <address@hidden>
The GLib Reference Manual says:
It is very important that all accesses to a particular integer or
pointer be performed using only this API and that different sizes
of operation are not mixed or used on overlapping memory
regions. Never read or assign directly from or to a value --
always use this API.
Signed-off-by: Markus Armbruster <address@hidden>
Reviewed-by: Laszlo Ersek <address@hidden>
Reviewed-by: Harsh Prateek Bora <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
trace/simple.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/trace/simple.c b/trace/simple.c
index ccbdb6a..592ff48 100644
--- a/trace/simple.c
+++ b/trace/simple.c
@@ -166,13 +166,13 @@ static gpointer writeout_thread(gpointer opaque)
for (;;) {
wait_for_trace_records_available();
- if (dropped_events) {
+ if (g_atomic_int_get(&dropped_events)) {
dropped.rec.event = DROPPED_EVENT_ID,
dropped.rec.timestamp_ns = get_clock();
dropped.rec.length = sizeof(TraceRecord) + sizeof(uint64_t),
dropped.rec.reserved = 0;
while (1) {
- dropped_count = dropped_events;
+ dropped_count = g_atomic_int_get(&dropped_events);
if (g_atomic_int_compare_and_exchange(&dropped_events,
dropped_count, 0)) {
break;
@@ -214,7 +214,7 @@ int trace_record_start(TraceBufferRecord *rec, TraceEventID
event, size_t datasi
uint64_t timestamp_ns = get_clock();
while (1) {
- old_idx = trace_idx;
+ old_idx = g_atomic_int_get(&trace_idx);
smp_rmb();
new_idx = old_idx + rec_len;
@@ -275,7 +275,8 @@ void trace_record_finish(TraceBufferRecord *rec)
record.event |= TRACE_RECORD_VALID;
write_to_buffer(rec->tbuf_idx, &record, sizeof(TraceRecord));
- if ((trace_idx - writeout_idx) > TRACE_BUF_FLUSH_THRESHOLD) {
+ if ((g_atomic_int_get(&trace_idx) - writeout_idx)
+ > TRACE_BUF_FLUSH_THRESHOLD) {
flush_trace_file(false);
}
}
--
1.8.1