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authorMarkus Armbruster <armbru@redhat.com>2013-01-25 16:43:39 +0100
committerStefan Hajnoczi <stefanha@redhat.com>2013-02-05 21:52:55 +0100
commitb6b2c9628084f1672b92393cf84039a075a95301 (patch)
treebf1f4ed008c6c5c3585a996f13d0013cf934f191 /trace
parente722d705ae7648a6bd94848319a11eb0afd58a17 (diff)
trace: Clean up the "try to update atomic until it worked" loops
Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Harsh Prateek Bora <harsh@linux.vnet.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'trace')
-rw-r--r--trace/simple.c18
1 files changed, 5 insertions, 13 deletions
diff --git a/trace/simple.c b/trace/simple.c
index 592ff483cc..74701e3272 100644
--- a/trace/simple.c
+++ b/trace/simple.c
@@ -171,13 +171,10 @@ static gpointer writeout_thread(gpointer opaque)
dropped.rec.timestamp_ns = get_clock();
dropped.rec.length = sizeof(TraceRecord) + sizeof(uint64_t),
dropped.rec.reserved = 0;
- while (1) {
+ do {
dropped_count = g_atomic_int_get(&dropped_events);
- if (g_atomic_int_compare_and_exchange(&dropped_events,
- dropped_count, 0)) {
- break;
- }
- }
+ } while (!g_atomic_int_compare_and_exchange(&dropped_events,
+ dropped_count, 0));
dropped.rec.arguments[0] = dropped_count;
unused = fwrite(&dropped.rec, dropped.rec.length, 1, trace_fp);
}
@@ -213,7 +210,7 @@ int trace_record_start(TraceBufferRecord *rec, TraceEventID event, size_t datasi
uint32_t rec_len = sizeof(TraceRecord) + datasize;
uint64_t timestamp_ns = get_clock();
- while (1) {
+ do {
old_idx = g_atomic_int_get(&trace_idx);
smp_rmb();
new_idx = old_idx + rec_len;
@@ -223,12 +220,7 @@ int trace_record_start(TraceBufferRecord *rec, TraceEventID event, size_t datasi
g_atomic_int_inc(&dropped_events);
return -ENOSPC;
}
-
- if (g_atomic_int_compare_and_exchange(&trace_idx,
- old_idx, new_idx)) {
- break;
- }
- }
+ } while (!g_atomic_int_compare_and_exchange(&trace_idx, old_idx, new_idx));
idx = old_idx % TRACE_BUF_LEN;