summaryrefslogtreecommitdiff
path: root/absl/synchronization
diff options
context:
space:
mode:
authorGravatar Abseil Team <absl-team@google.com>2020-04-17 08:13:06 -0700
committerGravatar Mark Barolak <mbar@google.com>2020-04-17 11:58:29 -0400
commitb35973e3e35cb1eccb086d6a549c253c49579474 (patch)
tree2acab21a7c8039c1b4e7b7e5b580ac64aa743291 /absl/synchronization
parentdb5773a721a50d1fc8c9b51efea0e70be4003d36 (diff)
Export of internal Abseil changes
-- d857e6e1f9b09a3eb5abd890677a98b23346f07a by Abseil Team <absl-team@google.com>: Simplify internal TryAcquireWithSpinning. No point declaring the `result` variable: we can just return the results directly. PiperOrigin-RevId: 307045800 -- 421952252bc23be51f47f7d23f3422bad1ed382c by Derek Mauro <dmauro@google.com>: Add custom sink support for `absl::Format()` through an ADL extension mechanism. Users can now define `void AbslFormatFlush(MySink* dest, absl::string_view part)` to allow `absl::Format()` to append to a custom sink. PiperOrigin-RevId: 306929052 -- c73d5cdb62cd58ea421ed1aeeab78a0ffcfeeefb by Matt Calabrese <calabrese@google.com>: Internal-only conformance-testing macro ABSL_INTERNAL_ASSERT_CONFORMANCE_OF for compile-time and runtime checks of a specified type, expected properties of that type, and a logically-ordered series of equivalence classes of that type. PiperOrigin-RevId: 306885512 -- a8c2495a07f37d68907855e3f0535bd5c27a3b52 by Abseil Team <absl-team@google.com>: Internal change PiperOrigin-RevId: 306766753 GitOrigin-RevId: d857e6e1f9b09a3eb5abd890677a98b23346f07a Change-Id: Ic23c92ac74f9ffcbb2471ff8c6691f4b7b20354b
Diffstat (limited to 'absl/synchronization')
-rw-r--r--absl/synchronization/mutex.cc12
1 files changed, 5 insertions, 7 deletions
diff --git a/absl/synchronization/mutex.cc b/absl/synchronization/mutex.cc
index 6ee5f235..8cda5a1c 100644
--- a/absl/synchronization/mutex.cc
+++ b/absl/synchronization/mutex.cc
@@ -1439,20 +1439,18 @@ void Mutex::AssertNotHeld() const {
// may spin for a short while if the lock cannot be acquired immediately.
static bool TryAcquireWithSpinning(std::atomic<intptr_t>* mu) {
int c = mutex_globals.spinloop_iterations;
- int result = -1; // result of operation: 0=false, 1=true, -1=unknown
-
do { // do/while somewhat faster on AMD
intptr_t v = mu->load(std::memory_order_relaxed);
- if ((v & (kMuReader|kMuEvent)) != 0) { // a reader or tracing -> give up
- result = 0;
+ if ((v & (kMuReader|kMuEvent)) != 0) {
+ return false; // a reader or tracing -> give up
} else if (((v & kMuWriter) == 0) && // no holder -> try to acquire
mu->compare_exchange_strong(v, kMuWriter | v,
std::memory_order_acquire,
std::memory_order_relaxed)) {
- result = 1;
+ return true;
}
- } while (result == -1 && --c > 0);
- return result == 1;
+ } while (--c > 0);
+ return false;
}
ABSL_XRAY_LOG_ARGS(1) void Mutex::Lock() {