Add android_mallopt M_GET_DECAY_TIME_ENABLED.
The bionic benchmarks set the decay time in various ways, but
don't necessarily restore it properly. Add a new method for
getting the current decay time and then a way to restore it.
Right now the assumption is that the decay time defaults to zero,
but in the near future that assumption might be incorrect. Therefore
using this method will future proof the code.
Bug: 302212507
Test: Unit tests pass for both static and dynamic executables.
Test: Ran bionic benchmarks that were modified.
Change-Id: Ia77ff9ffee3081c5c1c02cb4309880f33b284e82
diff --git a/libc/bionic/malloc_common.cpp b/libc/bionic/malloc_common.cpp
index e159fdc..3c4884b 100644
--- a/libc/bionic/malloc_common.cpp
+++ b/libc/bionic/malloc_common.cpp
@@ -110,12 +110,27 @@
if (param == M_BIONIC_ZERO_INIT) {
return SetHeapZeroInitialize(value);
}
+
// The rest we pass on...
+ int retval;
auto dispatch_table = GetDispatchTable();
if (__predict_false(dispatch_table != nullptr)) {
- return dispatch_table->mallopt(param, value);
+ retval = dispatch_table->mallopt(param, value);
+ } else {
+ retval = Malloc(mallopt)(param, value);
}
- return Malloc(mallopt)(param, value);
+
+ // Track the M_DECAY_TIME mallopt calls.
+ if (param == M_DECAY_TIME && retval == 1) {
+ __libc_globals.mutate([value](libc_globals* globals) {
+ if (value == 0) {
+ atomic_store(&globals->decay_time_enabled, false);
+ } else {
+ atomic_store(&globals->decay_time_enabled, true);
+ }
+ });
+ }
+ return retval;
}
extern "C" void* malloc(size_t bytes) {
@@ -341,6 +356,14 @@
*reinterpret_cast<bool*>(arg) = atomic_load(&__libc_globals->memtag_stack);
return true;
}
+ if (opcode == M_GET_DECAY_TIME_ENABLED) {
+ if (arg == nullptr || arg_size != sizeof(bool)) {
+ errno = EINVAL;
+ return false;
+ }
+ *reinterpret_cast<bool*>(arg) = atomic_load(&__libc_globals->decay_time_enabled);
+ return true;
+ }
errno = ENOTSUP;
return false;
}