Return memory to OS right after free (not in the async thread).

Summary:
In order to avoid starting a separate thread to return unused memory to
the system (the thread interferes with process startup on Android,
Zygota waits for all threads to exit before fork, but this thread never
exits), try to return it right after free.

Reviewers: eugenis

Subscribers: cryptoad, filcab, danalbert, kubabrecka, llvm-commits

Patch by Aleksey Shlyapnikov.

Differential Revision: https://reviews.llvm.org/D27003

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@288091 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 1 deletions

diff --git a/lib/scudo/scudo_allocator.cpp b/lib/scudo/scudo_allocator.cpp
index 9de7cb64c..243561349 100644
--- a/lib/scudo/scudo_allocator.cpp
+++ b/lib/scudo/scudo_allocator.cpp
@@ -212,6 +212,7 @@ static thread_local QuarantineCache ThreadQuarantineCache;
 
 void AllocatorOptions::setFrom(const Flags *f, const CommonFlags *cf) {
   MayReturnNull = cf->allocator_may_return_null;
+  ReleaseToOSIntervalMs = cf->allocator_release_to_os_interval_ms;
   QuarantineSizeMb = f->QuarantineSizeMb;
   ThreadLocalQuarantineSizeKb = f->ThreadLocalQuarantineSizeKb;
   DeallocationTypeMismatch = f->DeallocationTypeMismatch;
@@ -221,6 +222,7 @@ void AllocatorOptions::setFrom(const Flags *f, const CommonFlags *cf) {
 
 void AllocatorOptions::copyTo(Flags *f, CommonFlags *cf) const {
   cf->allocator_may_return_null = MayReturnNull;
+  cf->allocator_release_to_os_interval_ms = ReleaseToOSIntervalMs;
   f->QuarantineSizeMb = QuarantineSizeMb;
   f->ThreadLocalQuarantineSizeKb = ThreadLocalQuarantineSizeKb;
   f->DeallocationTypeMismatch = DeallocationTypeMismatch;
@@ -276,7 +278,7 @@ struct Allocator {
     DeallocationTypeMismatch = Options.DeallocationTypeMismatch;
     DeleteSizeMismatch = Options.DeleteSizeMismatch;
     ZeroContents = Options.ZeroContents;
-    BackendAllocator.Init(Options.MayReturnNull);
+    BackendAllocator.Init(Options.MayReturnNull, Options.ReleaseToOSIntervalMs);
     AllocatorQuarantine.Init(
         static_cast<uptr>(Options.QuarantineSizeMb) << 20,
         static_cast<uptr>(Options.ThreadLocalQuarantineSizeKb) << 10);