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, 0 insertions, 9 deletions

diff --git a/lib/sanitizer_common/sanitizer_common_libcdep.cc b/lib/sanitizer_common/sanitizer_common_libcdep.cc
index 288ca9556..49ca961f3 100644
--- a/lib/sanitizer_common/sanitizer_common_libcdep.cc
+++ b/lib/sanitizer_common/sanitizer_common_libcdep.cc
@@ -70,18 +70,11 @@ void SetSoftRssLimitExceededCallback(void (*Callback)(bool exceeded)) {
   SoftRssLimitExceededCallback = Callback;
 }
 
-static AllocatorReleaseToOSCallback ReleseCallback;
-void SetAllocatorReleaseToOSCallback(AllocatorReleaseToOSCallback Callback) {
-  CHECK_EQ(ReleseCallback, nullptr);
-  ReleseCallback = Callback;
-}
-
 #if SANITIZER_LINUX && !SANITIZER_GO
 void BackgroundThread(void *arg) {
   uptr hard_rss_limit_mb = common_flags()->hard_rss_limit_mb;
   uptr soft_rss_limit_mb = common_flags()->soft_rss_limit_mb;
   bool heap_profile = common_flags()->heap_profile;
-  bool allocator_release_to_os = common_flags()->allocator_release_to_os;
   uptr prev_reported_rss = 0;
   uptr prev_reported_stack_depot_size = 0;
   bool reached_soft_rss_limit = false;
@@ -127,7 +120,6 @@ void BackgroundThread(void *arg) {
           SoftRssLimitExceededCallback(false);
       }
     }
-    if (allocator_release_to_os && ReleseCallback) ReleseCallback();
     if (heap_profile &&
         current_rss_mb > rss_during_last_reported_profile * 1.1) {
       Printf("\n\nHEAP PROFILE at RSS %zdMb\n", current_rss_mb);
@@ -162,7 +154,6 @@ void MaybeStartBackgroudThread() {
   // Start the background thread if one of the rss limits is given.
   if (!common_flags()->hard_rss_limit_mb &&
       !common_flags()->soft_rss_limit_mb &&
-      !common_flags()->allocator_release_to_os &&
       !common_flags()->heap_profile) return;
   if (!&real_pthread_create) return;  // Can't spawn the thread anyway.
   internal_start_thread(BackgroundThread, nullptr);