Release memory to OS only when the requested range covers the entire page

Summary:
The current code was sometimes attempting to release huge chunks of
memory due to undesired RoundUp/RoundDown interaction when the requested
range is fully contained within one memory page.

Reviewers: eugenis

Subscribers: kubabrecka, llvm-commits

Patch by Aleksey Shlyapnikov.

Differential Revision: https://reviews.llvm.org/D27228

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@288271 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 6 insertions, 6 deletions

diff --git a/lib/tsan/rtl/tsan_mman.cc b/lib/tsan/rtl/tsan_mman.cc
index 4ca7baeef..2dea24915 100644
--- a/lib/tsan/rtl/tsan_mman.cc
+++ b/lib/tsan/rtl/tsan_mman.cc
@@ -54,7 +54,8 @@ struct MapUnmapCallback {
     diff = p + size - RoundDown(p + size, kPageSize);
     if (diff != 0)
       size -= diff;
-    ReleaseMemoryToOS((uptr)MemToMeta(p), size / kMetaRatio);
+    uptr p_meta = (uptr)MemToMeta(p);
+    ReleaseMemoryPagesToOS(p_meta, p_meta + size / kMetaRatio);
   }
 };
 
diff --git a/lib/tsan/rtl/tsan_platform_linux.cc b/lib/tsan/rtl/tsan_platform_linux.cc
index 233de103f..3313288a7 100644
--- a/lib/tsan/rtl/tsan_platform_linux.cc
+++ b/lib/tsan/rtl/tsan_platform_linux.cc
@@ -134,7 +134,7 @@ void WriteMemoryProfile(char *buf, uptr buf_size, uptr nthread, uptr nlive) {
 void FlushShadowMemoryCallback(
     const SuspendedThreadsList &suspended_threads_list,
     void *argument) {
-  ReleaseMemoryToOS(ShadowBeg(), ShadowEnd() - ShadowBeg());
+  ReleaseMemoryPagesToOS(ShadowBeg(), ShadowEnd());
 }
 #endif
 
diff --git a/lib/tsan/rtl/tsan_rtl.cc b/lib/tsan/rtl/tsan_rtl.cc
index 87a1c838e..804f3cf64 100644
--- a/lib/tsan/rtl/tsan_rtl.cc
+++ b/lib/tsan/rtl/tsan_rtl.cc
@@ -234,9 +234,7 @@ static void StopBackgroundThread() {
 #endif
 
 void DontNeedShadowFor(uptr addr, uptr size) {
-  uptr shadow_beg = MemToShadow(addr);
-  uptr shadow_end = MemToShadow(addr + size);
-  ReleaseMemoryToOS(shadow_beg, shadow_end - shadow_beg);
+  ReleaseMemoryPagesToOS(MemToShadow(addr), MemToShadow(addr + size));
 }
 
 void MapShadow(uptr addr, uptr size) {
diff --git a/lib/tsan/rtl/tsan_rtl_thread.cc b/lib/tsan/rtl/tsan_rtl_thread.cc
index 40c3b3127..5b17dc60b 100644
--- a/lib/tsan/rtl/tsan_rtl_thread.cc
+++ b/lib/tsan/rtl/tsan_rtl_thread.cc
@@ -68,7 +68,8 @@ void ThreadContext::OnCreated(void *arg) {
 
 void ThreadContext::OnReset() {
   CHECK_EQ(sync.size(), 0);
-  ReleaseMemoryToOS(GetThreadTrace(tid), TraceSize() * sizeof(Event));
+  uptr trace_p = GetThreadTrace(tid);
+  ReleaseMemoryPagesToOS(trace_p, trace_p + TraceSize() * sizeof(Event));
   //!!! ReleaseMemoryToOS(GetThreadTraceHeader(tid), sizeof(Trace));
 }