diff --git a/compiler-rt/lib/asan/asan_allocator.cc b/compiler-rt/lib/asan/asan_allocator.cc
index b570f0d98f30..9719aac321d5 100644
--- a/compiler-rt/lib/asan/asan_allocator.cc
+++ b/compiler-rt/lib/asan/asan_allocator.cc
@@ -132,7 +132,7 @@ static void PoisonHeapPartialRightRedzone(uptr mem, uptr size) {
 }
 
 static u8 *MmapNewPagesAndPoisonShadow(uptr size) {
-  CHECK(IsAligned(size, kPageSize));
+  CHECK(IsAligned(size, GetPageSizeCached()));
   u8 *res = (u8*)MmapOrDie(size, __FUNCTION__);
   PoisonShadow((uptr)res, size, kAsanHeapLeftRedzoneMagic);
   if (flags()->debug) {
@@ -534,12 +534,13 @@ class MallocInfo {
     uptr mmap_size = Max(size, kMinMmapSize);
     uptr n_chunks = mmap_size / size;
     CHECK(n_chunks * size == mmap_size);
-    if (size < kPageSize) {
+    uptr PageSize = GetPageSizeCached();
+    if (size < PageSize) {
       // Size is small, just poison the last chunk.
       n_chunks--;
     } else {
       // Size is large, allocate an extra page at right and poison it.
-      mmap_size += kPageSize;
+      mmap_size += PageSize;
     }
     CHECK(n_chunks > 0);
     u8 *mem = MmapNewPagesAndPoisonShadow(mmap_size);
@@ -813,18 +814,19 @@ void *asan_realloc(void *p, uptr size, StackTrace *stack) {
 }
 
 void *asan_valloc(uptr size, StackTrace *stack) {
-  void *ptr = (void*)Allocate(kPageSize, size, stack);
+  void *ptr = (void*)Allocate(GetPageSizeCached(), size, stack);
   __asan_malloc_hook(ptr, size);
   return ptr;
 }
 
 void *asan_pvalloc(uptr size, StackTrace *stack) {
-  size = RoundUpTo(size, kPageSize);
+  uptr PageSize = GetPageSizeCached();
+  size = RoundUpTo(size, PageSize);
   if (size == 0) {
     // pvalloc(0) should allocate one page.
-    size = kPageSize;
+    size = PageSize;
   }
-  void *ptr = (void*)Allocate(kPageSize, size, stack);
+  void *ptr = (void*)Allocate(PageSize, size, stack);
   __asan_malloc_hook(ptr, size);
   return ptr;
 }
@@ -943,7 +945,7 @@ uptr FakeStack::ClassMmapSize(uptr size_class) {
 }
 
 void FakeStack::AllocateOneSizeClass(uptr size_class) {
-  CHECK(ClassMmapSize(size_class) >= kPageSize);
+  CHECK(ClassMmapSize(size_class) >= GetPageSizeCached());
   uptr new_mem = (uptr)MmapOrDie(
       ClassMmapSize(size_class), __FUNCTION__);
   // Printf("T%d new_mem[%zu]: %p-%p mmap %zu\n",
diff --git a/compiler-rt/lib/asan/asan_linux.cc b/compiler-rt/lib/asan/asan_linux.cc
index a70adeeeacc3..2f89a1ef541e 100644
--- a/compiler-rt/lib/asan/asan_linux.cc
+++ b/compiler-rt/lib/asan/asan_linux.cc
@@ -176,9 +176,10 @@ void ClearShadowMemoryForContext(void *context) {
   uptr sp = (uptr)ucp->uc_stack.ss_sp;
   uptr size = ucp->uc_stack.ss_size;
   // Align to page size.
-  uptr bottom = sp & ~(kPageSize - 1);
+  uptr PageSize = GetPageSizeCached();
+  uptr bottom = sp & ~(PageSize - 1);
   size += sp - bottom;
-  size = RoundUpTo(size, kPageSize);
+  size = RoundUpTo(size, PageSize);
   PoisonShadow(bottom, size, 0);
 }
 #else
diff --git a/compiler-rt/lib/asan/asan_malloc_mac.cc b/compiler-rt/lib/asan/asan_malloc_mac.cc
index 5b47e120fc87..b32c18ef2d9c 100644
--- a/compiler-rt/lib/asan/asan_malloc_mac.cc
+++ b/compiler-rt/lib/asan/asan_malloc_mac.cc
@@ -165,7 +165,7 @@ void *mz_valloc(malloc_zone_t *zone, size_t size) {
     return malloc_zone_valloc(system_malloc_zone, size);
   }
   GET_STACK_TRACE_HERE_FOR_MALLOC;
-  return asan_memalign(kPageSize, size, &stack);
+  return asan_memalign(GetPageSizeCached(), size, &stack);
 }
 
 #define GET_ZONE_FOR_PTR(ptr) \
diff --git a/compiler-rt/lib/asan/asan_rtl.cc b/compiler-rt/lib/asan/asan_rtl.cc
index 5d0c966fb9af..28a8c03f6359 100644
--- a/compiler-rt/lib/asan/asan_rtl.cc
+++ b/compiler-rt/lib/asan/asan_rtl.cc
@@ -165,8 +165,8 @@ void ShowStatsAndAbort() {
 // ---------------------- mmap -------------------- {{{1
 // Reserve memory range [beg, end].
 static void ReserveShadowMemoryRange(uptr beg, uptr end) {
-  CHECK((beg % kPageSize) == 0);
-  CHECK(((end + 1) % kPageSize) == 0);
+  CHECK((beg % GetPageSizeCached()) == 0);
+  CHECK(((end + 1) % GetPageSizeCached()) == 0);
   uptr size = end - beg + 1;
   void *res = MmapFixedNoReserve(beg, size);
   if (res != (void*)beg) {
@@ -271,8 +271,9 @@ void NOINLINE __asan_handle_no_return() {
   int local_stack;
   AsanThread *curr_thread = asanThreadRegistry().GetCurrent();
   CHECK(curr_thread);
+  uptr PageSize = GetPageSizeCached();
   uptr top = curr_thread->stack_top();
-  uptr bottom = ((uptr)&local_stack - kPageSize) & ~(kPageSize-1);
+  uptr bottom = ((uptr)&local_stack - PageSize) & ~(PageSize-1);
   PoisonShadow(bottom, top - bottom, 0);
 }
 
diff --git a/compiler-rt/lib/asan/asan_stats.cc b/compiler-rt/lib/asan/asan_stats.cc
index 4f39ba61b298..cf8cadf39fa1 100644
--- a/compiler-rt/lib/asan/asan_stats.cc
+++ b/compiler-rt/lib/asan/asan_stats.cc
@@ -43,7 +43,7 @@ void AsanStats::Print() {
   Printf("Stats: %zuM really freed by %zu calls\n",
              really_freed>>20, real_frees);
   Printf("Stats: %zuM (%zu full pages) mmaped in %zu calls\n",
-             mmaped>>20, mmaped / kPageSize, mmaps);
+             mmaped>>20, mmaped / GetPageSizeCached(), mmaps);
 
   PrintMallocStatsArray("  mmaps   by size class: ", mmaped_by_size);
   PrintMallocStatsArray("  mallocs by size class: ", malloced_by_size);
diff --git a/compiler-rt/lib/asan/asan_thread.cc b/compiler-rt/lib/asan/asan_thread.cc
index 7f60ca913acc..a77e435793d6 100644
--- a/compiler-rt/lib/asan/asan_thread.cc
+++ b/compiler-rt/lib/asan/asan_thread.cc
@@ -28,15 +28,16 @@ AsanThread::AsanThread(LinkerInitialized x)
 
 AsanThread *AsanThread::Create(u32 parent_tid, thread_callback_t start_routine,
                                void *arg, StackTrace *stack) {
-  uptr size = RoundUpTo(sizeof(AsanThread), kPageSize);
+  uptr PageSize = GetPageSizeCached();
+  uptr size = RoundUpTo(sizeof(AsanThread), PageSize);
   AsanThread *thread = (AsanThread*)MmapOrDie(size, __FUNCTION__);
   thread->start_routine_ = start_routine;
   thread->arg_ = arg;
 
-  const uptr kSummaryAllocSize = kPageSize;
+  const uptr kSummaryAllocSize = PageSize;
   CHECK_LE(sizeof(AsanThreadSummary), kSummaryAllocSize);
   AsanThreadSummary *summary =
-      (AsanThreadSummary*)MmapOrDie(kPageSize, "AsanThreadSummary");
+      (AsanThreadSummary*)MmapOrDie(PageSize, "AsanThreadSummary");
   summary->Init(parent_tid, stack);
   summary->set_thread(thread);
   thread->set_summary(summary);
@@ -66,7 +67,7 @@ void AsanThread::Destroy() {
   // and we don't want it to have any poisoned stack.
   ClearShadowForThreadStack();
   fake_stack().Cleanup();
-  uptr size = RoundUpTo(sizeof(AsanThread), kPageSize);
+  uptr size = RoundUpTo(sizeof(AsanThread), GetPageSizeCached());
   UnmapOrDie(this, size);
 }
 
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common.cc b/compiler-rt/lib/sanitizer_common/sanitizer_common.cc
index e0f9997e49d2..49297affd7db 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common.cc
@@ -16,6 +16,13 @@
 
 namespace __sanitizer {
 
+uptr GetPageSizeCached() {
+  static uptr PageSize;
+  if (!PageSize)
+    PageSize = GetPageSize();
+  return PageSize;
+}
+
 // By default, dump to stderr. If report_fd is kInvalidFd, try to obtain file
 // descriptor by opening file in report_path.
 static fd_t report_fd = kStderrFd;
@@ -77,7 +84,8 @@ void RawWrite(const char *buffer) {
 
 uptr ReadFileToBuffer(const char *file_name, char **buff,
                       uptr *buff_size, uptr max_len) {
-  const uptr kMinFileLen = kPageSize;
+  uptr PageSize = GetPageSizeCached();
+  uptr kMinFileLen = PageSize;
   uptr read_len = 0;
   *buff = 0;
   *buff_size = 0;
@@ -91,8 +99,8 @@ uptr ReadFileToBuffer(const char *file_name, char **buff,
     // Read up to one page at a time.
     read_len = 0;
     bool reached_eof = false;
-    while (read_len + kPageSize <= size) {
-      uptr just_read = internal_read(fd, *buff + read_len, kPageSize);
+    while (read_len + PageSize <= size) {
+      uptr just_read = internal_read(fd, *buff + read_len, PageSize);
       if (just_read == 0) {
         reached_eof = true;
         break;
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common.h b/compiler-rt/lib/sanitizer_common/sanitizer_common.h
index d6af5f8f838c..1842446f63f8 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common.h
@@ -42,6 +42,9 @@ const uptr kCacheLineSize = 64;
 const uptr kMmapGranularity = 1UL << 16;
 #endif
 
+uptr GetPageSize();
+uptr GetPageSizeCached();
+uptr GetMmapGranularity();
 // Threads
 int GetPid();
 uptr GetTid();
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_posix.cc b/compiler-rt/lib/sanitizer_common/sanitizer_posix.cc
index 8117fd47ddec..d98460a0c115 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_posix.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_posix.cc
@@ -32,6 +32,13 @@
 namespace __sanitizer {
 
 // ------------- sanitizer_common.h
+uptr GetPageSize() {
+  return sysconf(_SC_PAGESIZE);
+}
+
+uptr GetMmapGranularity() {
+  return GetPageSize();
+}
 
 int GetPid() {
   return getpid();
@@ -42,7 +49,7 @@ uptr GetThreadSelf() {
 }
 
 void *MmapOrDie(uptr size, const char *mem_type) {
-  size = RoundUpTo(size, kPageSize);
+  size = RoundUpTo(size, GetPageSizeCached());
   void *res = internal_mmap(0, size,
                             PROT_READ | PROT_WRITE,
                             MAP_PRIVATE | MAP_ANON, -1, 0);
@@ -74,8 +81,9 @@ void UnmapOrDie(void *addr, uptr size) {
 }
 
 void *MmapFixedNoReserve(uptr fixed_addr, uptr size) {
-  void *p = internal_mmap((void*)(fixed_addr & ~(kPageSize - 1)),
-      RoundUpTo(size, kPageSize),
+  uptr PageSize = GetPageSizeCached();
+  void *p = internal_mmap((void*)(fixed_addr & ~(PageSize - 1)),
+      RoundUpTo(size, PageSize),
       PROT_READ | PROT_WRITE,
       MAP_PRIVATE | MAP_ANON | MAP_FIXED | MAP_NORESERVE,
       -1, 0);
@@ -98,7 +106,7 @@ void *MapFileToMemory(const char *file_name, uptr *buff_size) {
   uptr fsize = internal_filesize(fd);
   CHECK_NE(fsize, (uptr)-1);
   CHECK_GT(fsize, 0);
-  *buff_size = RoundUpTo(fsize, kPageSize);
+  *buff_size = RoundUpTo(fsize, GetPageSizeCached());
   void *map = internal_mmap(0, *buff_size, PROT_READ, MAP_PRIVATE, fd, 0);
   return (map == MAP_FAILED) ? 0 : map;
 }
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_win.cc b/compiler-rt/lib/sanitizer_common/sanitizer_win.cc
index 90bf35a43953..31ae7f1e6957 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_win.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_win.cc
@@ -23,6 +23,14 @@
 namespace __sanitizer {
 
 // --------------------- sanitizer_common.h
+uptr GetPageSize() {
+  return 1U << 14;  // FIXME: is this configurable?
+}
+
+uptr GetMmapGranularity() {
+  return 1U << 16;  // FIXME: is this configurable?
+}
+
 bool FileExists(const char *filename) {
   UNIMPLEMENTED();
 }
diff --git a/compiler-rt/lib/tsan/rtl/tsan_interceptors.cc b/compiler-rt/lib/tsan/rtl/tsan_interceptors.cc
index 8be58d4eb3b9..4149c76afbec 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_interceptors.cc
+++ b/compiler-rt/lib/tsan/rtl/tsan_interceptors.cc
@@ -566,13 +566,13 @@ TSAN_INTERCEPTOR(void*, memalign, uptr align, uptr sz) {
 
 TSAN_INTERCEPTOR(void*, valloc, uptr sz) {
   SCOPED_TSAN_INTERCEPTOR(valloc, sz);
-  return user_alloc(thr, pc, sz, kPageSize);
+  return user_alloc(thr, pc, sz, GetPageSizeCached());
 }
 
 TSAN_INTERCEPTOR(void*, pvalloc, uptr sz) {
   SCOPED_TSAN_INTERCEPTOR(pvalloc, sz);
-  sz = RoundUp(sz, kPageSize);
-  return user_alloc(thr, pc, sz, kPageSize);
+  sz = RoundUp(sz, GetPageSizeCached());
+  return user_alloc(thr, pc, sz, GetPageSizeCached());
 }
 
 TSAN_INTERCEPTOR(int, posix_memalign, void **memptr, uptr align, uptr sz) {