modify msync code so that only base address is page-aligned (arangodb#6585)

jsteemann · web-flow · commit 5a13afd96d28 · 2018-09-25T09:37:03.000+02:00
according to man msync, there is no need for the end address to be page-aligned
also use uintptr_t consistently instead of intptr_t
diff --git a/lib/Basics/memory-map.h b/lib/Basics/memory-map.h
@@ -106,14 +106,12 @@ int TRI_MMFileUnlock(void* memoryAddress, size_t numOfBytes);
 
 static inline int TRI_MSync(int fd, char const* begin, char const* end) {
   size_t pageSize = arangodb::PageSizeFeature::getPageSize();
-  uintptr_t p = (intptr_t)begin;
-  uintptr_t q = (intptr_t)end;
-  uintptr_t g = (intptr_t)pageSize;
+  uintptr_t p = (uintptr_t)begin;
+  uintptr_t g = (uintptr_t)pageSize;
 
   char* b = (char*)((p / g) * g);
-  char* e = (char*)(((q + g - 1) / g) * g);
 
-  return TRI_FlushMMFile(fd, b, e - b, MS_SYNC);
+  return TRI_FlushMMFile(fd, b, end - b, MS_SYNC);
 }
 
 #endif
