From: Christopher Dykes <cdykes@fb.com>
Date: Thu, 4 Aug 2016 23:00:55 +0000 (-0700)
Subject: Don't attempt to mmap an anonymous shared piece of memory
X-Git-Tag: v2016.08.08.00~9
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=b837180a88e62576ab8cd4b85ee67f91771d945f;p=folly.git

Don't attempt to mmap an anonymous shared piece of memory

Summary: The portability implementation of `mmap` for Windows doesn't currently support anonymous shared allocations, as they are non-trivial to manage, and the places this is being used doesn't actually need the memory to be allocated as shared, so allocate it as private instead.

Reviewed By: yfeldblum

Differential Revision: D3671495

fbshipit-source-id: e74d4fd925363fef16c1bf8445da1ff32bf8266d
---

diff --git a/folly/test/AtomicHashArrayTest.cpp b/folly/test/AtomicHashArrayTest.cpp
index 92be30da..9e53635e 100644
--- a/folly/test/AtomicHashArrayTest.cpp
+++ b/folly/test/AtomicHashArrayTest.cpp
@@ -73,7 +73,7 @@ class MmapAllocator {
 
   T *allocate(size_t n) {
     void *p = mmap(nullptr, n * sizeof(T), PROT_READ | PROT_WRITE,
-        MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+        MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
     if (p == MAP_FAILED) throw std::bad_alloc();
     return (T *)p;
   }