[compiler-rt] [scudo] Add unmap and eviction stats to Secondary (PR #210465)

[Sadaf Ebrahimi via llvm-commits]

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@@ -957,6 +961,8 @@ void MapAllocator<Config>::deallocate(const Options &Options, void *Ptr)
     // Note that the `H->MemMap` is stored on the pages managed by itself. Take
     // over the ownership before unmap() so that any operation along with
     // unmap() won't touch inaccessible pages.
+    ScopedLock L(Mutex);
+    EvictedBySizeCount++;
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sadafebrahimi wrote:

The counter for total unmaps was removed. First because unmap() is not a member function of MapAllocator or MapAllocatorCache so adding a counter to it requires a global atomic variable which you said I shouldn't use and second because it's the total of the two stats I added. 

https://github.com/llvm/llvm-project/pull/210465