Merge pull request #18196 from ttuegel/ghc-madv-free

ghc801: disable MADV_FREE

pkgs/development/compilers/ghc/8.0.1.nix

@@ -28,7 +28,7 @@ stdenv.mkDerivation rec {
     # Fix https://ghc.haskell.org/trac/ghc/ticket/12130
     (fetchFilteredPatch { url = https://git.haskell.org/ghc.git/patch/4d71cc89b4e9648f3fbb29c8fcd25d725616e265; sha256 = "0syaxb4y4s2dc440qmrggb4vagvqqhb55m6mx12rip4i9qhxl8k0"; })
     (fetchFilteredPatch { url = https://git.haskell.org/ghc.git/patch/2f8cd14fe909a377b3e084a4f2ded83a0e6d44dd; sha256 = "06zvlgcf50ab58bw6yw3krn45dsmhg4cmlz4nqff8k4z1f1bj01v"; })
-  ];
+  ] ++ stdenv.lib.optional stdenv.isLinux ./ghc-no-madv-free.patch;
 
   buildInputs = [ ghc perl hscolour ];
 

pkgs/development/compilers/ghc/ghc-no-madv-free.patch

@@ -0,0 +1,18 @@
+diff --git a/rts/posix/OSMem.c b/rts/posix/OSMem.c
+index 99620ee..e052a84 100644
+--- a/rts/posix/OSMem.c
++++ b/rts/posix/OSMem.c
+@@ -523,13 +523,7 @@ void osDecommitMemory(void *at, W_ size)
+         sysErrorBelch("unable to make released memory unaccessible");
+ #endif
+ 
+-#ifdef MADV_FREE
+-    // Try MADV_FREE first, FreeBSD has both and MADV_DONTNEED
+-    // just swaps memory out
+-    r = madvise(at, size, MADV_FREE);
+-#else
+     r = madvise(at, size, MADV_DONTNEED);
+-#endif
+     if(r < 0)
+         sysErrorBelch("unable to decommit memory");
+ }