From adf5ca2ce0b19d218ac210e2bb57fa07c2f064ba Mon Sep 17 00:00:00 2001
From: Ben Wolsieffer <benwolsieffer@gmail.com>
Date: Sun, 8 Sep 2019 22:53:23 -0400
Subject: [PATCH] jemalloc450: disable transparent huge pages on ARM

---
 pkgs/development/libraries/jemalloc/common.nix | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/pkgs/development/libraries/jemalloc/common.nix b/pkgs/development/libraries/jemalloc/common.nix
index c41455a65441..128910e00f21 100644
--- a/pkgs/development/libraries/jemalloc/common.nix
+++ b/pkgs/development/libraries/jemalloc/common.nix
@@ -24,6 +24,13 @@ stdenv.mkDerivation rec {
   configureFlags = []
     ++ optional stripPrefix "--with-jemalloc-prefix="
     ++ optional disableInitExecTls "--disable-initial-exec-tls"
+    # jemalloc is unable to correctly detect transparent hugepage support on
+    # ARM (https://github.com/jemalloc/jemalloc/issues/526), and the default
+    # kernel ARMv6/7 kernel does not enable it, so we explicitly disable support
+    ++ optionals (stdenv.isAarch32 && versionOlder version "5") [
+      "--disable-thp"
+      "je_cv_thp=no"
+    ]
   ;
 
   doCheck = true;