From 6b69c45d36b5c830d1fe882a5bd74a5cf0fa8b51 Mon Sep 17 00:00:00 2001
From: Michael Heller <21163552+mdheller@users.noreply.github.com>
Date: Thu, 23 Jul 2026 09:02:06 -0400
Subject: [PATCH] =?UTF-8?q?windows:=20cap=20mach=20build=20at=20-j$(nproc)?=
 =?UTF-8?q?=20=E2=80=94=20memory-based=20parallelism=20OOM-kills=2016GB=20?=
 =?UTF-8?q?CI=20runners=20(exit=20143)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 scripts/build-windows-cross.sh | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/scripts/build-windows-cross.sh b/scripts/build-windows-cross.sh
index 5d8662e..5df56ea 100755
--- a/scripts/build-windows-cross.sh
+++ b/scripts/build-windows-cross.sh
@@ -157,7 +157,10 @@ export PATH="$MOZ_CLANG_BIN:$HOME/.cargo/bin:$PATH"
 ulimit -n "$NOFILE"
 
 ./mach configure
-./mach build
+# Cap parallelism at the core count: mach's memory heuristic over-parallelizes
+# on 16GB CI runners and a burst of rustc processes gets the job SIGTERM'd
+# (exit 143, ~10min in). -j$(nproc) is also correct on the big sovereign builder.
+./mach build -j"$(nproc)"
 ./mach package
 
 log "artifacts"