Makefile: Run submakes in parallel

This is just to save me always typing -jN on the command line.

diff --git a/build/Makefile b/build/Makefile
index 90ce9728361a9e95a26f9f663b246dcdd3d2034f..7cbe967e3058634a8587e69f8e457a42ad631b58 100644 (file)
--- a/build/Makefile
+++ b/build/Makefile
@@ -1,5 +1,7 @@
 all: buildroot/images/rootfs.cpio.uboot linux-4.4/vmlinux
 
+NPROC:=$(shell nproc)
+
 # TX2 U-Boot does not support FIT images
 image.fit: buildroot/images/rootfs.cpio.uboot linux-4.4/vmlinux
        mkimage -f auto -d linux-4.4/arch/arm64/boot/Image -i buildroot/images/rootfs.cpio.uboot -b linux-4.4/arch/arm64/boot/dts/tegra186-quill-p3310-1000-c03-00-base.dtb image.fit
@@ -10,7 +12,7 @@ buildroot/images/rootfs.cpio.uboot: rootfs-overlay/lib/firmware/jailhouse.bin ro
 rootfs-overlay/lib/firmware/jailhouse.bin: linux-4.4/vmlinux
 rootfs-overlay/lib/firmware/jailhouse.bin: ../jailhouse/include/jailhouse/config.h
 rootfs-overlay/lib/firmware/jailhouse.bin: $(addprefix ../jailhouse/,$(shell cd ../jailhouse && git ls-files))
-       $(MAKE) -C ../jailhouse install KDIR=$(CURDIR)/linux-4.4 ARCH=arm64 DESTDIR=$(CURDIR)/rootfs-overlay
+       $(MAKE) -C ../jailhouse -j$(NPROC) install KDIR=$(CURDIR)/linux-4.4 ARCH=arm64 DESTDIR=$(CURDIR)/rootfs-overlay
        mkdir -p rootfs-overlay/jailhouse/configs/ rootfs-overlay/jailhouse/demos/
 #      cp ../jailhouse/inmates/demos/arm64/my-demo.bin rootfs-overlay/jailhouse/demos/
        cp ../jailhouse/configs/arm64/jetson-tx2.cell rootfs-overlay/jailhouse/configs/
@@ -24,10 +26,10 @@ rootfs-overlay/lib/firmware/jailhouse.bin: $(addprefix ../jailhouse/,$(shell cd
        mv --update $@.tmp $@
 
 rootfs-overlay/lib/modules/4.4.38+/modules.dep: linux-4.4/vmlinux
-       $(MAKE) -C linux-4.4 modules_install INSTALL_MOD_PATH=$(CURDIR)/rootfs-overlay
+       $(MAKE) -C linux-4.4 -j$(NPROC)  modules_install INSTALL_MOD_PATH=$(CURDIR)/rootfs-overlay
 
 linux-4.4/vmlinux:
-       $(MAKE) -C $(@D)
+       $(MAKE) -C $(@D) -j$(NPROC)
 
 clean:
        rm buildroot/images/rootfs.cpio.uboot linux-4.4/vmlinux