[PATCH] x86_64: Do not use -ffunction-sections for modules (409f89e0) · Commits · 戴 / test

Currently CONFIG_REORDER uses -ffunction-sections for all code; however, creating a separate section for each function is not useful for modules and just adds bloat. Moving this option from CFLAGS to CFLAGS_KERNEL shrinks module object files (e.g., the module tree for a kernel built with most drivers as modules shrinked from 54M to 46M), and decreases the number of sysfs files in /sys/module/*/sections/ directories. Signed-off-by:

Sergey Vlasov <vsu@altlinux.ru> Signed-off-by:

Andi Kleen <ak@suse.de> Signed-off-by:

Linus Torvalds <torvalds@osdl.org>

arch/x86_64/Makefile

+3 −1

Original line number	Diff line number	Diff line
		@@ -27,6 +27,7 @@ LDFLAGS_vmlinux :=
		CHECKFLAGS += -D__x86_64__ -m64

		cflags-y :=
		cflags-kernel-y :=
		cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8)
		cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona)
		cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic)
		@@ -35,7 +36,7 @@ cflags-y += -m64
		cflags-y += -mno-red-zone
		cflags-y += -mcmodel=kernel
		cflags-y += -pipe
		cflags-$(CONFIG_REORDER) += -ffunction-sections
		cflags-kernel-$(CONFIG_REORDER) += -ffunction-sections
		# this makes reading assembly source easier, but produces worse code
		# actually it makes the kernel smaller too.
		cflags-y += -fno-reorder-blocks
		@@ -55,6 +56,7 @@ cflags-y += $(call cc-option,-funit-at-a-time)
		cflags-y += $(call cc-option,-mno-sse -mno-mmx -mno-sse2 -mno-3dnow,)

		CFLAGS += $(cflags-y)
		CFLAGS_KERNEL += $(cflags-kernel-y)
		AFLAGS += -m64

		head-y := arch/x86_64/kernel/head.o arch/x86_64/kernel/head64.o arch/x86_64/kernel/init_task.o

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