On Fri, Jan 17, 2020 at 5:37 AM Toke Høiland-Jørgensen toke@redhat.com wrote:
From: Toke Høiland-Jørgensen toke@redhat.com
The runqslower tool refuses to build without a file to read vmlinux BTF from. The build fails with an error message to override the location by setting the VMLINUX_BTF variable if autodetection fails. However, the Makefile doesn't actually work with that override - the error message is still emitted.
Fix this by including the value of VMLINUX_BTF in the expansion, and only emitting the error message if the *result* is empty. Also permit running 'make clean' even though no VMLINUX_BTF is set.
Fixes: 9c01546d26d2 ("tools/bpf: Add runqslower tool to tools/bpf") Signed-off-by: Toke Høiland-Jørgensen toke@redhat.com
approach looks good, thanks, few nits below
tools/bpf/runqslower/Makefile | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/tools/bpf/runqslower/Makefile b/tools/bpf/runqslower/Makefile index cff2fbcd29a8..b62fc9646c39 100644 --- a/tools/bpf/runqslower/Makefile +++ b/tools/bpf/runqslower/Makefile @@ -10,13 +10,9 @@ CFLAGS := -g -Wall
# Try to detect best kernel BTF source KERNEL_REL := $(shell uname -r) -ifneq ("$(wildcard /sys/kernel/btf/vmlinux)","") -VMLINUX_BTF := /sys/kernel/btf/vmlinux -else ifneq ("$(wildcard /boot/vmlinux-$(KERNEL_REL))","") -VMLINUX_BTF := /boot/vmlinux-$(KERNEL_REL) -else -$(error "Can't detect kernel BTF, use VMLINUX_BTF to specify it explicitly") -endif +VMLINUX_BTF_PATHS := /sys/kernel/btf/vmlinux /boot/vmlinux-$(KERNEL_REL) +VMLINUX_BTF_PATH := $(abspath $(or $(VMLINUX_BTF),$(firstword \
$(wildcard $(VMLINUX_BTF_PATHS)))))
you can drop abspath, relative path for VMLINUX_BTF would work just fine
abs_out := $(abspath $(OUTPUT)) ifeq ($(V),1) @@ -67,9 +63,13 @@ $(OUTPUT): $(call msg,MKDIR,$@) $(Q)mkdir -p $(OUTPUT)
-$(OUTPUT)/vmlinux.h: $(VMLINUX_BTF) | $(OUTPUT) $(BPFTOOL) +$(OUTPUT)/vmlinux.h: $(VMLINUX_BTF_PATH) | $(OUTPUT) $(BPFTOOL) $(call msg,GEN,$@)
$(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@
@if [ ! -e "$(VMLINUX_BTF_PATH)" ] ; then \
$(Q), not @
echo "Couldn't find kernel BTF; set VMLINUX_BTF to specify its location."; \exit 1;\
nit: please align 's (same above for VMLONUX_BTF_PATH) at the right edge as it's done everywhere in this Makefile
fi$(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF_PATH) format c > $@$(OUTPUT)/libbpf.a: | $(OUTPUT) $(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC) \