On Wed, Jan 15, 2020 at 6:13 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.
Do you have example command with VMLINUX_BTF override that didn't work (and what error message was emitted)?
Fix this by only doing auto-detection if no override is set. And while we're at it, also look for a vmlinux file in the current kernel build dir if none if found on the running kernel.
Fixes: 9c01546d26d2 ("tools/bpf: Add runqslower tool to tools/bpf") Signed-off-by: Toke Høiland-Jørgensen toke@redhat.com
tools/bpf/runqslower/Makefile | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/tools/bpf/runqslower/Makefile b/tools/bpf/runqslower/Makefile index cff2fbcd29a8..fb93ce2bf2fe 100644 --- a/tools/bpf/runqslower/Makefile +++ b/tools/bpf/runqslower/Makefile @@ -10,12 +10,16 @@ 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") +ifeq ("$(VMLINUX_BTF)","")
- ifneq ("$(wildcard /sys/kernel/btf/vmlinux)","")
- VMLINUX_BTF := /sys/kernel/btf/vmlinux
- else ifneq ("$(wildcard /boot/vmlinux-$(KERNEL_REL))","")
- VMLINUX_BTF := /boot/vmlinux-$(KERNEL_REL)
- else ifneq ("$(wildcard $(abspath ../../../vmlinux))","")
- VMLINUX_BTF := $(abspath ../../../vmlinux)
I'm planning to mirror runqslower into libbpf Github repo and this ../../../vmlinux piece will be completely out of place in that context. Also it only will help when building kernel in-tree. So I'd rather not add this.
- else
- $(error "Can't detect kernel BTF, use VMLINUX_BTF to specify it explicitly")
- endif
endif
abs_out := $(abspath $(OUTPUT))