On Tue, Nov 10, 2020 at 8:45 AM Jean-Philippe Brucker
<jean-philippe@xxxxxxxxxx> wrote:
>
> Commit ba2fd563b740 ("tools/bpftool: Support passing BPFTOOL_VERSION to
> make") changed BPFTOOL_VERSION to a recursively expanded variable,
> forcing it to be recomputed on every expansion of CFLAGS and
> dramatically slowing down the bpftool build. Restore BPFTOOL_VERSION as
> a simply expanded variable, guarded by an ifeq().
>
> Fixes: ba2fd563b740 ("tools/bpftool: Support passing BPFTOOL_VERSION to make")
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
> ---
Thanks a lot! I verified that it does restore the previous build speed.
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> v3: new
> ---
> tools/bpf/bpftool/Makefile | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
> index d566bced135e..804ade95929f 100644
> --- a/tools/bpf/bpftool/Makefile
> +++ b/tools/bpf/bpftool/Makefile
> @@ -30,7 +30,9 @@ LIBBPF = $(LIBBPF_PATH)libbpf.a
> LIBBPF_BOOTSTRAP_OUTPUT = $(BOOTSTRAP_OUTPUT)libbpf/
> LIBBPF_BOOTSTRAP = $(LIBBPF_BOOTSTRAP_OUTPUT)libbpf.a
>
> -BPFTOOL_VERSION ?= $(shell make -rR --no-print-directory -sC ../../.. kernelversion)
> +ifeq ($(BPFTOOL_VERSION),)
> +BPFTOOL_VERSION := $(shell make -rR --no-print-directory -sC ../../.. kernelversion)
> +endif
>
> $(LIBBPF_OUTPUT) $(BOOTSTRAP_OUTPUT) $(LIBBPF_BOOTSTRAP_OUTPUT):
> $(QUIET_MKDIR)mkdir -p $@
> --
> 2.29.1
>
