On Fri, May 10, 2024 at 7:01 AM Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx> wrote: > > On Thu, May 9, 2024 at 1:20 AM Alan Maguire <alan.maguire@xxxxxxxxxx> wrote: > > > > On 07/05/2024 17:48, Andrii Nakryiko wrote: > > > On Tue, May 7, 2024 at 6:55 AM Alan Maguire <alan.maguire@xxxxxxxxxx> wrote: > > >> > > >> The btf_features list can be used for pahole v1.26 and later - > > >> it is useful because if a feature is not yet implemented it will > > >> not exit with a failure message. This will allow us to add feature > > >> requests to the pahole options without having to check pahole versions > > >> in future; if the version of pahole supports the feature it will be > > >> added. > > >> > > >> Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx> > > >> Tested-by: Eduard Zingerman <eddyz87@xxxxxxxxx> > > >> --- > > >> scripts/Makefile.btf | 15 +++++++++++++-- > > >> 1 file changed, 13 insertions(+), 2 deletions(-) > > >> > > >> diff --git a/scripts/Makefile.btf b/scripts/Makefile.btf > > >> index 82377e470aed..2d6e5ed9081e 100644 > > >> --- a/scripts/Makefile.btf > > >> +++ b/scripts/Makefile.btf > > >> @@ -3,6 +3,8 @@ > > >> pahole-ver := $(CONFIG_PAHOLE_VERSION) > > >> pahole-flags-y := > > >> > > >> +ifeq ($(call test-le, $(pahole-ver), 125),y) > > >> + > > >> # pahole 1.18 through 1.21 can't handle zero-sized per-CPU vars > > >> ifeq ($(call test-le, $(pahole-ver), 121),y) > > >> pahole-flags-$(call test-ge, $(pahole-ver), 118) += --skip_encoding_btf_vars > > >> @@ -12,8 +14,17 @@ pahole-flags-$(call test-ge, $(pahole-ver), 121) += --btf_gen_floats > > >> > > >> pahole-flags-$(call test-ge, $(pahole-ver), 122) += -j > > >> > > >> -pahole-flags-$(CONFIG_PAHOLE_HAS_LANG_EXCLUDE) += --lang_exclude=rust > > >> +ifeq ($(pahole-ver), 125) > > > > > > it's a bit of a scope creep, but isn't it strange that we don't have > > > test-eq and have to work-around that with more verbose constructs? > > > > Looking at the history, I _think_ the concern that motivated the numeric > > comparison constructs was the shell process fork required for numeric > > comparisons. In the equality case, ifeq would work for both strings and > > numeric values. Adding a test-eq (in a similar form to test-ge) would > > require a fallback to shell expansion for older Make without intcmp, and > > that would be slower than using ifeq, if less verbose. > > > > > Let's do a good service to the community and add test-eq (and maybe > > > test-ne while at it, don't know, up to Masahiro)? > > > > > > > Sure, I'm happy to do this if kbuild folks agree. I've cc'ed them; I > > neglected to do this in the original patch, apologies about that. > > > > Ok, let's see if Masahiro would like this improvement or not. For now > this patch gets us into a nicer place where there are legacy parts and > a better --btf_features setup completely separate, so I applied the > patch as is to bpf-next. If we decide to do test-eq, we can improve > this further separately. Thanks! That is a noise change. You did not need to modify the line in the first place. The previous pahole-flags-$(call test-ge, $(pahole-ver), 125) works as-is. -- Best Regards Masahiro Yamada
