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| author | Quentin Monnet <quentin@isovalent.com> | 2021-10-09 23:03:40 +0200 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2021-10-20 01:41:37 +0200 |
| commit | ced846c65e8ffdaac7138936cdbbc9337a939fb9 (patch) | |
| tree | 8ce283b2764c2b263103c8cafebf79dfbd3426b2 /tools/bpf/bpftool | |
| parent | bpftool: Fix install for libbpf's internal header(s) (diff) | |
| download | linux-ced846c65e8ffdaac7138936cdbbc9337a939fb9.tar.xz linux-ced846c65e8ffdaac7138936cdbbc9337a939fb9.zip | |
bpftool: Do not FORCE-build libbpf
In bpftool's Makefile, libbpf has a FORCE dependency, to make sure we
rebuild it in case its source files changed. Let's instead make the
rebuild depend on the source files directly, through a call to the
"$(wildcard ...)" function. This avoids descending into libbpf's
directory if there is nothing to update.
Do the same for the bootstrap libbpf version.
This results in a slightly faster operation and less verbose output when
running make a second time in bpftool's directory.
Before:
Auto-detecting system features:
... libbfd: [ on ]
... disassembler-four-args: [ on ]
... zlib: [ on ]
... libcap: [ on ]
... clang-bpf-co-re: [ on ]
make[1]: Entering directory '/root/dev/linux/tools/lib/bpf'
make[1]: Entering directory '/root/dev/linux/tools/lib/bpf'
make[1]: Nothing to be done for 'install_headers'.
make[1]: Leaving directory '/root/dev/linux/tools/lib/bpf'
make[1]: Leaving directory '/root/dev/linux/tools/lib/bpf'
After:
Auto-detecting system features:
... libbfd: [ on ]
... disassembler-four-args: [ on ]
... zlib: [ on ]
... libcap: [ on ]
... clang-bpf-co-re: [ on ]
Other ways to clean up the output could be to pass the "-s" option, or
to redirect the output to >/dev/null, when calling make recursively to
descend into libbpf's directory. However, this would suppress some
useful output if something goes wrong during the build. A better
alternative would be to pass "--no-print-directory" to the recursive
make, but that would still leave us with some noise for
"install_headers". Skipping the descent into libbpf's directory if no
source file has changed works best, and seems the most logical option
overall.
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20211009210341.6291-3-quentin@isovalent.com
Diffstat (limited to 'tools/bpf/bpftool')
| -rw-r--r-- | tools/bpf/bpftool/Makefile | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile index 646fd40b3253..331019f6d5b1 100644 --- a/tools/bpf/bpftool/Makefile +++ b/tools/bpf/bpftool/Makefile @@ -42,7 +42,7 @@ endif $(LIBBPF_OUTPUT) $(BOOTSTRAP_OUTPUT) $(LIBBPF_BOOTSTRAP_OUTPUT): $(QUIET_MKDIR)mkdir -p $@ -$(LIBBPF): FORCE | $(LIBBPF_OUTPUT) +$(LIBBPF): $(wildcard $(BPF_DIR)/*.[ch] $(BPF_DIR)/Makefile) | $(LIBBPF_OUTPUT) $(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(LIBBPF_OUTPUT) \ DESTDIR=$(LIBBPF_DESTDIR) prefix= $(LIBBPF) install_headers @@ -50,7 +50,7 @@ $(LIBBPF_INTERNAL_HDRS): $(LIBBPF_HDRS_DIR)/%.h: $(BPF_DIR)/%.h $(LIBBPF) $(call QUIET_INSTALL, $@) $(Q)install -m 644 -t $(LIBBPF_HDRS_DIR) $< -$(LIBBPF_BOOTSTRAP): FORCE | $(LIBBPF_BOOTSTRAP_OUTPUT) +$(LIBBPF_BOOTSTRAP): $(wildcard $(BPF_DIR)/*.[ch] $(BPF_DIR)/Makefile) | $(LIBBPF_BOOTSTRAP_OUTPUT) $(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(LIBBPF_BOOTSTRAP_OUTPUT) \ ARCH= CC=$(HOSTCC) LD=$(HOSTLD) $@ |