| Message ID | 20230125085350.xg6u73ozznpum4u5@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | A question of KVM selftests' makefile | expand |
On Wed, Jan 25, 2023, Yu Zhang wrote: > Hi all, > > Currently, unlike the build system of Linux kernel, KVM selftests will > have to run "make clean && make" to rebuild the entire test suite, once > a header file is modified. > > Is it designed like this on purpose, My #1 rule: never assume anything weird in KVM was an explicit design choice :-) > or does anyone wanna change it? Yes! > I hacked the makefile by using "-MD" as EXTRA_CFLAGS, so that dependency > rules can be generated for each target object, whose prerequisites contains > the source file and the included header files as well. > > However, this change has its own costs. E.g., new ".o" and ".d" files will > occupy more storage. And performance-wise, the benifit could be limited, > because for now, most header files are needed by almost every ".c" files. > But with the evolution of KVM selftests, more ".h" files may be added. Some > of which may be of special usage. E.g., file "include/x86_64/mce.h" is only > used by "x86_64/ucna_injection_test". Having to rebuild the whole test suite > just because one specific header is touched would be annoying. > > I am not sure if this change is worthy, Absolutely worthy, I've run afoul of the lack of dependency tracking far too many times. > or if there's a better solution. This part I don't know. I would have cobbled together something long ago if I wasn't so clueless about Makefiles.
On 1/25/23 09:53, Yu Zhang wrote: > x := $(shell mkdir -p $(sort $(dir $(LIBKVM_C_OBJ) $(LIBKVM_S_OBJ)))) > $(LIBKVM_C_OBJ): $(OUTPUT)/%.o: %.c > - $(CC) $(CFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c $< -o $@ > + $(CC) $(CFLAGS) $(CPPFLAGS) $(EXTRA_CFLAGS) $(TARGET_ARCH) -c $< -o $@ Yes, this all looks very good. Feel free to post it as a patch! Paolo
On Wed, Jan 25, 2023 at 07:46:47PM +0100, Paolo Bonzini wrote: > On 1/25/23 09:53, Yu Zhang wrote: > > x := $(shell mkdir -p $(sort $(dir $(LIBKVM_C_OBJ) $(LIBKVM_S_OBJ)))) > > $(LIBKVM_C_OBJ): $(OUTPUT)/%.o: %.c > > - $(CC) $(CFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c $< -o $@ > > + $(CC) $(CFLAGS) $(CPPFLAGS) $(EXTRA_CFLAGS) $(TARGET_ARCH) -c $< -o $@ > > Yes, this all looks very good. Feel free to post it as a patch! > > Paolo > Thank you so much, Paolo & Sean! Just posted the patch! B.R. Yu
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index 1750f91dd936..b329e0d1a460 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -180,6 +180,8 @@ TEST_GEN_PROGS += $(TEST_GEN_PROGS_$(ARCH_DIR)) TEST_GEN_PROGS_EXTENDED += $(TEST_GEN_PROGS_EXTENDED_$(ARCH_DIR)) LIBKVM += $(LIBKVM_$(ARCH_DIR)) +OVERRIDE_TARGETS = 1 + # lib.mak defines $(OUTPUT), prepends $(OUTPUT)/ to $(TEST_GEN_PROGS), and most # importantly defines, i.e. overwrites, $(CC) (unless `make -e` or `make CC=`, # which causes the environment variable to override the makefile). @@ -198,9 +200,11 @@ CFLAGS += -Wall -Wstrict-prototypes -Wuninitialized -O2 -g -std=gnu99 \ -fno-builtin-memcmp -fno-builtin-memcpy -fno-builtin-memset \ -fno-stack-protector -fno-PIE -I$(LINUX_TOOL_INCLUDE) \ -I$(LINUX_TOOL_ARCH_INCLUDE) -I$(LINUX_HDR_PATH) -Iinclude \ - -I$(<D) -Iinclude/$(ARCH_DIR) -I ../rseq -I.. $(EXTRA_CFLAGS) \ + -I$(<D) -Iinclude/$(ARCH_DIR) -I ../rseq -I.. \ $(KHDR_INCLUDES) +EXTRA_CFLAGS += -MD + no-pie-option := $(call try-run, echo 'int main(void) { return 0; }' | \ $(CC) -Werror $(CFLAGS) -no-pie -x c - -o "$$TMP", -no-pie) @@ -218,11 +222,22 @@ LIBKVM_S_OBJ := $(patsubst %.S, $(OUTPUT)/%.o, $(LIBKVM_S)) LIBKVM_STRING_OBJ := $(patsubst %.c, $(OUTPUT)/%.o, $(LIBKVM_STRING)) LIBKVM_OBJS = $(LIBKVM_C_OBJ) $(LIBKVM_S_OBJ) $(LIBKVM_STRING_OBJ) -EXTRA_CLEAN += $(LIBKVM_OBJS) cscope.* +TEST_GEN_OBJ = $(patsubst %, %.o, $(TEST_GEN_PROGS)) +TEST_GEN_OBJ += $(patsubst %, %.o, $(TEST_GEN_PROGS_EXTENDED)) +TEST_DEP_FILES = $(patsubst %.o, %.d, $(TEST_GEN_OBJ)) +TEST_DEP_FILES += $(patsubst %.o, %.d, $(LIBKVM_OBJS)) +-include $(TEST_DEP_FILES) + +$(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED): %: %.o + $(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) $(TARGET_ARCH) $< $(LIBKVM_OBJS) $(LDLIBS) -o $@ +$(TEST_GEN_OBJ): %.o: %.c + $(CC) $(CFLAGS) $(CPPFLAGS) $(EXTRA_CFLAGS) $(TARGET_ARCH) -c $< -o $@ + +EXTRA_CLEAN += $(LIBKVM_OBJS) $(TEST_DEP_FILES) $(TEST_GEN_OBJ) cscope.* x := $(shell mkdir -p $(sort $(dir $(LIBKVM_C_OBJ) $(LIBKVM_S_OBJ)))) $(LIBKVM_C_OBJ): $(OUTPUT)/%.o: %.c - $(CC) $(CFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c $< -o $@ + $(CC) $(CFLAGS) $(CPPFLAGS) $(EXTRA_CFLAGS) $(TARGET_ARCH) -c $< -o $@ $(LIBKVM_S_OBJ): $(OUTPUT)/%.o: %.S $(CC) $(CFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c $< -o $@