On Wed, Oct 26, 2022 at 07:45:08AM +0200, Willy Tarreau wrote: > Paul and myself got trapped a few times by not seeing the effects of > applying a patch to the nolibc source code until a "make clean" was > issued in the nolibc directory. It's particularly annoying when trying > to confirm that a proposed patch really solves a problem (or that > reverting it reintroduces the problem). > > The reason for the sysroot not being rebuilt was that it can be quite > slow. But in fact it's only slow after a "make clean" issued at the > kernel's topdir, because it's the main "make headers" that can take a > tens of seconds; as long as "usr/include" still contains headers, the > "headers_install" phase is only a quick "rsync", and rebuilding the > whole nolibc sysroot takes a bit less than one second, which is perfectly > acceptable for a test, even more once the time lost caused by misleading > results if factored in. > > This patch marks the sysroot target as phony and starts by clearing > the previous sysroot for the current architecture before reinstalling > it. Thanks to this, applying a patch to nolibc makes the effect > immediately visible to "make nolibc-test": > > $ time make -j -C tools/testing/selftests/nolibc nolibc-test > make: Entering directory '/k/tools/testing/selftests/nolibc' > MKDIR sysroot/x86/include > make[1]: Entering directory '/k/tools/include/nolibc' > make[2]: Entering directory '/k' > make[2]: Leaving directory '/k' > make[2]: Entering directory '/k' > INSTALL /k/tools/testing/selftests/nolibc/sysroot/sysroot/include > make[2]: Leaving directory '/k' > make[1]: Leaving directory '/k/tools/include/nolibc' > CC nolibc-test > make: Leaving directory '/k/tools/testing/selftests/nolibc' > > real 0m0.869s > user 0m0.716s > sys 0m0.149s > > Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx> > Link: https://lore.kernel.org/all/20221021155645.GK5600@paulmck-ThinkPad-P17-Gen-1/ > Signed-off-by: Willy Tarreau <w@xxxxxx> Works like a champ with reverting and unreverting c9388e0c1c6c ("tools/nolibc/string: Fix memcmp() implementation"), thank you!!! I have queued this. I expect to push this into the next merge window, thus avoiding the need to document the need for "make clean" in my pull request. ;-) Thanx, Paul > --- > tools/testing/selftests/nolibc/Makefile | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile > index 69ea659caca9..22f1e1d73fa8 100644 > --- a/tools/testing/selftests/nolibc/Makefile > +++ b/tools/testing/selftests/nolibc/Makefile > @@ -95,6 +95,7 @@ all: run > sysroot: sysroot/$(ARCH)/include > > sysroot/$(ARCH)/include: > + $(Q)rm -rf sysroot/$(ARCH) sysroot/sysroot > $(QUIET_MKDIR)mkdir -p sysroot > $(Q)$(MAKE) -C ../../../include/nolibc ARCH=$(ARCH) OUTPUT=$(CURDIR)/sysroot/ headers_standalone > $(Q)mv sysroot/sysroot sysroot/$(ARCH) > @@ -133,3 +134,5 @@ clean: > $(Q)rm -rf initramfs > $(call QUIET_CLEAN, run.out) > $(Q)rm -rf run.out > + > +.PHONY: sysroot/$(ARCH)/include > -- > 2.35.3 >
