| Message ID | 20250602232233.224099-1-khaledelnaggarlinux@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [RESEND] selftests/mm/run_vmtests.sh: skip hugevm tests if write_to_hugetlbfs is missing | expand |
On 03/06/2025 5:12 am, Andrew Morton wrote: > On Tue, 3 Jun 2025 02:22:32 +0300 Khaled Elnaggar <khaledelnaggarlinux@gmail.com> wrote: > >> The hugevm tests 'charge_reserved_hugetlb.sh' and 'hugetlb_reparenting_test.sh' >> depend on the 'write_to_hugetlbfs' binary to simulate writes to hugetlbfs >> while checking reservations asynchronously in the background. >> >> When this binary is missing (e.g., excluded from the build), these tests hang >> for up to 180 seconds. During this time, run_vmtests.sh is eventually killed >> due to timeout, aborting all subsequent tests. >> >> This patch skips these tests if the binary is not found, preventing delays >> and ensuring that the test suite runs to completion. > > OK, but why is write_to_hugetlbfs missing? If we're in a situation > where we _could_ run it then we _should_ run it! The user wants to > test stuff so we should test as much as we can. > So I'm thinking that it would be preferable to make sure the dang thing > is there? > Totally agree, let me try to explain how I understand the issue. The write_to_hugetlbfs binary is built from selftests/mm/Makefile, lines 136–142. It is only compiled if ARCH matches one of the explicitly listed 64-bit architectures: ``` ifneq (,$(filter $(ARCH),arm64 mips64 parisc64 powerpc riscv64 s390x sparc64 x86_64 s390)) TEST_GEN_FILES += va_high_addr_switch ifneq ($(ARCH),riscv64) TEST_GEN_FILES += virtual_address_range endif TEST_GEN_FILES += write_to_hugetlbfs endif ``` However, when the MM selftests are run from the kernel’s top-level Makefile, (root directory for example: make defconfig sudo make kselftest TARGETS=mm ARCH is resolved as x86, even on an x86_64 machine (Debian in my case), ARCH=x86 is the reason why the binary gets excluded from the build system. As far as I understand, the top-level Makefile normalizes both i.86 and x86_64 to x86 for ARCH variable: Makfile: lines: 383,403 383:include $(srctree)/scripts/subarch.include 403:ARCH ?= $(SUBARCH) scripts/subarch.include: line: 7 7:SUBARCH := $(shell uname -m | sed -e s/i.86/x86/ -e s/x86_64/x86/ \ This mapping probably makes sense for selecting the correct arch/ directory (since we have arch/x86, not arch/x86_64) for top-level Makefile. But the mm selftests Makefile expects ARCH to differentiate between x86 and x86_64 to decide whether to build certain binaries. As a result, the 64-bit-only binaries like write_to_hugetlbfs are skipped during build, yet still expected at runtime (by run_vmtests.sh). That's why this whole issue of the missing executable does not happen when ran from selftests/mm using something like: sudo make -C tools/testing/selftests/mm Because then selftests/mm/Makefile arch detection rus as intended. You're right — the proper fix is to improve how we propagate architecture information from the top-level Makefile to selftests. But since that's a larger change (and possibly beyond what I can safely attempt at this point), this patch is just a targeted workaround to avoid test stalls when the binary is missing. I hope I haven't gone completely wrong with this analysis, happy to improve or revise it further if needed.
diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh index dddd1dd8af14..0b55395ee2cb 100755 --- a/tools/testing/selftests/mm/run_vmtests.sh +++ b/tools/testing/selftests/mm/run_vmtests.sh @@ -375,8 +375,13 @@ CATEGORY="process_mrelease" run_test ./mrelease_test CATEGORY="mremap" run_test ./mremap_test CATEGORY="hugetlb" run_test ./thuge-gen + +# the following tests depend on write_to_hugetlbfs binary +if [ -x ./write_to_hugetlbfs ]; then CATEGORY="hugetlb" run_test ./charge_reserved_hugetlb.sh -cgroup-v2 CATEGORY="hugetlb" run_test ./hugetlb_reparenting_test.sh -cgroup-v2 +fi + if $RUN_DESTRUCTIVE; then nr_hugepages_tmp=$(cat /proc/sys/vm/nr_hugepages) enable_soft_offline=$(cat /proc/sys/vm/enable_soft_offline)
The hugevm tests 'charge_reserved_hugetlb.sh' and 'hugetlb_reparenting_test.sh' depend on the 'write_to_hugetlbfs' binary to simulate writes to hugetlbfs while checking reservations asynchronously in the background. When this binary is missing (e.g., excluded from the build), these tests hang for up to 180 seconds. During this time, run_vmtests.sh is eventually killed due to timeout, aborting all subsequent tests. This patch skips these tests if the binary is not found, preventing delays and ensuring that the test suite runs to completion. Signed-off-by: Khaled Elnaggar <khaledelnaggarlinux@gmail.com> --- tools/testing/selftests/mm/run_vmtests.sh | 5 +++++ 1 file changed, 5 insertions(+) -- 2.47.2