Some systems (e.g. minimal or real-time kernels) may not enable
Transparent Hugepages (THP), causing MADV_HUGEPAGE to return EINVAL. This
patch introduces a runtime check using the existing THP sysfs interface
and skips the hugepage merging test (`-H`) when THP is not available.
To avoid those failures:
# -----------------------------
# running ./ksm_tests -H -s 100
# -----------------------------
# ksm_tests: MADV_HUGEPAGE: Invalid argument
# [FAIL]
not ok 1 ksm_tests -H -s 100 # exit=2
# --------------------
# running ./khugepaged
# --------------------
# Reading PMD pagesize failed# [FAIL]
not ok 1 khugepaged # exit=1
# --------------------
# running ./soft-dirty
# --------------------
# TAP version 13
# 1..15
# ok 1 Test test_simple
# ok 2 Test test_vma_reuse dirty bit of allocated page
# ok 3 Test test_vma_reuse dirty bit of reused address page
# Bail out! Reading PMD pagesize failed# Planned tests != run tests (15 != 3)
# # Totals: pass:3 fail:0 xfail:0 xpass:0 skip:0 error:0
# [FAIL]
not ok 1 soft-dirty # exit=1
# SUMMARY: PASS=0 SKIP=0 FAIL=1
# -------------------
# running ./migration
# -------------------
# TAP version 13
# 1..3
# # Starting 3 tests from 1 test cases.
# # RUN migration.private_anon ...
# # OK migration.private_anon
# ok 1 migration.private_anon
# # RUN migration.shared_anon ...
# # OK migration.shared_anon
# ok 2 migration.shared_anon
# # RUN migration.private_anon_thp ...
# # migration.c:196:private_anon_thp:Expected madvise(ptr, TWOMEG, MADV_HUGEPAGE) (-1) == 0 (0)
# # private_anon_thp: Test terminated by assertion
# # FAIL migration.private_anon_thp
# not ok 3 migration.private_anon_thp
# # FAILED: 2 / 3 tests passed.
# # Totals: pass:2 fail:1 xfail:0 xpass:0 skip:0 error:0
# [FAIL]
not ok 1 migration # exit=1
It's true that CONFIG_TRANSPARENT_HUGEPAGE=y is explicitly enabled in
tools/testing/selftests/mm/config, so ideally the runtime environment
should also support THP.
However, in practice, we've found that on some systems:
- THP is disabled at boot time (transparent_hugepage=never)
- Or manually disabled via sysfs
- Or unavailable in RT kernels, containers, or minimal CI environments
In these cases, the test will fail with EINVAL on madvise(MADV_HUGEPAGE),
even though the kernel config is correct.
To make the test suite more robust and avoid false negatives, this patch
adds a runtime check for /sys/kernel/mm/transparent_hugepage/enabled.
If THP is not available, the hugepage test (-H) is skipped with a clear
message.
Link: https://lkml.kernel.org/r/20250624032748.393836-1-liwang@redhat.com
Signed-off-by: Li Wang <liwang@redhat.com>
Cc: Aruna Ramakrishna <aruna.ramakrishna@oracle.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Joey Gouly <joey.gouly@arm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Keith Lucas <keith.lucas@oracle.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "selftest/mm: Remove warnings found by adding compiler flags".
Recently, I reviewed a patch on the mm/kselftest mailing list about a test
which had obvious type mismatch fix in it. It was strange why that wasn't
caught during development and when patch was accepted. This led me to
discover that those extra compiler options to catch these warnings aren't
being used. When I added them, I found tens of warnings in just mm suite.
In this series, I'm fixing those warnings in a few files. More fixes will
be sent later.
This patch (of 4):
Remove cost from the return type as it is ignored anyways and generates
the warning:
warning: type qualifiers ignored on function return type [-Wignored-qualifiers]
Link: https://lkml.kernel.org/r/20241209185624.2245158-1-usama.anjum@collabora.com
Link: https://lkml.kernel.org/r/20241209185624.2245158-2-usama.anjum@collabora.com
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
