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Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Kevin Brodsky Cc: linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Yeoreum Yun X-Mailer: b4 0.13.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1965; i=yeoreum.yun@arm.com; h=from:subject:message-id; bh=+m47CDGBLu+2KKry0pk847eP8rBPBT/djc8BljXHXXc=; b=owEB7QES/pANAwAKAW3Vw9FaxTEzAcsmYgBqjtsbvrNCvj4po7sJrnN7TSfCTIQVoy1AQhX+2 NKWHsYjt8uJAbMEAAEKAB0WIQQtg+CS3QUzuFh1pJ1t1cPRWsUxMwUCao7bGwAKCRBt1cPRWsUx M+T4DADC0+md4koOHJPRiqUozSeGzQ4ENUdfN4dbVq+ldDlUffw8Fv/oYwph24FW/hJqA4qcCxt RTVIf9PqIjHGWEkD/hfzjT4PuS8oUL4FzlzeYN+9qhWxXOBbUZzO5LNzxpzHE9y/xkIYLzP3iNF YEY0KE2YnNBPGGEqbmzF50YKjdbb7/5Ai8ytW9zBQtBFX2M2tCWN1we1dIy09ZYjy6vHUo/Vw00 cuSUalRsW8OY+toor32GvdjcSQX2Ki+8Ld3/Q+YG+uA9wyedY7SslfvjwhogNpYl4gfdEltJxE9 /lBGLuoYWUXXAGR8dJe4ALH9h55Pyx8NqYwWamNDyhgCMGDy0d2dvsIf2I3vOX69zFho+RTK4Hr +jLWA1SFMp7/QeIwkRL9g7MzT9gpO+n7PtjywTbs9DY6GqdVaFXvb4DV+CIzOtuI/mYGjMOgAde W1vBkXWcBpvAGSF+DNwRXyU/+sQ/lezOqofApHi5IGNs7IV2bDi3vgBmHw7a0JOKqAg4k= X-Developer-Key: i=yeoreum.yun@arm.com; a=openpgp; fpr=2D83E092DD0533B85875A49D6DD5C3D15AC53133 X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 1262214000A X-Stat-Signature: 6tknokrhozehukgyuydcozqtcddmgf5t X-HE-Tag: 1787747105-254939 X-HE-Meta: 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 SMgaf2Mu BcyrUmZIVeYN+z+DsHyZssnHEbEF6NuVZrOwsi0kROW21YSWQtKWBmc2W1k+L8ooBzP6XfTVPeg5DYZZrqUjVNiQyN/ee8FgLnWh9NbxymUWBSwaL1x+0ZslHFOYAoBWZHVEdZu9ASZ/jGUJRiRWA9hA5fNT/eD9k57ysOFZ5y/VzObnLcnZZIEuW5okphUK+XhCdkB43iAsvgoDCJlrEjeSRH3QFtfCPSHCPUYfJGUvtjba/pSEAdYY/dsXNJjSpVDdPu+B80YwzDIxSbQcWSTiifKe1V3AQUzJVBVqIoGrmzFIoDjfUpC9VvlX87n6IOJ5CnvWK081QslfPflyik6xGq+ZrKR3VPfp0 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: split_huge_page_test can fail for the following reasons: 1. During the test, khugepaged may collapse previously split pages again, causing intermittent failures. 2. Since glibc commit 321e1fc73f (“malloc: Enable 2MB THP by default on AArch64”), glibc may call madvise(MADV_HUGEPAGE) for sufficiently large allocations made by memalign(). The underlying VMA may start at a different address from the aligned address returned by memalign(). Moreover, a subsequent madvise(MADV_HUGEPAGE) call does not split the VMA because it already has the same advice. This causes the test to fail because the check_huge_xxx() helpers incorrectly require the address returned by memalign() to match the VMA start address reported in /proc/self/smaps. Address these issues by applying MADV_NOHUGEPAGE after faulting in the huge page, preventing khugepaged from collapsing it again, and by replacing the use of /proc/self/smaps in the check_huge_xxx() helpers with /proc/self/pagemap and /proc/kpageflags. This patch based on mm-unstable --- Changes in v2: - rebase to mm-unstable. - add message in case of failure of madvise() with MADV_NOHUGEPAGE. - fix wrong setup expected_huge in check_huge_shmem(). - Link to v1: https://lore.kernel.org/r/20260820-fix_split-v1-0-ab430c58c7cf@arm.com --- Yeoreum Yun (2): kselftest: mm: prevent random failure of huge page split for khugepaged kselftest: mm: replace usage of /proc/self/smaps for check_huge_xxx() helper tools/testing/selftests/mm/split_huge_page_test.c | 15 +++ tools/testing/selftests/mm/vm_util.c | 130 +++++++++++++--------- tools/testing/selftests/mm/vm_util.h | 1 + 3 files changed, 92 insertions(+), 54 deletions(-) --- base-commit: 169393fff5d1ec2690934067eeb95544ff5ebdd7 change-id: 20260820-fix_split-f44939ec44b8 Best regards, -- Sincerely, Yeoreum Yun