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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=2222; i=yeoreum.yun@arm.com; h=from:subject:message-id; bh=USOUzZRz3c0fHctBAtbTyU36BIoeCR2Irm1oymvy1Z0=; b=owEB7QES/pANAwAKAW3Vw9FaxTEzAcsmYgBqkUK7FZ6xrgwXi+C79j9XWUXPL157DEfNDeyvK NH3vM1BzjWJAbMEAAEKAB0WIQQtg+CS3QUzuFh1pJ1t1cPRWsUxMwUCapFCuwAKCRBt1cPRWsUx M8p4C/9JENjCUm3iTLSylTH5Q2XPNcCbR8DJj9nKskBTusG5Hj6XCUUnfr//3gO/7CasIBssnuu B5ReHNHtaHq/lbokLssbDICO5An0Q53c0pJkWddWHavvXdESeXDlqJUeVal3P19As4xwZ6zvPej iaIGGwh4QB5YrDenpijUtphEjykFlkYzIFuAMb+JtrgiWhTPAFDIG3x76EAuZrn+AdutCKtujHS xKxrfLCQk74x5IsRkOf/BQLbUa61rJmpNsN7odwpztE8dyrY1CUB0y+/XVcaAhu9iB+3ax9iX8g 1QEJ3PN/v6fXsBRQVzMR/Z8ED9czEPNzsn9nmDHMn781/Kwf/MOp2OLbsU/IGQaPTSmjZaYDCiU OvOnZOEtGwYuN9cKB3tz5pCVh+2r7qm+f0Z7Z46BOeD4mxVYeYrfeaH2MIqjTQK0FOY7KbWZWiA 2J5KY1SnR/DxPXOj3QvgCtoVO9TVWeIZb9nzhOg1Wl0Zt0ESeEMW1MwQsMRmr5BmoNa4k= X-Developer-Key: i=yeoreum.yun@arm.com; a=openpgp; fpr=2D83E092DD0533B85875A49D6DD5C3D15AC53133 X-Stat-Signature: 8rhuszzhmi933s7ei3obubjwax4e4q4q X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 31CB31A0006 X-Rspam-User: X-HE-Tag: 1787904704-598613 X-HE-Meta: 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 9zSdedRH v4T3C6azTt+h1Fv5fRkgmY4FfX7M9cYEEjZ2OP5F+o0ooeprPiC1ZZyJoHaBZWhSVTw7/zbZvlv6FLF3pffofwwJ3S1RPUd1PfeaNYlJAlDgTVL7XfxsZ4PvWF7WvAvBSJOg1rAx6PFVOrAX3RINcOGe5uSIAAHeS3nJMEE0/QbS57Aqhbf4NhVDpiyhbaMHILFUIILG6+q3qCqlPrvc9xroIeosy0Y+C1gEBUYOJ5DVdmn6NHN+KPYrkvIU9QNqebtx2lcqw1WtmL685xZXXVo1Pp7UdelbHvgUjUi9OARneZH1VV05rANZ4OtNaztYxOje8A08fVYNXQrJ6sbnDlduQ3fXIe/3vspZ9 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 v3: - change message in case of failure of madvise() with MADV_NOHUGEPAGE. - fix collapse_single_mthp (mthp_khugepaged:anon) test case failure. - Link to v2: https://lore.kernel.org/all/20260826-fix_split-v2-0-71153c7f579a@arm.com/ 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 | 145 ++++++++++++++-------- tools/testing/selftests/mm/vm_util.h | 1 + 3 files changed, 107 insertions(+), 54 deletions(-) --- base-commit: 234e77148199ae43b83a0a03a3f481e03460a286 change-id: 20260820-fix_split-f44939ec44b8 Best regards, -- Sincerely, Yeoreum Yun