From: "Kiryl Shutsemau (Meta)" <[email protected]> Its fault-time THP construction (x hpage_pmd_nr) cannot hand out a 512M order-13 page on arm64/64K, bailing the whole binary. Skip when hpage_pmd_size > 32M; MADV_COLLAPSE-driven cases still exercise PMD-order collapse there. No effect on 4K (2M) or 16K (32M) PMDs.
Assisted-by: Claude-Code:claude-opus-5 Signed-off-by: Kiryl Shutsemau (Meta) <[email protected]> --- tools/testing/selftests/mm/khugepaged.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/tools/testing/selftests/mm/khugepaged.c b/tools/testing/selftests/mm/khugepaged.c index 81001e15765c..b43e060b4118 100644 --- a/tools/testing/selftests/mm/khugepaged.c +++ b/tools/testing/selftests/mm/khugepaged.c @@ -857,6 +857,21 @@ static void collapse_compound_extreme(struct collapse_context *c, struct mem_ops void *p; int i; + /* + * Builds a PMD's worth of distinct PTE-mapped compound pages by cycling + * hpage_pmd_nr fault-time THPs through mremap. Fault-time THP allocation + * is best-effort, and this needs hpage_pmd_nr PMD-order pages in a row: + * fine at a 2M (4K base) or 32M (16K base) PMD, but a 512M PMD (arm64/64K) + * is an order-13 allocation the allocator cannot reliably hand out even + * once, let alone 8192 times. Cap at a 32M PMD; MADV_COLLAPSE-driven cases + * still cover PMD-order collapse on the larger configs. + */ + if (hpage_pmd_size > (32UL << 20)) { + ksft_test_result_skip("%s: PMD too large for fault-time THP construction\n", + __func__); + return; + } + p = ops->setup_area(1); ksft_print_msg("Construct PTE page table full of different PTE-mapped compound pages\n"); for (i = 0; i < hpage_pmd_nr; i++) { -- 2.54.0
