The test will fail as below on x86_64 with cpu la57 support (will skip if no la57 support). Note, the test requries nr_hugepages to be set first.
# running bash ./va_high_addr_switch.sh # ------------------------------------- # mmap(addr_switch_hint - pagesize, pagesize): 0x7f55b60fa000 - OK # mmap(addr_switch_hint - pagesize, (2 * pagesize)): 0x7f55b60f9000 - OK # mmap(addr_switch_hint, pagesize): 0x800000000000 - OK # mmap(addr_switch_hint, 2 * pagesize, MAP_FIXED): 0x800000000000 - OK # mmap(NULL): 0x7f55b60f9000 - OK # mmap(low_addr): 0x40000000 - OK # mmap(high_addr): 0x1000000000000 - OK # mmap(high_addr) again: 0xffff55b6136000 - OK # mmap(high_addr, MAP_FIXED): 0x1000000000000 - OK # mmap(-1): 0xffff55b6134000 - OK # mmap(-1) again: 0xffff55b6132000 - OK # mmap(addr_switch_hint - pagesize, pagesize): 0x7f55b60fa000 - OK # mmap(addr_switch_hint - pagesize, 2 * pagesize): 0x7f55b60f9000 - OK # mmap(addr_switch_hint - pagesize/2 , 2 * pagesize): 0x7f55b60f7000 - OK # mmap(addr_switch_hint, pagesize): 0x800000000000 - OK # mmap(addr_switch_hint, 2 * pagesize, MAP_FIXED): 0x800000000000 - OK # mmap(NULL, MAP_HUGETLB): 0x7f55b5c00000 - OK # mmap(low_addr, MAP_HUGETLB): 0x40000000 - OK # mmap(high_addr, MAP_HUGETLB): 0x1000000000000 - OK # mmap(high_addr, MAP_HUGETLB) again: 0xffff55b5e00000 - OK # mmap(high_addr, MAP_FIXED | MAP_HUGETLB): 0x1000000000000 - OK # mmap(-1, MAP_HUGETLB): 0x7f55b5c00000 - OK # mmap(-1, MAP_HUGETLB) again: 0x7f55b5a00000 - OK # mmap(addr_switch_hint - pagesize, 2*hugepagesize, MAP_HUGETLB): 0x800000000000 - FAILED # mmap(addr_switch_hint , 2*hugepagesize, MAP_FIXED | MAP_HUGETLB): 0x800000000000 - OK # [FAIL]
addr_switch_hint is defined as DFEFAULT_MAP_WINDOW in the failed test (for x86_64, DFEFAULT_MAP_WINDOW is defined as (1UL<<47) - pagesize) in 64 bit.
Before commit cc92882ee218 ("mm: drop hugetlb_get_unmapped_area{_*} functions"), for x86_64 hugetlb_get_unmapped_area() is handled in arch code arch/x86/mm/hugetlbpage.c and addr is checked with map_address_hint_valid() after align with 'addr &= huge_page_mask(h)' which is a round down way, and it will fail the check because the addr is within the DEFAULT_MAP_WINDOW but (addr + len) is above the DFEFAULT_MAP_WINDOW. So it wil go through the hugetlb_get_unmmaped_area_top_down() to find an area within the DFEFAULT_MAP_WINDOW.
After commit cc92882ee218 ("mm: drop hugetlb_get_unmapped_area{_*} functions"). The addr hint for hugetlb_get_unmmaped_area() will be rounded up and aligned to hugepage size with ALIGN() for all arches. And after the align, the addr will be above the default MAP_DEFAULT_WINDOW, and the map_addresshint_valid() check will pass because both aligned addr (addr0) and (addr + len) are above the DEFAULT_MAP_WINDOW, and the aligned hint address (0x800000000000) is returned as an suitable gap is found there, in arch_get_unmapped_area_topdown().
To still cover the case that addr is within the DEFAULT_MAP_WINDOW, and addr + len is above the DFEFAULT_MAP_WINDOW, make the addr hint one hugepage lower, so that after the align it's still within DEFAULT_MAP_WINDOW, and the addr + len (2 hugepages) will be above DEFAULT_MAP_WINDOW.
Fixes: cc92882ee218 ("mm: drop hugetlb_get_unmapped_area{_*} functions") Signed-off-by: Chunyu Hu chuhu@redhat.com --- tools/testing/selftests/mm/va_high_addr_switch.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/mm/va_high_addr_switch.c b/tools/testing/selftests/mm/va_high_addr_switch.c index 896b3f73fc53..bd96dc3b5931 100644 --- a/tools/testing/selftests/mm/va_high_addr_switch.c +++ b/tools/testing/selftests/mm/va_high_addr_switch.c @@ -230,10 +230,10 @@ void testcases_init(void) .msg = "mmap(-1, MAP_HUGETLB) again", }, { - .addr = (void *)(addr_switch_hint - pagesize), + .addr = (void *)(addr_switch_hint - pagesize - hugepagesize), .size = 2 * hugepagesize, .flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS, - .msg = "mmap(addr_switch_hint - pagesize, 2*hugepagesize, MAP_HUGETLB)", + .msg = "mmap(addr_switch_hint - pagesize - hugepagesize, 2*hugepagesize, MAP_HUGETLB)", .low_addr_required = 1, .keep_mapped = 1, },