* [PATCH v2 0/3] Fix va_high_addr_switch.sh test failure @ 2025-09-08 12:47 Chunyu Hu 2025-09-08 12:47 ` [PATCH v2 1/3] selftests/mm: fix hugepages cleanup too early Chunyu Hu 0 siblings, 1 reply; 7+ messages in thread From: Chunyu Hu @ 2025-09-08 12:47 UTC (permalink / raw) To: akpm, david, shuah, linux-mm Cc: linux-kselftest, linux-kernel, lorenzo.stoakes, Liam.Howlett, vbabka, rppt, surenb, mhocko, chuhu The three patches fix the va_high_addr_switch.sh test failure on x86_64. Patch 1 fixes the hugepage setup issue that nr_hugepages is reset too early in run_vmtests.sh and break the later va_high_addr_switch testing. Patch 2 adds hugepage setup in va_high_addr_switch test, so that it can still work if vm_runtests.sh changes the hugepage setup someday. Patch 3 fixes the test failure caused by the hint addr align method change in hugetlb_get_unmapped_area(). Changes in v2: - patch 1 renames nr_hugepgs_origin to orig_nr_hugepgs - add a patch 2 to setup hugeapges in va_high_addr_switch test Chunyu Hu (3): selftests/mm: fix hugepages cleanup too early selftests/mm: alloc hugepages in va_high_addr_switch test selftests/mm: fix va_high_addr_switch.sh failure on x86_64 tools/testing/selftests/mm/run_vmtests.sh | 9 ++++- .../selftests/mm/va_high_addr_switch.c | 4 +- .../selftests/mm/va_high_addr_switch.sh | 37 +++++++++++++++++++ 3 files changed, 46 insertions(+), 4 deletions(-) -- 2.49.0 ^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v2 1/3] selftests/mm: fix hugepages cleanup too early 2025-09-08 12:47 [PATCH v2 0/3] Fix va_high_addr_switch.sh test failure Chunyu Hu @ 2025-09-08 12:47 ` Chunyu Hu 2025-09-08 12:47 ` [PATCH v2 2/3] selftests/mm: alloc hugepages in va_high_addr_switch test Chunyu Hu 2025-09-08 12:53 ` [PATCH v2 1/3] selftests/mm: fix hugepages cleanup too early David Hildenbrand 0 siblings, 2 replies; 7+ messages in thread From: Chunyu Hu @ 2025-09-08 12:47 UTC (permalink / raw) To: akpm, david, shuah, linux-mm Cc: linux-kselftest, linux-kernel, lorenzo.stoakes, Liam.Howlett, vbabka, rppt, surenb, mhocko, chuhu The nr_hugepgs variable is used to keep the original nr_hugepages at the hugepage setup step at test beginning. After userfaultfd test, a cleaup is executed, both /sys/kernel/mm/hugepages/hugepages-*/nr_hugepages and /proc/sys//vm/nr_hugepages are reset to 'original' value before userfaultfd test starts. Issue here is the value used to restore /proc/sys/vm/nr_hugepages is nr_hugepgs which is the initial value before the vm_runtests.sh runs, not the value before userfaultfd test starts. 'va_high_addr_swith.sh' tests runs after that will possibly see no hugepages available for test, and got EINVAL when mmap(HUGETLB), making the result invalid. And before pkey tests, nr_hugepgs is changed to be used as a temp variable to save nr_hugepages before pkey test, and restore it after pkey tests finish. The original nr_hugepages value is not tracked anymore, so no way to restore it after all tests finish. Add a new variable orig_nr_hugepgs to save the original nr_hugepages, and and restore it to nr_hugepages after all tests finish. And change to use the nr_hugepgs variable to save the /proc/sys/vm/nr_hugeages after hugepage setup, it's also the value before userfaultfd test starts, and the correct value to be restored after userfaultfd finishes. The va_high_addr_switch.sh broken will be resolved. Signed-off-by: Chunyu Hu <chuhu@redhat.com> --- Changes in v2 - rename nr_hugepgs_origin to orig_nr_hugepgs --- tools/testing/selftests/mm/run_vmtests.sh | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh index 471e539d82b8..9866e4221bc2 100755 --- a/tools/testing/selftests/mm/run_vmtests.sh +++ b/tools/testing/selftests/mm/run_vmtests.sh @@ -172,13 +172,13 @@ fi # set proper nr_hugepages if [ -n "$freepgs" ] && [ -n "$hpgsize_KB" ]; then - nr_hugepgs=$(cat /proc/sys/vm/nr_hugepages) + orig_nr_hugepgs=$(cat /proc/sys/vm/nr_hugepages) needpgs=$((needmem_KB / hpgsize_KB)) tries=2 while [ "$tries" -gt 0 ] && [ "$freepgs" -lt "$needpgs" ]; do lackpgs=$((needpgs - freepgs)) echo 3 > /proc/sys/vm/drop_caches - if ! echo $((lackpgs + nr_hugepgs)) > /proc/sys/vm/nr_hugepages; then + if ! echo $((lackpgs + orig_nr_hugepgs)) > /proc/sys/vm/nr_hugepages; then echo "Please run this test as root" exit $ksft_skip fi @@ -189,6 +189,7 @@ if [ -n "$freepgs" ] && [ -n "$hpgsize_KB" ]; then done < /proc/meminfo tries=$((tries - 1)) done + nr_hugepgs=$(cat /proc/sys/vm/nr_hugepages) if [ "$freepgs" -lt "$needpgs" ]; then printf "Not enough huge pages available (%d < %d)\n" \ "$freepgs" "$needpgs" @@ -532,6 +533,10 @@ CATEGORY="page_frag" run_test ./test_page_frag.sh aligned CATEGORY="page_frag" run_test ./test_page_frag.sh nonaligned +if [ "${HAVE_HUGEPAGES}" = 1 ]; then + echo "$orig_nr_hugepgs" > /proc/sys/vm/nr_hugepages +fi + echo "SUMMARY: PASS=${count_pass} SKIP=${count_skip} FAIL=${count_fail}" | tap_prefix echo "1..${count_total}" | tap_output -- 2.49.0 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH v2 2/3] selftests/mm: alloc hugepages in va_high_addr_switch test 2025-09-08 12:47 ` [PATCH v2 1/3] selftests/mm: fix hugepages cleanup too early Chunyu Hu @ 2025-09-08 12:47 ` Chunyu Hu 2025-09-08 12:47 ` [PATCH v2 3/3] selftests/mm: fix va_high_addr_switch.sh failure on x86_64 Chunyu Hu 2025-09-08 12:53 ` [PATCH v2 1/3] selftests/mm: fix hugepages cleanup too early David Hildenbrand 1 sibling, 1 reply; 7+ messages in thread From: Chunyu Hu @ 2025-09-08 12:47 UTC (permalink / raw) To: akpm, david, shuah, linux-mm Cc: linux-kselftest, linux-kernel, lorenzo.stoakes, Liam.Howlett, vbabka, rppt, surenb, mhocko, chuhu Alloc hugepages in the test internally, so we don't fully rely on the run_vmtests.sh. If run_vmtests.sh does that great, free hugepages is enough for being used to run the test, leave it as it is, otherwise setup the hugepages in the test. Save the original nr_hugepages value and restore it after test finish, so leave a stable test envronment. Signed-off-by: Chunyu Hu <chuhu@redhat.com> --- .../selftests/mm/va_high_addr_switch.sh | 37 +++++++++++++++++++ 1 file changed, 37 insertions(+) diff --git a/tools/testing/selftests/mm/va_high_addr_switch.sh b/tools/testing/selftests/mm/va_high_addr_switch.sh index 325de53966b6..a7d4b02b21dd 100755 --- a/tools/testing/selftests/mm/va_high_addr_switch.sh +++ b/tools/testing/selftests/mm/va_high_addr_switch.sh @@ -9,6 +9,7 @@ # Kselftest framework requirement - SKIP code is 4. ksft_skip=4 +orig_nr_hugepages=0 skip() { @@ -76,5 +77,41 @@ check_test_requirements() esac } +save_nr_hugepages() +{ + orig_nr_hugepages=$(cat /proc/sys/vm/nr_hugepages) +} + +restore_nr_hugepages() +{ + echo "$orig_nr_hugepages" > /proc/sys/vm/nr_hugepages +} + +setup_nr_hugepages() +{ + local needpgs=$1 + while read -r name size unit; do + if [ "$name" = "HugePages_Free:" ]; then + freepgs="$size" + break + fi + done < /proc/meminfo + if [ "$freepgs" -ge "$needpgs" ]; then + return + fi + local hpgs=$((orig_nr_hugepages + needpgs)) + echo $hpgs > /proc/sys/vm/nr_hugepages + + local nr_hugepgs=$(cat /proc/sys/vm/nr_hugepages) + if [ "$nr_hugepgs" != "$hpgs" ]; then + restore_nr_hugepages + skip "$0: no enough hugepages for testing" + fi +} + check_test_requirements +save_nr_hugepages +# 4 keep_mapped pages, and one for tmp usage +setup_nr_hugepages 5 ./va_high_addr_switch --run-hugetlb +restore_nr_hugepages -- 2.49.0 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH v2 3/3] selftests/mm: fix va_high_addr_switch.sh failure on x86_64 2025-09-08 12:47 ` [PATCH v2 2/3] selftests/mm: alloc hugepages in va_high_addr_switch test Chunyu Hu @ 2025-09-08 12:47 ` Chunyu Hu 2025-09-08 13:09 ` David Hildenbrand 0 siblings, 1 reply; 7+ messages in thread From: Chunyu Hu @ 2025-09-08 12:47 UTC (permalink / raw) To: akpm, david, shuah, linux-mm Cc: linux-kselftest, linux-kernel, lorenzo.stoakes, Liam.Howlett, vbabka, rppt, surenb, mhocko, chuhu 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, }, -- 2.49.0 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v2 3/3] selftests/mm: fix va_high_addr_switch.sh failure on x86_64 2025-09-08 12:47 ` [PATCH v2 3/3] selftests/mm: fix va_high_addr_switch.sh failure on x86_64 Chunyu Hu @ 2025-09-08 13:09 ` David Hildenbrand 2025-09-09 6:28 ` Chunyu Hu 0 siblings, 1 reply; 7+ messages in thread From: David Hildenbrand @ 2025-09-08 13:09 UTC (permalink / raw) To: Chunyu Hu, akpm, shuah, linux-mm Cc: linux-kselftest, linux-kernel, lorenzo.stoakes, Liam.Howlett, vbabka, rppt, surenb, mhocko On 08.09.25 14:47, Chunyu Hu wrote: > 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), Wouldn't it be more deterministic to do the alignment/rounding ourselves? (void *)(ALIGN_DOWN(addr_switch_hint - pagesize), hugepagesize) Unfortunately we don't have an ALIGN_DOWN helper available yet. We could just move the one in pkey-helpers.h into vm_util.h But now I realize that, likely, .addr = (void *)(addr_switch_hint - hugepagesize), would just work and be aligned? -- Cheers David / dhildenb ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2 3/3] selftests/mm: fix va_high_addr_switch.sh failure on x86_64 2025-09-08 13:09 ` David Hildenbrand @ 2025-09-09 6:28 ` Chunyu Hu 0 siblings, 0 replies; 7+ messages in thread From: Chunyu Hu @ 2025-09-09 6:28 UTC (permalink / raw) To: David Hildenbrand Cc: akpm, shuah, linux-mm, linux-kselftest, linux-kernel, lorenzo.stoakes, Liam.Howlett, vbabka, rppt, surenb, mhocko On Mon, Sep 08, 2025 at 03:09:24PM +0200, David Hildenbrand wrote: > On 08.09.25 14:47, Chunyu Hu wrote: > > 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), > > Wouldn't it be more deterministic to do the alignment/rounding ourselves? > > (void *)(ALIGN_DOWN(addr_switch_hint - pagesize), hugepagesize) > > Unfortunately we don't have an ALIGN_DOWN helper available yet. > > We could just move the one in pkey-helpers.h into vm_util.h Thanks for the review! This is good idea and it would be more deterministic if we provide an aligned address directly, then the kernel change won't affect the test. > > > But now I realize that, likely, > > .addr = (void *)(addr_switch_hint - hugepagesize), > > would just work and be aligned? Yes, it's aligned to the hugepagesize, align down and works. I prefer this way as it's easier and all other tests in the file do like this. Thanks for the suggestion. I thought we would lose some test coverage on testing if it will work when an un-hugepagesize aligned addr is provided. Do you think it's necessary? If not, I'll change to: .addr = (void *)(addr_switch_hint - hugepagesize), or we can add them both if necesasry. > > -- > Cheers > > David / dhildenb > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2 1/3] selftests/mm: fix hugepages cleanup too early 2025-09-08 12:47 ` [PATCH v2 1/3] selftests/mm: fix hugepages cleanup too early Chunyu Hu 2025-09-08 12:47 ` [PATCH v2 2/3] selftests/mm: alloc hugepages in va_high_addr_switch test Chunyu Hu @ 2025-09-08 12:53 ` David Hildenbrand 1 sibling, 0 replies; 7+ messages in thread From: David Hildenbrand @ 2025-09-08 12:53 UTC (permalink / raw) To: Chunyu Hu, akpm, shuah, linux-mm Cc: linux-kselftest, linux-kernel, lorenzo.stoakes, Liam.Howlett, vbabka, rppt, surenb, mhocko On 08.09.25 14:47, Chunyu Hu wrote: > The nr_hugepgs variable is used to keep the original nr_hugepages at the > hugepage setup step at test beginning. After userfaultfd test, a cleaup is > executed, both /sys/kernel/mm/hugepages/hugepages-*/nr_hugepages and > /proc/sys//vm/nr_hugepages are reset to 'original' value before userfaultfd > test starts. > > Issue here is the value used to restore /proc/sys/vm/nr_hugepages is > nr_hugepgs which is the initial value before the vm_runtests.sh runs, not > the value before userfaultfd test starts. 'va_high_addr_swith.sh' tests > runs after that will possibly see no hugepages available for test, and got > EINVAL when mmap(HUGETLB), making the result invalid. > > And before pkey tests, nr_hugepgs is changed to be used as a temp variable > to save nr_hugepages before pkey test, and restore it after pkey tests > finish. The original nr_hugepages value is not tracked anymore, so no way > to restore it after all tests finish. > > Add a new variable orig_nr_hugepgs to save the original nr_hugepages, and > and restore it to nr_hugepages after all tests finish. And change to use > the nr_hugepgs variable to save the /proc/sys/vm/nr_hugeages after hugepage > setup, it's also the value before userfaultfd test starts, and the correct > value to be restored after userfaultfd finishes. The va_high_addr_switch.sh > broken will be resolved. > > Signed-off-by: Chunyu Hu <chuhu@redhat.com> > Acked-by: David Hildenbrand <david@redhat.com> -- Cheers David / dhildenb ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2025-09-09 6:28 UTC | newest] Thread overview: 7+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2025-09-08 12:47 [PATCH v2 0/3] Fix va_high_addr_switch.sh test failure Chunyu Hu 2025-09-08 12:47 ` [PATCH v2 1/3] selftests/mm: fix hugepages cleanup too early Chunyu Hu 2025-09-08 12:47 ` [PATCH v2 2/3] selftests/mm: alloc hugepages in va_high_addr_switch test Chunyu Hu 2025-09-08 12:47 ` [PATCH v2 3/3] selftests/mm: fix va_high_addr_switch.sh failure on x86_64 Chunyu Hu 2025-09-08 13:09 ` David Hildenbrand 2025-09-09 6:28 ` Chunyu Hu 2025-09-08 12:53 ` [PATCH v2 1/3] selftests/mm: fix hugepages cleanup too early David Hildenbrand
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