On 10 Mar 2026, at 5:49, Sayali Patil wrote:
> The hugepage-mremap selftest uses a default size of 10MB, which is
> sufficient for small huge page sizes. However, when the huge page size
> is large (e.g. 1GB), 10MB is smaller than a single huge page.
> As a result, the test does not trigger PMD sharing and the
> corresponding unshare path in mremap(), causing the
> test to fail (mremap succeeds where a failure is expected).
>
> Update run_vmtest.sh to use twice the huge page size when the huge page
> size exceeds 10MB, while retaining the 10MB default for smaller huge
> pages. This ensures the test exercises the intended PMD sharing and
> unsharing paths for larger huge page sizes.
>
> Before patch:
> running ./hugepage-mremap
> ------------------------------
> TAP version 13
> 1..1
> Map haddr: Returned address is 0x7eaa40000000
> Map daddr: Returned address is 0x7daa40000000
> Map vaddr: Returned address is 0x7faa40000000
> Address returned by mmap() = 0x7fffaa600000
> Mremap: Returned address is 0x7faa40000000
> First hex is 0
> First hex is 3020100
> Bail out! mremap: Expected failure, but call succeeded
> Planned tests != run tests (1 != 0)
> Totals: pass:0 fail:0 xfail:0 xpass:0 skip:0 error:0
> [FAIL]
> not ok 1 hugepage-mremap # exit=1
>
> Before patch:
> running ./hugepage-mremap
> ------------------------------
> TAP version 13
> 1..1
> Map haddr: Returned address is 0x7eaa40000000
> Map daddr: Returned address is 0x7daa40000000
> Map vaddr: Returned address is 0x7faa40000000
> Address returned by mmap() = 0x7fffaa600000
> Mremap: Returned address is 0x7faa40000000
> First hex is 0
> First hex is 3020100
> Bail out! mremap: Expected failure, but call succeeded
> Planned tests != run tests (1 != 0)
> Totals: pass:0 fail:0 xfail:0 xpass:0 skip:0 error:0
> [FAIL]
> not ok 1 hugepage-mremap # exit=1
>
> After patch:
> running ./hugepage-mremap 2048
> ------------------------------
> TAP version 13
> 1..1
> Map haddr: Returned address is 0x7eaa40000000
> Map daddr: Returned address is 0x7daa40000000
> Map vaddr: Returned address is 0x7faa40000000
> Address returned by mmap() = 0x7fff13000000
> Mremap: Returned address is 0x7faa40000000
> First hex is 0
> First hex is 3020100
> ok 1 Read same data
> Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0
> [PASS]
> ok 1 hugepage-mremap 2048
>
> Fixes: f77a286de48c ("mm, hugepages: make memory size variable in
> hugepage-mremap selftest")
> Signed-off-by: Sayali Patil <[email protected]>
> ---
> tools/testing/selftests/mm/run_vmtests.sh | 13 ++++++++++++-
> 1 file changed, 12 insertions(+), 1 deletion(-)
>
Makes sense.
Acked-by: Zi Yan <[email protected]>
Best Regards,
Yan, Zi
