Re: [PATCH 06/13] selftest/mm: adjust hugepage-mremap test size for large huge pages

[Zi Yan <ziy@nvidia.com>]

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 <sayalip@linux.ibm.com>
> ---
>  tools/testing/selftests/mm/run_vmtests.sh | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
>

Makes sense.

Acked-by: Zi Yan <ziy@nvidia.com>

Best Regards,
Yan, Zi