Re: [PATCH v2 3/5] selftests/mm: skip khugepaged swap tests without swap

[Sarthak Sharma <sarthak.sharma@arm.com>]

Hi Usama!

On 7/24/26 3:54 PM, Muhammad Usama Anjum wrote:
> collapse_swapin_single_pte and collapse_max_ptes_swap require
> MADV_PAGEOUT to replace anonymous pages with swap entries. On swapless
> systems there is no backing store with which to create those entries,
> so check_swap() reports missing setup rather than broken khugepaged
> behavior.
> 
> Swapless configurations are common on Android and other constrained
> test devices. Failing these cases obscures actionable results from the
> rest of the khugepaged suite.
> 
> Check /proc/swaps before either swap-dependent case and skip when no
> active swap area exists. With swap present, retain the existing
> MADV_PAGEOUT and swap-entry assertions unchanged.
> 
> Print each existing swapout diagnostic before the prerequisite check
> so skip() completes a KTAP diagnostic line instead of emitting an
> unprefixed message.
> 
> Signed-off-by: Muhammad Usama Anjum <usama.anjum@arm.com>
> ---
> Changes since v1:
> - Print swapout diagnostics before reporting no-swap skips.

Thank you for the changes. The test output is now KTAP formatted as:

# Run test: collapse_swapin_single_pte (khugepaged:anon)
# Swapout one page... No active swap
ok 16 # SKIP collapse_swapin_single_pte
#
# Run test: collapse_swapin_single_pte (madvise:anon)
# Swapout one page... No active swap
ok 17 # SKIP collapse_swapin_single_pte
#
# Run test: collapse_max_ptes_swap (khugepaged:anon)
# Swapout 65 of 512 pages... No active swap
ok 18 # SKIP collapse_max_ptes_swap
#
# Run test: collapse_max_ptes_swap (madvise:anon)
# Swapout 65 of 512 pages... No active swap
ok 19 # SKIP collapse_max_ptes_swap

Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>