On 7/26/26 13:56, Mike Rapoport wrote: > Hi Rik, > > On Fri, Jul 24, 2026 at 06:29:34PM -0400, Rik van Riel wrote: >> follow_page_mask() now batches a PTE-mapped large folio (mTHP) into one >> contiguous run for the slow get_user_pages() path. A mis-batched run would >> hand back the wrong pages or a stale COW copy, which the existing tests do >> not catch: gup_test checks only pin/unpin integrity, and cow exercises COW >> mostly at PMD size. >> >> Add mthp_gup_cow_test. It forces 64kB-only mTHP, writes a per-page-distinct >> pattern, then pins the region on the slow path (PIN_LONGTERM without >> USE_FAST) and compares the bytes the kernel copies back from the pinned >> pages against that pattern. >> >> The test covers a read pin, a write pin, and COW after fork(): a child >> write-pins to force per-page unshare and checks the copied contents, then >> rewrites its copy while the parent verifies its own contents are intact. >> >> It also reports how many pages sit in contiguous large-folio runs, so a >> kernel without mTHP shows light coverage rather than passing vacuously. >> >> Assisted-by: Claude:claude-opus-4.8 >> Signed-off-by: Rik van Riel <[email protected]> >> --- >> tools/testing/selftests/mm/Makefile | 1 + >> .../testing/selftests/mm/mthp_gup_cow_test.c | 213 ++++++++++++++++++ >> tools/testing/selftests/mm/run_vmtests.sh | 1 + >> 3 files changed, 215 insertions(+) >> create mode 100644 tools/testing/selftests/mm/mthp_gup_cow_test.c >> >> + >> +static long PS; >> +static int fails; >> +static int tap; >> + >> +static void ok(int cond, const char *desc) >> +{ >> + printf("%s %d %s\n", cond ? "ok" : "not ok", ++tap, desc); > > Please (instruct claude to) use ksft_* helpers for printing messages and > tracking failed and passed tests.
I'm afraid we won't have time to keep repeating the following: Documentation/process/coding-assistants.rst * Reviewing all AI-generated code [...] * Taking full responsibility for the contribution -- Cheers, David
