On 15/07/2023 01:04, John Hubbard wrote:
On 7/13/23 06:54, Ryan Roberts wrote:
arm64 does not support the soft-dirty PTE bit. However there are tests in `madv_populate` and `soft-dirty` which assume it is supported and cause spurious failures to be reported when preferred behaviour would be to mark the tests as skipped.
Unfortunately, the only way to determine if the soft-dirty dirty bit is supported is to write to a page, then see if the bit is set in /proc/self/pagemap. But the tests that we want to conditionally execute are testing precicesly this. So if we introduced this feature check, we could accedentally turn a real failure (on a system that claims to support soft-dirty) into a skip.
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diff --git a/tools/testing/selftests/mm/soft-dirty.c b/tools/testing/selftests/mm/soft-dirty.c index cc5f144430d4..8a2cd161ec4d 100644 --- a/tools/testing/selftests/mm/soft-dirty.c +++ b/tools/testing/selftests/mm/soft-dirty.c
Hi Ryan,
Probably very similar to what David is requesting: given that arm64 definitively does not support soft dirty, I'd suggest that we not even *build* the soft dirty tests on arm64!
There is no need to worry about counting, skipping or waiving such tests, either. Because it's just a non-issue: one does not care about test status for something that is documented as "this feature is simply unavailable here".
OK fair enough. I'll follow this approach for v2.
Thanks for the review!
thanks,