Shuah Khan skhan@linuxfoundation.org writes:
On 2/28/22 2:37 AM, David Hildenbrand wrote:
On 24.02.22 22:23, Muhammad Usama Anjum wrote:
This introduces three tests:
- Sanity check soft dirty basic semantics: allocate area, clean, dirty,
check if the SD bit flipped. 2) Check VMA reuse: validate the VM_SOFTDIRTY usage 3) Check soft-dirty on huge pages
This was motivated by Will Deacon's fix commit 912efa17e512 ("mm: proc: Invalidate TLB after clearing soft-dirty page state"). I was tracking the same issue that he fixed, and this test would have caught it.
A note that madv_populate.c already contains some SOFTDIRTY tests regarding MADV_POPULATE. Eventually we want to factor out softdirty/pagemap handling+checks for easier reuse.
Is this patch unnecessary then?
It is not unnecessary since the madv test doesn't cover the bug tested here, afaik. But, as mentioned when I originally submitted this patch, it should be merged into selftests/vm/madv_populate.c or, at least, reuse that existing infrastructure.
https://lore.kernel.org/lkml/87lf553z5g.fsf@collabora.com/