On Fri, 5 Jan 2024 07:54:19 -0800 Breno Leitao <leitao@xxxxxxxxxx> wrote: > This test stresses the race between of madvise(DONTNEED), a page fault > and a parallel huge page mmap, which should fail due to lack of > available page available for mapping. > > This test case must run on a system with one and only one huge page > available. > > # echo 1 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages Can't the test framework perform this configuration prior to running the test? > During setup, the test allocates the only available page, and starts > three threads: > > - thread 1: > * madvise(MADV_DONTNEED) on the allocated huge page > - thread 2: > * Write to the allocated huge page > - thread 3: > * Tries to allocated (steal) an extra huge page (which is not > available) > > thread 3 should never succeed in the allocation, since the only huge > page was never unmapped, and should be reserved. > > Touching the old page after thread3 allocation will raise a SIGBUS. > It's a bit strange to merge a selftest which is expected to fail because of a known but unfixed kernel bug. But I'll toss the test in there anyway, as we deserve to get bug reports ;)
