From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [PATCH v4 00/10] hugetlbfs: add fallocate support Date: Wed, 22 Jul 2015 15:30:23 -0700 Message-ID: <20150722153023.e8f15eb4e490f79cc029c8cd@linux-foundation.org> References: <1437502184-14269-1-git-send-email-mike.kravetz@oracle.com> <20150722150647.2597c7e5be9ee1eecc438b6f@linux-foundation.org> <1437603594.3298.5.camel@stgolabs.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1437603594.3298.5.camel-h16yJtLeMjHk1uMJSBkQmQ@public.gmane.org> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Davidlohr Bueso Cc: Mike Kravetz , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Dave Hansen , Naoya Horiguchi , David Rientjes , Hugh Dickins , Aneesh Kumar , Hillf Danton , Christoph Hellwig , Michal Hocko List-Id: linux-api@vger.kernel.org On Wed, 22 Jul 2015 15:19:54 -0700 Davidlohr Bueso wrote: > > > > I didn't know that libhugetlbfs has tests. I wonder if that makes > > tools/testing/selftests/vm's hugetlbfstest harmful? > > Why harmful? Redundant, maybe(?). The presence of the in-kernel tests will cause people to add stuff to them when it would be better if they were to apply that effort to making libhugetlbfs better. Or vice versa. Mike's work is an example. Someone later makes a change to hugetlbfs, runs the kernel selftest and says "yay, everything works", unaware that they just broke fallocate support. > Does anyone even use selftests for > hugetlbfs regression testing? Lets see, we also have these: > > - hugepage-{mmap,shm}.c > - map_hugetlb.c > > There's probably a lot of room for improvement here. selftests is a pretty scrappy place. It's partly a dumping ground for things so useful test code doesn't just get lost and bitrotted. Partly a framework so people who add features can easily test them. Partly to provide tools to architecture maintainers when they wire up new syscalls and the like. Unless there's some good reason to retain the hugetlb part of selftests, I'm thinking we should just remove it to avoid distracting/misleading people. Or possibly move the libhugetlbfs test code into the kernel tree and maintain it there.