On Wed, 16 Sep 2020, Dan Williams wrote: > On Wed, Sep 16, 2020 at 3:57 AM Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote: > > > > > > > > I'm submitting this patch that adds the required exports (so that we could > > use __copy_from_user_flushcache on x86, arm64 and powerpc). Please, queue > > it for the next merge window. > > Why? This should go with the first user, and it's not clear that it > needs to be relative to the current dax_operations export scheme. Before nvfs gets included in the kernel, I need to distribute it as a module. So, it would make my maintenance easier. But if you don't want to export it now, no problem, I can just copy __copy_user_flushcache from the kernel to the module. > My first question about nvfs is how it compares to a daxfs with > executables and other binaries configured to use page cache with the > new per-file dax facility? nvfs is faster than dax-based filesystems on metadata-heavy operations because it doesn't have the overhead of the buffer cache and bios. See this: http://people.redhat.com/~mpatocka/nvfs/BENCHMARKS Mikulas
