On Wed, Dec 15, 2021 at 10:06:29AM +0800, Shiyang Ruan wrote: > > > 在 2021/12/14 23:40, Christoph Hellwig 写道: > > On Thu, Dec 02, 2021 at 04:48:48PM +0800, Shiyang Ruan wrote: > > > In order to introduce dax holder registration, we need a write lock for > > > dax. Change the current lock to percpu_rw_semaphore and introduce a > > > write lock for registration. > > > > Why do we need to change the existing, global locking for that? > > I think we have talked about this in the previous v7 patchset: > > > https://lore.kernel.org/nvdimm/20210924130959.2695749-1-ruansy.fnst@xxxxxxxxxxx/T/#m4031bc3dc49dcbaac6f8d99877f910fa9a6f998a Any kind of rationale needs to go into the patch description. > I didn't test in benchmarks for now. Could you show me which one I should > test this code on? I am not familiar with this... Just normal read/write I/O on a DAX device.