On 4/8/22 7:25 PM, Vivek Goyal wrote: > On Fri, Apr 08, 2022 at 10:36:40AM +0800, JeffleXu wrote: >> >> >> On 4/7/22 10:10 PM, Vivek Goyal wrote: >>> On Sat, Apr 02, 2022 at 06:32:50PM +0800, Jeffle Xu wrote: >>>> Move dmap free worker kicker inside the critical region, so that extra >>>> spinlock lock/unlock could be avoided. >>>> >>>> Suggested-by: Liu Jiang <gerry@xxxxxxxxxxxxxxxxx> >>>> Signed-off-by: Jeffle Xu <jefflexu@xxxxxxxxxxxxxxxxx> >>> >>> Looks good to me. Have you done any testing to make sure nothing is >>> broken. >> >> xfstests -g quick shows no regression. The tested virtiofs is mounted >> with "dax=always". > > I think xfstests might not trigger reclaim. You probably will have to > run something like blogbench with a small dax window like 1G so that > heavy reclaim happens. Actually, I configured the DAX window to 8MB, i.e. 4 slots when running xfstests. Thus I think the reclaim path is most likely triggered. > > For fun, I sometimes used to run it with a window of just say 16 dax > ranges so that reclaim was so heavy that if there was a bug, it will > show up. > Yeah, my colleague had ever reported that a DAX window of 4KB will cause hang in our internal OS (which is 4.19, we back ported virtiofs to 4.19). But then I found that this issue doesn't exist in the latest upstream. The reason seems that in the upstream kernel, devm_memremap_pages() called in virtio_fs_setup_dax() will fail directly since the dax window (4KB) is not aligned with the sparse memory section. -- Thanks, Jeffle
