On Fri, May 24, 2019 at 04:12:12AM -0400, Jason Wang wrote: > Hi: > > This series tries to access virtqueue metadata through kernel virtual > address instead of copy_user() friends since they had too much > overheads like checks, spec barriers or even hardware feature > toggling like SMAP. This is done through setup kernel address through > direct mapping and co-opreate VM management with MMU notifiers. > > Test shows about 23% improvement on TX PPS. TCP_STREAM doesn't see > obvious improvement. > > Thanks Thanks this is queued for next. Did you want to rebase and repost packed ring support on top? IIUC it's on par with split ring with these patches. > Changes from RFC V3: > - rebase to net-next > - Tweak on the comments > Changes from RFC V2: > - switch to use direct mapping instead of vmap() > - switch to use spinlock + RCU to synchronize MMU notifier and vhost > data/control path > - set dirty pages in the invalidation callbacks > - always use copy_to/from_users() friends for the archs that may need > flush_dcache_pages() > - various minor fixes > Changes from V4: > - use invalidate_range() instead of invalidate_range_start() > - track dirty pages > Changes from V3: > - don't try to use vmap for file backed pages > - rebase to master > Changes from V2: > - fix buggy range overlapping check > - tear down MMU notifier during vhost ioctl to make sure > invalidation request can read metadata userspace address and vq size > without holding vq mutex. > Changes from V1: > - instead of pinning pages, use MMU notifier to invalidate vmaps > and remap duing metadata prefetch > - fix build warning on MIPS > > Jason Wang (6): > vhost: generalize adding used elem > vhost: fine grain userspace memory accessors > vhost: rename vq_iotlb_prefetch() to vq_meta_prefetch() > vhost: introduce helpers to get the size of metadata area > vhost: factor out setting vring addr and num > vhost: access vq metadata through kernel virtual address > > drivers/vhost/net.c | 4 +- > drivers/vhost/vhost.c | 850 ++++++++++++++++++++++++++++++++++++------ > drivers/vhost/vhost.h | 38 +- > 3 files changed, 766 insertions(+), 126 deletions(-) > > -- > 2.18.1
