On Thu, Feb 21, 2019 at 03:16:45AM +0000, Gonglei (Arei) wrote: > > > > > -----Original Message----- > > From: Zhao Yan [mailto:yan.y.z...@intel.com] > > Sent: Thursday, February 21, 2019 10:05 AM > > To: Gonglei (Arei) <arei.gong...@huawei.com> > > Cc: alex.william...@redhat.com; qemu-devel@nongnu.org; > > intel-gvt-...@lists.freedesktop.org; zhengxiao...@alibaba-inc.com; > > yi.l....@intel.com; eskul...@redhat.com; ziye.y...@intel.com; > > coh...@redhat.com; shuangtai....@alibaba-inc.com; dgilb...@redhat.com; > > zhi.a.w...@intel.com; mlevi...@redhat.com; pa...@linux.ibm.com; > > a...@ozlabs.ru; eau...@redhat.com; fel...@nutanix.com; > > jonathan.dav...@nutanix.com; changpeng....@intel.com; ken....@amd.com; > > kwankh...@nvidia.com; kevin.t...@intel.com; c...@nvidia.com; > > k...@vger.kernel.org > > Subject: Re: [PATCH 0/5] QEMU VFIO live migration > > > > > > > > > > > 5) About log sync, why not register log_global_start/stop in > > > > vfio_memory_listener? > > > > > > > > > > > > > > seems log_global_start/stop cannot be iterately called in pre-copy > > > > phase? > > > > for dirty pages in system memory, it's better to transfer dirty data > > > > iteratively to reduce down time, right? > > > > > > > > > > We just need invoking only once for start and stop logging. Why we need to > > call > > > them literately? See memory_listener of vhost. > > > > > the dirty pages in system memory produces by device is incremental. > > if it can be got iteratively, the dirty pages in stop-and-copy phase can be > > minimal. > > :) > > > I mean starting or stopping the capability of logging, not log sync. > > We register the below callbacks: > > .log_sync = vfio_log_sync, > .log_global_start = vfio_log_global_start, > .log_global_stop = vfio_log_global_stop, > .log_global_start is also a good point to notify logging state. But if notifying in .save_setup handler, we can do fine-grained control of when to notify of logging starting together with get_buffer operation. Is there any special benifit by registering to .log_global_start/stop?
> Regards, > -Gonglei
