On Thu, Feb 21, 2019 at 03:16:45AM +0000, Gonglei (Arei) wrote: > > > > > -----Original Message----- > > From: Zhao Yan [mailto:yan.y.zhao@xxxxxxxxx] > > Sent: Thursday, February 21, 2019 10:05 AM > > To: Gonglei (Arei) <arei.gonglei@xxxxxxxxxx> > > Cc: alex.williamson@xxxxxxxxxx; qemu-devel@xxxxxxxxxx; > > intel-gvt-dev@xxxxxxxxxxxxxxxxxxxxx; Zhengxiao.zx@xxxxxxxxxxxxxxx; > > yi.l.liu@xxxxxxxxx; eskultet@xxxxxxxxxx; ziye.yang@xxxxxxxxx; > > cohuck@xxxxxxxxxx; shuangtai.tst@xxxxxxxxxxxxxxx; dgilbert@xxxxxxxxxx; > > zhi.a.wang@xxxxxxxxx; mlevitsk@xxxxxxxxxx; pasic@xxxxxxxxxxxxx; > > aik@xxxxxxxxx; eauger@xxxxxxxxxx; felipe@xxxxxxxxxxx; > > jonathan.davies@xxxxxxxxxxx; changpeng.liu@xxxxxxxxx; Ken.Xue@xxxxxxx; > > kwankhede@xxxxxxxxxx; kevin.tian@xxxxxxxxx; cjia@xxxxxxxxxx; > > kvm@xxxxxxxxxxxxxxx > > 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
