Hi Michael, > -----Original Message----- > From: Zhoujian (jay) > Sent: Friday, December 15, 2017 12:52 PM > To: 'Michael S. Tsirkin' <m...@redhat.com> > Cc: Dr. David Alan Gilbert <dgilb...@redhat.com>; qemu-devel@nongnu.org; > Huangweidong (C) <weidong.hu...@huawei.com>; Gonglei (Arei) > <arei.gong...@huawei.com>; wangxin (U) <wangxinxin.w...@huawei.com>; > Liuzhe (Cloud Open Labs, NFV) <gary.liu...@huawei.com>; Igor Mammedov > <imamm...@redhat.com> > Subject: RE: [PATCH 0/2] vhost: two fixes > > Hi Michael, > > > -----Original Message----- > > From: Michael S. Tsirkin [mailto:m...@redhat.com] > > Sent: Friday, December 15, 2017 12:36 PM > > To: Zhoujian (jay) <jianjay.z...@huawei.com> > > Cc: Dr. David Alan Gilbert <dgilb...@redhat.com>; > > qemu-devel@nongnu.org; Huangweidong (C) <weidong.hu...@huawei.com>; > > Gonglei (Arei) <arei.gong...@huawei.com>; wangxin (U) > > <wangxinxin.w...@huawei.com>; Liuzhe (Cloud Open Labs, NFV) > > <gary.liu...@huawei.com>; Igor Mammedov <imamm...@redhat.com> > > Subject: Re: [PATCH 0/2] vhost: two fixes > > > > On Fri, Dec 15, 2017 at 02:38:35AM +0000, Zhoujian (jay) wrote: > > > Hi Dave, > > > > > > > -----Original Message----- > > > > From: Dr. David Alan Gilbert [mailto:dgilb...@redhat.com] > > > > Sent: Friday, December 15, 2017 3:49 AM > > > > To: Michael S. Tsirkin <m...@redhat.com> > > > > Cc: Zhoujian (jay) <jianjay.z...@huawei.com>; > > > > qemu-devel@nongnu.org; Huangweidong (C) > > > > <weidong.hu...@huawei.com>; Gonglei (Arei) > > > > <arei.gong...@huawei.com>; wangxin (U) > > > > <wangxinxin.w...@huawei.com>; Liuzhe (Cloud Open Labs, NFV) > > > > <gary.liu...@huawei.com>; Igor Mammedov <imamm...@redhat.com> > > > > Subject: Re: [PATCH 0/2] vhost: two fixes > > > > > > > > * Michael S. Tsirkin (m...@redhat.com) wrote: > > > > > On Fri, Dec 15, 2017 at 12:36:30AM +0800, Jay Zhou wrote: > > > > > > Jay Zhou (2): > > > > > > vhost: add used memslot number for vhost-user > > > > > > vhost: double check memslot number > > > > > > > > > > > > hw/virtio/vhost-user.c | 31 > +++++++++++++++++++++++++ > > > > > > hw/virtio/vhost.c | 49 > > > > ++++++++++++++++++++++++++++++++++----- > > > > > > include/hw/virtio/vhost-backend.h | 4 ++++ > > > > > > 3 files changed, 78 insertions(+), 6 deletions(-) > > > > > > > > > > Cc two developers working on these files right now. > > > > > > > > I have to admit to not understanding the 'used_memslots' variable. > > > > > > > > * It's a global in vhost.c > > > > * but set by vhost_set_memory that's called from the listener > > associated > > > > with each individual vhost > > > > * While they're probably always the same, the merging code calls > > > > the vhost_backend_can_merge method for each device, so the number > > > > of regions can be different. > > > > > > > > > > Your mean for some devices the new added MemoryRegionSection can be > > > merged, but for others it can not be merged? IIUC the vhost_mem for > > > each vhost_dev is the same. > > > > > > Meanwhile, I think it is more reasonable to add globals in > > > vhost-backend.c and vhost-user.c respectively instead of > > > 'used_memslots'. The reason is explained in patch 1. What do you think? > > > > > > Regards, > > > Jay > > > > I'd rather avoid globals completely if possible. > > > > It is possible, we could add a 'used_memslots' variable in struct > vhost_dev for per device. I will try to do it in v2. >
If the globals don't exist, the disadvantage I found is that the check "if memslots number exceeds" will be moved from the beginning to the end in vhost_dev_init, does it acceptable? Or are there other ideas to avoid globals? To be honest, I prefer to add globals in vhost-backend.c and vhost-user.c respectively, the value of used_memslots for the same type of backend is the same. Regards, Jay
