Ah, sorry. I looked at it without the context. Thanks. --
Best regards, Nikita Kalyazin, n.kalyazin at samsung.com Software Engineer CE OS Group Samsung R&D Institute Russia Tel: +7 (495) 797-25-00 #3816 Tel: +7 (495) 797-25-03 Office #1501, 12-1, Dvintsev str., Moscow, 127018, Russia On Fri, May 15, 2015 at 05:23:35PM +0200, Michael S. Tsirkin wrote: > On Fri, May 15, 2015 at 04:43:33PM +0300, Nikita Kalyazin wrote: > > Hi, > > > > > > Maybe I missed a part of the discussion, but is there any special purpose > > for using rte_mb (both read and write fence) here rather than rte_wmb > > (write fence only)? > > The fence is between write of used->idx and read of avail->flags, so > rte_wmb won't do anything useful. > > > -- > > > > Best regards, > > > > Nikita Kalyazin, > > n.kalyazin at samsung.com > > > > Software Engineer > > CE OS Group > > Samsung R&D Institute Russia > > Tel: +7 (495) 797-25-00 #3816 > > Tel: +7 (495) 797-25-03 > > Office #1501, 12-1, Dvintsev str., > > Moscow, 127018, Russia > > > > On Wed, May 13, 2015 at 12:46:30PM +0200, Thomas Monjalon wrote: > > > 2015-04-29 19:11, Huawei Xie: > > > > update of used->idx and read of avail->flags could be reordered. > > > > memory fence should be used to ensure the order, otherwise guest could > > > > see a stale used->idx value after it toggles the interrupt suppression > > > > flag. > > > > After guest sets the interrupt suppression flag, it will check if there > > > > is more buffer to process through used->idx. If it sees a stale value, > > > > it will exit the processing while host willn't send interrupt to guest. > > > > > > > > Signed-off-by: Huawei Xie <huawei.xie at intel.com> > > > > > > Applied with following title, thanks > > > vhost: fix virtio freeze due to missed interrupt > > >
