> -----Original Message----- > From: Vitaly Kuznetsov [mailto:vkuznets@xxxxxxxxxx] > Sent: Monday, January 26, 2015 2:39 AM > To: Greg Kroah-Hartman > Cc: KY Srinivasan; devel@xxxxxxxxxxxxxxxxxxxxxx; Haiyang Zhang; linux- > kernel@xxxxxxxxxxxxxxx; Dexuan Cui > Subject: Re: [PATCH v3] Drivers: hv: vmbus: prevent cpu offlining on newer > hypervisors > > Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> writes: > > > On Mon, Jan 12, 2015 at 05:50:11PM +0100, Vitaly Kuznetsov wrote: > >> When an SMP Hyper-V guest is running on top of 2012R2 Server and > >> secondary cpus are sent offline (with echo 0 > > >> /sys/devices/system/cpu/cpu$cpu/online) > >> the system freeze is observed. This happens due to the fact that on > >> newer hypervisors (Win8, WS2012R2, ...) vmbus channel handlers are > >> distributed across all cpus (see init_vp_index() function in > >> drivers/hv/channel_mgmt.c) and on cpu offlining nobody reassigns them > >> to CPU0. Prevent cpu offlining when vmbus is loaded until the issue is > fixed host-side. > >> > >> This patch also disables hibernation but it is OK as it is also > >> broken (MCE error is hit on resume). Suspend still works. > >> > >> Tested with WS2008R2 and WS2012R2. > >> > >> Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> > >> Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> > >> --- > >> Changes since v2: > >> - repair the build when vmbus is builded as a module [Greg KH] by saving > >> current cpu_disable pointer to previous_cpu_disable and restoring it on > >> unload; > >> - return -ENOSYS (same as native_cpu_disable when > !CONFIG_HOTPLUG_CPU) instead > >> of -1 in hyperv_cpu_disable(). > >> > >> Changes since v1: > >> - introduce hv_cpu_hotplug_quirk() function to not spread #ifdefs > >> [Greg KH]; > >> - add pr_notice() message "hv_vmbus: CPU offlining is not supported by > >> hypervisor". > >> --- > >> drivers/hv/vmbus_drv.c | 36 > ++++++++++++++++++++++++++++++++++++ > >> 1 file changed, 36 insertions(+) > > > > Doesn't apply to my char-misc-test branch at all :( > > Another mid-air collision with K.Y's "Drivers: hv: vmbus: Implement a > clockevent device", please use the attached version. No functional changes > are required, I just fixed the merge conflict (includes). > > Othere than that (and sorry for meddling), would it it be better if you switch > to 'pull requests' workflow with K.Y? There is a lot of ongoing work in hyperv > nowdays and such collisions seem otherwise inevitable ... I will co-ordinate and forward Hyper-V patches to Greg. K. Y > > -- > Vitaly _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
