On Wed, Feb 22, 2012 at 12:46:28PM +0100, Gerd Hoffmann wrote: > On 02/21/12 22:39, Alon Levy wrote: > > This changes the behavior of the monitor command. After the previous > > patch, there is no longer an option of deadlock with virt-manager, but > > ppm_save is called too early, before the update has completed. With this > > patch it is called at the correct moment, but that means there is a race > > between the monitor command completing and the screendump file being saved. > > > > The only solution is to use an asynchronous monitor command. For a > > previous round of this see: > > http://lists.gnu.org/archive/html/qemu-devel/2011-10/msg02810.html > > > > Since that's contentious, I'm suggesting we do something that is almost > > correct and doesn't hang, instead of correct and hangs. The screendump > > user can inotify on the directory and the file if need be. For casual > > monitor usage there is no difference. > > I still think we should defer that and figure how to fix that properly, > either using (internally) async monitor commands via qapi, or using an > event. > > > +typedef struct QXLPPMSaveBHData { > > + PCIQXLDevice *qxl; > > + QXLCookie *cookie; > > +} QXLPPMSaveBHData; > > Is there a need for a separate struct? I think you can just stick the > filename into the QXLCookie struct, then write out screen shots in the > update area bottom half, no?
You don't get the cookie in the update_area bottom half. It's solemnly for update_area_complete. It's not easy to associate a cookie with it, since it may be called by the server without previous provocation from qemu. I'll take another look. > > cheers, > Gerd > >