On Fri, 11 Jul 2014 17:47:05 +0200 Boris BREZILLON <boris.brezillon@xxxxxxxxxxxxxxxxxx> wrote: > On Fri, 11 Jul 2014 11:41:12 -0400 > Rob Clark <robdclark@xxxxxxxxx> wrote: > > > On Fri, Jul 11, 2014 at 11:17 AM, Boris BREZILLON > > <boris.brezillon@xxxxxxxxxxxxxxxxxx> wrote: > > > Make use of lists instead of kfifo in order to dynamically allocate > > > task entry when someone require some delayed work, and thus preventing > > > drm_flip_work_queue from directly calling func instead of queuing this > > > call. > > > This allow drm_flip_work_queue to be safely called even within irq > > > handlers. > > > > > > Add new helper functions to allocate a flip work task and queue it when > > > needed. This prevents allocating data within irq context (which might > > > impact the time spent in the irq handler). > > > > > > Signed-off-by: Boris BREZILLON <boris.brezillon@xxxxxxxxxxxxxxxxxx> > > > --- > > > Hi Rob, > > > > > > This is a proposal for what you suggested (dynamically growing the drm > > > flip work queue in order to avoid direct call of work->func when calling > > > drm_flip_work_queue). > > > > > > I'm not sure this is exactly what you expected, because I'm now using > > > lists instead of kfifo (and thus lose the lockless part), but at least > > > we can now safely call drm_flip_work_queue or drm_flip_work_queue_task > > > from irq handlers :-). > > > > > > You were also worried about queueing the same framebuffer multiple times > > > and with this implementation you shouldn't have any problem (at least with > > > drm_flip_work_queue, what people do with drm_flip_work_queue_task is their > > > own responsability, but they should allocate one task for each operation > > > even if they are manipulating the same framebuffer). > > > > yeah, if we are dynamically allocating the list nodes, that solves the > > queuing-up-multiple-times issue.. > > > > I wonder if drm_flip_work_allocate_task() should use GPF_ATOMIC when > > allocating? > > That's funny, I was actually modifying the API to pass gfp_t flags to > this function ;-) > > > I guess maybe it is possible to pre-allocate the task > > from non-irq context, and then queue it from irq context.. it makes > > the API a bit more complex, but there are only a couple users > > currently, so I suppose this should be doable. > > I tried to keep the existing API so that existing users won't see the > difference (I guess none of them are calling drm_flip_work_queue). Some words are missing :-): (I guess none of them are calling drm_flip_work_queue from irq handlers). > > I just added the drm_flip_work_allocate_task and > drm_flip_work_queue_task for those who want more control on the > queuing process. > > Best Regards, > > Boris > > > > > -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
