On Sun, Feb 10, 2019 at 05:39:20PM +0100, Thomas Gleixner wrote: > On Fri, 25 Jan 2019, Ming Lei wrote: > > > Use the callback of .setup_affinity() to re-caculate number > > of queues, and build irqs affinity with help of irq_build_affinity(). > > > > Then nvme_setup_irqs() gets simplified a lot. > > I'm pretty sure you can achieve the same by reworking the core code without > that callback.
Could you share the idea a bit? As I mentioned, the re-distribution needs driver's knowledge. > > > + /* Fill out vectors at the beginning that don't need affinity */ > > + for (curvec = 0; curvec < affd->pre_vectors; curvec++) > > + cpumask_copy(&masks[curvec].mask, cpu_possible_mask); > > cpu_possible_mask is wrong. Why are you deliberately trying to make this > special? There is absolutely no reason to do so. It is just for avoiding to export 'irq_default_affinity'. > > These interrupts are not managed and therefore the initial affinity has to > be irq_default_affinity. Setting them to cpu_possible_mask can and probably > will evade a well thought out default affinity mask, which was set to > isolate a set of cores from general purpose interrupts. > > This is exactly the thing which happens with driver special stuff and which > needs to be avoided. There is nothing special about this NVME setup and > yes, I can see why the current core code is a bit tedious to work with, but > that does not justify that extra driver magic by any means. OK, thanks for your explanation. Thanks, Ming
