On Fri, Dec 26, 2025 at 3:37 PM Michael S. Tsirkin <[email protected]> wrote: > > On Fri, Dec 26, 2025 at 09:31:26AM +0800, Jason Wang wrote: > > On Fri, Dec 26, 2025 at 12:27 AM Michael S. Tsirkin <[email protected]> wrote: > > > > > > On Thu, Dec 25, 2025 at 03:33:29PM +0800, Jason Wang wrote: > > > > On Wed, Dec 24, 2025 at 9:48 AM Michael S. Tsirkin <[email protected]> > > > > wrote: > > > > > > > > > > On Wed, Dec 24, 2025 at 09:37:14AM +0800, Xuan Zhuo wrote: > > > > > > > > > > > > Hi Jason, > > > > > > > > > > > > I'm wondering why we even need this refill work. Why not simply let > > > > > > NAPI retry > > > > > > the refill on its next run if the refill fails? That would seem > > > > > > much simpler. > > > > > > This refill work complicates maintenance and often introduces a lot > > > > > > of > > > > > > concurrency issues and races. > > > > > > > > > > > > Thanks. > > > > > > > > > > refill work can refill from GFP_KERNEL, napi only from ATOMIC. > > > > > > > > > > And if GFP_ATOMIC failed, aggressively retrying might not be a great > > > > > idea. > > > > > > > > Btw, I see some drivers are doing things as Xuan said. E.g > > > > mlx5e_napi_poll() did: > > > > > > > > busy |= INDIRECT_CALL_2(rq->post_wqes, > > > > mlx5e_post_rx_mpwqes, > > > > mlx5e_post_rx_wqes, > > > > > > > > ... > > > > > > > > if (busy) { > > > > if (likely(mlx5e_channel_no_affinity_change(c))) { > > > > work_done = budget; > > > > goto out; > > > > ... > > > > > > > > > is busy a GFP_ATOMIC allocation failure? > > > > Yes, and I think the logic here is to fallback to ksoftirqd if the > > allocation fails too much. > > > > Thanks > > > True. I just don't know if this works better or worse than the > current design, but it is certainly simpler and we never actually > worried about the performance of the current one. > > > So you know, let's roll with this approach. > > I do however ask that some testing is done on the patch forcing these OOM > situations just to see if we are missing something obvious. > > > the beauty is the patch can be very small: > 1. patch 1 do not schedule refill ever, just retrigger napi > 2. remove all the now dead code > > this way patch 1 will be small and backportable to stable.
I fully agree here. Thanks
