On Wed, 25 Sep 2024 21:42:06 +0200 Wojciech Panfil <wojciech.pan...@intel.com> wrote:
> Issue: > Two threads: > > - A, executing rte_eal_alarm_cancel, > - B, executing eal_alarm_callback. > > Such case can cause starvation of thread B. Please see that there is a > small time window between lock and unlock in thread A, so thread B must > be switched to within a very small time window, so that it can obtain > the lock. > > Solution to this problem is use sched_yield(), which puts current thread > (A) at the end of thread execution priority queue and allows thread B to > execute. > > The issue can be observed e.g. on hot-pluggable device detach path. > On such path, rte_alarm can used to check if DPDK has completed > the detachment. Waiting for completion, rte_eal_alarm_cancel > is called, while another thread periodically calls eal_alarm_callback > causing the issue to occur. > > Signed-off-by: Wojciech Panfil <wojciech.pan...@intel.com> It would be good to get test for this in the DPDK functional test. See: https://patchwork.dpdk.org/project/dpdk/patch/20240809152540.9568-4-step...@networkplumber.org/ Reviewed-by: Stephen Hemminger <step...@networkplumber.org>
