>On Fri, Mar 19, 2021 at 04:00:36PM +0800, Wang Qing wrote: >> When touch_softlockup_watchdog() is called, only wq_watchdog_touched_cpu >> updated, while the unbound worker_pool running on its core uses >> wq_watchdog_touched to determine whether locked up. This may be mischecked. > >Can you please elaborate here, preferably with a concrete scenario where the >new code is better?
The previous code is problematic for judging whether the unbound pool is locked up: When the expected single cpu stall occurs, only wq_watchdog_touched_cpu is updated, However, the unbound pool uses wq_watchdog_touched to determine whether it is locked up, so when the unbound pool is running in a scenario where the cpu stall is expected, a misjudgment will occur, because wq_watchdog_touched only be update when all the cpu stall as expect. So we need to update wq_watchdog_touched in touch_softlockup_watchdog(), and it is only used for unbound pool, it will not affect the bound pool in any way. Thanks, Qing > >Thanks. > >-- >tejun
