Le Wed, Apr 03, 2024 at 04:22:12PM +0530, Neeraj Upadhyay a écrit : > When all wait heads are in use, which can happen when > rcu_sr_normal_gp_cleanup_work()'s callback processing > is slow, any new synchronize_rcu() user's rcu_synchronize > node's processing is deferred to future GP periods. This > can result in long list of synchronize_rcu() invocations > waiting for full grace period processing, which can delay > freeing of memory. Mitigate this problem by using first > node in the list as wait tail when all wait heads are in use. > While methods to speed up callback processing would be needed > to recover from this situation, allowing new nodes to complete > their grace period can help prevent delays due to a fixed > number of wait head nodes. > > Signed-off-by: Neeraj Upadhyay <Neeraj.Upadhyay@xxxxxxx> Looking at it again, I'm not sure if it's a good idea to optimize the thing that far. It's already a tricky state machine to review and the workqueue has SR_NORMAL_GP_WAIT_HEAD_MAX - 1 = 4 grace periods worth of time to execute. Such a tense situation may happen of course but, should we really work around that? I let you guys judge. In the meantime, I haven't found correctness issues: Reviewed-by: Frederic Weisbecker <frederic@xxxxxxxxxx> Thanks.
