From: Yan Zhai Date: Tue, 19 Mar 2024 20:44:40 +0000 (-0700) Subject: bpf: report RCU QS in cpumap kthread X-Git-Tag: v5.15.153~8 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=387daae8b092cd98b00c1d75ac06eebe1eaa29d4;p=thirdparty%2Fkernel%2Fstable.git bpf: report RCU QS in cpumap kthread [ Upstream commit 00bf63122459e87193ee7f1bc6161c83a525569f ] When there are heavy load, cpumap kernel threads can be busy polling packets from redirect queues and block out RCU tasks from reaching quiescent states. It is insufficient to just call cond_resched() in such context. Periodically raise a consolidated RCU QS before cond_resched fixes the problem. Fixes: 6710e1126934 ("bpf: introduce new bpf cpu map type BPF_MAP_TYPE_CPUMAP") Reviewed-by: Jesper Dangaard Brouer Signed-off-by: Yan Zhai Acked-by: Paul E. McKenney Acked-by: Jesper Dangaard Brouer Link: https://lore.kernel.org/r/c17b9f1517e19d813da3ede5ed33ee18496bb5d8.1710877680.git.yan@cloudflare.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c index f7de5b313cc5b..a8429cfb4ae8c 100644 --- a/kernel/bpf/cpumap.c +++ b/kernel/bpf/cpumap.c @@ -305,6 +305,7 @@ static int cpu_map_bpf_prog_run(struct bpf_cpu_map_entry *rcpu, void **frames, static int cpu_map_kthread_run(void *data) { struct bpf_cpu_map_entry *rcpu = data; + unsigned long last_qs = jiffies; complete(&rcpu->kthread_running); set_current_state(TASK_INTERRUPTIBLE); @@ -330,10 +331,12 @@ static int cpu_map_kthread_run(void *data) if (__ptr_ring_empty(rcpu->queue)) { schedule(); sched = 1; + last_qs = jiffies; } else { __set_current_state(TASK_RUNNING); } } else { + rcu_softirq_qs_periodic(last_qs); sched = cond_resched(); }