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authorYan Zhai <yan@cloudflare.com>2024-03-19 13:44:40 -0700
committerJakub Kicinski <kuba@kernel.org>2024-03-20 21:05:43 -0700
commit00bf63122459e87193ee7f1bc6161c83a525569f (patch)
treebb54c5de6214b985d103ec0d400e6b8d9527e10f /kernel/bpf
parentd6dbbb11247c71203785a2c9da474c36f4b19eae (diff)
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bpf: report RCU QS in cpumap kthread
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 <hawk@kernel.org> Signed-off-by: Yan Zhai <yan@cloudflare.com> Acked-by: Paul E. McKenney <paulmck@kernel.org> Acked-by: Jesper Dangaard Brouer <hawk@kernel.org> Link: https://lore.kernel.org/r/c17b9f1517e19d813da3ede5ed33ee18496bb5d8.1710877680.git.yan@cloudflare.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'kernel/bpf')
-rw-r--r--kernel/bpf/cpumap.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c
index 9ee8da477465..a8e34416e960 100644
--- a/kernel/bpf/cpumap.c
+++ b/kernel/bpf/cpumap.c
@@ -263,6 +263,7 @@ 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);
@@ -288,10 +289,12 @@ 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();
}