Ksawlii/kernel_samsung_a53x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

bpf: report RCU QS in cpumap kthread

Browse source 
[ 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 <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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Yan Zhai 2024-03-19 13:44:40 -07:00 committed by Ksawlii
parent 6912841581
commit 02392667f3
1 changed files with 3 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
kernel/bpf/cpumap.c
View file

@ -299,6 +299,7 @@ static int cpu_map_bpf_prog_run_xdp(struct bpf_cpu_map_entry *rcpu,
static int cpu_map_kthread_run(void *data)
{
struct bpf_cpu_map_entry *rcpu = data;
unsigned long last_qs = jiffies;
set_current_state(TASK_INTERRUPTIBLE);
@ -322,10 +323,12 @@ 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();
}