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authorCheng Yu2024-04-24 21:24:38 +0800
committerIngo Molnar2024-05-17 09:53:54 +0200
commit49217ea147df7647cb89161b805c797487783fc0 (patch)
tree9825a820f10d5ace4617eb006d31ff579e700635
parent7cb7fb5b49399fc59f1c44686d82c0df0776c8c6 (diff)
sched/core: Fix incorrect initialization of the 'burst' parameter in cpu_max_write()
In the cgroup v2 CPU subsystem, assuming we have a cgroup named 'test', and we set cpu.max and cpu.max.burst: # echo 1000000 > /sys/fs/cgroup/test/cpu.max # echo 1000000 > /sys/fs/cgroup/test/cpu.max.burst then we check cpu.max and cpu.max.burst: # cat /sys/fs/cgroup/test/cpu.max 1000000 100000 # cat /sys/fs/cgroup/test/cpu.max.burst 1000000 Next we set cpu.max again and check cpu.max and cpu.max.burst: # echo 2000000 > /sys/fs/cgroup/test/cpu.max # cat /sys/fs/cgroup/test/cpu.max 2000000 100000 # cat /sys/fs/cgroup/test/cpu.max.burst 1000 ... we find that the cpu.max.burst value changed unexpectedly. In cpu_max_write(), the unit of the burst value returned by tg_get_cfs_burst() is microseconds, while in cpu_max_write(), the burst unit used for calculation should be nanoseconds, which leads to the bug. To fix it, get the burst value directly from tg->cfs_bandwidth.burst. Fixes: f4183717b370 ("sched/fair: Introduce the burstable CFS controller") Reported-by: Qixin Liao <liaoqixin@huawei.com> Signed-off-by: Cheng Yu <serein.chengyu@huawei.com> Signed-off-by: Zhang Qiao <zhangqiao22@huawei.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Tested-by: Vincent Guittot <vincent.guittot@linaro.org> Link: https://lore.kernel.org/r/20240424132438.514720-1-serein.chengyu@huawei.com
-rw-r--r--kernel/sched/core.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 1a914388144a..f88f50552acb 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -11402,7 +11402,7 @@ static ssize_t cpu_max_write(struct kernfs_open_file *of,
{
struct task_group *tg = css_tg(of_css(of));
u64 period = tg_get_cfs_period(tg);
- u64 burst = tg_get_cfs_burst(tg);
+ u64 burst = tg->cfs_bandwidth.burst;
u64 quota;
int ret;