Messages in this thread | | | Date | Thu, 20 Oct 2022 14:35:24 +0800 | Subject | Re: [RESEND] sched/fair: Add min_ratio for cfs bandwidth_control | From | Chuyi Zhou <> |
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在 2022/10/20 05:21, Tejun Heo 写道: > Hello, > > On Wed, Oct 19, 2022 at 11:15:51AM +0800, Chuyi Zhou wrote: >> Tasks may be throttled when holding locks for a long time by current >> cfs bandwidth control mechanism once users set a too small quota/period >> ratio, which can result whole system get stuck[1]. >> >> In order to prevent the above situation from happening, this patch adds >> sysctl_sched_cfs_bandwidth_min_ratio in /proc/sys/kernel, which indicates >> the minimum percentage of quota/period users can set. The default value is >> zero and users can set quota and period without triggering this constraint. >> >> Link[1]:https://lore.kernel.org/lkml/5987be34-b527-4ff5-a17d-5f6f0dc94d6d@huawei.com/T/ >> Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com> >> Suggested-by: Abel Wu <wuyun.abel@bytedance.com> > > This is a bit of a bandaid. I think what we really need to do is only > throttling when running in userspace. In kernel space, it should just keep > accumulating used cycles as debt which should be paid back before userspace > code can run again so that we don't throttle at random places in the kernel. > > Thanks. > Got it. Thanks for your advice. Chuyi Zhou
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