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To: Chen Jinghuang Cc: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , linux-kernel@vger.kernel.org, Madadi Vineeth Reddy References: <20260211021215.3610597-1-chenjinghuang2@huawei.com> Content-Language: en-US From: Madadi Vineeth Reddy In-Reply-To: <20260211021215.3610597-1-chenjinghuang2@huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-GUID: Dc1hW1DX2VM09i4AajBZ4FXq7yQBV124 X-Proofpoint-ORIG-GUID: 4AmpBOEXUfR0oU5sFbv0d5GhyHLhyU7x X-Authority-Analysis: v=2.4 cv=JdWxbEKV c=1 sm=1 tr=0 ts=698d4b79 cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=IkcTkHD0fZMA:10 a=HzLeVaNsDn8A:10 a=VkNPw1HP01LnGYTKEx00:22 a=Mpw57Om8IfrbqaoTuvik:22 a=GgsMoib0sEa3-_RKJdDe:22 a=i0EeH86SAAAA:8 a=VnNF1IyMAAAA:8 a=vQSaTQVC-0w5NISv42gA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMjEyMDAyMSBTYWx0ZWRfXyMZtFVW6e5Lk m41pRwjlYWsG6jWkFviqLM9BbNmxNdJ7UV2hbI7v+9z044Rfo811iY2w3TtATEvaZBKSMdoBcI2 lPaSw6cknEEzfQFZY2GZ96KZY/o3C/JHExJ2PzhCOmv0NemdxbeybaaJxvFDcavxh+6uP2nEptp yvWXiCwXfzMNv2gWwz2F38blXb5fHYhleIvSaJ6MXq6+tci0QtwsO0V029nFD534wjcud5rZryN WKQBbRGAE6RYOkNFuAOPrt+pOIuMM+jl5MrKAH/ZGYmoC46SD71A5thnmbClZsQ6wSxU8xCmy0n 2VVWeiGxP7ecewt1cITCGf+Mvub6p7i4+nn6640mbk9zbjehNLh2J5pGk0oWiYtYAXFlFMYRMdM LXvvm9Q493hNyfZedeS6DwcO92c9cwOnFARiqUQ0YFjSvnTKTo74yri4/xE1phJn4u4mrQIUq5I 75mQwEWI6hi5PVMjnXA== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-02-12_01,2026-02-11_04,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 clxscore=1011 impostorscore=0 bulkscore=0 lowpriorityscore=0 suspectscore=0 adultscore=0 spamscore=0 malwarescore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2601150000 definitions=main-2602120021 On 11/02/26 07:42, Chen Jinghuang wrote: > For example: > > # cat /proc/sys/kernel/sched_rt_runtime_us > 950000 > # echo 940000 > /proc/sys/kernel/sched_rt_runtime_us > -bash: echo: write error: Invalid argument > > This occurs because when the global RT quota is reduced while the root > cgroup’s ratio remains unchanged, the root cgroup’s proportion ends up > exceeding the global RT ratio. This is unreasonable: the root cgroup’s > ratio should be updated when the global RT ratio changes. > > This patch ensures the root cgroup’s RT quota is adjusted whenever the > global RT quota is modified. > > Signed-off-by: Chen Ridong > Signed-off-by: Chen Jinghuang > --- > kernel/sched/rt.c | 12 +++++++++++- > 1 file changed, 11 insertions(+), 1 deletion(-) > > diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c > index f1867fe8e5c5..30770ba7be4e 100644 > --- a/kernel/sched/rt.c > +++ b/kernel/sched/rt.c > @@ -2814,9 +2814,11 @@ long sched_group_rt_period(struct task_group *tg) > static int sched_rt_global_constraints(void) > { > int ret = 0; > + u64 period = global_rt_period(); > + u64 runtime = global_rt_runtime(); > > mutex_lock(&rt_constraints_mutex); > - ret = __rt_schedulable(NULL, 0, 0); > + ret = __rt_schedulable(&root_task_group, period, runtime); > mutex_unlock(&rt_constraints_mutex); > > return ret; > @@ -2856,6 +2858,14 @@ static int sched_rt_global_validate(void) > > static void sched_rt_do_global(void) > { > +#ifdef CONFIG_RT_GROUP_SCHED > + if (!rt_group_sched_enabled()) > + return; > + > + WARN_ON_ONCE(tg_set_rt_bandwidth(&root_task_group, > + global_rt_period(), > + global_rt_runtime())); > +#endif > } > > static int sched_rt_handler(const struct ctl_table *table, int write, void *buffer, Hi Chen, Tested this patch on POWER11 system Without the patch: echo 940000 > /proc/sys/kernel/sched_rt_runtime_us -bash: echo: write error: Invalid argument With patch: echo 940000 > /proc/sys/kernel/sched_rt_runtime_us cat /proc/sys/kernel/sched_rt_runtime_us 940000 Works as expected. Tested-by: Madadi Vineeth Reddy Thanks, Vineeth