| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <202512221734.SzKNollL-lkp@intel.com>
Date: Mon, 22 Dec 2025 17:31:23 +0800
From: kernel test robot <lkp@...el.com>
To: Wanpeng Li <kernellwp@...il.com>, Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
Paolo Bonzini <pbonzini@...hat.com>,
Sean Christopherson <seanjc@...gle.com>
Cc: oe-kbuild-all@...ts.linux.dev, K Prateek Nayak <kprateek.nayak@....com>,
Christian Borntraeger <borntraeger@...ux.ibm.com>,
Steven Rostedt <rostedt@...dmis.org>,
Vincent Guittot <vincent.guittot@...aro.org>,
Juri Lelli <juri.lelli@...hat.com>, linux-kernel@...r.kernel.org,
kvm@...r.kernel.org, Wanpeng Li <wanpengli@...cent.com>
Subject: Re: [PATCH v2 5/9] sched/fair: Wire up yield deboost in
yield_to_task_fair()
Hi Wanpeng,
kernel test robot noticed the following build errors:
[auto build test ERROR on kvm/queue]
[also build test ERROR on kvm/next tip/sched/core peterz-queue/sched/core tip/master linus/master v6.19-rc2 next-20251219]
[cannot apply to kvm/linux-next tip/auto-latest]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Wanpeng-Li/sched-fair-Add-rate-limiting-and-validation-helpers/20251219-125353
base: https://git.kernel.org/pub/scm/virt/kvm/kvm.git queue
patch link: https://lore.kernel.org/r/20251219035334.39790-6-kernellwp%40gmail.com
patch subject: [PATCH v2 5/9] sched/fair: Wire up yield deboost in yield_to_task_fair()
config: i386-randconfig-003-20251222 (https://download.01.org/0day-ci/archive/20251222/202512221734.SzKNollL-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.4.0-5) 12.4.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251222/202512221734.SzKNollL-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@...el.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202512221734.SzKNollL-lkp@intel.com/
All errors (new ones prefixed by >>):
ld: kernel/sched/fair.o: in function `yield_deboost_calculate_penalty':
>> kernel/sched/fair.c:9213:(.text+0x278d): undefined reference to `__udivdi3'
vim +9213 kernel/sched/fair.c
9a700d273608de Wanpeng Li 2025-12-19 9176
9a700d273608de Wanpeng Li 2025-12-19 9177 /*
9a700d273608de Wanpeng Li 2025-12-19 9178 * Calculate vruntime penalty for yield deboost.
9a700d273608de Wanpeng Li 2025-12-19 9179 *
9a700d273608de Wanpeng Li 2025-12-19 9180 * The penalty is based on:
9a700d273608de Wanpeng Li 2025-12-19 9181 * - Fairness gap: vruntime difference between yielding and target tasks
9a700d273608de Wanpeng Li 2025-12-19 9182 * - Scheduling granularity: base unit for penalty calculation
9a700d273608de Wanpeng Li 2025-12-19 9183 * - Queue size: adaptive caps to prevent starvation in larger queues
9a700d273608de Wanpeng Li 2025-12-19 9184 *
9a700d273608de Wanpeng Li 2025-12-19 9185 * Queue-size-based caps (multiplier of granularity):
9a700d273608de Wanpeng Li 2025-12-19 9186 * 2 tasks: 6.0x - Strongest push for 2-task ping-pong scenarios
9a700d273608de Wanpeng Li 2025-12-19 9187 * 3 tasks: 4.0x
9a700d273608de Wanpeng Li 2025-12-19 9188 * 4-6: 2.5x
9a700d273608de Wanpeng Li 2025-12-19 9189 * 7-8: 2.0x
9a700d273608de Wanpeng Li 2025-12-19 9190 * 9-12: 1.5x
9a700d273608de Wanpeng Li 2025-12-19 9191 * >12: 1.0x - Minimal push to avoid starvation
9a700d273608de Wanpeng Li 2025-12-19 9192 *
9a700d273608de Wanpeng Li 2025-12-19 9193 * Returns the calculated penalty value.
9a700d273608de Wanpeng Li 2025-12-19 9194 */
9a700d273608de Wanpeng Li 2025-12-19 9195 static u64 __maybe_unused
9a700d273608de Wanpeng Li 2025-12-19 9196 yield_deboost_calculate_penalty(struct rq *rq, struct sched_entity *se_y_lca,
9a700d273608de Wanpeng Li 2025-12-19 9197 struct sched_entity *se_t_lca,
9a700d273608de Wanpeng Li 2025-12-19 9198 struct task_struct *p_target, int h_nr_queued)
9a700d273608de Wanpeng Li 2025-12-19 9199 {
9a700d273608de Wanpeng Li 2025-12-19 9200 u64 gran, need, penalty, maxp;
9a700d273608de Wanpeng Li 2025-12-19 9201 u64 weighted_need, base;
9a700d273608de Wanpeng Li 2025-12-19 9202
9a700d273608de Wanpeng Li 2025-12-19 9203 gran = calc_delta_fair(sysctl_sched_base_slice, se_y_lca);
9a700d273608de Wanpeng Li 2025-12-19 9204
9a700d273608de Wanpeng Li 2025-12-19 9205 /* Calculate fairness gap */
9a700d273608de Wanpeng Li 2025-12-19 9206 need = 0;
9a700d273608de Wanpeng Li 2025-12-19 9207 if (se_t_lca->vruntime > se_y_lca->vruntime)
9a700d273608de Wanpeng Li 2025-12-19 9208 need = se_t_lca->vruntime - se_y_lca->vruntime;
9a700d273608de Wanpeng Li 2025-12-19 9209
9a700d273608de Wanpeng Li 2025-12-19 9210 /* Base penalty is granularity plus 110% of fairness gap */
9a700d273608de Wanpeng Li 2025-12-19 9211 penalty = gran;
9a700d273608de Wanpeng Li 2025-12-19 9212 if (need) {
9a700d273608de Wanpeng Li 2025-12-19 @9213 weighted_need = need + need / 10;
9a700d273608de Wanpeng Li 2025-12-19 9214 if (weighted_need > U64_MAX - penalty)
9a700d273608de Wanpeng Li 2025-12-19 9215 weighted_need = U64_MAX - penalty;
9a700d273608de Wanpeng Li 2025-12-19 9216 penalty += weighted_need;
9a700d273608de Wanpeng Li 2025-12-19 9217 }
9a700d273608de Wanpeng Li 2025-12-19 9218
9a700d273608de Wanpeng Li 2025-12-19 9219 /* Apply debounce to reduce ping-pong */
9a700d273608de Wanpeng Li 2025-12-19 9220 penalty = yield_deboost_apply_debounce(rq, p_target, penalty, need, gran);
9a700d273608de Wanpeng Li 2025-12-19 9221
9a700d273608de Wanpeng Li 2025-12-19 9222 /* Queue-size-based upper bound */
9a700d273608de Wanpeng Li 2025-12-19 9223 if (h_nr_queued == 2)
9a700d273608de Wanpeng Li 2025-12-19 9224 maxp = gran * 6;
9a700d273608de Wanpeng Li 2025-12-19 9225 else if (h_nr_queued == 3)
9a700d273608de Wanpeng Li 2025-12-19 9226 maxp = gran * 4;
9a700d273608de Wanpeng Li 2025-12-19 9227 else if (h_nr_queued <= 6)
9a700d273608de Wanpeng Li 2025-12-19 9228 maxp = (gran * 5) / 2;
9a700d273608de Wanpeng Li 2025-12-19 9229 else if (h_nr_queued <= 8)
9a700d273608de Wanpeng Li 2025-12-19 9230 maxp = gran * 2;
9a700d273608de Wanpeng Li 2025-12-19 9231 else if (h_nr_queued <= 12)
9a700d273608de Wanpeng Li 2025-12-19 9232 maxp = (gran * 3) / 2;
9a700d273608de Wanpeng Li 2025-12-19 9233 else
9a700d273608de Wanpeng Li 2025-12-19 9234 maxp = gran;
9a700d273608de Wanpeng Li 2025-12-19 9235
9a700d273608de Wanpeng Li 2025-12-19 9236 penalty = clamp(penalty, gran, maxp);
9a700d273608de Wanpeng Li 2025-12-19 9237
9a700d273608de Wanpeng Li 2025-12-19 9238 /* Baseline push when no fairness gap exists */
9a700d273608de Wanpeng Li 2025-12-19 9239 if (need == 0) {
9a700d273608de Wanpeng Li 2025-12-19 9240 if (h_nr_queued == 3)
9a700d273608de Wanpeng Li 2025-12-19 9241 base = (gran * 15) / 16;
9a700d273608de Wanpeng Li 2025-12-19 9242 else if (h_nr_queued >= 4 && h_nr_queued <= 6)
9a700d273608de Wanpeng Li 2025-12-19 9243 base = (gran * 5) / 8;
9a700d273608de Wanpeng Li 2025-12-19 9244 else if (h_nr_queued >= 7 && h_nr_queued <= 8)
9a700d273608de Wanpeng Li 2025-12-19 9245 base = gran / 2;
9a700d273608de Wanpeng Li 2025-12-19 9246 else if (h_nr_queued >= 9 && h_nr_queued <= 12)
9a700d273608de Wanpeng Li 2025-12-19 9247 base = (gran * 3) / 8;
9a700d273608de Wanpeng Li 2025-12-19 9248 else if (h_nr_queued > 12)
9a700d273608de Wanpeng Li 2025-12-19 9249 base = gran / 4;
9a700d273608de Wanpeng Li 2025-12-19 9250 else
9a700d273608de Wanpeng Li 2025-12-19 9251 base = gran;
9a700d273608de Wanpeng Li 2025-12-19 9252
9a700d273608de Wanpeng Li 2025-12-19 9253 if (penalty < base)
9a700d273608de Wanpeng Li 2025-12-19 9254 penalty = base;
9a700d273608de Wanpeng Li 2025-12-19 9255 }
9a700d273608de Wanpeng Li 2025-12-19 9256
9a700d273608de Wanpeng Li 2025-12-19 9257 return penalty;
9a700d273608de Wanpeng Li 2025-12-19 9258 }
9a700d273608de Wanpeng Li 2025-12-19 9259
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Powered by blists - more mailing lists