| cpuset.c (d477f8c202d1f0d4791ab1263ca7657bbe5cf79e) | cpuset.c (99c8b231ae6c6ca4ca2fd1c0b3701071f589661f) |
|---|---|
| 1/* 2 * kernel/cpuset.c 3 * 4 * Processor and Memory placement constraints for sets of tasks. 5 * 6 * Copyright (C) 2003 BULL SA. 7 * Copyright (C) 2004-2007 Silicon Graphics, Inc. 8 * Copyright (C) 2006 Google, Inc --- 715 unchanged lines hidden (view full) --- 724 * This function builds a partial partition of the systems CPUs 725 * A 'partial partition' is a set of non-overlapping subsets whose 726 * union is a subset of that set. 727 * The output of this function needs to be passed to kernel/sched/core.c 728 * partition_sched_domains() routine, which will rebuild the scheduler's 729 * load balancing domains (sched domains) as specified by that partial 730 * partition. 731 * | 1/* 2 * kernel/cpuset.c 3 * 4 * Processor and Memory placement constraints for sets of tasks. 5 * 6 * Copyright (C) 2003 BULL SA. 7 * Copyright (C) 2004-2007 Silicon Graphics, Inc. 8 * Copyright (C) 2006 Google, Inc --- 715 unchanged lines hidden (view full) --- 724 * This function builds a partial partition of the systems CPUs 725 * A 'partial partition' is a set of non-overlapping subsets whose 726 * union is a subset of that set. 727 * The output of this function needs to be passed to kernel/sched/core.c 728 * partition_sched_domains() routine, which will rebuild the scheduler's 729 * load balancing domains (sched domains) as specified by that partial 730 * partition. 731 * |
| 732 * See "What is sched_load_balance" in Documentation/cgroup-v1/cpusets.txt | 732 * See "What is sched_load_balance" in Documentation/cgroup-v1/cpusets.rst |
| 733 * for a background explanation of this. 734 * 735 * Does not return errors, on the theory that the callers of this 736 * routine would rather not worry about failures to rebuild sched 737 * domains when operating in the severe memory shortage situations 738 * that could cause allocation failures below. 739 * 740 * Must be called with cpuset_mutex held. --- 2508 unchanged lines hidden (view full) --- 3249 3250 spin_lock_irqsave(&callback_lock, flags); 3251 rcu_read_lock(); 3252 guarantee_online_cpus(task_cs(tsk), pmask); 3253 rcu_read_unlock(); 3254 spin_unlock_irqrestore(&callback_lock, flags); 3255} 3256 | 733 * for a background explanation of this. 734 * 735 * Does not return errors, on the theory that the callers of this 736 * routine would rather not worry about failures to rebuild sched 737 * domains when operating in the severe memory shortage situations 738 * that could cause allocation failures below. 739 * 740 * Must be called with cpuset_mutex held. --- 2508 unchanged lines hidden (view full) --- 3249 3250 spin_lock_irqsave(&callback_lock, flags); 3251 rcu_read_lock(); 3252 guarantee_online_cpus(task_cs(tsk), pmask); 3253 rcu_read_unlock(); 3254 spin_unlock_irqrestore(&callback_lock, flags); 3255} 3256 |
| 3257/** 3258 * cpuset_cpus_allowed_fallback - final fallback before complete catastrophe. 3259 * @tsk: pointer to task_struct with which the scheduler is struggling 3260 * 3261 * Description: In the case that the scheduler cannot find an allowed cpu in 3262 * tsk->cpus_allowed, we fall back to task_cs(tsk)->cpus_allowed. In legacy 3263 * mode however, this value is the same as task_cs(tsk)->effective_cpus, 3264 * which will not contain a sane cpumask during cases such as cpu hotplugging. 3265 * This is the absolute last resort for the scheduler and it is only used if 3266 * _every_ other avenue has been traveled. 3267 **/ 3268 | |
| 3269void cpuset_cpus_allowed_fallback(struct task_struct *tsk) 3270{ 3271 rcu_read_lock(); | 3257void cpuset_cpus_allowed_fallback(struct task_struct *tsk) 3258{ 3259 rcu_read_lock(); |
| 3272 do_set_cpus_allowed(tsk, is_in_v2_mode() ? 3273 task_cs(tsk)->cpus_allowed : cpu_possible_mask); | 3260 do_set_cpus_allowed(tsk, task_cs(tsk)->effective_cpus); |
| 3274 rcu_read_unlock(); 3275 3276 /* 3277 * We own tsk->cpus_allowed, nobody can change it under us. 3278 * 3279 * But we used cs && cs->cpus_allowed lockless and thus can 3280 * race with cgroup_attach_task() or update_cpumask() and get 3281 * the wrong tsk->cpus_allowed. However, both cases imply the --- 311 unchanged lines hidden --- | 3261 rcu_read_unlock(); 3262 3263 /* 3264 * We own tsk->cpus_allowed, nobody can change it under us. 3265 * 3266 * But we used cs && cs->cpus_allowed lockless and thus can 3267 * race with cgroup_attach_task() or update_cpumask() and get 3268 * the wrong tsk->cpus_allowed. However, both cases imply the --- 311 unchanged lines hidden --- |