Instead of relying on static allocations for the sched_domain and sched_group trees, dynamically allocate and RCU free them. Allocating this dynamically also allows for some build_sched_groups() simplification since we can now (like with other simplifications) rely on the sched_domain tree instead of hard-coded knowledge. One tricky to note is that detach_destroy_domains() needs to hold rcu_read_lock() over the entire tear-down, per-cpu is not sufficient since that can lead to partial sched_group existance (could possibly be solved by doing the tear-down backwards but this is much more robust). A concequence of the above is that we can no longer print the sched_domain debug stuff from cpu_attach_domain() since that might now run with preemption disabled (due to classic RCU etc.) and sched_domain_debug() does some GFP_KERNEL allocations. Another thing to note is that we now fully rely on normal RCU and not RCU-sched, this is because with the new and exiting RCU flavours we grew over the years BH doesn't necessarily hold off RCU-sched grace periods (-rt is known to break this). This would in fact already cause us grief since we do sched_domain/sched_group iterations from softirq context. This patch is somewhat larger than I would like it to be, but I didn't find any means of shrinking/splitting this. Signed-off-by: Peter Zijlstra --- include/linux/sched.h | 5 kernel/sched.c | 480 +++++++++++++++++++------------------------------- kernel/sched_fair.c | 30 ++- 3 files changed, 219 insertions(+), 296 deletions(-) Index: linux-2.6/include/linux/sched.h =================================================================== --- linux-2.6.orig/include/linux/sched.h +++ linux-2.6/include/linux/sched.h @@ -868,6 +868,7 @@ static inline int sd_power_saving_flags( struct sched_group { struct sched_group *next; /* Must be a circular list */ + atomic_t ref; /* * CPU power of this group, SCHED_LOAD_SCALE being max power for a @@ -973,6 +974,10 @@ struct sched_domain { #ifdef CONFIG_SCHED_DEBUG char *name; #endif + union { + void *private; /* used during construction */ + struct rcu_head rcu; /* used during destruction */ + }; unsigned int span_weight; /* Index: linux-2.6/kernel/sched.c =================================================================== --- linux-2.6.orig/kernel/sched.c +++ linux-2.6/kernel/sched.c @@ -417,6 +417,7 @@ struct rt_rq { */ struct root_domain { atomic_t refcount; + struct rcu_head rcu; cpumask_var_t span; cpumask_var_t online; @@ -571,7 +572,7 @@ static inline int cpu_of(struct rq *rq) #define rcu_dereference_check_sched_domain(p) \ rcu_dereference_check((p), \ - rcu_read_lock_sched_held() || \ + rcu_read_lock_held() || \ lockdep_is_held(&sched_domains_mutex)) /* @@ -6558,12 +6559,11 @@ sd_parent_degenerate(struct sched_domain return 1; } -static void free_rootdomain(struct root_domain *rd) +static void free_rootdomain(struct rcu_head *rcu) { - synchronize_sched(); + struct root_domain *rd = container_of(rcu, struct root_domain, rcu); cpupri_cleanup(&rd->cpupri); - free_cpumask_var(rd->rto_mask); free_cpumask_var(rd->online); free_cpumask_var(rd->span); @@ -6604,7 +6604,7 @@ static void rq_attach_root(struct rq *rq raw_spin_unlock_irqrestore(&rq->lock, flags); if (old_rd) - free_rootdomain(old_rd); + call_rcu_sched(&old_rd->rcu, free_rootdomain); } static int init_rootdomain(struct root_domain *rd) @@ -6655,6 +6655,25 @@ static struct root_domain *alloc_rootdom return rd; } +static void free_sched_domain(struct rcu_head *rcu) +{ + struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); + if (atomic_dec_and_test(&sd->groups->ref)) + kfree(sd->groups); + kfree(sd); +} + +static void destroy_sched_domain(struct sched_domain *sd, int cpu) +{ + call_rcu(&sd->rcu, free_sched_domain); +} + +static void destroy_sched_domains(struct sched_domain *sd, int cpu) +{ + for (; sd; sd = sd->parent) + destroy_sched_domain(sd, cpu); +} + /* * Attach the domain 'sd' to 'cpu' as its base domain. Callers must * hold the hotplug lock. @@ -6675,20 +6694,25 @@ cpu_attach_domain(struct sched_domain *s tmp->parent = parent->parent; if (parent->parent) parent->parent->child = tmp; + destroy_sched_domain(parent, cpu); } else tmp = tmp->parent; } if (sd && sd_degenerate(sd)) { + tmp = sd; sd = sd->parent; + destroy_sched_domain(tmp, cpu); if (sd) sd->child = NULL; } - sched_domain_debug(sd, cpu); +// sched_domain_debug(sd, cpu); rq_attach_root(rq, rd); + tmp = rq->sd; rcu_assign_pointer(rq->sd, sd); + destroy_sched_domains(tmp, cpu); } /* cpus with isolated domains */ @@ -6704,56 +6728,6 @@ static int __init isolated_cpu_setup(cha __setup("isolcpus=", isolated_cpu_setup); -/* - * init_sched_build_groups takes the cpumask we wish to span, and a pointer - * to a function which identifies what group(along with sched group) a CPU - * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids - * (due to the fact that we keep track of groups covered with a struct cpumask). - * - * init_sched_build_groups will build a circular linked list of the groups - * covered by the given span, and will set each group's ->cpumask correctly, - * and ->cpu_power to 0. - */ -static void -init_sched_build_groups(const struct cpumask *span, - const struct cpumask *cpu_map, - int (*group_fn)(int cpu, const struct cpumask *cpu_map, - struct sched_group **sg, - struct cpumask *tmpmask), - struct cpumask *covered, struct cpumask *tmpmask) -{ - struct sched_group *first = NULL, *last = NULL; - int i; - - cpumask_clear(covered); - - for_each_cpu(i, span) { - struct sched_group *sg; - int group = group_fn(i, cpu_map, &sg, tmpmask); - int j; - - if (cpumask_test_cpu(i, covered)) - continue; - - cpumask_clear(sched_group_cpus(sg)); - sg->cpu_power = 0; - - for_each_cpu(j, span) { - if (group_fn(j, cpu_map, NULL, tmpmask) != group) - continue; - - cpumask_set_cpu(j, covered); - cpumask_set_cpu(j, sched_group_cpus(sg)); - } - if (!first) - first = sg; - if (last) - last->next = sg; - last = sg; - } - last->next = first; -} - #define SD_NODES_PER_DOMAIN 16 #ifdef CONFIG_NUMA @@ -6844,154 +6818,96 @@ struct static_sched_domain { DECLARE_BITMAP(span, CONFIG_NR_CPUS); }; +struct sd_data { + struct sched_domain **__percpu sd; + struct sched_group **__percpu sg; +}; + struct s_data { #ifdef CONFIG_NUMA int sd_allnodes; #endif cpumask_var_t nodemask; cpumask_var_t send_covered; - cpumask_var_t tmpmask; struct sched_domain ** __percpu sd; + struct sd_data sdd[SD_LV_MAX]; struct root_domain *rd; }; enum s_alloc { sa_rootdomain, sa_sd, - sa_tmpmask, + sa_sd_storage, sa_send_covered, sa_nodemask, sa_none, }; /* - * SMT sched-domains: + * Assumes the sched_domain tree is fully constructed */ -#ifdef CONFIG_SCHED_SMT -static DEFINE_PER_CPU(struct static_sched_domain, cpu_domains); -static DEFINE_PER_CPU(struct static_sched_group, sched_groups); - -static int -cpu_to_cpu_group(int cpu, const struct cpumask *cpu_map, - struct sched_group **sg, struct cpumask *unused) +static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) { - if (sg) - *sg = &per_cpu(sched_groups, cpu).sg; - return cpu; -} -#endif /* CONFIG_SCHED_SMT */ + struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); + struct sched_domain *child = sd->child; -/* - * multi-core sched-domains: - */ -#ifdef CONFIG_SCHED_MC -static DEFINE_PER_CPU(struct static_sched_domain, core_domains); -static DEFINE_PER_CPU(struct static_sched_group, sched_group_core); + if (child) + cpu = cpumask_first(sched_domain_span(child)); -static int -cpu_to_core_group(int cpu, const struct cpumask *cpu_map, - struct sched_group **sg, struct cpumask *mask) -{ - int group; -#ifdef CONFIG_SCHED_SMT - cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map); - group = cpumask_first(mask); -#else - group = cpu; -#endif if (sg) - *sg = &per_cpu(sched_group_core, group).sg; - return group; + *sg = *per_cpu_ptr(sdd->sg, cpu); + + return cpu; } -#endif /* CONFIG_SCHED_MC */ /* - * book sched-domains: + * build_sched_groups takes the cpumask we wish to span, and a pointer + * to a function which identifies what group(along with sched group) a CPU + * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids + * (due to the fact that we keep track of groups covered with a struct cpumask). + * + * build_sched_groups will build a circular linked list of the groups + * covered by the given span, and will set each group's ->cpumask correctly, + * and ->cpu_power to 0. */ -#ifdef CONFIG_SCHED_BOOK -static DEFINE_PER_CPU(struct static_sched_domain, book_domains); -static DEFINE_PER_CPU(struct static_sched_group, sched_group_book); - -static int -cpu_to_book_group(int cpu, const struct cpumask *cpu_map, - struct sched_group **sg, struct cpumask *mask) -{ - int group = cpu; -#ifdef CONFIG_SCHED_MC - cpumask_and(mask, cpu_coregroup_mask(cpu), cpu_map); - group = cpumask_first(mask); -#elif defined(CONFIG_SCHED_SMT) - cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map); - group = cpumask_first(mask); -#endif - if (sg) - *sg = &per_cpu(sched_group_book, group).sg; - return group; -} -#endif /* CONFIG_SCHED_BOOK */ - -static DEFINE_PER_CPU(struct static_sched_domain, phys_domains); -static DEFINE_PER_CPU(struct static_sched_group, sched_group_phys); - -static int -cpu_to_phys_group(int cpu, const struct cpumask *cpu_map, - struct sched_group **sg, struct cpumask *mask) +static void +build_sched_groups(struct sched_domain *sd, struct cpumask *covered) { - int group; -#ifdef CONFIG_SCHED_BOOK - cpumask_and(mask, cpu_book_mask(cpu), cpu_map); - group = cpumask_first(mask); -#elif defined(CONFIG_SCHED_MC) - cpumask_and(mask, cpu_coregroup_mask(cpu), cpu_map); - group = cpumask_first(mask); -#elif defined(CONFIG_SCHED_SMT) - cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map); - group = cpumask_first(mask); -#else - group = cpu; -#endif - if (sg) - *sg = &per_cpu(sched_group_phys, group).sg; - return group; -} - -#ifdef CONFIG_NUMA -static DEFINE_PER_CPU(struct static_sched_domain, node_domains); -static DEFINE_PER_CPU(struct static_sched_group, sched_group_node); + struct sched_group *first = NULL, *last = NULL; + struct sd_data *sdd = sd->private; + const struct cpumask *span = sched_domain_span(sd); + int i; -static int cpu_to_node_group(int cpu, const struct cpumask *cpu_map, - struct sched_group **sg, - struct cpumask *nodemask) -{ - int group; + cpumask_clear(covered); - cpumask_and(nodemask, cpumask_of_node(cpu_to_node(cpu)), cpu_map); - group = cpumask_first(nodemask); + for_each_cpu(i, span) { + struct sched_group *sg; + int group = get_group(i, sdd, &sg); + int j; - if (sg) - *sg = &per_cpu(sched_group_node, group).sg; - return group; -} + if (cpumask_test_cpu(i, covered)) + continue; -static DEFINE_PER_CPU(struct static_sched_domain, allnodes_domains); -static DEFINE_PER_CPU(struct static_sched_group, sched_group_allnodes); + cpumask_clear(sched_group_cpus(sg)); + sg->cpu_power = 0; -static int cpu_to_allnodes_group(int cpu, const struct cpumask *cpu_map, - struct sched_group **sg, - struct cpumask *nodemask) -{ - int group; + for_each_cpu(j, span) { + if (get_group(j, sdd, NULL) != group) + continue; - cpumask_and(nodemask, cpumask_of_node(cpu_to_node(cpu)), cpu_map); - group = cpumask_first(nodemask); + cpumask_set_cpu(j, covered); + cpumask_set_cpu(j, sched_group_cpus(sg)); + } - if (sg) - *sg = &per_cpu(sched_group_allnodes, group).sg; - return group; + if (!first) + first = sg; + if (last) + last->next = sg; + last = sg; + } + last->next = first; } -#endif /* CONFIG_NUMA */ - /* * Initialize sched groups cpu_power. * @@ -7025,15 +6941,15 @@ static void init_sched_groups_power(int # define SD_INIT_NAME(sd, type) do { } while (0) #endif -#define SD_INIT(sd, type) sd_init_##type(sd) - -#define SD_INIT_FUNC(type) \ -static noinline void sd_init_##type(struct sched_domain *sd) \ -{ \ - memset(sd, 0, sizeof(*sd)); \ - *sd = SD_##type##_INIT; \ - sd->level = SD_LV_##type; \ - SD_INIT_NAME(sd, type); \ +#define SD_INIT_FUNC(type) \ +static noinline struct sched_domain *sd_init_##type(struct s_data *d, int cpu) \ +{ \ + struct sched_domain *sd = *per_cpu_ptr(d->sdd[SD_LV_##type].sd, cpu); \ + *sd = SD_##type##_INIT; \ + sd->level = SD_LV_##type; \ + SD_INIT_NAME(sd, type); \ + sd->private = &d->sdd[SD_LV_##type]; \ + return sd; \ } SD_INIT_FUNC(CPU) @@ -7089,13 +7005,22 @@ static void set_domain_attribute(struct static void __free_domain_allocs(struct s_data *d, enum s_alloc what, const struct cpumask *cpu_map) { + int i, j; + switch (what) { case sa_rootdomain: - free_rootdomain(d->rd); /* fall through */ + free_rootdomain(&d->rd->rcu); /* fall through */ case sa_sd: free_percpu(d->sd); /* fall through */ - case sa_tmpmask: - free_cpumask_var(d->tmpmask); /* fall through */ + case sa_sd_storage: + for (i = 0; i < SD_LV_MAX; i++) { + for_each_cpu(j, cpu_map) { + kfree(*per_cpu_ptr(d->sdd[i].sd, j)); + kfree(*per_cpu_ptr(d->sdd[i].sg, j)); + } + free_percpu(d->sdd[i].sd); + free_percpu(d->sdd[i].sg); + } /* fall through */ case sa_send_covered: free_cpumask_var(d->send_covered); /* fall through */ case sa_nodemask: @@ -7108,25 +7033,70 @@ static void __free_domain_allocs(struct static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, const struct cpumask *cpu_map) { + int i, j; + + memset(d, 0, sizeof(*d)); + if (!alloc_cpumask_var(&d->nodemask, GFP_KERNEL)) return sa_none; if (!alloc_cpumask_var(&d->send_covered, GFP_KERNEL)) return sa_nodemask; - if (!alloc_cpumask_var(&d->tmpmask, GFP_KERNEL)) - return sa_send_covered; - d->sd = alloc_percpu(struct sched_domain *); - if (!d->sd) { - printk(KERN_WARNING "Cannot alloc per-cpu pointers\n"); - return sa_tmpmask; + for (i = 0; i < SD_LV_MAX; i++) { + d->sdd[i].sd = alloc_percpu(struct sched_domain *); + if (!d->sdd[i].sd) + return sa_sd_storage; + + d->sdd[i].sg = alloc_percpu(struct sched_group *); + if (!d->sdd[i].sg) + return sa_sd_storage; + + for_each_cpu(j, cpu_map) { + struct sched_domain *sd; + struct sched_group *sg; + + sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), + GFP_KERNEL, cpu_to_node(j)); + if (!sd) + return sa_sd_storage; + + *per_cpu_ptr(d->sdd[i].sd, j) = sd; + + sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), + GFP_KERNEL, cpu_to_node(j)); + if (!sg) + return sa_sd_storage; + + *per_cpu_ptr(d->sdd[i].sg, j) = sg; + } } + d->sd = alloc_percpu(struct sched_domain *); + if (!d->sd) + return sa_sd_storage; d->rd = alloc_rootdomain(); - if (!d->rd) { - printk(KERN_WARNING "Cannot alloc root domain\n"); + if (!d->rd) return sa_sd; - } return sa_rootdomain; } +/* + * NULL the sd_data elements we've used to build the sched_domain and + * sched_group structure so that the subsequent __free_domain_allocs() + * will not free the data we're using. + */ +static void claim_allocations(int cpu, struct sched_domain *sd) +{ + struct sd_data *sdd = sd->private; + struct sched_group *sg = sd->groups; + + WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); + *per_cpu_ptr(sdd->sd, cpu) = NULL; + + if (cpu == cpumask_first(sched_group_cpus(sg))) { + WARN_ON_ONCE(*per_cpu_ptr(sdd->sg, cpu) != sg); + *per_cpu_ptr(sdd->sg, cpu) = NULL; + } +} + static struct sched_domain *__build_numa_sched_domains(struct s_data *d, const struct cpumask *cpu_map, struct sched_domain_attr *attr, int i) { @@ -7137,24 +7107,20 @@ static struct sched_domain *__build_numa d->sd_allnodes = 0; if (cpumask_weight(cpu_map) > SD_NODES_PER_DOMAIN * cpumask_weight(d->nodemask)) { - sd = &per_cpu(allnodes_domains, i).sd; - SD_INIT(sd, ALLNODES); + sd = sd_init_ALLNODES(d, i); set_domain_attribute(sd, attr); cpumask_copy(sched_domain_span(sd), cpu_map); - cpu_to_allnodes_group(i, cpu_map, &sd->groups, d->tmpmask); d->sd_allnodes = 1; } parent = sd; - sd = &per_cpu(node_domains, i).sd; - SD_INIT(sd, NODE); + sd = sd_init_NODE(d, i); set_domain_attribute(sd, attr); sched_domain_node_span(cpu_to_node(i), sched_domain_span(sd)); sd->parent = parent; if (parent) parent->child = sd; cpumask_and(sched_domain_span(sd), sched_domain_span(sd), cpu_map); - cpu_to_node_group(i, cpu_map, &sd->groups, d->tmpmask); #endif return sd; } @@ -7164,14 +7130,12 @@ static struct sched_domain *__build_cpu_ struct sched_domain *parent, int i) { struct sched_domain *sd; - sd = &per_cpu(phys_domains, i).sd; - SD_INIT(sd, CPU); + sd = sd_init_CPU(d, i); set_domain_attribute(sd, attr); cpumask_copy(sched_domain_span(sd), d->nodemask); sd->parent = parent; if (parent) parent->child = sd; - cpu_to_phys_group(i, cpu_map, &sd->groups, d->tmpmask); return sd; } @@ -7181,13 +7145,11 @@ static struct sched_domain *__build_book { struct sched_domain *sd = parent; #ifdef CONFIG_SCHED_BOOK - sd = &per_cpu(book_domains, i).sd; - SD_INIT(sd, BOOK); + sd = sd_init_BOOK(d, i); set_domain_attribute(sd, attr); cpumask_and(sched_domain_span(sd), cpu_map, cpu_book_mask(i)); sd->parent = parent; parent->child = sd; - cpu_to_book_group(i, cpu_map, &sd->groups, d->tmpmask); #endif return sd; } @@ -7198,13 +7160,11 @@ static struct sched_domain *__build_mc_s { struct sched_domain *sd = parent; #ifdef CONFIG_SCHED_MC - sd = &per_cpu(core_domains, i).sd; - SD_INIT(sd, MC); + sd = sd_init_MC(d, i); set_domain_attribute(sd, attr); cpumask_and(sched_domain_span(sd), cpu_map, cpu_coregroup_mask(i)); sd->parent = parent; parent->child = sd; - cpu_to_core_group(i, cpu_map, &sd->groups, d->tmpmask); #endif return sd; } @@ -7215,92 +7175,32 @@ static struct sched_domain *__build_smt_ { struct sched_domain *sd = parent; #ifdef CONFIG_SCHED_SMT - sd = &per_cpu(cpu_domains, i).sd; - SD_INIT(sd, SIBLING); + sd = sd_init_SIBLING(d, i); set_domain_attribute(sd, attr); cpumask_and(sched_domain_span(sd), cpu_map, topology_thread_cpumask(i)); sd->parent = parent; parent->child = sd; - cpu_to_cpu_group(i, cpu_map, &sd->groups, d->tmpmask); #endif return sd; } -static void build_sched_groups(struct s_data *d, struct sched_domain *sd, - const struct cpumask *cpu_map, int cpu) -{ - switch (sd->level) { -#ifdef CONFIG_SCHED_SMT - case SD_LV_SIBLING: /* set up CPU (sibling) groups */ - if (cpu == cpumask_first(sched_domain_span(sd))) - init_sched_build_groups(sched_domain_span(sd), cpu_map, - &cpu_to_cpu_group, - d->send_covered, d->tmpmask); - break; -#endif -#ifdef CONFIG_SCHED_MC - case SD_LV_MC: /* set up multi-core groups */ - if (cpu == cpumask_first(sched_domain_span(sd))) - init_sched_build_groups(sched_domain_span(sd), cpu_map, - &cpu_to_core_group, - d->send_covered, d->tmpmask); - break; -#endif -#ifdef CONFIG_SCHED_BOOK - case SD_LV_BOOK: /* set up book groups */ - if (cpu == cpumask_first(sched_domain_span(sd))) - init_sched_build_groups(sched_domain_span(sd), cpu_map, - &cpu_to_book_group, - d->send_covered, d->tmpmask); - break; -#endif - case SD_LV_CPU: /* set up physical groups */ - if (cpu == cpumask_first(sched_domain_span(sd))) - init_sched_build_groups(sched_domain_span(sd), cpu_map, - &cpu_to_phys_group, - d->send_covered, d->tmpmask); - break; -#ifdef CONFIG_NUMA - case SD_LV_NODE: - if (cpu == cpumask_first(sched_domain_span(sd))) - init_sched_build_groups(sched_domain_span(sd), cpu_map, - &cpu_to_node_group, - d->send_covered, d->tmpmask); - - case SD_LV_ALLNODES: - if (cpu == cpumask_first(cpu_map)) - init_sched_build_groups(cpu_map, cpu_map, - &cpu_to_allnodes_group, - d->send_covered, d->tmpmask); - break; -#endif - default: - break; - } -} - /* * Build sched domains for a given set of cpus and attach the sched domains * to the individual cpus */ -static int __build_sched_domains(const struct cpumask *cpu_map, - struct sched_domain_attr *attr) +static int build_sched_domains(const struct cpumask *cpu_map, + struct sched_domain_attr *attr) { enum s_alloc alloc_state = sa_none; + struct sched_domain *sd; struct s_data d; - struct sched_domain *sd, *tmp; int i; -#ifdef CONFIG_NUMA - d.sd_allnodes = 0; -#endif alloc_state = __visit_domain_allocation_hell(&d, cpu_map); if (alloc_state != sa_rootdomain) goto error; - /* - * Set up domains for cpus specified by the cpu_map. - */ + /* Set up domains for cpus specified by the cpu_map. */ for_each_cpu(i, cpu_map) { cpumask_and(d.nodemask, cpumask_of_node(cpu_to_node(i)), cpu_map); @@ -7312,10 +7212,19 @@ static int __build_sched_domains(const s sd = __build_smt_sched_domain(&d, cpu_map, attr, sd, i); *per_cpu_ptr(d.sd, i) = sd; + } + + /* Build the groups for the domains */ + for_each_cpu(i, cpu_map) { + for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { + sd->span_weight = cpumask_weight(sched_domain_span(sd)); + get_group(i, sd->private, &sd->groups); + atomic_inc(&sd->groups->ref); - for (tmp = sd; tmp; tmp = tmp->parent) { - tmp->span_weight = cpumask_weight(sched_domain_span(tmp)); - build_sched_groups(&d, tmp, cpu_map, i); + if (i != cpumask_first(sched_domain_span(sd))) + continue; + + build_sched_groups(sd, d.send_covered); } } @@ -7324,18 +7233,22 @@ static int __build_sched_domains(const s if (!cpumask_test_cpu(i, cpu_map)) continue; - sd = *per_cpu_ptr(d.sd, i); - for (; sd; sd = sd->parent) + for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { + claim_allocations(i, sd); init_sched_groups_power(i, sd); + } } /* Attach the domains */ + rcu_read_lock(); for_each_cpu(i, cpu_map) { sd = *per_cpu_ptr(d.sd, i); cpu_attach_domain(sd, d.rd, i); +// sched_domain_debug(sd, i); } + rcu_read_unlock(); - __free_domain_allocs(&d, sa_tmpmask, cpu_map); + __free_domain_allocs(&d, sa_sd, cpu_map); return 0; error: @@ -7343,11 +7256,6 @@ static int __build_sched_domains(const s return -ENOMEM; } -static int build_sched_domains(const struct cpumask *cpu_map) -{ - return __build_sched_domains(cpu_map, NULL); -} - static cpumask_var_t *doms_cur; /* current sched domains */ static int ndoms_cur; /* number of sched domains in 'doms_cur' */ static struct sched_domain_attr *dattr_cur; @@ -7411,31 +7319,24 @@ static int init_sched_domains(const stru doms_cur = &fallback_doms; cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); dattr_cur = NULL; - err = build_sched_domains(doms_cur[0]); + err = build_sched_domains(doms_cur[0], NULL); register_sched_domain_sysctl(); return err; } -static void destroy_sched_domains(const struct cpumask *cpu_map, - struct cpumask *tmpmask) -{ -} - /* * Detach sched domains from a group of cpus specified in cpu_map * These cpus will now be attached to the NULL domain */ static void detach_destroy_domains(const struct cpumask *cpu_map) { - /* Save because hotplug lock held. */ - static DECLARE_BITMAP(tmpmask, CONFIG_NR_CPUS); int i; + rcu_read_lock(); for_each_cpu(i, cpu_map) cpu_attach_domain(NULL, &def_root_domain, i); - synchronize_sched(); - destroy_sched_domains(cpu_map, to_cpumask(tmpmask)); + rcu_read_unlock(); } /* handle null as "default" */ @@ -7524,8 +7425,7 @@ void partition_sched_domains(int ndoms_n goto match2; } /* no match - add a new doms_new */ - __build_sched_domains(doms_new[i], - dattr_new ? dattr_new + i : NULL); + build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); match2: ; } Index: linux-2.6/kernel/sched_fair.c =================================================================== --- linux-2.6.orig/kernel/sched_fair.c +++ linux-2.6/kernel/sched_fair.c @@ -1621,6 +1621,7 @@ static int select_idle_sibling(struct ta /* * Otherwise, iterate the domains and find an elegible idle cpu. */ + rcu_read_lock(); for_each_domain(target, sd) { if (!(sd->flags & SD_SHARE_PKG_RESOURCES)) break; @@ -1640,6 +1641,7 @@ static int select_idle_sibling(struct ta cpumask_test_cpu(prev_cpu, sched_domain_span(sd))) break; } + rcu_read_unlock(); return target; } @@ -1672,6 +1674,7 @@ select_task_rq_fair(struct rq *rq, struc new_cpu = prev_cpu; } + rcu_read_lock(); for_each_domain(cpu, tmp) { if (!(tmp->flags & SD_LOAD_BALANCE)) continue; @@ -1722,9 +1725,10 @@ select_task_rq_fair(struct rq *rq, struc if (affine_sd) { if (cpu == prev_cpu || wake_affine(affine_sd, p, sync)) - return select_idle_sibling(p, cpu); - else - return select_idle_sibling(p, prev_cpu); + prev_cpu = cpu; + + new_cpu = select_idle_sibling(p, prev_cpu); + goto unlock; } while (sd) { @@ -1765,6 +1769,8 @@ select_task_rq_fair(struct rq *rq, struc } /* while loop will break here if sd == NULL */ } +unlock: + rcu_read_unlock(); return new_cpu; } @@ -3466,6 +3472,7 @@ static void idle_balance(int this_cpu, s raw_spin_unlock(&this_rq->lock); update_shares(this_cpu); + rcu_read_lock(); for_each_domain(this_cpu, sd) { unsigned long interval; int balance = 1; @@ -3487,6 +3494,7 @@ static void idle_balance(int this_cpu, s break; } } + rcu_read_unlock(); raw_spin_lock(&this_rq->lock); @@ -3535,6 +3543,7 @@ static int active_load_balance_cpu_stop( double_lock_balance(busiest_rq, target_rq); /* Search for an sd spanning us and the target CPU. */ + rcu_read_lock(); for_each_domain(target_cpu, sd) { if ((sd->flags & SD_LOAD_BALANCE) && cpumask_test_cpu(busiest_cpu, sched_domain_span(sd))) @@ -3550,6 +3559,7 @@ static int active_load_balance_cpu_stop( else schedstat_inc(sd, alb_failed); } + rcu_read_unlock(); double_unlock_balance(busiest_rq, target_rq); out_unlock: busiest_rq->active_balance = 0; @@ -3676,6 +3686,7 @@ static int find_new_ilb(int cpu) { struct sched_domain *sd; struct sched_group *ilb_group; + int ilb = nr_cpu_ids; /* * Have idle load balancer selection from semi-idle packages only @@ -3691,20 +3702,25 @@ static int find_new_ilb(int cpu) if (cpumask_weight(nohz.idle_cpus_mask) < 2) goto out_done; + rcu_read_lock(); for_each_flag_domain(cpu, sd, SD_POWERSAVINGS_BALANCE) { ilb_group = sd->groups; do { - if (is_semi_idle_group(ilb_group)) - return cpumask_first(nohz.grp_idle_mask); + if (is_semi_idle_group(ilb_group)) { + ilb = cpumask_first(nohz.grp_idle_mask); + goto unlock; + } ilb_group = ilb_group->next; } while (ilb_group != sd->groups); } +unlock: + rcu_read_unlock(); out_done: - return nr_cpu_ids; + return ilb; } #else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */ static inline int find_new_ilb(int call_cpu) @@ -3838,6 +3854,7 @@ static void rebalance_domains(int cpu, e update_shares(cpu); + rcu_read_lock(); for_each_domain(cpu, sd) { if (!(sd->flags & SD_LOAD_BALANCE)) continue; @@ -3886,6 +3903,7 @@ static void rebalance_domains(int cpu, e if (!balance) break; } + rcu_read_unlock(); /* * next_balance will be updated only when there is a need.