[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen staging] xen/sched: fix cpu hotplug
commit d84473689611eed32fd90b27e614f28af767fa3f Author: Juergen Gross <jgross@xxxxxxxx> AuthorDate: Mon Sep 5 09:00:05 2022 +0200 Commit: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> CommitDate: Mon Sep 5 11:42:30 2022 +0100 xen/sched: fix cpu hotplug Cpu unplugging is calling schedule_cpu_rm() via stop_machine_run() with interrupts disabled, thus any memory allocation or freeing must be avoided. Since commit 5047cd1d5dea ("xen/common: Use enhanced ASSERT_ALLOC_CONTEXT in xmalloc()") this restriction is being enforced via an assertion, which will now fail. Fix this by allocating needed memory before entering stop_machine_run() and freeing any memory only after having finished stop_machine_run(). Fixes: 1ec410112cdd ("xen/sched: support differing granularity in schedule_cpu_[add/rm]()") Reported-by: Gao Ruifeng <ruifeng.gao@xxxxxxxxx> Signed-off-by: Juergen Gross <jgross@xxxxxxxx> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx> Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> Tested-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> --- xen/common/sched/core.c | 25 +++++++++++++---- xen/common/sched/cpupool.c | 69 ++++++++++++++++++++++++++++++++++++---------- xen/common/sched/private.h | 5 ++-- 3 files changed, 77 insertions(+), 22 deletions(-) diff --git a/xen/common/sched/core.c b/xen/common/sched/core.c index 588826cdbd..83455fbde1 100644 --- a/xen/common/sched/core.c +++ b/xen/common/sched/core.c @@ -3247,7 +3247,7 @@ out: * by alloc_cpu_rm_data() is modified only in case the cpu in question is * being moved from or to a cpupool. */ -struct cpu_rm_data *alloc_cpu_rm_data(unsigned int cpu) +struct cpu_rm_data *alloc_cpu_rm_data(unsigned int cpu, bool aff_alloc) { struct cpu_rm_data *data; const struct sched_resource *sr; @@ -3260,6 +3260,17 @@ struct cpu_rm_data *alloc_cpu_rm_data(unsigned int cpu) if ( !data ) goto out; + if ( aff_alloc ) + { + if ( !alloc_affinity_masks(&data->affinity) ) + { + XFREE(data); + goto out; + } + } + else + memset(&data->affinity, 0, sizeof(data->affinity)); + data->old_ops = sr->scheduler; data->vpriv_old = idle_vcpu[cpu]->sched_unit->priv; data->ppriv_old = sr->sched_priv; @@ -3280,6 +3291,7 @@ struct cpu_rm_data *alloc_cpu_rm_data(unsigned int cpu) { while ( idx > 0 ) sched_res_free(&data->sr[--idx]->rcu); + free_affinity_masks(&data->affinity); XFREE(data); goto out; } @@ -3302,6 +3314,7 @@ void free_cpu_rm_data(struct cpu_rm_data *mem, unsigned int cpu) { sched_free_udata(mem->old_ops, mem->vpriv_old); sched_free_pdata(mem->old_ops, mem->ppriv_old, cpu); + free_affinity_masks(&mem->affinity); xfree(mem); } @@ -3312,17 +3325,18 @@ void free_cpu_rm_data(struct cpu_rm_data *mem, unsigned int cpu) * The cpu is already marked as "free" and not valid any longer for its * cpupool. */ -int schedule_cpu_rm(unsigned int cpu) +int schedule_cpu_rm(unsigned int cpu, struct cpu_rm_data *data) { struct sched_resource *sr; - struct cpu_rm_data *data; struct sched_unit *unit; spinlock_t *old_lock; unsigned long flags; int idx = 0; unsigned int cpu_iter; + bool free_data = !data; - data = alloc_cpu_rm_data(cpu); + if ( !data ) + data = alloc_cpu_rm_data(cpu, false); if ( !data ) return -ENOMEM; @@ -3390,7 +3404,8 @@ int schedule_cpu_rm(unsigned int cpu) sched_deinit_pdata(data->old_ops, data->ppriv_old, cpu); rcu_read_unlock(&sched_res_rculock); - free_cpu_rm_data(data, cpu); + if ( free_data ) + free_cpu_rm_data(data, cpu); return 0; } diff --git a/xen/common/sched/cpupool.c b/xen/common/sched/cpupool.c index aac3a269b7..b2c6f520c3 100644 --- a/xen/common/sched/cpupool.c +++ b/xen/common/sched/cpupool.c @@ -411,22 +411,28 @@ int cpupool_move_domain(struct domain *d, struct cpupool *c) } /* Update affinities of all domains in a cpupool. */ -static void cpupool_update_node_affinity(const struct cpupool *c) +static void cpupool_update_node_affinity(const struct cpupool *c, + struct affinity_masks *masks) { - struct affinity_masks masks; + struct affinity_masks local_masks; struct domain *d; - if ( !alloc_affinity_masks(&masks) ) - return; + if ( !masks ) + { + if ( !alloc_affinity_masks(&local_masks) ) + return; + masks = &local_masks; + } rcu_read_lock(&domlist_read_lock); for_each_domain_in_cpupool(d, c) - domain_update_node_aff(d, &masks); + domain_update_node_aff(d, masks); rcu_read_unlock(&domlist_read_lock); - free_affinity_masks(&masks); + if ( masks == &local_masks ) + free_affinity_masks(masks); } /* @@ -460,15 +466,17 @@ static int cpupool_assign_cpu_locked(struct cpupool *c, unsigned int cpu) rcu_read_unlock(&sched_res_rculock); - cpupool_update_node_affinity(c); + cpupool_update_node_affinity(c, NULL); return 0; } -static int cpupool_unassign_cpu_finish(struct cpupool *c) +static int cpupool_unassign_cpu_finish(struct cpupool *c, + struct cpu_rm_data *mem) { int cpu = cpupool_moving_cpu; const cpumask_t *cpus; + struct affinity_masks *masks = mem ? &mem->affinity : NULL; int ret; if ( c != cpupool_cpu_moving ) @@ -491,7 +499,7 @@ static int cpupool_unassign_cpu_finish(struct cpupool *c) */ if ( !ret ) { - ret = schedule_cpu_rm(cpu); + ret = schedule_cpu_rm(cpu, mem); if ( ret ) cpumask_andnot(&cpupool_free_cpus, &cpupool_free_cpus, cpus); else @@ -503,7 +511,7 @@ static int cpupool_unassign_cpu_finish(struct cpupool *c) } rcu_read_unlock(&sched_res_rculock); - cpupool_update_node_affinity(c); + cpupool_update_node_affinity(c, masks); return ret; } @@ -567,7 +575,7 @@ static long cf_check cpupool_unassign_cpu_helper(void *info) cpupool_cpu_moving->cpupool_id, cpupool_moving_cpu); spin_lock(&cpupool_lock); - ret = cpupool_unassign_cpu_finish(c); + ret = cpupool_unassign_cpu_finish(c, NULL); spin_unlock(&cpupool_lock); debugtrace_printk("cpupool_unassign_cpu ret=%ld\n", ret); @@ -714,7 +722,7 @@ static int cpupool_cpu_add(unsigned int cpu) * This function is called in stop_machine context, so we can be sure no * non-idle vcpu is active on the system. */ -static void cpupool_cpu_remove(unsigned int cpu) +static void cpupool_cpu_remove(unsigned int cpu, struct cpu_rm_data *mem) { int ret; @@ -722,7 +730,7 @@ static void cpupool_cpu_remove(unsigned int cpu) if ( !cpumask_test_cpu(cpu, &cpupool_free_cpus) ) { - ret = cpupool_unassign_cpu_finish(cpupool0); + ret = cpupool_unassign_cpu_finish(cpupool0, mem); BUG_ON(ret); } cpumask_clear_cpu(cpu, &cpupool_free_cpus); @@ -788,7 +796,7 @@ static void cpupool_cpu_remove_forced(unsigned int cpu) { ret = cpupool_unassign_cpu_start(c, master_cpu); BUG_ON(ret); - ret = cpupool_unassign_cpu_finish(c); + ret = cpupool_unassign_cpu_finish(c, NULL); BUG_ON(ret); } } @@ -1006,12 +1014,24 @@ void cf_check dump_runq(unsigned char key) static int cf_check cpu_callback( struct notifier_block *nfb, unsigned long action, void *hcpu) { + static struct cpu_rm_data *mem; + unsigned int cpu = (unsigned long)hcpu; int rc = 0; switch ( action ) { case CPU_DOWN_FAILED: + if ( system_state <= SYS_STATE_active ) + { + if ( mem ) + { + free_cpu_rm_data(mem, cpu); + mem = NULL; + } + rc = cpupool_cpu_add(cpu); + } + break; case CPU_ONLINE: if ( system_state <= SYS_STATE_active ) rc = cpupool_cpu_add(cpu); @@ -1019,12 +1039,31 @@ static int cf_check cpu_callback( case CPU_DOWN_PREPARE: /* Suspend/Resume don't change assignments of cpus to cpupools. */ if ( system_state <= SYS_STATE_active ) + { rc = cpupool_cpu_remove_prologue(cpu); + if ( !rc ) + { + ASSERT(!mem); + mem = alloc_cpu_rm_data(cpu, true); + rc = mem ? 0 : -ENOMEM; + } + } break; case CPU_DYING: /* Suspend/Resume don't change assignments of cpus to cpupools. */ if ( system_state <= SYS_STATE_active ) - cpupool_cpu_remove(cpu); + { + ASSERT(mem); + cpupool_cpu_remove(cpu, mem); + } + break; + case CPU_DEAD: + if ( system_state <= SYS_STATE_active ) + { + ASSERT(mem); + free_cpu_rm_data(mem, cpu); + mem = NULL; + } break; case CPU_RESUME_FAILED: cpupool_cpu_remove_forced(cpu); diff --git a/xen/common/sched/private.h b/xen/common/sched/private.h index e286849a13..0126a4bb9e 100644 --- a/xen/common/sched/private.h +++ b/xen/common/sched/private.h @@ -603,6 +603,7 @@ void free_affinity_masks(struct affinity_masks *affinity); /* Memory allocation related data for schedule_cpu_rm(). */ struct cpu_rm_data { + struct affinity_masks affinity; const struct scheduler *old_ops; void *ppriv_old; void *vpriv_old; @@ -617,9 +618,9 @@ struct scheduler *scheduler_alloc(unsigned int sched_id); void scheduler_free(struct scheduler *sched); int cpu_disable_scheduler(unsigned int cpu); int schedule_cpu_add(unsigned int cpu, struct cpupool *c); -struct cpu_rm_data *alloc_cpu_rm_data(unsigned int cpu); +struct cpu_rm_data *alloc_cpu_rm_data(unsigned int cpu, bool aff_alloc); void free_cpu_rm_data(struct cpu_rm_data *mem, unsigned int cpu); -int schedule_cpu_rm(unsigned int cpu); +int schedule_cpu_rm(unsigned int cpu, struct cpu_rm_data *mem); int sched_move_domain(struct domain *d, struct cpupool *c); struct cpupool *cpupool_get_by_id(unsigned int poolid); void cpupool_put(struct cpupool *pool); -- generated by git-patchbot for /home/xen/git/xen.git#staging
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