diff options
Diffstat (limited to 'features/rt/cpuset-Convert-callback_lock-to-raw_spinlock_t.patch')
| -rw-r--r-- | features/rt/cpuset-Convert-callback_lock-to-raw_spinlock_t.patch | 328 |
1 files changed, 328 insertions, 0 deletions
diff --git a/features/rt/cpuset-Convert-callback_lock-to-raw_spinlock_t.patch b/features/rt/cpuset-Convert-callback_lock-to-raw_spinlock_t.patch new file mode 100644 index 00000000..115f4072 --- /dev/null +++ b/features/rt/cpuset-Convert-callback_lock-to-raw_spinlock_t.patch @@ -0,0 +1,328 @@ +From f2031242ce940802f8703826b47dfd2e1290f97c Mon Sep 17 00:00:00 2001 +From: Mike Galbraith <efault@gmx.de> +Date: Sun, 8 Jan 2017 09:32:25 +0100 +Subject: [PATCH 160/191] cpuset: Convert callback_lock to raw_spinlock_t + +The two commits below add up to a cpuset might_sleep() splat for RT: + +8447a0fee974 cpuset: convert callback_mutex to a spinlock +344736f29b35 cpuset: simplify cpuset_node_allowed API + +BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:995 +in_atomic(): 0, irqs_disabled(): 1, pid: 11718, name: cset +CPU: 135 PID: 11718 Comm: cset Tainted: G E 4.10.0-rt1-rt #4 +Hardware name: Intel Corporation BRICKLAND/BRICKLAND, BIOS BRHSXSD1.86B.0056.R01.1409242327 09/24/2014 +Call Trace: + ? dump_stack+0x5c/0x81 + ? ___might_sleep+0xf4/0x170 + ? rt_spin_lock+0x1c/0x50 + ? __cpuset_node_allowed+0x66/0xc0 + ? ___slab_alloc+0x390/0x570 <disables IRQs> + ? anon_vma_fork+0x8f/0x140 + ? copy_page_range+0x6cf/0xb00 + ? anon_vma_fork+0x8f/0x140 + ? __slab_alloc.isra.74+0x5a/0x81 + ? anon_vma_fork+0x8f/0x140 + ? kmem_cache_alloc+0x1b5/0x1f0 + ? anon_vma_fork+0x8f/0x140 + ? copy_process.part.35+0x1670/0x1ee0 + ? _do_fork+0xdd/0x3f0 + ? _do_fork+0xdd/0x3f0 + ? do_syscall_64+0x61/0x170 + ? entry_SYSCALL64_slow_path+0x25/0x25 + +The later ensured that a NUMA box WILL take callback_lock in atomic +context by removing the allocator and reclaim path __GFP_HARDWALL +usage which prevented such contexts from taking callback_mutex. + +One option would be to reinstate __GFP_HARDWALL protections for +RT, however, as the 8447a0fee974 changelog states: + +The callback_mutex is only used to synchronize reads/updates of cpusets' +flags and cpu/node masks. These operations should always proceed fast so +there's no reason why we can't use a spinlock instead of the mutex. + +Cc: stable-rt@vger.kernel.org +Signed-off-by: Mike Galbraith <efault@gmx.de> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + kernel/cgroup/cpuset.c | 70 +++++++++++++++++++++--------------------- + 1 file changed, 35 insertions(+), 35 deletions(-) + +diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c +index 5258b68153e0..fb8715c1edfc 100644 +--- a/kernel/cgroup/cpuset.c ++++ b/kernel/cgroup/cpuset.c +@@ -345,7 +345,7 @@ void cpuset_read_unlock(void) + percpu_up_read(&cpuset_rwsem); + } + +-static DEFINE_SPINLOCK(callback_lock); ++static DEFINE_RAW_SPINLOCK(callback_lock); + + static struct workqueue_struct *cpuset_migrate_mm_wq; + +@@ -1280,7 +1280,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, + * Newly added CPUs will be removed from effective_cpus and + * newly deleted ones will be added back to effective_cpus. + */ +- spin_lock_irq(&callback_lock); ++ raw_spin_lock_irq(&callback_lock); + if (adding) { + cpumask_or(parent->subparts_cpus, + parent->subparts_cpus, tmp->addmask); +@@ -1299,7 +1299,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, + } + + parent->nr_subparts_cpus = cpumask_weight(parent->subparts_cpus); +- spin_unlock_irq(&callback_lock); ++ raw_spin_unlock_irq(&callback_lock); + + return cmd == partcmd_update; + } +@@ -1404,7 +1404,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) + continue; + rcu_read_unlock(); + +- spin_lock_irq(&callback_lock); ++ raw_spin_lock_irq(&callback_lock); + + cpumask_copy(cp->effective_cpus, tmp->new_cpus); + if (cp->nr_subparts_cpus && +@@ -1435,7 +1435,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) + = cpumask_weight(cp->subparts_cpus); + } + } +- spin_unlock_irq(&callback_lock); ++ raw_spin_unlock_irq(&callback_lock); + + WARN_ON(!is_in_v2_mode() && + !cpumask_equal(cp->cpus_allowed, cp->effective_cpus)); +@@ -1553,7 +1553,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, + return -EINVAL; + } + +- spin_lock_irq(&callback_lock); ++ raw_spin_lock_irq(&callback_lock); + cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed); + + /* +@@ -1564,7 +1564,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, + cs->cpus_allowed); + cs->nr_subparts_cpus = cpumask_weight(cs->subparts_cpus); + } +- spin_unlock_irq(&callback_lock); ++ raw_spin_unlock_irq(&callback_lock); + + update_cpumasks_hier(cs, &tmp); + +@@ -1758,9 +1758,9 @@ static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems) + continue; + rcu_read_unlock(); + +- spin_lock_irq(&callback_lock); ++ raw_spin_lock_irq(&callback_lock); + cp->effective_mems = *new_mems; +- spin_unlock_irq(&callback_lock); ++ raw_spin_unlock_irq(&callback_lock); + + WARN_ON(!is_in_v2_mode() && + !nodes_equal(cp->mems_allowed, cp->effective_mems)); +@@ -1828,9 +1828,9 @@ static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs, + if (retval < 0) + goto done; + +- spin_lock_irq(&callback_lock); ++ raw_spin_lock_irq(&callback_lock); + cs->mems_allowed = trialcs->mems_allowed; +- spin_unlock_irq(&callback_lock); ++ raw_spin_unlock_irq(&callback_lock); + + /* use trialcs->mems_allowed as a temp variable */ + update_nodemasks_hier(cs, &trialcs->mems_allowed); +@@ -1921,9 +1921,9 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, + spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs)) + || (is_spread_page(cs) != is_spread_page(trialcs))); + +- spin_lock_irq(&callback_lock); ++ raw_spin_lock_irq(&callback_lock); + cs->flags = trialcs->flags; +- spin_unlock_irq(&callback_lock); ++ raw_spin_unlock_irq(&callback_lock); + + if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed) + rebuild_sched_domains_locked(); +@@ -2432,7 +2432,7 @@ static int cpuset_common_seq_show(struct seq_file *sf, void *v) + cpuset_filetype_t type = seq_cft(sf)->private; + int ret = 0; + +- spin_lock_irq(&callback_lock); ++ raw_spin_lock_irq(&callback_lock); + + switch (type) { + case FILE_CPULIST: +@@ -2454,7 +2454,7 @@ static int cpuset_common_seq_show(struct seq_file *sf, void *v) + ret = -EINVAL; + } + +- spin_unlock_irq(&callback_lock); ++ raw_spin_unlock_irq(&callback_lock); + return ret; + } + +@@ -2767,14 +2767,14 @@ static int cpuset_css_online(struct cgroup_subsys_state *css) + + cpuset_inc(); + +- spin_lock_irq(&callback_lock); ++ raw_spin_lock_irq(&callback_lock); + if (is_in_v2_mode()) { + cpumask_copy(cs->effective_cpus, parent->effective_cpus); + cs->effective_mems = parent->effective_mems; + cs->use_parent_ecpus = true; + parent->child_ecpus_count++; + } +- spin_unlock_irq(&callback_lock); ++ raw_spin_unlock_irq(&callback_lock); + + if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags)) + goto out_unlock; +@@ -2801,12 +2801,12 @@ static int cpuset_css_online(struct cgroup_subsys_state *css) + } + rcu_read_unlock(); + +- spin_lock_irq(&callback_lock); ++ raw_spin_lock_irq(&callback_lock); + cs->mems_allowed = parent->mems_allowed; + cs->effective_mems = parent->mems_allowed; + cpumask_copy(cs->cpus_allowed, parent->cpus_allowed); + cpumask_copy(cs->effective_cpus, parent->cpus_allowed); +- spin_unlock_irq(&callback_lock); ++ raw_spin_unlock_irq(&callback_lock); + out_unlock: + percpu_up_write(&cpuset_rwsem); + put_online_cpus(); +@@ -2862,7 +2862,7 @@ static void cpuset_css_free(struct cgroup_subsys_state *css) + static void cpuset_bind(struct cgroup_subsys_state *root_css) + { + percpu_down_write(&cpuset_rwsem); +- spin_lock_irq(&callback_lock); ++ raw_spin_lock_irq(&callback_lock); + + if (is_in_v2_mode()) { + cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask); +@@ -2873,7 +2873,7 @@ static void cpuset_bind(struct cgroup_subsys_state *root_css) + top_cpuset.mems_allowed = top_cpuset.effective_mems; + } + +- spin_unlock_irq(&callback_lock); ++ raw_spin_unlock_irq(&callback_lock); + percpu_up_write(&cpuset_rwsem); + } + +@@ -2970,12 +2970,12 @@ hotplug_update_tasks_legacy(struct cpuset *cs, + { + bool is_empty; + +- spin_lock_irq(&callback_lock); ++ raw_spin_lock_irq(&callback_lock); + cpumask_copy(cs->cpus_allowed, new_cpus); + cpumask_copy(cs->effective_cpus, new_cpus); + cs->mems_allowed = *new_mems; + cs->effective_mems = *new_mems; +- spin_unlock_irq(&callback_lock); ++ raw_spin_unlock_irq(&callback_lock); + + /* + * Don't call update_tasks_cpumask() if the cpuset becomes empty, +@@ -3012,10 +3012,10 @@ hotplug_update_tasks(struct cpuset *cs, + if (nodes_empty(*new_mems)) + *new_mems = parent_cs(cs)->effective_mems; + +- spin_lock_irq(&callback_lock); ++ raw_spin_lock_irq(&callback_lock); + cpumask_copy(cs->effective_cpus, new_cpus); + cs->effective_mems = *new_mems; +- spin_unlock_irq(&callback_lock); ++ raw_spin_unlock_irq(&callback_lock); + + if (cpus_updated) + update_tasks_cpumask(cs); +@@ -3170,7 +3170,7 @@ static void cpuset_hotplug_workfn(struct work_struct *work) + + /* synchronize cpus_allowed to cpu_active_mask */ + if (cpus_updated) { +- spin_lock_irq(&callback_lock); ++ raw_spin_lock_irq(&callback_lock); + if (!on_dfl) + cpumask_copy(top_cpuset.cpus_allowed, &new_cpus); + /* +@@ -3190,17 +3190,17 @@ static void cpuset_hotplug_workfn(struct work_struct *work) + } + } + cpumask_copy(top_cpuset.effective_cpus, &new_cpus); +- spin_unlock_irq(&callback_lock); ++ raw_spin_unlock_irq(&callback_lock); + /* we don't mess with cpumasks of tasks in top_cpuset */ + } + + /* synchronize mems_allowed to N_MEMORY */ + if (mems_updated) { +- spin_lock_irq(&callback_lock); ++ raw_spin_lock_irq(&callback_lock); + if (!on_dfl) + top_cpuset.mems_allowed = new_mems; + top_cpuset.effective_mems = new_mems; +- spin_unlock_irq(&callback_lock); ++ raw_spin_unlock_irq(&callback_lock); + update_tasks_nodemask(&top_cpuset); + } + +@@ -3301,11 +3301,11 @@ void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask) + { + unsigned long flags; + +- spin_lock_irqsave(&callback_lock, flags); ++ raw_spin_lock_irqsave(&callback_lock, flags); + rcu_read_lock(); + guarantee_online_cpus(task_cs(tsk), pmask); + rcu_read_unlock(); +- spin_unlock_irqrestore(&callback_lock, flags); ++ raw_spin_unlock_irqrestore(&callback_lock, flags); + } + + /** +@@ -3366,11 +3366,11 @@ nodemask_t cpuset_mems_allowed(struct task_struct *tsk) + nodemask_t mask; + unsigned long flags; + +- spin_lock_irqsave(&callback_lock, flags); ++ raw_spin_lock_irqsave(&callback_lock, flags); + rcu_read_lock(); + guarantee_online_mems(task_cs(tsk), &mask); + rcu_read_unlock(); +- spin_unlock_irqrestore(&callback_lock, flags); ++ raw_spin_unlock_irqrestore(&callback_lock, flags); + + return mask; + } +@@ -3462,14 +3462,14 @@ bool __cpuset_node_allowed(int node, gfp_t gfp_mask) + return true; + + /* Not hardwall and node outside mems_allowed: scan up cpusets */ +- spin_lock_irqsave(&callback_lock, flags); ++ raw_spin_lock_irqsave(&callback_lock, flags); + + rcu_read_lock(); + cs = nearest_hardwall_ancestor(task_cs(current)); + allowed = node_isset(node, cs->mems_allowed); + rcu_read_unlock(); + +- spin_unlock_irqrestore(&callback_lock, flags); ++ raw_spin_unlock_irqrestore(&callback_lock, flags); + return allowed; + } + +-- +2.19.1 + |