diff options
Diffstat (limited to 'kernel/cgroup')
| -rw-r--r-- | kernel/cgroup/cpuset.c | 40 | ||||
| -rw-r--r-- | kernel/cgroup/rstat.c | 25 |
2 files changed, 54 insertions, 11 deletions
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 6d3ac19cc2ac..3bc4301466f3 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -4202,7 +4202,7 @@ static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs) } /* - * cpuset_node_allowed - Can we allocate on a memory node? + * cpuset_current_node_allowed - Can current task allocate on a memory node? * @node: is this an allowed node? * @gfp_mask: memory allocation flags * @@ -4241,7 +4241,7 @@ static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs) * GFP_KERNEL - any node in enclosing hardwalled cpuset ok * GFP_USER - only nodes in current tasks mems allowed ok. */ -bool cpuset_node_allowed(int node, gfp_t gfp_mask) +bool cpuset_current_node_allowed(int node, gfp_t gfp_mask) { struct cpuset *cs; /* current cpuset ancestors */ bool allowed; /* is allocation in zone z allowed? */ @@ -4275,6 +4275,42 @@ bool cpuset_node_allowed(int node, gfp_t gfp_mask) return allowed; } +bool cpuset_node_allowed(struct cgroup *cgroup, int nid) +{ + struct cgroup_subsys_state *css; + struct cpuset *cs; + bool allowed; + + /* + * In v1, mem_cgroup and cpuset are unlikely in the same hierarchy + * and mems_allowed is likely to be empty even if we could get to it, + * so return true to avoid taking a global lock on the empty check. + */ + if (!cpuset_v2()) + return true; + + css = cgroup_get_e_css(cgroup, &cpuset_cgrp_subsys); + if (!css) + return true; + + /* + * Normally, accessing effective_mems would require the cpuset_mutex + * or callback_lock - but node_isset is atomic and the reference + * taken via cgroup_get_e_css is sufficient to protect css. + * + * Since this interface is intended for use by migration paths, we + * relax locking here to avoid taking global locks - while accepting + * there may be rare scenarios where the result may be innaccurate. + * + * Reclaim and migration are subject to these same race conditions, and + * cannot make strong isolation guarantees, so this is acceptable. + */ + cs = container_of(css, struct cpuset, css); + allowed = node_isset(nid, cs->effective_mems); + css_put(css); + return allowed; +} + /** * cpuset_spread_node() - On which node to begin search for a page * @rotor: round robin rotor diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c index ce4752ab9e09..cbeaa499a96a 100644 --- a/kernel/cgroup/rstat.c +++ b/kernel/cgroup/rstat.c @@ -47,8 +47,20 @@ static spinlock_t *ss_rstat_lock(struct cgroup_subsys *ss) static raw_spinlock_t *ss_rstat_cpu_lock(struct cgroup_subsys *ss, int cpu) { - if (ss) + if (ss) { + /* + * Depending on config, the subsystem per-cpu lock type may be an + * empty struct. In enviromnents where this is the case, allocation + * of this field is not performed in ss_rstat_init(). Avoid a + * cpu-based offset relative to NULL by returning early. When the + * lock type is zero in size, the corresponding lock functions are + * no-ops so passing them NULL is acceptable. + */ + if (sizeof(*ss->rstat_ss_cpu_lock) == 0) + return NULL; + return per_cpu_ptr(ss->rstat_ss_cpu_lock, cpu); + } return per_cpu_ptr(&rstat_base_cpu_lock, cpu); } @@ -510,20 +522,15 @@ int __init ss_rstat_init(struct cgroup_subsys *ss) { int cpu; -#ifdef CONFIG_SMP /* - * On uniprocessor machines, arch_spinlock_t is defined as an empty - * struct. Avoid allocating a size of zero by having this block - * excluded in this case. It's acceptable to leave the subsystem locks - * unitialized since the associated lock functions are no-ops in the - * non-smp case. + * Depending on config, the subsystem per-cpu lock type may be an empty + * struct. Avoid allocating a size of zero in this case. */ - if (ss) { + if (ss && sizeof(*ss->rstat_ss_cpu_lock)) { ss->rstat_ss_cpu_lock = alloc_percpu(raw_spinlock_t); if (!ss->rstat_ss_cpu_lock) return -ENOMEM; } -#endif spin_lock_init(ss_rstat_lock(ss)); for_each_possible_cpu(cpu) |