diff options
Diffstat (limited to 'fs/proc')
| -rw-r--r-- | fs/proc/internal.h | 4 | ||||
| -rw-r--r-- | fs/proc/stat.c | 14 | ||||
| -rw-r--r-- | fs/proc/task_mmu.c | 53 |
3 files changed, 64 insertions, 7 deletions
diff --git a/fs/proc/internal.h b/fs/proc/internal.h index cceaab07ad54..43973b084abf 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -12,6 +12,7 @@ #include <linux/sched.h> #include <linux/proc_fs.h> struct ctl_table_header; +struct mempolicy; extern struct proc_dir_entry proc_root; #ifdef CONFIG_PROC_SYSCTL @@ -74,6 +75,9 @@ struct proc_maps_private { #ifdef CONFIG_MMU struct vm_area_struct *tail_vma; #endif +#ifdef CONFIG_NUMA + struct mempolicy *task_mempolicy; +#endif }; void proc_init_inodecache(void); diff --git a/fs/proc/stat.c b/fs/proc/stat.c index 64c3b3172367..e296572c73ed 100644 --- a/fs/proc/stat.c +++ b/fs/proc/stat.c @@ -45,10 +45,13 @@ static cputime64_t get_iowait_time(int cpu) static u64 get_idle_time(int cpu) { - u64 idle, idle_time = get_cpu_idle_time_us(cpu, NULL); + u64 idle, idle_time = -1ULL; + + if (cpu_online(cpu)) + idle_time = get_cpu_idle_time_us(cpu, NULL); if (idle_time == -1ULL) - /* !NO_HZ so we can rely on cpustat.idle */ + /* !NO_HZ or cpu offline so we can rely on cpustat.idle */ idle = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE]; else idle = usecs_to_cputime64(idle_time); @@ -58,10 +61,13 @@ static u64 get_idle_time(int cpu) static u64 get_iowait_time(int cpu) { - u64 iowait, iowait_time = get_cpu_iowait_time_us(cpu, NULL); + u64 iowait, iowait_time = -1ULL; + + if (cpu_online(cpu)) + iowait_time = get_cpu_iowait_time_us(cpu, NULL); if (iowait_time == -1ULL) - /* !NO_HZ so we can rely on cpustat.iowait */ + /* !NO_HZ or cpu offline so we can rely on cpustat.iowait */ iowait = kcpustat_cpu(cpu).cpustat[CPUTIME_IOWAIT]; else iowait = usecs_to_cputime64(iowait_time); diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 79827ce03e3b..90c63f9392a5 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -90,10 +90,55 @@ static void pad_len_spaces(struct seq_file *m, int len) seq_printf(m, "%*c", len, ' '); } +#ifdef CONFIG_NUMA +/* + * These functions are for numa_maps but called in generic **maps seq_file + * ->start(), ->stop() ops. + * + * numa_maps scans all vmas under mmap_sem and checks their mempolicy. + * Each mempolicy object is controlled by reference counting. The problem here + * is how to avoid accessing dead mempolicy object. + * + * Because we're holding mmap_sem while reading seq_file, it's safe to access + * each vma's mempolicy, no vma objects will never drop refs to mempolicy. + * + * A task's mempolicy (task->mempolicy) has different behavior. task->mempolicy + * is set and replaced under mmap_sem but unrefed and cleared under task_lock(). + * So, without task_lock(), we cannot trust get_vma_policy() because we cannot + * gurantee the task never exits under us. But taking task_lock() around + * get_vma_plicy() causes lock order problem. + * + * To access task->mempolicy without lock, we hold a reference count of an + * object pointed by task->mempolicy and remember it. This will guarantee + * that task->mempolicy points to an alive object or NULL in numa_maps accesses. + */ +static void hold_task_mempolicy(struct proc_maps_private *priv) +{ + struct task_struct *task = priv->task; + + task_lock(task); + priv->task_mempolicy = task->mempolicy; + mpol_get(priv->task_mempolicy); + task_unlock(task); +} +static void release_task_mempolicy(struct proc_maps_private *priv) +{ + mpol_put(priv->task_mempolicy); +} +#else +static void hold_task_mempolicy(struct proc_maps_private *priv) +{ +} +static void release_task_mempolicy(struct proc_maps_private *priv) +{ +} +#endif + static void vma_stop(struct proc_maps_private *priv, struct vm_area_struct *vma) { if (vma && vma != priv->tail_vma) { struct mm_struct *mm = vma->vm_mm; + release_task_mempolicy(priv); up_read(&mm->mmap_sem); mmput(mm); } @@ -132,7 +177,7 @@ static void *m_start(struct seq_file *m, loff_t *pos) tail_vma = get_gate_vma(priv->task->mm); priv->tail_vma = tail_vma; - + hold_task_mempolicy(priv); /* Start with last addr hint */ vma = find_vma(mm, last_addr); if (last_addr && vma) { @@ -159,6 +204,7 @@ out: if (vma) return vma; + release_task_mempolicy(priv); /* End of vmas has been reached */ m->version = (tail_vma != NULL)? 0: -1UL; up_read(&mm->mmap_sem); @@ -1158,6 +1204,7 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid) struct vm_area_struct *vma = v; struct numa_maps *md = &numa_priv->md; struct file *file = vma->vm_file; + struct task_struct *task = proc_priv->task; struct mm_struct *mm = vma->vm_mm; struct mm_walk walk = {}; struct mempolicy *pol; @@ -1177,7 +1224,7 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid) walk.private = md; walk.mm = mm; - pol = get_vma_policy(proc_priv->task, vma, vma->vm_start); + pol = get_vma_policy(task, vma, vma->vm_start); mpol_to_str(buffer, sizeof(buffer), pol, 0); mpol_cond_put(pol); @@ -1189,7 +1236,7 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid) } else if (vma->vm_start <= mm->brk && vma->vm_end >= mm->start_brk) { seq_printf(m, " heap"); } else { - pid_t tid = vm_is_stack(proc_priv->task, vma, is_pid); + pid_t tid = vm_is_stack(task, vma, is_pid); if (tid != 0) { /* * Thread stack in /proc/PID/task/TID/maps or |