diff options
| -rw-r--r-- | include/linux/freezer.h | 48 | ||||
| -rw-r--r-- | include/linux/sched.h | 1 | ||||
| -rw-r--r-- | kernel/fork.c | 3 | ||||
| -rw-r--r-- | kernel/power/process.c | 29 |
4 files changed, 59 insertions, 22 deletions
diff --git a/include/linux/freezer.h b/include/linux/freezer.h index db5423eae24..c9435252e8e 100644 --- a/include/linux/freezer.h +++ b/include/linux/freezer.h @@ -81,7 +81,49 @@ static inline int try_to_freeze(void) return 0; } -extern void thaw_some_processes(int all); +/* + * The PF_FREEZER_SKIP flag should be set by a vfork parent right before it + * calls wait_for_completion(&vfork) and reset right after it returns from this + * function. Next, the parent should call try_to_freeze() to freeze itself + * appropriately in case the child has exited before the freezing of tasks is + * complete. However, we don't want kernel threads to be frozen in unexpected + * places, so we allow them to block freeze_processes() instead or to set + * PF_NOFREEZE if needed and PF_FREEZER_SKIP is only set for userland vfork + * parents. Fortunately, in the ____call_usermodehelper() case the parent won't + * really block freeze_processes(), since ____call_usermodehelper() (the child) + * does a little before exec/exit and it can't be frozen before waking up the + * parent. + */ + +/* + * If the current task is a user space one, tell the freezer not to count it as + * freezable. + */ +static inline void freezer_do_not_count(void) +{ + if (current->mm) + current->flags |= PF_FREEZER_SKIP; +} + +/* + * If the current task is a user space one, tell the freezer to count it as + * freezable again and try to freeze it. + */ +static inline void freezer_count(void) +{ + if (current->mm) { + current->flags &= ~PF_FREEZER_SKIP; + try_to_freeze(); + } +} + +/* + * Check if the task should be counted as freezeable by the freezer + */ +static inline int freezer_should_skip(struct task_struct *p) +{ + return !!(p->flags & PF_FREEZER_SKIP); +} #else static inline int frozen(struct task_struct *p) { return 0; } @@ -96,5 +138,7 @@ static inline void thaw_processes(void) {} static inline int try_to_freeze(void) { return 0; } - +static inline void freezer_do_not_count(void) {} +static inline void freezer_count(void) {} +static inline int freezer_should_skip(struct task_struct *p) { return 0; } #endif diff --git a/include/linux/sched.h b/include/linux/sched.h index a81897e2a24..870b75e348a 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1182,6 +1182,7 @@ static inline void put_task_struct(struct task_struct *t) #define PF_SPREAD_SLAB 0x02000000 /* Spread some slab caches over cpuset */ #define PF_MEMPOLICY 0x10000000 /* Non-default NUMA mempolicy */ #define PF_MUTEX_TESTER 0x20000000 /* Thread belongs to the rt mutex tester */ +#define PF_FREEZER_SKIP 0x40000000 /* Freezer should not count it as freezeable */ /* * Only the _current_ task can read/write to tsk->flags, but other diff --git a/kernel/fork.c b/kernel/fork.c index 87069cfc18a..73ad5cda1bc 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -45,6 +45,7 @@ #include <linux/acct.h> #include <linux/tsacct_kern.h> #include <linux/cn_proc.h> +#include <linux/freezer.h> #include <linux/delayacct.h> #include <linux/taskstats_kern.h> #include <linux/random.h> @@ -1405,7 +1406,9 @@ long do_fork(unsigned long clone_flags, } if (clone_flags & CLONE_VFORK) { + freezer_do_not_count(); wait_for_completion(&vfork); + freezer_count(); if (unlikely (current->ptrace & PT_TRACE_VFORK_DONE)) { current->ptrace_message = nr; ptrace_notify ((PTRACE_EVENT_VFORK_DONE << 8) | SIGTRAP); diff --git a/kernel/power/process.c b/kernel/power/process.c index 02e490e311e..eefca8581fa 100644 --- a/kernel/power/process.c +++ b/kernel/power/process.c @@ -120,22 +120,12 @@ static unsigned int try_to_freeze_tasks(int freeze_user_space) cancel_freezing(p); continue; } - if (is_user_space(p)) { - if (!freeze_user_space) - continue; - - /* Freeze the task unless there is a vfork - * completion pending - */ - if (!p->vfork_done) - freeze_process(p); - } else { - if (freeze_user_space) - continue; - - freeze_process(p); - } - todo++; + if (is_user_space(p) == !freeze_user_space) + continue; + + freeze_process(p); + if (!freezer_should_skip(p)) + todo++; } while_each_thread(g, p); read_unlock(&tasklist_lock); yield(); /* Yield is okay here */ @@ -161,7 +151,8 @@ static unsigned int try_to_freeze_tasks(int freeze_user_space) continue; task_lock(p); - if (freezeable(p) && !frozen(p)) + if (freezeable(p) && !frozen(p) && + !freezer_should_skip(p)) printk(KERN_ERR " %s\n", p->comm); cancel_freezing(p); @@ -210,9 +201,7 @@ static void thaw_tasks(int thaw_user_space) if (is_user_space(p) == !thaw_user_space) continue; - if (!thaw_process(p)) - printk(KERN_WARNING " Strange, %s not stopped\n", - p->comm ); + thaw_process(p); } while_each_thread(g, p); read_unlock(&tasklist_lock); } |