| From 6301cb95c119ebf324bb96ee226fa9ddffad80a7 Mon Sep 17 00:00:00 2001 |
| From: Thomas Gleixner <tglx@linutronix.de> |
| Date: Fri, 17 Jul 2009 14:15:47 +0200 |
| Subject: sched: fix nr_uninterruptible accounting of frozen tasks really |
| |
| From: Thomas Gleixner <tglx@linutronix.de> |
| |
| commit 6301cb95c119ebf324bb96ee226fa9ddffad80a7 upstream. |
| |
| commit e3c8ca8336 (sched: do not count frozen tasks toward load) broke |
| the nr_uninterruptible accounting on freeze/thaw. On freeze the task |
| is excluded from accounting with a check for (task->flags & |
| PF_FROZEN), but that flag is cleared before the task is thawed. So |
| while we prevent that the task with state TASK_UNINTERRUPTIBLE |
| is accounted to nr_uninterruptible on freeze we decrement |
| nr_uninterruptible on thaw. |
| |
| Use a separate flag which is handled by the freezing task itself. Set |
| it before calling the scheduler with TASK_UNINTERRUPTIBLE state and |
| clear it after we return from frozen state. |
| |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| include/linux/sched.h | 3 ++- |
| kernel/freezer.c | 7 +++++++ |
| 2 files changed, 9 insertions(+), 1 deletion(-) |
| |
| --- a/include/linux/sched.h |
| +++ b/include/linux/sched.h |
| @@ -206,7 +206,7 @@ extern unsigned long long time_sync_thre |
| ((task->state & (__TASK_STOPPED | __TASK_TRACED)) != 0) |
| #define task_contributes_to_load(task) \ |
| ((task->state & TASK_UNINTERRUPTIBLE) != 0 && \ |
| - (task->flags & PF_FROZEN) == 0) |
| + (task->flags & PF_FREEZING) == 0) |
| |
| #define __set_task_state(tsk, state_value) \ |
| do { (tsk)->state = (state_value); } while (0) |
| @@ -1630,6 +1630,7 @@ extern cputime_t task_gtime(struct task_ |
| #define PF_MEMALLOC 0x00000800 /* Allocating memory */ |
| #define PF_FLUSHER 0x00001000 /* responsible for disk writeback */ |
| #define PF_USED_MATH 0x00002000 /* if unset the fpu must be initialized before use */ |
| +#define PF_FREEZING 0x00004000 /* freeze in progress. do not account to load */ |
| #define PF_NOFREEZE 0x00008000 /* this thread should not be frozen */ |
| #define PF_FROZEN 0x00010000 /* frozen for system suspend */ |
| #define PF_FSTRANS 0x00020000 /* inside a filesystem transaction */ |
| --- a/kernel/freezer.c |
| +++ b/kernel/freezer.c |
| @@ -44,12 +44,19 @@ void refrigerator(void) |
| recalc_sigpending(); /* We sent fake signal, clean it up */ |
| spin_unlock_irq(¤t->sighand->siglock); |
| |
| + /* prevent accounting of that task to load */ |
| + current->flags |= PF_FREEZING; |
| + |
| for (;;) { |
| set_current_state(TASK_UNINTERRUPTIBLE); |
| if (!frozen(current)) |
| break; |
| schedule(); |
| } |
| + |
| + /* Remove the accounting blocker */ |
| + current->flags &= ~PF_FREEZING; |
| + |
| pr_debug("%s left refrigerator\n", current->comm); |
| __set_current_state(save); |
| } |