Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756154AbZG1X5h (ORCPT ); Tue, 28 Jul 2009 19:57:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754737AbZG1X5g (ORCPT ); Tue, 28 Jul 2009 19:57:36 -0400 Received: from kroah.org ([198.145.64.141]:35821 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753786AbZG1XuI (ORCPT ); Tue, 28 Jul 2009 19:50:08 -0400 X-Mailbox-Line: From gregkh@mini.kroah.org Tue Jul 28 16:41:57 2009 Message-Id: <20090728234157.365935237@mini.kroah.org> User-Agent: quilt/0.48-1 Date: Tue, 28 Jul 2009 16:41:09 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Thomas Gleixner Subject: [patch 40/71] sched: fix nr_uninterruptible accounting of frozen tasks really References: <20090728234029.868717854@mini.kroah.org> Content-Disposition: inline; filename=sched-fix-nr_uninterruptible-accounting-of-frozen-tasks-really.patch In-Reply-To: <20090728234756.GA11917@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2842 Lines: 66 2.6.30-stable review patch. If anyone has any objections, please let us know. ------------------ From: Thomas Gleixner 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 Signed-off-by: Greg Kroah-Hartman --- 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); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/