Re: Preempt note in the logs (and patch)

[Dag Nygren]

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> Hi,
> =

> On Sat, 24 Aug 2002, Dag Nygren wrote:
> > just installed the preempt stuff on a 2.4.19 here
> > running on a laptop and keep getting the
> > "dreaded"  exited with preempt_count 1
> > messages.
> > there is modprobe,kdeinit,aplay,less,find,grep,automount
> > and others misbehaving.
> =

> Not much. That's just unclean preempt.

Anyway I cannot have it on the laptop so I made the sysctl patch
I was talking about myself (The one that switches that message on
or off. The default is on as wo. the patch)

It is diffed against a kernel with the ck2 patch applied,
ie. lowlatency+preempt.

Here it is, if you are interested out there:

Best from Finland

-- =

Dag Nygren                               email: [e-mail]
Oy Espoon NewTech Ab                     phone: [phone]
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02360 ESBO                              Mobile: [phone]
FINLAND

--==_Exmh_14562106260
Content-Type: application/x-patch ; name="preemponoff.patch"
Content-Description: preemponoff.patch
Content-Disposition: attachment; filename="preemponoff.patch"

*** ./kernel/exit.c.orig	Sat Aug 24 12:08:59 2002
--- ./kernel/exit.c	Sat Aug 24 12:21:05 2002
***************
*** 24,29 ****
--- 24,31 ----
  extern void sem_exit (void);
  extern struct task_struct *child_reaper;
  
+ int sysctl_warn_preempt = 1;	/* Warn about preempted tasks still holding locks */
+ 
  int getrusage(struct task_struct *, int, struct rusage *);
  
  static void release_task(struct task_struct * p)
***************
*** 496,502 ****
  	tsk->flags |= PF_EXITING;
  	del_timer_sync(&tsk->real_timer);
  
! 	if (unlikely(preempt_get_count()))
  		printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
  				current->comm, current->pid,
  				preempt_get_count());
--- 498,504 ----
  	tsk->flags |= PF_EXITING;
  	del_timer_sync(&tsk->real_timer);
  
! 	if (sysctl_warn_preempt && unlikely(preempt_get_count()))
  		printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
  				current->comm, current->pid,
  				preempt_get_count());
*** ./kernel/sysctl.c.orig	Sat Aug 24 12:07:26 2002
--- ./kernel/sysctl.c	Sat Aug 24 12:22:03 2002
***************
*** 74,79 ****
--- 74,81 ----
  extern int sem_ctls[];
  #endif
  
+ extern int sysctl_warn_preempt;
+ 
  #ifdef __sparc__
  extern char reboot_command [];
  extern int stop_a_enabled;
***************
*** 260,265 ****
--- 262,269 ----
  	{KERN_LOWLATENCY, "lowlatency", &enable_lowlatency, sizeof (int),
  	 0644, NULL, &proc_dointvec},
  #endif
+ 	{KERN_PREEMPTWARN, "preemptwarnings", &sysctl_warn_preempt, sizeof (int),
+ 	 0644, NULL, &proc_dointvec},
  	{0}
  };
  
*** ./include/linux/sysctl.h.orig	Sat Aug 24 12:06:09 2002
--- ./include/linux/sysctl.h	Sat Aug 24 12:07:07 2002
***************
*** 125,130 ****
--- 125,131 ----
  	KERN_TAINTED=53,	/* int: various kernel tainted flags */
  	KERN_CADPID=54,		/* int: PID of the process to notify on CAD */
  	KERN_LOWLATENCY=55,     /* int: enable low latency scheduling */
+ 	KERN_PREEMPTWARN=56,     /* int: enable warnings about preempted processes */
  };
  
  

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