Re: oom-killer disable for iscsi/lvm2/multipath userland critical sections

2005-04-01 Thread Dmitry Yusupov
Andrea,

I just successfully tested the patch on my environment. It actually
resolved OOM-killer problem for my iscsid.

Important note: daemon's parent must be init.

In my test, OOM-killer killed everything around but iscsid, and iscsid
successfully finished registration of new SCSI host in the middle of
crazy OOM-killer :)

Thanks!
Dima

On Sat, 2005-04-02 at 00:14 +0200, Andrea Arcangeli wrote:
> Hello,
> 
> some private discussion (that was continuing some kernel-summit-discuss
> thread) ended in the below patch. I also liked a textual "disable"
> instead of value "-17" (internally to the kernel it could be represented
> the same way, but the /proc parsing would be more complicated). If you
> prefer textual "disable" we can change this of course.
> 
> Comments welcome.
> 
> From: Andrea Arcangeli <[EMAIL PROTECTED]>
> Subject: oom killer protection
> 
> iscsi/lvm2/multipath needs guaranteed protection from the oom-killer.
> 
> Signed-off-by: Andrea Arcangeli <[EMAIL PROTECTED]>
> 
> --- 2.6.12-seccomp/fs/proc/base.c.~1~ 2005-03-25 05:13:28.0 +0100
> +++ 2.6.12-seccomp/fs/proc/base.c 2005-04-01 23:47:22.0 +0200
> @@ -751,7 +751,7 @@ static ssize_t oom_adjust_write(struct f
>   if (copy_from_user(buffer, buf, count))
>   return -EFAULT;
>   oom_adjust = simple_strtol(buffer, , 0);
> - if (oom_adjust < -16 || oom_adjust > 15)
> + if ((oom_adjust < -16 || oom_adjust > 15) && oom_adjust != OOM_DISABLE)
>   return -EINVAL;
>   if (*end == '\n')
>   end++;
> --- 2.6.12-seccomp/include/linux/mm.h.~1~ 2005-03-25 05:13:28.0 
> +0100
> +++ 2.6.12-seccomp/include/linux/mm.h 2005-04-01 23:53:11.0 +0200
> @@ -856,5 +856,8 @@ int in_gate_area_no_task(unsigned long a
>  #define in_gate_area(task, addr) ({(void)task; in_gate_area_no_task(addr);})
>  #endif   /* __HAVE_ARCH_GATE_AREA */
>  
> +/* /proc//oom_adj set to -17 protects from the oom-killer */
> +#define OOM_DISABLE -17
> +
>  #endif /* __KERNEL__ */
>  #endif /* _LINUX_MM_H */
> --- 2.6.12-seccomp/mm/oom_kill.c.~1~  2005-03-08 01:02:30.0 +0100
> +++ 2.6.12-seccomp/mm/oom_kill.c  2005-04-01 23:46:18.0 +0200
> @@ -145,7 +145,7 @@ static struct task_struct * select_bad_p
>   do_posix_clock_monotonic_gettime();
>   do_each_thread(g, p)
>   /* skip the init task with pid == 1 */
> - if (p->pid > 1) {
> + if (p->pid > 1 && p->oomkilladj != OOM_DISABLE) {
>   unsigned long points;
>  
>   /*
> -
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Re: oom-killer disable for iscsi/lvm2/multipath userland critical sections

2005-04-01 Thread Dmitry Yusupov
Andrea,

I just successfully tested the patch on my environment. It actually
resolved OOM-killer problem for my iscsid.

Important note: daemon's parent must be init.

In my test, OOM-killer killed everything around but iscsid, and iscsid
successfully finished registration of new SCSI host in the middle of
crazy OOM-killer :)

Thanks!
Dima

On Sat, 2005-04-02 at 00:14 +0200, Andrea Arcangeli wrote:
 Hello,
 
 some private discussion (that was continuing some kernel-summit-discuss
 thread) ended in the below patch. I also liked a textual disable
 instead of value -17 (internally to the kernel it could be represented
 the same way, but the /proc parsing would be more complicated). If you
 prefer textual disable we can change this of course.
 
 Comments welcome.
 
 From: Andrea Arcangeli [EMAIL PROTECTED]
 Subject: oom killer protection
 
 iscsi/lvm2/multipath needs guaranteed protection from the oom-killer.
 
 Signed-off-by: Andrea Arcangeli [EMAIL PROTECTED]
 
 --- 2.6.12-seccomp/fs/proc/base.c.~1~ 2005-03-25 05:13:28.0 +0100
 +++ 2.6.12-seccomp/fs/proc/base.c 2005-04-01 23:47:22.0 +0200
 @@ -751,7 +751,7 @@ static ssize_t oom_adjust_write(struct f
   if (copy_from_user(buffer, buf, count))
   return -EFAULT;
   oom_adjust = simple_strtol(buffer, end, 0);
 - if (oom_adjust  -16 || oom_adjust  15)
 + if ((oom_adjust  -16 || oom_adjust  15)  oom_adjust != OOM_DISABLE)
   return -EINVAL;
   if (*end == '\n')
   end++;
 --- 2.6.12-seccomp/include/linux/mm.h.~1~ 2005-03-25 05:13:28.0 
 +0100
 +++ 2.6.12-seccomp/include/linux/mm.h 2005-04-01 23:53:11.0 +0200
 @@ -856,5 +856,8 @@ int in_gate_area_no_task(unsigned long a
  #define in_gate_area(task, addr) ({(void)task; in_gate_area_no_task(addr);})
  #endif   /* __HAVE_ARCH_GATE_AREA */
  
 +/* /proc/pid/oom_adj set to -17 protects from the oom-killer */
 +#define OOM_DISABLE -17
 +
  #endif /* __KERNEL__ */
  #endif /* _LINUX_MM_H */
 --- 2.6.12-seccomp/mm/oom_kill.c.~1~  2005-03-08 01:02:30.0 +0100
 +++ 2.6.12-seccomp/mm/oom_kill.c  2005-04-01 23:46:18.0 +0200
 @@ -145,7 +145,7 @@ static struct task_struct * select_bad_p
   do_posix_clock_monotonic_gettime(uptime);
   do_each_thread(g, p)
   /* skip the init task with pid == 1 */
 - if (p-pid  1) {
 + if (p-pid  1  p-oomkilladj != OOM_DISABLE) {
   unsigned long points;
  
   /*
 -
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