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 05:13:28.000000000 +0100
+++ 2.6.12-seccomp/fs/proc/base.c       2005-04-01 23:47:22.000000000 +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 05:13:28.000000000 
+0100
+++ 2.6.12-seccomp/include/linux/mm.h   2005-04-01 23:53:11.000000000 +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 01:02:30.000000000 +0100
+++ 2.6.12-seccomp/mm/oom_kill.c        2005-04-01 23:46:18.000000000 +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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