From: Andrea Arcangeli <andrea@suse.de>
Date: Sat, 16 Apr 2005 22:24:05 +0000 (-0700)
Subject: [PATCH] oom-killer disable for iscsi/lvm2/multipath userland critical sections
X-Git-Tag: v2.6.12-rc3~229
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=79befd0c08c4766f8fa27e37ac2a70e40840a56a;p=linux-2.6

[PATCH] oom-killer disable for iscsi/lvm2/multipath userland critical sections

iscsi/lvm2/multipath needs guaranteed protection from the oom-killer, so
make the magical value of -17 in /proc/<pid>/oom_adj defeat the oom-killer
altogether.

(akpm: we still need to document oom_adj and friends in
Documentation/filesystems/proc.txt!)

Signed-off-by: Andrea Arcangeli <andrea@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/fs/proc/base.c b/fs/proc/base.c
index dad8ea4e00..39fd336cfd 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -751,7 +751,7 @@ static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
 	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++;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 6a931374d6..85f7d1bea9 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -857,5 +857,8 @@ int in_gate_area_no_task(unsigned long addr);
 #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 */
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 9595a0f6c4..4bbb1cb104 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -145,7 +145,7 @@ static struct task_struct * select_bad_process(void)
 	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;
 
 			/*