From 79befd0c08c4766f8fa27e37ac2a70e40840a56a Mon Sep 17 00:00:00 2001
From: Andrea Arcangeli <andrea@suse.de>
Date: Sat, 16 Apr 2005 15:24:05 -0700
Subject: [PATCH] [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>
---
fs/proc/base.c | 2 +-
include/linux/mm.h | 3 +++
mm/oom_kill.c | 2 +-
3 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index dad8ea4e00a0..39fd336cfdb9 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 6a931374d6c4..85f7d1bea937 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 9595a0f6c4b8..4bbb1cb10495 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;
/*
--
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