From fadd8fbd153c12963f8fe3c9ef7f8967f286f98b Mon Sep 17 00:00:00 2001 From: KAMEZAWA Hiroyuki Date: Fri, 23 Jun 2006 02:03:13 -0700 Subject: [PATCH] [PATCH] support for panic at OOM This patch adds panic_on_oom sysctl under sys.vm. When sysctl vm.panic_on_oom = 1, the kernel panics intead of killing rogue processes. And if vm.panic_on_oom is 0 the kernel will do oom_kill() in the same way as it does today. Of course, the default value is 0 and only root can modifies it. In general, oom_killer works well and kill rogue processes. So the whole system can survive. But there are environments where panic is preferable rather than kill some processes. Signed-off-by: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/sysctl/vm.txt | 13 +++++++++++++ include/linux/sysctl.h | 1 + kernel/sysctl.c | 9 +++++++++ mm/oom_kill.c | 3 +++ 4 files changed, 26 insertions(+) diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index a46c10fcddfc..2dc246af4885 100644 --- a/Documentation/sysctl/vm.txt +++ b/Documentation/sysctl/vm.txt @@ -29,6 +29,7 @@ Currently, these files are in /proc/sys/vm: - drop-caches - zone_reclaim_mode - zone_reclaim_interval +- panic_on_oom ============================================================== @@ -178,3 +179,15 @@ Time is set in seconds and set by default to 30 seconds. Reduce the interval if undesired off node allocations occur. However, too frequent scans will have a negative impact onoff node allocation performance. +============================================================= + +panic_on_oom + +This enables or disables panic on out-of-memory feature. If this is set to 1, +the kernel panics when out-of-memory happens. If this is set to 0, the kernel +will kill some rogue process, called oom_killer. Usually, oom_killer can kill +rogue processes and system will survive. If you want to panic the system +rather than killing rogue processes, set this to 1. + +The default value is 0. + diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index cee944dbdcd4..c7132029af0f 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -186,6 +186,7 @@ enum VM_PERCPU_PAGELIST_FRACTION=30,/* int: fraction of pages in each percpu_pagelist */ VM_ZONE_RECLAIM_MODE=31, /* reclaim local zone memory before going off node */ VM_ZONE_RECLAIM_INTERVAL=32, /* time period to wait after reclaim failure */ + VM_PANIC_ON_OOM=33, /* panic at out-of-memory */ }; diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 0d656e61621d..072ac446810a 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -59,6 +59,7 @@ extern int proc_nr_files(ctl_table *table, int write, struct file *filp, extern int C_A_D; extern int sysctl_overcommit_memory; extern int sysctl_overcommit_ratio; +extern int sysctl_panic_on_oom; extern int max_threads; extern int sysrq_enabled; extern int core_uses_pid; @@ -701,6 +702,14 @@ static ctl_table vm_table[] = { .mode = 0644, .proc_handler = &proc_dointvec, }, + { + .ctl_name = VM_PANIC_ON_OOM, + .procname = "panic_on_oom", + .data = &sysctl_panic_on_oom, + .maxlen = sizeof(sysctl_panic_on_oom), + .mode = 0644, + .proc_handler = &proc_dointvec, + }, { .ctl_name = VM_OVERCOMMIT_RATIO, .procname = "overcommit_ratio", diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 042e6436c3ee..f9bb3cf32384 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -22,6 +22,7 @@ #include #include +int sysctl_panic_on_oom; /* #define DEBUG */ /** @@ -344,6 +345,8 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order) break; case CONSTRAINT_NONE: + if (sysctl_panic_on_oom) + panic("out of memory. panic_on_oom is selected\n"); retry: /* * Rambo mode: Shoot down a process and hope it solves whatever