Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=fe071d7e8aae5745c009c808bb8933f22a9e305a
Commit: fe071d7e8aae5745c009c808bb8933f22a9e305a
Parent: ff0ceb9deb6eb017f52900b708d49cfa77bf25fb
Author: David Rientjes <[EMAIL PROTECTED]>
AuthorDate: Tue Oct 16 23:25:56 2007 -0700
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Wed Oct 17 08:42:46 2007 -0700
oom: add oom_kill_allocating_task sysctl
Adds a new sysctl, 'oom_kill_allocating_task', which will automatically kill
the OOM-triggering task instead of scanning through the tasklist to find a
memory-hogging target. This is helpful for systems with an insanely large
number of tasks where scanning the tasklist significantly degrades
performance.
Cc: Andrea Arcangeli <[EMAIL PROTECTED]>
Acked-by: Christoph Lameter <[EMAIL PROTECTED]>
Signed-off-by: David Rientjes <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
Documentation/sysctl/vm.txt | 22 ++++++++++++++++++++++
kernel/sysctl.c | 9 +++++++++
mm/oom_kill.c | 13 ++++++++-----
3 files changed, 39 insertions(+), 5 deletions(-)
diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
index a0ccc5b..17346da 100644
--- a/Documentation/sysctl/vm.txt
+++ b/Documentation/sysctl/vm.txt
@@ -31,6 +31,7 @@ Currently, these files are in /proc/sys/vm:
- min_unmapped_ratio
- min_slab_ratio
- panic_on_oom
+- oom_kill_allocating_task
- mmap_min_address
- numa_zonelist_order
@@ -220,6 +221,27 @@ The default value is 0.
1 and 2 are for failover of clustering. Please select either
according to your policy of failover.
+=============================================================
+
+oom_kill_allocating_task
+
+This enables or disables killing the OOM-triggering task in
+out-of-memory situations.
+
+If this is set to zero, the OOM killer will scan through the entire
+tasklist and select a task based on heuristics to kill. This normally
+selects a rogue memory-hogging task that frees up a large amount of
+memory when killed.
+
+If this is set to non-zero, the OOM killer simply kills the task that
+triggered the out-of-memory condition. This avoids the expensive
+tasklist scan.
+
+If panic_on_oom is selected, it takes precedence over whatever value
+is used in oom_kill_allocating_task.
+
+The default value is 0.
+
==============================================================
mmap_min_addr
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index c676b5e..5e63de0 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -63,6 +63,7 @@ extern int print_fatal_signals;
extern int sysctl_overcommit_memory;
extern int sysctl_overcommit_ratio;
extern int sysctl_panic_on_oom;
+extern int sysctl_oom_kill_allocating_task;
extern int max_threads;
extern int core_uses_pid;
extern int suid_dumpable;
@@ -781,6 +782,14 @@ static ctl_table vm_table[] = {
.proc_handler = &proc_dointvec,
},
{
+ .ctl_name = CTL_UNNUMBERED,
+ .procname = "oom_kill_allocating_task",
+ .data = &sysctl_oom_kill_allocating_task,
+ .maxlen = sizeof(sysctl_oom_kill_allocating_task),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec,
+ },
+ {
.ctl_name = VM_OVERCOMMIT_RATIO,
.procname = "overcommit_ratio",
.data = &sysctl_overcommit_ratio,
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 6e999c8..00d0bd7 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -27,6 +27,7 @@
#include <linux/notifier.h>
int sysctl_panic_on_oom;
+int sysctl_oom_kill_allocating_task;
static DEFINE_MUTEX(zone_scan_mutex);
/* #define DEBUG */
@@ -471,14 +472,16 @@ void out_of_memory(struct zonelist *zonelist, gfp_t
gfp_mask, int order)
"No available memory (MPOL_BIND)");
break;
- case CONSTRAINT_CPUSET:
- oom_kill_process(current, points,
- "No available memory in cpuset");
- break;
-
case CONSTRAINT_NONE:
if (sysctl_panic_on_oom)
panic("out of memory. panic_on_oom is selected\n");
+ /* Fall-through */
+ case CONSTRAINT_CPUSET:
+ if (sysctl_oom_kill_allocating_task) {
+ oom_kill_process(current, points,
+ "Out of memory
(oom_kill_allocating_task)");
+ break;
+ }
retry:
/*
* Rambo mode: Shoot down a process and hope it solves whatever
-
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