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From e2494e8c48c510ccefc889393f5d776b5e3824ac Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.org>
Date: Mon, 27 Nov 2017 17:14:54 +0000
Subject: [PATCH] cgroup: Disable cgroup "memory" by default
Some Raspberry Pis have limited RAM and most users won't use the
cgroup memory support so it is disabled by default. Enable with:
cgroup_enable=memory
See: https://github.com/raspberrypi/linux/issues/1950
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
---
kernel/cgroup/cgroup.c | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -5875,6 +5875,9 @@ int __init cgroup_init_early(void)
return 0;
}
+static u16 cgroup_enable_mask __initdata;
+static int __init cgroup_disable(char *str);
+
/**
* cgroup_init - cgroup initialization
*
@@ -5913,6 +5916,12 @@ int __init cgroup_init(void)
mutex_unlock(&cgroup_mutex);
+ /*
+ * Apply an implicit disable, knowing that an explicit enable will
+ * prevent if from doing anything.
+ */
+ cgroup_disable("memory");
+
for_each_subsys(ss, ssid) {
if (ss->early_init) {
struct cgroup_subsys_state *css =
@@ -6503,6 +6512,10 @@ static int __init cgroup_disable(char *s
strcmp(token, ss->legacy_name))
continue;
+ /* An explicit cgroup_enable overrides a disable */
+ if (cgroup_enable_mask & (1 << i))
+ continue;
+
static_branch_disable(cgroup_subsys_enabled_key[i]);
pr_info("Disabling %s control group subsystem\n",
ss->name);
@@ -6521,6 +6534,31 @@ static int __init cgroup_disable(char *s
}
__setup("cgroup_disable=", cgroup_disable);
+static int __init cgroup_enable(char *str)
+{
+ struct cgroup_subsys *ss;
+ char *token;
+ int i;
+
+ while ((token = strsep(&str, ",")) != NULL) {
+ if (!*token)
+ continue;
+
+ for_each_subsys(ss, i) {
+ if (strcmp(token, ss->name) &&
+ strcmp(token, ss->legacy_name))
+ continue;
+
+ cgroup_enable_mask |= 1 << i;
+ static_branch_enable(cgroup_subsys_enabled_key[i]);
+ pr_info("Enabling %s control group subsystem\n",
+ ss->name);
+ }
+ }
+ return 1;
+}
+__setup("cgroup_enable=", cgroup_enable);
+
void __init __weak enable_debug_cgroup(void) { }
static int __init enable_cgroup_debug(char *str)
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