Commit 30312730 authored by Tejun Heo's avatar Tejun Heo
Browse files

cgroup: Add "no" prefixed mount options 



We allow modifying these mount options via remount. Let's add "no" prefixed
variants so that they can be turned off too.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
parent 671c11f0

Documentation/admin-guide/cgroup-v2.rst

+3 −3
Original line number Diff line number Diff line
@@ -177,14 +177,14 @@ disabling controllers in v1 and make them always available in v2. 


cgroup v2 currently supports the following mount options.



  nsdelegate

  [no]nsdelegate

	Consider cgroup namespaces as delegation boundaries.  This

	option is system wide and can only be set on mount or modified

	through remount from the init namespace.  The mount option is

	ignored on non-init namespace mounts.  Please refer to the

	Delegation section for details.



  memory_localevents

  memory_[no]localevents

        Only populate memory.events with data for the current cgroup,

        and not any subtrees. This is legacy behaviour, the default

        behaviour without this option is to include subtree counts.
@@ -192,7 +192,7 @@ cgroup v2 currently supports the following mount options. 
        modified through remount from the init namespace. The mount

        option is ignored on non-init namespace mounts.



  memory_recursiveprot

  memory_[no]recursiveprot

        Recursively apply memory.min and memory.low protection to

        entire subtrees, without requiring explicit downward

        propagation into leaf cgroups.  This allows protecting entire

kernel/cgroup/cgroup.c

+15 −5
Original line number Diff line number Diff line
@@ -279,8 +279,6 @@ bool cgroup_ssid_enabled(int ssid) 
 *

 * - When mounting an existing superblock, mount options should match.

 *

 * - Remount is disallowed.

 *

 * - rename(2) is disallowed.

 *

 * - "tasks" is removed.  Everything should be at process granularity.  Use
@@ -1859,16 +1857,19 @@ int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node, 
}



enum cgroup2_param {

	Opt_nsdelegate,

	Opt_memory_localevents,

	Opt_memory_recursiveprot,

	Opt_nsdelegate, Opt_nonsdelegate,

	Opt_memory_localevents, Opt_memory_nolocalevents,

	Opt_memory_recursiveprot, Opt_memory_norecursiveprot,

	nr__cgroup2_params

};



static const struct fs_parameter_spec cgroup2_fs_parameters[] = {

	fsparam_flag("nsdelegate",		Opt_nsdelegate),

	fsparam_flag("nonsdelegate",		Opt_nonsdelegate),

	fsparam_flag("memory_localevents",	Opt_memory_localevents),

	fsparam_flag("memory_nolocalevents",	Opt_memory_nolocalevents),

	fsparam_flag("memory_recursiveprot",	Opt_memory_recursiveprot),

	fsparam_flag("memory_norecursiveprot",	Opt_memory_norecursiveprot),

	{}

};
@@ -1886,12 +1887,21 @@ static int cgroup2_parse_param(struct fs_context *fc, struct fs_parameter *param 
	case Opt_nsdelegate:

		ctx->flags |= CGRP_ROOT_NS_DELEGATE;

		return 0;

	case Opt_nonsdelegate:

		ctx->flags &= ~CGRP_ROOT_NS_DELEGATE;

		return 0;

	case Opt_memory_localevents:

		ctx->flags |= CGRP_ROOT_MEMORY_LOCAL_EVENTS;

		return 0;

	case Opt_memory_nolocalevents:

		ctx->flags &= ~CGRP_ROOT_MEMORY_LOCAL_EVENTS;

		return 0;

	case Opt_memory_recursiveprot:

		ctx->flags |= CGRP_ROOT_MEMORY_RECURSIVE_PROT;

		return 0;

	case Opt_memory_norecursiveprot:

		ctx->flags &= ~CGRP_ROOT_MEMORY_RECURSIVE_PROT;

		return 0;

	}

	return -EINVAL;

}