diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index f0f03d5470b5..4bd0bee22a0d 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -184,6 +184,14 @@ cgroup v2 currently supports the following mount options.
 	ignored on non-init namespace mounts.  Please refer to the
 	Delegation section for details.
 
+  [no]favordynmods
+        Reduce the latencies of dynamic cgroup modifications such as
+        task migrations and controller on/offs at the cost of making
+        hot path operations such as forks and exits more expensive.
+        The static usage pattern of creating a cgroup, enabling
+        controllers, and then seeding it with CLONE_INTO_CGROUP is
+        not affected by this option.
+
   memory_[no]localevents
         Only populate memory.events with data for the current cgroup,
         and not any subtrees. This is legacy behaviour, the default
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 672de25e3ec8..63bf43c7ca3b 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -88,20 +88,33 @@ enum {
 	 */
 	CGRP_ROOT_NS_DELEGATE	= (1 << 3),
 
+	/*
+	 * Reduce latencies on dynamic cgroup modifications such as task
+	 * migrations and controller on/offs by disabling percpu operation on
+	 * cgroup_threadgroup_rwsem. This makes hot path operations such as
+	 * forks and exits into the slow path and more expensive.
+	 *
+	 * The static usage pattern of creating a cgroup, enabling controllers,
+	 * and then seeding it with CLONE_INTO_CGROUP doesn't require write
+	 * locking cgroup_threadgroup_rwsem and thus doesn't benefit from
+	 * favordynmod.
+	 */
+	CGRP_ROOT_FAVOR_DYNMODS = (1 << 4),
+
 	/*
 	 * Enable cpuset controller in v1 cgroup to use v2 behavior.
 	 */
-	CGRP_ROOT_CPUSET_V2_MODE = (1 << 4),
+	CGRP_ROOT_CPUSET_V2_MODE = (1 << 16),
 
 	/*
 	 * Enable legacy local memory.events.
 	 */
-	CGRP_ROOT_MEMORY_LOCAL_EVENTS = (1 << 5),
+	CGRP_ROOT_MEMORY_LOCAL_EVENTS = (1 << 17),
 
 	/*
 	 * Enable recursive subtree protection
 	 */
-	CGRP_ROOT_MEMORY_RECURSIVE_PROT = (1 << 6),
+	CGRP_ROOT_MEMORY_RECURSIVE_PROT = (1 << 18),
 };
 
 /* cftype->flags */
diff --git a/init/Kconfig b/init/Kconfig
index c984afc489de..c93b10b3de3f 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -936,6 +936,16 @@ if CGROUPS
 config PAGE_COUNTER
 	bool
 
+config CGROUP_FAVOR_DYNMODS
+        bool "Favor dynamic modification latency reduction by default"
+        help
+          This option enables the "favordynmods" mount option by default
+          which reduces the latencies of dynamic cgroup modifications such
+          as task migrations and controller on/offs at the cost of making
+          hot path operations such as forks and exits more expensive.
+
+          Say N if unsure.
+
 config MEMCG
 	bool "Memory controller"
 	select PAGE_COUNTER
diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h
index 5da09c74228d..36b740cb3d59 100644
--- a/kernel/cgroup/cgroup-internal.h
+++ b/kernel/cgroup/cgroup-internal.h
@@ -233,6 +233,7 @@ void cgroup_kn_unlock(struct kernfs_node *kn);
 int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
 			  struct cgroup_namespace *ns);
 
+void cgroup_favor_dynmods(struct cgroup_root *root, bool favor);
 void cgroup_free_root(struct cgroup_root *root);
 void init_cgroup_root(struct cgroup_fs_context *ctx);
 int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask);
diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
index afc6c0e9c966..2ade21b54dc4 100644
--- a/kernel/cgroup/cgroup-v1.c
+++ b/kernel/cgroup/cgroup-v1.c
@@ -875,6 +875,8 @@ static int cgroup1_show_options(struct seq_file *seq, struct kernfs_root *kf_roo
 		seq_puts(seq, ",xattr");
 	if (root->flags & CGRP_ROOT_CPUSET_V2_MODE)
 		seq_puts(seq, ",cpuset_v2_mode");
+	if (root->flags & CGRP_ROOT_FAVOR_DYNMODS)
+		seq_puts(seq, ",favordynmods");
 
 	spin_lock(&release_agent_path_lock);
 	if (strlen(root->release_agent_path))
@@ -898,6 +900,8 @@ enum cgroup1_param {
 	Opt_noprefix,
 	Opt_release_agent,
 	Opt_xattr,
+	Opt_favordynmods,
+	Opt_nofavordynmods,
 };
 
 const struct fs_parameter_spec cgroup1_fs_parameters[] = {
@@ -909,6 +913,8 @@ const struct fs_parameter_spec cgroup1_fs_parameters[] = {
 	fsparam_flag  ("noprefix",	Opt_noprefix),
 	fsparam_string("release_agent",	Opt_release_agent),
 	fsparam_flag  ("xattr",		Opt_xattr),
+	fsparam_flag  ("favordynmods",	Opt_favordynmods),
+	fsparam_flag  ("nofavordynmods", Opt_nofavordynmods),
 	{}
 };
 
@@ -960,6 +966,12 @@ int cgroup1_parse_param(struct fs_context *fc, struct fs_parameter *param)
 	case Opt_xattr:
 		ctx->flags |= CGRP_ROOT_XATTR;
 		break;
+	case Opt_favordynmods:
+		ctx->flags |= CGRP_ROOT_FAVOR_DYNMODS;
+		break;
+	case Opt_nofavordynmods:
+		ctx->flags &= ~CGRP_ROOT_FAVOR_DYNMODS;
+		break;
 	case Opt_release_agent:
 		/* Specifying two release agents is forbidden */
 		if (ctx->release_agent)
@@ -1211,8 +1223,11 @@ static int cgroup1_root_to_use(struct fs_context *fc)
 	init_cgroup_root(ctx);
 
 	ret = cgroup_setup_root(root, ctx->subsys_mask);
-	if (ret)
+	if (!ret)
+		cgroup_favor_dynmods(root, ctx->flags & CGRP_ROOT_FAVOR_DYNMODS);
+	else
 		cgroup_free_root(root);
+
 	return ret;
 }
 
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 9ce24d5cf2d5..7d023d42a6a5 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -1305,6 +1305,20 @@ struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root)
 	return root_cgrp->root;
 }
 
+void cgroup_favor_dynmods(struct cgroup_root *root, bool favor)
+{
+	bool favoring = root->flags & CGRP_ROOT_FAVOR_DYNMODS;
+
+	/* see the comment above CGRP_ROOT_FAVOR_DYNMODS definition */
+	if (favor && !favoring) {
+		rcu_sync_enter(&cgroup_threadgroup_rwsem.rss);
+		root->flags |= CGRP_ROOT_FAVOR_DYNMODS;
+	} else if (!favor && favoring) {
+		rcu_sync_exit(&cgroup_threadgroup_rwsem.rss);
+		root->flags &= ~CGRP_ROOT_FAVOR_DYNMODS;
+	}
+}
+
 static int cgroup_init_root_id(struct cgroup_root *root)
 {
 	int id;
@@ -1365,6 +1379,7 @@ static void cgroup_destroy_root(struct cgroup_root *root)
 		cgroup_root_count--;
 	}
 
+	cgroup_favor_dynmods(root, false);
 	cgroup_exit_root_id(root);
 
 	mutex_unlock(&cgroup_mutex);
@@ -1858,6 +1873,7 @@ int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node,
 
 enum cgroup2_param {
 	Opt_nsdelegate, Opt_nonsdelegate,
+	Opt_favordynmods, Opt_nofavordynmods,
 	Opt_memory_localevents, Opt_memory_nolocalevents,
 	Opt_memory_recursiveprot, Opt_memory_norecursiveprot,
 	nr__cgroup2_params
@@ -1866,6 +1882,8 @@ enum cgroup2_param {
 static const struct fs_parameter_spec cgroup2_fs_parameters[] = {
 	fsparam_flag("nsdelegate",		Opt_nsdelegate),
 	fsparam_flag("nonsdelegate",		Opt_nonsdelegate),
+	fsparam_flag("favordynmods",		Opt_favordynmods),
+	fsparam_flag("nofavordynmods",		Opt_nofavordynmods),
 	fsparam_flag("memory_localevents",	Opt_memory_localevents),
 	fsparam_flag("memory_nolocalevents",	Opt_memory_nolocalevents),
 	fsparam_flag("memory_recursiveprot",	Opt_memory_recursiveprot),
@@ -1890,6 +1908,12 @@ static int cgroup2_parse_param(struct fs_context *fc, struct fs_parameter *param
 	case Opt_nonsdelegate:
 		ctx->flags &= ~CGRP_ROOT_NS_DELEGATE;
 		return 0;
+	case Opt_favordynmods:
+		ctx->flags |= CGRP_ROOT_FAVOR_DYNMODS;
+		return 0;
+	case Opt_nofavordynmods:
+		ctx->flags &= ~CGRP_ROOT_FAVOR_DYNMODS;
+		return 0;
 	case Opt_memory_localevents:
 		ctx->flags |= CGRP_ROOT_MEMORY_LOCAL_EVENTS;
 		return 0;
@@ -1914,6 +1938,9 @@ static void apply_cgroup_root_flags(unsigned int root_flags)
 		else
 			cgrp_dfl_root.flags &= ~CGRP_ROOT_NS_DELEGATE;
 
+		cgroup_favor_dynmods(&cgrp_dfl_root,
+				     root_flags & CGRP_ROOT_FAVOR_DYNMODS);
+
 		if (root_flags & CGRP_ROOT_MEMORY_LOCAL_EVENTS)
 			cgrp_dfl_root.flags |= CGRP_ROOT_MEMORY_LOCAL_EVENTS;
 		else
@@ -1930,6 +1957,8 @@ static int cgroup_show_options(struct seq_file *seq, struct kernfs_root *kf_root
 {
 	if (cgrp_dfl_root.flags & CGRP_ROOT_NS_DELEGATE)
 		seq_puts(seq, ",nsdelegate");
+	if (cgrp_dfl_root.flags & CGRP_ROOT_FAVOR_DYNMODS)
+		seq_puts(seq, ",favordynmods");
 	if (cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_LOCAL_EVENTS)
 		seq_puts(seq, ",memory_localevents");
 	if (cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_RECURSIVE_PROT)
@@ -1980,7 +2009,8 @@ void init_cgroup_root(struct cgroup_fs_context *ctx)
 	cgrp->root = root;
 	init_cgroup_housekeeping(cgrp);
 
-	root->flags = ctx->flags;
+	/* DYNMODS must be modified through cgroup_favor_dynmods() */
+	root->flags = ctx->flags & ~CGRP_ROOT_FAVOR_DYNMODS;
 	if (ctx->release_agent)
 		strscpy(root->release_agent_path, ctx->release_agent, PATH_MAX);
 	if (ctx->name)
@@ -2202,6 +2232,10 @@ static int cgroup_init_fs_context(struct fs_context *fc)
 	put_user_ns(fc->user_ns);
 	fc->user_ns = get_user_ns(ctx->ns->user_ns);
 	fc->global = true;
+
+#ifdef CONFIG_CGROUP_FAVOR_DYNMODS
+	ctx->flags |= CGRP_ROOT_FAVOR_DYNMODS;
+#endif
 	return 0;
 }
 
@@ -5854,12 +5888,6 @@ int __init cgroup_init(void)
 
 	cgroup_rstat_boot();
 
-	/*
-	 * The latency of the synchronize_rcu() is too high for cgroups,
-	 * avoid it at the cost of forcing all readers into the slow path.
-	 */
-	rcu_sync_enter_start(&cgroup_threadgroup_rwsem.rss);
-
 	get_user_ns(init_cgroup_ns.user_ns);
 
 	mutex_lock(&cgroup_mutex);
@@ -6771,6 +6799,7 @@ static ssize_t features_show(struct kobject *kobj, struct kobj_attribute *attr,
 {
 	return snprintf(buf, PAGE_SIZE,
 			"nsdelegate\n"
+			"favordynmods\n"
 			"memory_localevents\n"
 			"memory_recursiveprot\n");
 }