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Commit 8effcf18 authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
Browse files

Revert "cgroup: Use separate src/dst nodes when preloading css_sets for migration" 



This reverts commit cec2bbdc which is
commit 07fd5b6cdf3cc30bfde8fe0f644771688be04447 upstream.

It breaks the kernel ABI and is not something that is an issue for
Android devices, so revert it.

Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@google.com>
Change-Id: I89125948bbf90805d25a446afeab69f6581442bc
parent b8c97514

include/linux/cgroup-defs.h

+1 −2
Original line number Diff line number Diff line
@@ -250,8 +250,7 @@ struct css_set { 
	 * List of csets participating in the on-going migration either as

	 * source or destination.  Protected by cgroup_mutex.

	 */

	struct list_head mg_src_preload_node;

	struct list_head mg_dst_preload_node;

	struct list_head mg_preload_node;

	struct list_head mg_node;



	/*

kernel/cgroup/cgroup.c

+14 −23
Original line number Diff line number Diff line
@@ -727,8 +727,7 @@ struct css_set init_css_set = { 
	.task_iters		= LIST_HEAD_INIT(init_css_set.task_iters),

	.threaded_csets		= LIST_HEAD_INIT(init_css_set.threaded_csets),

	.cgrp_links		= LIST_HEAD_INIT(init_css_set.cgrp_links),

	.mg_src_preload_node	= LIST_HEAD_INIT(init_css_set.mg_src_preload_node),

	.mg_dst_preload_node	= LIST_HEAD_INIT(init_css_set.mg_dst_preload_node),

	.mg_preload_node	= LIST_HEAD_INIT(init_css_set.mg_preload_node),

	.mg_node		= LIST_HEAD_INIT(init_css_set.mg_node),



	/*
@@ -1202,8 +1201,7 @@ static struct css_set *find_css_set(struct css_set *old_cset, 
	INIT_LIST_HEAD(&cset->threaded_csets);

	INIT_HLIST_NODE(&cset->hlist);

	INIT_LIST_HEAD(&cset->cgrp_links);

	INIT_LIST_HEAD(&cset->mg_src_preload_node);

	INIT_LIST_HEAD(&cset->mg_dst_preload_node);

	INIT_LIST_HEAD(&cset->mg_preload_node);

	INIT_LIST_HEAD(&cset->mg_node);



	/* Copy the set of subsystem state objects generated in
@@ -2512,27 +2510,21 @@ int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp) 
 */

void cgroup_migrate_finish(struct cgroup_mgctx *mgctx)

{

	LIST_HEAD(preloaded);

	struct css_set *cset, *tmp_cset;



	lockdep_assert_held(&cgroup_mutex);



	spin_lock_irq(&css_set_lock);



	list_for_each_entry_safe(cset, tmp_cset, &mgctx->preloaded_src_csets,

				 mg_src_preload_node) {

		cset->mg_src_cgrp = NULL;

		cset->mg_dst_cgrp = NULL;

		cset->mg_dst_cset = NULL;

		list_del_init(&cset->mg_src_preload_node);

		put_css_set_locked(cset);

	}

	list_splice_tail_init(&mgctx->preloaded_src_csets, &preloaded);

	list_splice_tail_init(&mgctx->preloaded_dst_csets, &preloaded);



	list_for_each_entry_safe(cset, tmp_cset, &mgctx->preloaded_dst_csets,

				 mg_dst_preload_node) {

	list_for_each_entry_safe(cset, tmp_cset, &preloaded, mg_preload_node) {

		cset->mg_src_cgrp = NULL;

		cset->mg_dst_cgrp = NULL;

		cset->mg_dst_cset = NULL;

		list_del_init(&cset->mg_dst_preload_node);

		list_del_init(&cset->mg_preload_node);

		put_css_set_locked(cset);

	}
@@ -2574,7 +2566,7 @@ void cgroup_migrate_add_src(struct css_set *src_cset, 


	src_cgrp = cset_cgroup_from_root(src_cset, dst_cgrp->root);



	if (!list_empty(&src_cset->mg_src_preload_node))

	if (!list_empty(&src_cset->mg_preload_node))

		return;



	WARN_ON(src_cset->mg_src_cgrp);
@@ -2585,7 +2577,7 @@ void cgroup_migrate_add_src(struct css_set *src_cset, 
	src_cset->mg_src_cgrp = src_cgrp;

	src_cset->mg_dst_cgrp = dst_cgrp;

	get_css_set(src_cset);

	list_add_tail(&src_cset->mg_src_preload_node, &mgctx->preloaded_src_csets);

	list_add_tail(&src_cset->mg_preload_node, &mgctx->preloaded_src_csets);

}



/**
@@ -2610,7 +2602,7 @@ int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx) 


	/* look up the dst cset for each src cset and link it to src */

	list_for_each_entry_safe(src_cset, tmp_cset, &mgctx->preloaded_src_csets,

				 mg_src_preload_node) {

				 mg_preload_node) {

		struct css_set *dst_cset;

		struct cgroup_subsys *ss;

		int ssid;
@@ -2629,7 +2621,7 @@ int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx) 
		if (src_cset == dst_cset) {

			src_cset->mg_src_cgrp = NULL;

			src_cset->mg_dst_cgrp = NULL;

			list_del_init(&src_cset->mg_src_preload_node);

			list_del_init(&src_cset->mg_preload_node);

			put_css_set(src_cset);

			put_css_set(dst_cset);

			continue;
@@ -2637,8 +2629,8 @@ int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx) 


		src_cset->mg_dst_cset = dst_cset;



		if (list_empty(&dst_cset->mg_dst_preload_node))

			list_add_tail(&dst_cset->mg_dst_preload_node,

		if (list_empty(&dst_cset->mg_preload_node))

			list_add_tail(&dst_cset->mg_preload_node,

				      &mgctx->preloaded_dst_csets);

		else

			put_css_set(dst_cset);
@@ -2869,8 +2861,7 @@ static int cgroup_update_dfl_csses(struct cgroup *cgrp) 
		goto out_finish;



	spin_lock_irq(&css_set_lock);

	list_for_each_entry(src_cset, &mgctx.preloaded_src_csets,

			    mg_src_preload_node) {

	list_for_each_entry(src_cset, &mgctx.preloaded_src_csets, mg_preload_node) {

		struct task_struct *task, *ntask;



		/* all tasks in src_csets need to be migrated */