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author | Tejun Heo <tj@kernel.org> | 2017-01-16 03:03:41 +0300 |
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committer | Tejun Heo <tj@kernel.org> | 2017-01-16 03:03:41 +0300 |
commit | e595cd706982bff0211e6fafe5a108421e747fbc (patch) | |
tree | 4a8b664ac851fd9b8b4ed409c9d728994e76f797 /kernel/cgroup/cgroup-internal.h | |
parent | d8ebf5191d7fdf81ba34a7c3d726b99c34918030 (diff) | |
download | linux-e595cd706982bff0211e6fafe5a108421e747fbc.tar.xz |
cgroup: track migration context in cgroup_mgctx
cgroup migration is performed in four steps - css_set preloading,
addition of target tasks, actual migration, and clean up. A list
named preloaded_csets is used to track the preloading. This is a bit
too restricted and the code is already depending on the subtlety that
all source css_sets appear before destination ones.
Let's create struct cgroup_mgctx which keeps track of everything
during migration. Currently, it has separate preload lists for source
and destination csets and also embeds cgroup_taskset which is used
during the actual migration. This moves struct cgroup_taskset
definition to cgroup-internal.h.
This patch doesn't cause any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Zefan Li <lizefan@huawei.com>
Diffstat (limited to 'kernel/cgroup/cgroup-internal.h')
-rw-r--r-- | kernel/cgroup/cgroup-internal.h | 66 |
1 files changed, 60 insertions, 6 deletions
diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h index 589b0e7013ec..5f8c8ac5ab88 100644 --- a/kernel/cgroup/cgroup-internal.h +++ b/kernel/cgroup/cgroup-internal.h @@ -26,6 +26,61 @@ struct cgrp_cset_link { struct list_head cgrp_link; }; +/* used to track tasks and csets during migration */ +struct cgroup_taskset { + /* the src and dst cset list running through cset->mg_node */ + struct list_head src_csets; + struct list_head dst_csets; + + /* the subsys currently being processed */ + int ssid; + + /* + * Fields for cgroup_taskset_*() iteration. + * + * Before migration is committed, the target migration tasks are on + * ->mg_tasks of the csets on ->src_csets. After, on ->mg_tasks of + * the csets on ->dst_csets. ->csets point to either ->src_csets + * or ->dst_csets depending on whether migration is committed. + * + * ->cur_csets and ->cur_task point to the current task position + * during iteration. + */ + struct list_head *csets; + struct css_set *cur_cset; + struct task_struct *cur_task; +}; + +/* migration context also tracks preloading */ +struct cgroup_mgctx { + /* + * Preloaded source and destination csets. Used to guarantee + * atomic success or failure on actual migration. + */ + struct list_head preloaded_src_csets; + struct list_head preloaded_dst_csets; + + /* tasks and csets to migrate */ + struct cgroup_taskset tset; +}; + +#define CGROUP_TASKSET_INIT(tset) \ +{ \ + .src_csets = LIST_HEAD_INIT(tset.src_csets), \ + .dst_csets = LIST_HEAD_INIT(tset.dst_csets), \ + .csets = &tset.src_csets, \ +} + +#define CGROUP_MGCTX_INIT(name) \ +{ \ + LIST_HEAD_INIT(name.preloaded_src_csets), \ + LIST_HEAD_INIT(name.preloaded_dst_csets), \ + CGROUP_TASKSET_INIT(name.tset), \ +} + +#define DEFINE_CGROUP_MGCTX(name) \ + struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name) + struct cgroup_sb_opts { u16 subsys_mask; unsigned int flags; @@ -112,13 +167,12 @@ struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags, struct cgroup_namespace *ns); bool cgroup_may_migrate_to(struct cgroup *dst_cgrp); -void cgroup_migrate_finish(struct list_head *preloaded_csets); -void cgroup_migrate_add_src(struct css_set *src_cset, - struct cgroup *dst_cgrp, - struct list_head *preloaded_csets); -int cgroup_migrate_prepare_dst(struct list_head *preloaded_csets); +void cgroup_migrate_finish(struct cgroup_mgctx *mgctx); +void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp, + struct cgroup_mgctx *mgctx); +int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx); int cgroup_migrate(struct task_struct *leader, bool threadgroup, - struct cgroup_root *root); + struct cgroup_mgctx *mgctx, struct cgroup_root *root); int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader, bool threadgroup); |