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| author | Tejun Heo <tj@kernel.org> | 2016-03-08 11:51:26 -0500 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2016-03-08 11:51:26 -0500 |
| commit | e4857982f49d21c05a84351b56724bf353022355 (patch) | |
| tree | dc2e6039b714635e36ab148ed1ef20a9cbb01f4a /include/linux/cgroup-defs.h | |
| parent | 37ff9f8f474216d0cfca7565a4e0caa521ee6e7e (diff) | |
| download | linux-e4857982f49d21c05a84351b56724bf353022355.tar.gz linux-e4857982f49d21c05a84351b56724bf353022355.tar.bz2 linux-e4857982f49d21c05a84351b56724bf353022355.zip | |
cgroup: use css_set->mg_dst_cgrp for the migration target cgroup
Migration can be multi-target on the default hierarchy when a
controller is enabled - processes belonging to each child cgroup have
to be moved to the child cgroup itself to refresh css association.
This isn't a problem for cgroup_migrate_add_src() as each source
css_set still maps to single source and target cgroups; however,
cgroup_migrate_prepare_dst() is called once after all source css_sets
are added and thus might not have a single destination cgroup. This
is currently worked around by specifying NULL for @dst_cgrp and using
the source's default cgroup as destination as the only multi-target
migration in use is self-targetting. While this works, it's subtle
and clunky.
As all taget cgroups are already specified while preparing the source
css_sets, this clunkiness can easily be removed by recording the
target cgroup in each source css_set. This patch adds
css_set->mg_dst_cgrp which is recorded on cgroup_migrate_src() and
used by cgroup_migrate_prepare_dst(). This also makes migration code
ready for arbitrary multi-target migration.
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'include/linux/cgroup-defs.h')
| -rw-r--r-- | include/linux/cgroup-defs.h | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h index aae8c94de4b3..590291d56049 100644 --- a/include/linux/cgroup-defs.h +++ b/include/linux/cgroup-defs.h @@ -191,12 +191,13 @@ struct css_set { /* * If this cset is acting as the source of migration the following - * two fields are set. mg_src_cgrp is the source cgroup of the - * on-going migration and mg_dst_cset is the destination cset the - * target tasks on this cset should be migrated to. Protected by - * cgroup_mutex. + * two fields are set. mg_src_cgrp and mg_dst_cgrp are + * respectively the source and destination cgroups of the on-going + * migration. mg_dst_cset is the destination cset the target tasks + * on this cset should be migrated to. Protected by cgroup_mutex. */ struct cgroup *mg_src_cgrp; + struct cgroup *mg_dst_cgrp; struct css_set *mg_dst_cset; /* |