Messages in this thread Patch in this message | | | From | Tejun Heo <> | Subject | [PATCH 16/16] cgroup: allocate 2x cgrp_cset_links when setting up a new root | Date | Wed, 24 Feb 2016 17:02:48 -0500 |
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During prep, cgroup_setup_root() allocates cgrp_cset_links matching the number of existing css_sets to later link the new root. This is fine for now as the only operation which can happen inbetween is rebind_subsystems() and rebinding of empty subsystems doesn't create new css_sets.
However, while not yet allowed, with the recent reimplementation, rebind_subsystems() can rebind subsystems with descendant csses and thus can create new css_sets. This patch makes cgroup_setup_root() allocate 2x of the existing css_sets so that later use of live subsystem rebinding doesn't blow up.
Signed-off-by: Tejun Heo <tj@kernel.org> --- kernel/cgroup.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 744e1c6..a44c123 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1914,10 +1914,11 @@ static int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask) /* * We're accessing css_set_count without locking css_set_lock here, * but that's OK - it can only be increased by someone holding - * cgroup_lock, and that's us. The worst that can happen is that we - * have some link structures left over + * cgroup_lock, and that's us. Later rebinding may disable + * controllers on the default hierarchy and thus create new csets, + * which can't be more than the existing ones. Allocate 2x. */ - ret = allocate_cgrp_cset_links(css_set_count, &tmp_links); + ret = allocate_cgrp_cset_links(2 * css_set_count, &tmp_links); if (ret) goto cancel_ref; -- 2.5.0
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