[RFC PATCH-cgroup 6/6] cgroup: Make debug controller display bypass and subtree root modes info

Waiman Long
2017-06-14T15:05:37Z

This patch enables the debug controller to display the new bypass
mode and subtree root mode information.

Signed-off-by: Waiman Long <longman@redhat.com>
---
kernel/cgroup/cgroup-internal.h | 12 ++++++++++++
kernel/cgroup/cgroup.c | 9 ---------
kernel/cgroup/debug.c | 27 ++++++++++++++++++++-------
3 files changed, 32 insertions(+), 16 deletions(-)

diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h
index 0e81c61..6bb0a6a 100644
--- a/kernel/cgroup/cgroup-internal.h
+++ b/kernel/cgroup/cgroup-internal.h
@@ -151,6 +151,18 @@ static inline void get_css_set(struct css_set *cset)
refcount_inc(&cset->refcount);
}

+/*
+ * Return the cgroup parent.
+ */
+static inline struct cgroup *cgroup_parent(struct cgroup *cgrp)
+{
+ struct cgroup_subsys_state *parent_css = cgrp->self.parent;
+
+ if (parent_css)
+ return container_of(parent_css, struct cgroup, self);
+ return NULL;
+}
+
bool cgroup_ssid_enabled(int ssid);
bool cgroup_on_dfl(const struct cgroup *cgrp);

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 2a5bd49..6ffe900 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -322,15 +322,6 @@ static void cgroup_idr_remove(struct idr *idr, int id)
spin_unlock_bh(&cgroup_idr_lock);
}

-static struct cgroup *cgroup_parent(struct cgroup *cgrp)
-{
- struct cgroup_subsys_state *parent_css = cgrp->self.parent;
-
- if (parent_css)
- return container_of(parent_css, struct cgroup, self);
- return NULL;
-}
-
/* is @cgrp threaded? regardless of mixed / root / member? */
static bool cgroup_is_threaded(struct cgroup *cgrp)
{
diff --git a/kernel/cgroup/debug.c b/kernel/cgroup/debug.c
index be901c0..561539d 100644
--- a/kernel/cgroup/debug.c
+++ b/kernel/cgroup/debug.c
@@ -198,6 +198,7 @@ static int cgroup_css_links_read(struct seq_file *seq, void *v)
static int cgroup_subsys_states_read(struct seq_file *seq, void *v)
{
struct cgroup *cgrp = seq_css(seq)->cgroup;
+ struct cgroup *parent = cgroup_parent(cgrp);
struct cgroup_subsys *ss;
struct cgroup_subsys_state *css;
char pbuf[16];
@@ -206,9 +207,16 @@ static int cgroup_subsys_states_read(struct seq_file *seq, void *v)
mutex_lock(&cgroup_mutex);
for_each_subsys(ss, i) {
css = rcu_dereference_check(cgrp->subsys[ss->id], true);
- if (!css)
+ if (!css) {
+ u16 bypass = cgrp->bypass_ss_mask;
+
+ if (parent)
+ bypass |= parent->subtree_bypass;
+ if (bypass & (1 << ss->id))
+ seq_printf(seq, "%2d: %-4s\t- [Bypass]\n",
+ ss->id, ss->name);
continue;
-
+ }
pbuf[0] = '\0';

/* Show the parent CSS if applicable*/
@@ -234,6 +242,8 @@ static int cgroup_masks_read(struct seq_file *seq, void *v)
} mask_list[] = {
{ &cgrp->subtree_control, "subtree_control" },
{ &cgrp->subtree_ss_mask, "subtree_ss_mask" },
+ { &cgrp->subtree_bypass, "subtree_bypass" },
+ { &cgrp->bypass_ss_mask, "bypass_ss_mask" },
};

mutex_lock(&cgroup_mutex);
@@ -255,6 +265,8 @@ static int cgroup_masks_read(struct seq_file *seq, void *v)
if (cgrp->proc_cgrp)
seq_printf(seq, "thread mode : %s\n",
(cgrp->proc_cgrp == cgrp) ? "root" : "threaded");
+ if (test_bit(CGRP_SUBTREE_ROOT_MODE, &cgrp->flags))
+ seq_puts(seq, "subtree root mode: on\n");

mutex_unlock(&cgroup_mutex);
return 0;
@@ -314,11 +326,12 @@ static u64 releasable_read(struct cgroup_subsys_state *css, struct cftype *cft)
};

struct cgroup_subsys debug_cgrp_subsys = {
- .css_alloc = debug_css_alloc,
- .css_free = debug_css_free,
- .legacy_cftypes = debug_files,
- .dfl_cftypes = debug_files,
- .threaded = true,
+ .css_alloc = debug_css_alloc,
+ .css_free = debug_css_free,
+ .legacy_cftypes = debug_files,
+ .dfl_cftypes = debug_files,
+ .threaded = true,
+ .enabled_on_root = true,
};

/*
--
1.8.3.1