From 7a0cf0e74ab6cfd8e561f5f12860d4ff8844905a Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Fri, 21 Jul 2017 11:14:51 -0400 Subject: cgroup: update debug controller to print out thread mode information Update debug controller so that it prints out debug info about thread mode. 1) The relationship between proc_cset and threaded_csets are displayed. 2) The status of being a thread root or threaded cgroup is displayed. This patch is extracted from Waiman's larger patch. v2: - Removed [thread root] / [threaded] from debug.cgroup_css_links file as the same information is available from cgroup.type. Suggested by Waiman. - Threaded marking is moved to the previous patch. Patch-originally-by: Waiman Long Signed-off-by: Tejun Heo --- kernel/cgroup/debug.c | 52 +++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 38 insertions(+), 14 deletions(-) (limited to 'kernel/cgroup/debug.c') diff --git a/kernel/cgroup/debug.c b/kernel/cgroup/debug.c index 787a242fa69d..f661b4cc5efd 100644 --- a/kernel/cgroup/debug.c +++ b/kernel/cgroup/debug.c @@ -114,27 +114,49 @@ static int cgroup_css_links_read(struct seq_file *seq, void *v) { struct cgroup_subsys_state *css = seq_css(seq); struct cgrp_cset_link *link; - int dead_cnt = 0, extra_refs = 0; + int dead_cnt = 0, extra_refs = 0, threaded_csets = 0; spin_lock_irq(&css_set_lock); + list_for_each_entry(link, &css->cgroup->cset_links, cset_link) { struct css_set *cset = link->cset; struct task_struct *task; int count = 0; int refcnt = refcount_read(&cset->refcount); - seq_printf(seq, " %d", refcnt); - if (refcnt - cset->nr_tasks > 0) { - int extra = refcnt - cset->nr_tasks; - - seq_printf(seq, " +%d", extra); - /* - * Take out the one additional reference in - * init_css_set. - */ - if (cset == &init_css_set) - extra--; - extra_refs += extra; + /* + * Print out the proc_cset and threaded_cset relationship + * and highlight difference between refcount and task_count. + */ + seq_printf(seq, "css_set %pK", cset); + if (rcu_dereference_protected(cset->dom_cset, 1) != cset) { + threaded_csets++; + seq_printf(seq, "=>%pK", cset->dom_cset); + } + if (!list_empty(&cset->threaded_csets)) { + struct css_set *tcset; + int idx = 0; + + list_for_each_entry(tcset, &cset->threaded_csets, + threaded_csets_node) { + seq_puts(seq, idx ? "," : "<="); + seq_printf(seq, "%pK", tcset); + idx++; + } + } else { + seq_printf(seq, " %d", refcnt); + if (refcnt - cset->nr_tasks > 0) { + int extra = refcnt - cset->nr_tasks; + + seq_printf(seq, " +%d", extra); + /* + * Take out the one additional reference in + * init_css_set. + */ + if (cset == &init_css_set) + extra--; + extra_refs += extra; + } } seq_puts(seq, "\n"); @@ -163,10 +185,12 @@ static int cgroup_css_links_read(struct seq_file *seq, void *v) } spin_unlock_irq(&css_set_lock); - if (!dead_cnt && !extra_refs) + if (!dead_cnt && !extra_refs && !threaded_csets) return 0; seq_puts(seq, "\n"); + if (threaded_csets) + seq_printf(seq, "threaded css_sets = %d\n", threaded_csets); if (extra_refs) seq_printf(seq, "extra references = %d\n", extra_refs); if (dead_cnt) -- cgit v1.2.3