From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f200.google.com (mail-qk0-f200.google.com [209.85.220.200]) by kanga.kvack.org (Postfix) with ESMTP id 31E776B0374 for ; Mon, 15 May 2017 09:35:03 -0400 (EDT) Received: by mail-qk0-f200.google.com with SMTP id d14so52144068qkb.0 for ; Mon, 15 May 2017 06:35:03 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id q46si10727566qtb.158.2017.05.15.06.35.01 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 15 May 2017 06:35:02 -0700 (PDT) From: Waiman Long Subject: [RFC PATCH v2 14/17] cgroup: Enable printing of v2 controllers' cgroup hierarchy Date: Mon, 15 May 2017 09:34:13 -0400 Message-Id: <1494855256-12558-15-git-send-email-longman@redhat.com> In-Reply-To: <1494855256-12558-1-git-send-email-longman@redhat.com> References: <1494855256-12558-1-git-send-email-longman@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Tejun Heo , Li Zefan , Johannes Weiner , Peter Zijlstra , Ingo Molnar Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, kernel-team@fb.com, pjt@google.com, luto@amacapital.net, efault@gmx.de, longman@redhat.com This patch add a new debug control file on the cgroup v2 root directory to print out the cgroup hierarchy for each of the v2 controllers. Signed-off-by: Waiman Long --- kernel/cgroup/debug.c | 141 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 141 insertions(+) diff --git a/kernel/cgroup/debug.c b/kernel/cgroup/debug.c index a2dbf77..3adb26a 100644 --- a/kernel/cgroup/debug.c +++ b/kernel/cgroup/debug.c @@ -268,6 +268,141 @@ static int cgroup_masks_read(struct seq_file *seq, void *v) return 0; } +/* + * Print out all the child cgroup names that doesn't have a css for the + * corresponding cgroup_subsys. If a child cgroup has a css, put that into + * the given cglist to be processed in the next iteration. + */ +#define CGLIST_MAX 16 +static void print_hierarchy(struct seq_file *seq, + struct cgroup *cgrp, + struct cgroup_subsys *ss, + struct cgroup_subsys_state *css, + struct cgroup **cglist, + int *cgcnt) +{ + struct cgroup *child; + struct cgroup_subsys_state *child_css; + char cgname[64]; + + cgname[sizeof(cgname) - 1] = '\0'; + /* + * Iterate all live children of the given cgroup. + */ + list_for_each_entry(child, &cgrp->self.children, self.sibling) { + if (cgroup_is_dead(child)) + continue; + + child_css = rcu_dereference_check(child->subsys[ss->id], true); + if (child_css) { + WARN_ON(child_css->parent != css); + if (*cgcnt < CGLIST_MAX) { + cglist[*cgcnt] = child; + (*cgcnt)++; + } + continue; + } + + /* + * Skip resource domain cgroup + */ + if (test_bit(CGRP_RESOURCE_DOMAIN, &child->flags)) + continue; + + cgroup_name(child, cgname, sizeof(cgname)-1); + seq_putc(seq, ','); + seq_puts(seq, cgname); + print_hierarchy(seq, child, ss, css, cglist, cgcnt); + } +} + +/* + * Print the hierachies with respect to each controller for the default + * hierarchy. + * + * Each child level is printed on a separate line. Set of cgroups that + * have the same css will be grouped together and separated by comma. + * Process in those cgroups will be in the same node (css) in the + * controller's hierarchy. There is an exception that for resource + * domain cgroup, the processes associated with its parent and its + * affiliates will be mapped to the css of that resource domain cgroup + * instead. + * + * If there are more than CGLIST_MAX sets of cgroups in each level, + * the extra ones will be skipped. + */ +static int controller_hierachies_read(struct seq_file *seq, void *v) +{ + struct cgroup *root = seq_css(seq)->cgroup; + struct cgroup_subsys *ss; + struct cgroup_subsys_state *css; + struct cgroup *cgrp; + struct cgroup *cglist[CGLIST_MAX]; + struct cgroup *cg2list[CGLIST_MAX]; + int i, idx, cgnum, cg2num; + char cgname[64]; + + cgname[sizeof(cgname) - 1] = '\0'; + mutex_lock(&cgroup_mutex); + for_each_subsys(ss, i) { + if (!(root->root->subsys_mask & (1 << ss->id))) + continue; + seq_puts(seq, ss->name); + seq_puts(seq, ":\n"); + + cgnum = 1; + cg2num = 0; + cglist[0] = root; + idx = 0; + while (cgnum) { + if (idx) + seq_putc(seq, ' '); + cgrp = cglist[idx]; + if (test_bit(CGRP_RESOURCE_DOMAIN, &cgrp->flags)) { + struct cgroup *parent; + + parent = container_of(cgrp->self.parent, + struct cgroup, self); + cgroup_name(parent, cgname, sizeof(cgname)-1); + seq_printf(seq, "%s.rd", cgname); + } else { + cgroup_name(cgrp, cgname, sizeof(cgname)-1); + seq_puts(seq, cgname); + } + css = rcu_dereference_check(cgrp->subsys[ss->id], true); + WARN_ON(!css); + + if (cgrp == root) + seq_printf(seq, "[%d]", css->id); + else + seq_printf(seq, "[%d:P=%d]", css->id, + css->parent->id); + + /* + * List all the cgroups that use the current + * css. + */ + print_hierarchy(seq, cgrp, ss, css, cg2list, &cg2num); + + if (++idx < cgnum) + continue; + + /* + * Move cg2list to cglist. + */ + cgnum = cg2num; + idx = cg2num = 0; + if (cgnum) + memcpy(cglist, cg2list, + cgnum * sizeof(cglist[0])); + seq_putc(seq, '\n'); + } + seq_putc(seq, '\n'); + } + mutex_unlock(&cgroup_mutex); + return 0; +} + static u64 releasable_read(struct cgroup_subsys_state *css, struct cftype *cft) { return (!cgroup_is_populated(css->cgroup) && @@ -314,6 +449,12 @@ static u64 releasable_read(struct cgroup_subsys_state *css, struct cftype *cft) }, { + .name = "controller_hierachies", + .seq_show = controller_hierachies_read, + .flags = CFTYPE_ONLY_ON_ROOT|__CFTYPE_ONLY_ON_DFL, + }, + + { .name = "releasable", .read_u64 = releasable_read, }, -- 1.8.3.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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