Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753772AbbHKSBA (ORCPT ); Tue, 11 Aug 2015 14:01:00 -0400 Received: from mail-yk0-f178.google.com ([209.85.160.178]:33695 "EHLO mail-yk0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751712AbbHKR6Z (ORCPT ); Tue, 11 Aug 2015 13:58:25 -0400 From: Tejun Heo To: hannes@cmpxchg.org, lizefan@huawei.com Cc: mhocko@kernel.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Tejun Heo Subject: [PATCH 1/8] cgroup: replace "cgroup.populated" with "cgroup.events" Date: Tue, 11 Aug 2015 13:58:02 -0400 Message-Id: <1439315889-3492-2-git-send-email-tj@kernel.org> X-Mailer: git-send-email 2.4.3 In-Reply-To: <1439315889-3492-1-git-send-email-tj@kernel.org> References: <1439315889-3492-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4640 Lines: 122 memcg already uses "memory.events" for event reporting and other controllers may need event reporting too. Let's standardize on "$SUBSYS.events" interface file for reporting events which don't happen too frequently and thus can share event notification. "cgroup.populated" is replaced with "populated" field in "cgroup.events" and documentation is updated accordingly. Signed-off-by: Tejun Heo Cc: Li Zefan Cc: Johannes Weiner --- Documentation/cgroups/unified-hierarchy.txt | 15 ++++++++++----- include/linux/cgroup-defs.h | 2 +- kernel/cgroup.c | 17 +++++++++-------- 3 files changed, 20 insertions(+), 14 deletions(-) diff --git a/Documentation/cgroups/unified-hierarchy.txt b/Documentation/cgroups/unified-hierarchy.txt index 1ee9caf..7ea2bc1 100644 --- a/Documentation/cgroups/unified-hierarchy.txt +++ b/Documentation/cgroups/unified-hierarchy.txt @@ -341,11 +341,11 @@ is riddled with issues. unnecessarily complicated and probably done this way because event delivery itself was expensive. -Unified hierarchy implements an interface file "cgroup.populated" -which can be used to monitor whether the cgroup's subhierarchy has -tasks in it or not. Its value is 0 if there is no task in the cgroup -and its descendants; otherwise, 1. poll and [id]notify events are -triggered when the value changes. +Unified hierarchy implements "populated" field in "cgroup.events" +interface file which can be used to monitor whether the cgroup's +subhierarchy has tasks in it or not. Its value is 0 if there is no +task in the cgroup and its descendants; otherwise, 1. poll and +[id]notify events are triggered when the value changes. This is significantly lighter and simpler and trivially allows delegating management of subhierarchy - subhierarchy monitoring can @@ -435,6 +435,11 @@ may be specified in any order and not all pairs have to be specified. the first entry in the file. Specific entries can use "default" as its value to indicate inheritance of the default value. +- For events which are not very high frequency, an interface file + "events" should be created which lists event key value pairs. + Whenever a notifiable event happens, file modified event should be + generated on the file. + 5-4. Per-Controller Changes diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h index 5294f1f..74d241d 100644 --- a/include/linux/cgroup-defs.h +++ b/include/linux/cgroup-defs.h @@ -226,7 +226,7 @@ struct cgroup { struct kernfs_node *kn; /* cgroup kernfs entry */ struct kernfs_node *procs_kn; /* kn for "cgroup.procs" */ - struct kernfs_node *populated_kn; /* kn for "cgroup.subtree_populated" */ + struct kernfs_node *events_kn; /* kn for "cgroup.events" */ /* * The bitmask of subsystems enabled on the child cgroups. diff --git a/kernel/cgroup.c b/kernel/cgroup.c index c4d94a5..43535fc 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -519,8 +519,8 @@ static void cgroup_update_populated(struct cgroup *cgrp, bool populated) if (!trigger) break; - if (cgrp->populated_kn) - kernfs_notify(cgrp->populated_kn); + if (cgrp->events_kn) + kernfs_notify(cgrp->events_kn); cgrp = cgroup_parent(cgrp); } while (cgrp); } @@ -2944,9 +2944,10 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of, goto out_unlock; } -static int cgroup_populated_show(struct seq_file *seq, void *v) +static int cgroup_events_show(struct seq_file *seq, void *v) { - seq_printf(seq, "%d\n", (bool)seq_css(seq)->cgroup->populated_cnt); + seq_printf(seq, "populated %d\n", + (bool)seq_css(seq)->cgroup->populated_cnt); return 0; } @@ -3113,8 +3114,8 @@ static int cgroup_add_file(struct cgroup *cgrp, struct cftype *cft) if (cft->write == cgroup_procs_write) cgrp->procs_kn = kn; - else if (cft->seq_show == cgroup_populated_show) - cgrp->populated_kn = kn; + else if (cft->seq_show == cgroup_events_show) + cgrp->events_kn = kn; return 0; } @@ -4287,9 +4288,9 @@ static struct cftype cgroup_dfl_base_files[] = { .write = cgroup_subtree_control_write, }, { - .name = "cgroup.populated", + .name = "cgroup.events", .flags = CFTYPE_NOT_ON_ROOT, - .seq_show = cgroup_populated_show, + .seq_show = cgroup_events_show, }, { } /* terminate */ }; -- 2.4.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/