From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCH 07/14] cgroup: reorganize css init / exit paths Date: Thu, 8 Aug 2013 16:13:44 -0400 Message-ID: <1375992831-4650-8-git-send-email-tj@kernel.org> References: <1375992831-4650-1-git-send-email-tj@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=dMsaT9lIWCIwUBTuKb4U59eB7/YgnSePwTKQ+jHcOTo=; b=wCgQnCUirdrzHdecR1pUOeJabzqm1kchadVOef0AvwRA147yk+OxasWaYVy+Oim5+q FvSZNJfTRA8AO9RLQeW9awuMEKqjv07sXa1R+lt69iXuCCmxqoJlGEZk4RWXXIyj6I1x jA909xZovzJq0fEezQ6LOXVtf1upZgBc8ZmLDDOydf8jYGkNtXEFPJyqAt+J2SI8+kwy mSvZBd1at8Wdy9ZnegW9ANvkYDj3LWko6sJUxI/A+agyWFNTf0k3hVEr/AAxsnuepUNl Pdi8cJxpHAuVKlQsyuHOuPHe+BDTf3mwik3tacELJpgaigdiGuK4+YYd2dyb8WMaC+Dp qjCg== In-Reply-To: <1375992831-4650-1-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org Cc: Tejun Heo , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org css (cgroup_subsys_state) lifetime management is about to be restructured. In prepartion, make the following mostly trivial changes. * init_cgroup_css() is renamed to init_css() so that it's consistent with other css handling functions. * alloc_css_id(), online_css() and offline_css() updated to take @css instead of cgroups and subsys IDs. * Merge two separate loops - one around percpu_ref_get() and the other around online_css() - into one. This changes the order of operations a bit without any consequences. The first two changes don't make any functional differences and while the last one does change behavior, it is of no consequence. Signed-off-by: Tejun Heo --- kernel/cgroup.c | 60 +++++++++++++++++++++++++-------------------------------- 1 file changed, 26 insertions(+), 34 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index c271016..2a93bae 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -838,8 +838,7 @@ static struct backing_dev_info cgroup_backing_dev_info = { .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, }; -static int alloc_css_id(struct cgroup_subsys *ss, - struct cgroup *parent, struct cgroup *child); +static int alloc_css_id(struct cgroup_subsys_state *child_css); static struct inode *cgroup_new_inode(umode_t mode, struct super_block *sb) { @@ -4308,9 +4307,8 @@ static void css_release(struct percpu_ref *ref) schedule_work(&css->destroy_work); } -static void init_cgroup_css(struct cgroup_subsys_state *css, - struct cgroup_subsys *ss, - struct cgroup *cgrp) +static void init_css(struct cgroup_subsys_state *css, struct cgroup_subsys *ss, + struct cgroup *cgrp) { css->cgroup = cgrp; css->ss = ss; @@ -4327,9 +4325,9 @@ static void init_cgroup_css(struct cgroup_subsys_state *css, } /* invoke ->css_online() on a new CSS and mark it online if successful */ -static int online_css(struct cgroup_subsys *ss, struct cgroup *cgrp) +static int online_css(struct cgroup_subsys_state *css) { - struct cgroup_subsys_state *css = cgroup_css(cgrp, ss->subsys_id); + struct cgroup_subsys *ss = css->ss; int ret = 0; lockdep_assert_held(&cgroup_mutex); @@ -4342,9 +4340,9 @@ static int online_css(struct cgroup_subsys *ss, struct cgroup *cgrp) } /* if the CSS is online, invoke ->css_offline() on it and mark it offline */ -static void offline_css(struct cgroup_subsys *ss, struct cgroup *cgrp) +static void offline_css(struct cgroup_subsys_state *css) { - struct cgroup_subsys_state *css = cgroup_css(cgrp, ss->subsys_id); + struct cgroup_subsys *ss = css->ss; lockdep_assert_held(&cgroup_mutex); @@ -4442,10 +4440,10 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, goto err_free_all; } - init_cgroup_css(css, ss, cgrp); + init_css(css, ss, cgrp); if (ss->use_id) { - err = alloc_css_id(ss, parent, cgrp); + err = alloc_css_id(css); if (err) goto err_free_all; } @@ -4467,20 +4465,18 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, list_add_tail_rcu(&cgrp->sibling, &cgrp->parent->children); root->number_of_cgroups++; - /* each css holds a ref to the cgroup's dentry and the parent css */ + /* hold a ref to the parent's dentry */ + dget(parent->dentry); + for_each_root_subsys(root, ss) { struct cgroup_subsys_state *css = cgroup_css(cgrp, ss->subsys_id); + /* each css holds a ref to the cgroup and the parent css */ dget(dentry); percpu_ref_get(&css->parent->refcnt); - } - /* hold a ref to the parent's dentry */ - dget(parent->dentry); - - /* creation succeeded, notify subsystems */ - for_each_root_subsys(root, ss) { - err = online_css(ss, cgrp); + /* creation succeeded, notify subsystems */ + err = online_css(css); if (err) goto err_destroy; @@ -4700,7 +4696,7 @@ static void cgroup_offline_fn(struct work_struct *work) * initate destruction. */ for_each_root_subsys(cgrp->root, ss) - offline_css(ss, cgrp); + offline_css(cgroup_css(cgrp, ss->subsys_id)); /* * Put the css refs from cgroup_destroy_locked(). Each css holds @@ -4778,7 +4774,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss) css = ss->css_alloc(cgroup_css(cgroup_dummy_top, ss->subsys_id)); /* We don't handle early failures gracefully */ BUG_ON(IS_ERR(css)); - init_cgroup_css(css, ss, cgroup_dummy_top); + init_css(css, ss, cgroup_dummy_top); /* Update the init_css_set to contain a subsys * pointer to this state - since the subsystem is @@ -4793,7 +4789,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss) * need to invoke fork callbacks here. */ BUG_ON(!list_empty(&init_task.tasks)); - BUG_ON(online_css(ss, cgroup_dummy_top)); + BUG_ON(online_css(cgroup_css(cgroup_dummy_top, ss->subsys_id))); mutex_unlock(&cgroup_mutex); @@ -4866,8 +4862,8 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss) ss->root = &cgroup_dummy_root; /* our new subsystem will be attached to the dummy hierarchy. */ - init_cgroup_css(css, ss, cgroup_dummy_top); - /* init_idr must be after init_cgroup_css because it sets css->id. */ + init_css(css, ss, cgroup_dummy_top); + /* init_idr must be after init_css() because it sets css->id. */ if (ss->use_id) { ret = cgroup_init_idr(ss, css); if (ret) @@ -4897,7 +4893,7 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss) } write_unlock(&css_set_lock); - ret = online_css(ss, cgroup_dummy_top); + ret = online_css(cgroup_css(cgroup_dummy_top, ss->subsys_id)); if (ret) goto err_unload; @@ -4936,7 +4932,7 @@ void cgroup_unload_subsys(struct cgroup_subsys *ss) mutex_lock(&cgroup_mutex); - offline_css(ss, cgroup_dummy_top); + offline_css(cgroup_css(cgroup_dummy_top, ss->subsys_id)); if (ss->use_id) idr_destroy(&ss->idr); @@ -5588,20 +5584,16 @@ static int __init_or_module cgroup_init_idr(struct cgroup_subsys *ss, return 0; } -static int alloc_css_id(struct cgroup_subsys *ss, struct cgroup *parent, - struct cgroup *child) +static int alloc_css_id(struct cgroup_subsys_state *child_css) { - int subsys_id, i, depth = 0; - struct cgroup_subsys_state *parent_css, *child_css; + struct cgroup_subsys_state *parent_css = css_parent(child_css); struct css_id *child_id, *parent_id; + int i, depth; - subsys_id = ss->subsys_id; - parent_css = cgroup_css(parent, subsys_id); - child_css = cgroup_css(child, subsys_id); parent_id = rcu_dereference_protected(parent_css->id, true); depth = parent_id->depth + 1; - child_id = get_new_cssid(ss, depth); + child_id = get_new_cssid(child_css->ss, depth); if (IS_ERR(child_id)) return PTR_ERR(child_id); -- 1.8.3.1 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966493Ab3HHURL (ORCPT ); Thu, 8 Aug 2013 16:17:11 -0400 Received: from mail-vc0-f182.google.com ([209.85.220.182]:43600 "EHLO mail-vc0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966402Ab3HHUOP (ORCPT ); Thu, 8 Aug 2013 16:14:15 -0400 From: Tejun Heo To: lizefan@huawei.com Cc: containers@lists.linux-foundation.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Tejun Heo Subject: [PATCH 07/14] cgroup: reorganize css init / exit paths Date: Thu, 8 Aug 2013 16:13:44 -0400 Message-Id: <1375992831-4650-8-git-send-email-tj@kernel.org> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1375992831-4650-1-git-send-email-tj@kernel.org> References: <1375992831-4650-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org css (cgroup_subsys_state) lifetime management is about to be restructured. In prepartion, make the following mostly trivial changes. * init_cgroup_css() is renamed to init_css() so that it's consistent with other css handling functions. * alloc_css_id(), online_css() and offline_css() updated to take @css instead of cgroups and subsys IDs. * Merge two separate loops - one around percpu_ref_get() and the other around online_css() - into one. This changes the order of operations a bit without any consequences. The first two changes don't make any functional differences and while the last one does change behavior, it is of no consequence. Signed-off-by: Tejun Heo --- kernel/cgroup.c | 60 +++++++++++++++++++++++++-------------------------------- 1 file changed, 26 insertions(+), 34 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index c271016..2a93bae 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -838,8 +838,7 @@ static struct backing_dev_info cgroup_backing_dev_info = { .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, }; -static int alloc_css_id(struct cgroup_subsys *ss, - struct cgroup *parent, struct cgroup *child); +static int alloc_css_id(struct cgroup_subsys_state *child_css); static struct inode *cgroup_new_inode(umode_t mode, struct super_block *sb) { @@ -4308,9 +4307,8 @@ static void css_release(struct percpu_ref *ref) schedule_work(&css->destroy_work); } -static void init_cgroup_css(struct cgroup_subsys_state *css, - struct cgroup_subsys *ss, - struct cgroup *cgrp) +static void init_css(struct cgroup_subsys_state *css, struct cgroup_subsys *ss, + struct cgroup *cgrp) { css->cgroup = cgrp; css->ss = ss; @@ -4327,9 +4325,9 @@ static void init_cgroup_css(struct cgroup_subsys_state *css, } /* invoke ->css_online() on a new CSS and mark it online if successful */ -static int online_css(struct cgroup_subsys *ss, struct cgroup *cgrp) +static int online_css(struct cgroup_subsys_state *css) { - struct cgroup_subsys_state *css = cgroup_css(cgrp, ss->subsys_id); + struct cgroup_subsys *ss = css->ss; int ret = 0; lockdep_assert_held(&cgroup_mutex); @@ -4342,9 +4340,9 @@ static int online_css(struct cgroup_subsys *ss, struct cgroup *cgrp) } /* if the CSS is online, invoke ->css_offline() on it and mark it offline */ -static void offline_css(struct cgroup_subsys *ss, struct cgroup *cgrp) +static void offline_css(struct cgroup_subsys_state *css) { - struct cgroup_subsys_state *css = cgroup_css(cgrp, ss->subsys_id); + struct cgroup_subsys *ss = css->ss; lockdep_assert_held(&cgroup_mutex); @@ -4442,10 +4440,10 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, goto err_free_all; } - init_cgroup_css(css, ss, cgrp); + init_css(css, ss, cgrp); if (ss->use_id) { - err = alloc_css_id(ss, parent, cgrp); + err = alloc_css_id(css); if (err) goto err_free_all; } @@ -4467,20 +4465,18 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, list_add_tail_rcu(&cgrp->sibling, &cgrp->parent->children); root->number_of_cgroups++; - /* each css holds a ref to the cgroup's dentry and the parent css */ + /* hold a ref to the parent's dentry */ + dget(parent->dentry); + for_each_root_subsys(root, ss) { struct cgroup_subsys_state *css = cgroup_css(cgrp, ss->subsys_id); + /* each css holds a ref to the cgroup and the parent css */ dget(dentry); percpu_ref_get(&css->parent->refcnt); - } - /* hold a ref to the parent's dentry */ - dget(parent->dentry); - - /* creation succeeded, notify subsystems */ - for_each_root_subsys(root, ss) { - err = online_css(ss, cgrp); + /* creation succeeded, notify subsystems */ + err = online_css(css); if (err) goto err_destroy; @@ -4700,7 +4696,7 @@ static void cgroup_offline_fn(struct work_struct *work) * initate destruction. */ for_each_root_subsys(cgrp->root, ss) - offline_css(ss, cgrp); + offline_css(cgroup_css(cgrp, ss->subsys_id)); /* * Put the css refs from cgroup_destroy_locked(). Each css holds @@ -4778,7 +4774,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss) css = ss->css_alloc(cgroup_css(cgroup_dummy_top, ss->subsys_id)); /* We don't handle early failures gracefully */ BUG_ON(IS_ERR(css)); - init_cgroup_css(css, ss, cgroup_dummy_top); + init_css(css, ss, cgroup_dummy_top); /* Update the init_css_set to contain a subsys * pointer to this state - since the subsystem is @@ -4793,7 +4789,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss) * need to invoke fork callbacks here. */ BUG_ON(!list_empty(&init_task.tasks)); - BUG_ON(online_css(ss, cgroup_dummy_top)); + BUG_ON(online_css(cgroup_css(cgroup_dummy_top, ss->subsys_id))); mutex_unlock(&cgroup_mutex); @@ -4866,8 +4862,8 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss) ss->root = &cgroup_dummy_root; /* our new subsystem will be attached to the dummy hierarchy. */ - init_cgroup_css(css, ss, cgroup_dummy_top); - /* init_idr must be after init_cgroup_css because it sets css->id. */ + init_css(css, ss, cgroup_dummy_top); + /* init_idr must be after init_css() because it sets css->id. */ if (ss->use_id) { ret = cgroup_init_idr(ss, css); if (ret) @@ -4897,7 +4893,7 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss) } write_unlock(&css_set_lock); - ret = online_css(ss, cgroup_dummy_top); + ret = online_css(cgroup_css(cgroup_dummy_top, ss->subsys_id)); if (ret) goto err_unload; @@ -4936,7 +4932,7 @@ void cgroup_unload_subsys(struct cgroup_subsys *ss) mutex_lock(&cgroup_mutex); - offline_css(ss, cgroup_dummy_top); + offline_css(cgroup_css(cgroup_dummy_top, ss->subsys_id)); if (ss->use_id) idr_destroy(&ss->idr); @@ -5588,20 +5584,16 @@ static int __init_or_module cgroup_init_idr(struct cgroup_subsys *ss, return 0; } -static int alloc_css_id(struct cgroup_subsys *ss, struct cgroup *parent, - struct cgroup *child) +static int alloc_css_id(struct cgroup_subsys_state *child_css) { - int subsys_id, i, depth = 0; - struct cgroup_subsys_state *parent_css, *child_css; + struct cgroup_subsys_state *parent_css = css_parent(child_css); struct css_id *child_id, *parent_id; + int i, depth; - subsys_id = ss->subsys_id; - parent_css = cgroup_css(parent, subsys_id); - child_css = cgroup_css(child, subsys_id); parent_id = rcu_dereference_protected(parent_css->id, true); depth = parent_id->depth + 1; - child_id = get_new_cssid(ss, depth); + child_id = get_new_cssid(child_css->ss, depth); if (IS_ERR(child_id)) return PTR_ERR(child_id); -- 1.8.3.1