Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752556Ab0HYILq (ORCPT ); Wed, 25 Aug 2010 04:11:46 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:52994 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752153Ab0HYILn (ORCPT ); Wed, 25 Aug 2010 04:11:43 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Date: Wed, 25 Aug 2010 17:06:40 +0900 From: KAMEZAWA Hiroyuki To: KAMEZAWA Hiroyuki Cc: linux-mm@kvack.org, "nishimura@mxp.nes.nec.co.jp" , "balbir@linux.vnet.ibm.com" , gthelen@google.com, m-ikeda@ds.jp.nec.com, "akpm@linux-foundation.org" , "linux-kernel@vger.kernel.org" , "menage@google.com" , "lizf@cn.fujitsu.com" Subject: [PATCH 1/5] cgroup: do ID allocation under css allocator. Message-Id: <20100825170640.5f365629.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20100825170435.15f8eb73.kamezawa.hiroyu@jp.fujitsu.com> References: <20100825170435.15f8eb73.kamezawa.hiroyu@jp.fujitsu.com> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 3.0.3 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7971 Lines: 235 From: KAMEZAWA Hiroyuki Now, css'id is allocated after ->create() is called. But to make use of ID in ->create(), it should be available before ->create(). In another thinking, considering the ID is tightly coupled with "css", it should be allocated when "css" is allocated. This patch moves alloc_css_id() to css allocation routine. Now, only 2 subsys, memory and blkio are useing ID. (To support complicated hierarchy walk.) ID will be used in mem cgroup's ->create(), later. Note: If someone changes rules of css allocation, ID allocation should be moved too. Signed-off-by: KAMEZAWA Hiroyuki --- block/blk-cgroup.c | 9 ++++++++ include/linux/cgroup.h | 16 ++++++++------- kernel/cgroup.c | 50 ++++++++++++++----------------------------------- mm/memcontrol.c | 5 ++++ 4 files changed, 38 insertions(+), 42 deletions(-) Index: mmotm-0811/kernel/cgroup.c =================================================================== --- mmotm-0811.orig/kernel/cgroup.c +++ mmotm-0811/kernel/cgroup.c @@ -289,9 +289,6 @@ struct cg_cgroup_link { static struct css_set init_css_set; static struct cg_cgroup_link init_css_set_link; -static int cgroup_init_idr(struct cgroup_subsys *ss, - struct cgroup_subsys_state *css); - /* css_set_lock protects the list of css_set objects, and the * chain of tasks off each css_set. Nests outside task->alloc_lock * due to cgroup_iter_start() */ @@ -770,9 +767,6 @@ static struct backing_dev_info cgroup_ba .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, }; -static int alloc_css_id(struct cgroup_subsys *ss, - struct cgroup *parent, struct cgroup *child); - static struct inode *cgroup_new_inode(mode_t mode, struct super_block *sb) { struct inode *inode = new_inode(sb); @@ -3257,7 +3251,8 @@ static void init_cgroup_css(struct cgrou css->cgroup = cgrp; atomic_set(&css->refcnt, 1); css->flags = 0; - css->id = NULL; + if (!ss->use_id) + css->id = NULL; if (cgrp == dummytop) set_bit(CSS_ROOT, &css->flags); BUG_ON(cgrp->subsys[ss->subsys_id]); @@ -3342,12 +3337,6 @@ static long cgroup_create(struct cgroup goto err_destroy; } init_cgroup_css(css, ss, cgrp); - if (ss->use_id) { - err = alloc_css_id(ss, parent, cgrp); - if (err) - goto err_destroy; - } - /* At error, ->destroy() callback has to free assigned ID. */ } cgroup_lock_hierarchy(root); @@ -3709,17 +3698,6 @@ int __init_or_module cgroup_load_subsys( /* our new subsystem will be attached to the dummy hierarchy. */ init_cgroup_css(css, ss, dummytop); - /* init_idr must be after init_cgroup_css because it sets css->id. */ - if (ss->use_id) { - int ret = cgroup_init_idr(ss, css); - if (ret) { - dummytop->subsys[ss->subsys_id] = NULL; - ss->destroy(ss, dummytop); - subsys[i] = NULL; - mutex_unlock(&cgroup_mutex); - return ret; - } - } /* * Now we need to entangle the css into the existing css_sets. unlike @@ -3888,8 +3866,6 @@ int __init cgroup_init(void) struct cgroup_subsys *ss = subsys[i]; if (!ss->early_init) cgroup_init_subsys(ss); - if (ss->use_id) - cgroup_init_idr(ss, init_css_set.subsys[ss->subsys_id]); } /* Add init_css_set to the hash table */ @@ -4603,8 +4579,8 @@ err_out: } -static int __init_or_module cgroup_init_idr(struct cgroup_subsys *ss, - struct cgroup_subsys_state *rootcss) +static int cgroup_init_idr(struct cgroup_subsys *ss, + struct cgroup_subsys_state *rootcss) { struct css_id *newid; @@ -4616,21 +4592,25 @@ static int __init_or_module cgroup_init_ return PTR_ERR(newid); newid->stack[0] = newid->id; - newid->css = rootcss; - rootcss->id = newid; + rcu_assign_pointer(newid->css, rootcss); + rcu_assign_pointer(rootcss->id, newid); return 0; } -static int alloc_css_id(struct cgroup_subsys *ss, struct cgroup *parent, - struct cgroup *child) +int alloc_css_id(struct cgroup_subsys *ss, + struct cgroup *cgrp, struct cgroup_subsys_state *css) { int subsys_id, i, depth = 0; - struct cgroup_subsys_state *parent_css, *child_css; + struct cgroup_subsys_state *parent_css; + struct cgroup *parent; struct css_id *child_id, *parent_id; + if (cgrp == dummytop) + return cgroup_init_idr(ss, css); + + parent = cgrp->parent; subsys_id = ss->subsys_id; parent_css = parent->subsys[subsys_id]; - child_css = child->subsys[subsys_id]; parent_id = parent_css->id; depth = parent_id->depth + 1; @@ -4645,7 +4625,7 @@ static int alloc_css_id(struct cgroup_su * child_id->css pointer will be set after this cgroup is available * see cgroup_populate_dir() */ - rcu_assign_pointer(child_css->id, child_id); + rcu_assign_pointer(css->id, child_id); return 0; } Index: mmotm-0811/include/linux/cgroup.h =================================================================== --- mmotm-0811.orig/include/linux/cgroup.h +++ mmotm-0811/include/linux/cgroup.h @@ -583,9 +583,11 @@ int cgroup_attach_task_current_cg(struct /* * CSS ID is ID for cgroup_subsys_state structs under subsys. This only works * if cgroup_subsys.use_id == true. It can be used for looking up and scanning. - * CSS ID is assigned at cgroup allocation (create) automatically - * and removed when subsys calls free_css_id() function. This is because - * the lifetime of cgroup_subsys_state is subsys's matter. + * CSS ID must be assigned by subsys itself at cgroup creation and deleted + * when subsys calls free_css_id() function. This is because the life time of + * of cgroup_subsys_state is subsys's matter. + * + * ID->css look up is available after cgroup's directory is populated. * * Looking up and scanning function should be called under rcu_read_lock(). * Taking cgroup_mutex()/hierarchy_mutex() is not necessary for following calls. @@ -593,10 +595,10 @@ int cgroup_attach_task_current_cg(struct * destroyed". The caller should check css and cgroup's status. */ -/* - * Typically Called at ->destroy(), or somewhere the subsys frees - * cgroup_subsys_state. - */ +/* Should be called in ->create() by subsys itself */ +int alloc_css_id(struct cgroup_subsys *ss, struct cgroup *newgr, + struct cgroup_subsys_state *css); +/* Typically Called at ->destroy(), or somewhere the subsys frees css */ void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css); /* Find a cgroup_subsys_state which has given ID */ Index: mmotm-0811/mm/memcontrol.c =================================================================== --- mmotm-0811.orig/mm/memcontrol.c +++ mmotm-0811/mm/memcontrol.c @@ -4141,6 +4141,11 @@ mem_cgroup_create(struct cgroup_subsys * if (alloc_mem_cgroup_per_zone_info(mem, node)) goto free_out; + error = alloc_css_id(ss, cont, &mem->css); + if (error) + goto free_out; + /* Here, css_id(&mem->css) works. but css_lookup(id)->mem doesn't */ + /* root ? */ if (cont->parent == NULL) { int cpu; Index: mmotm-0811/block/blk-cgroup.c =================================================================== --- mmotm-0811.orig/block/blk-cgroup.c +++ mmotm-0811/block/blk-cgroup.c @@ -958,9 +958,13 @@ blkiocg_create(struct cgroup_subsys *sub { struct blkio_cgroup *blkcg; struct cgroup *parent = cgroup->parent; + int ret; if (!parent) { blkcg = &blkio_root_cgroup; + ret = alloc_css_id(subsys, cgroup, &blkcg->css); + if (ret) + return ERR_PTR(ret); goto done; } @@ -971,6 +975,11 @@ blkiocg_create(struct cgroup_subsys *sub blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL); if (!blkcg) return ERR_PTR(-ENOMEM); + ret = alloc_css_id(subsys, cgroup, &blkcg->css); + if (ret) { + kfree(blkcg); + return ERR_PTR(ret); + } blkcg->weight = BLKIO_WEIGHT_DEFAULT; done: -- 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/