From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 22 Aug 2008 20:34:57 +0900 From: KAMEZAWA Hiroyuki Subject: [RFC][PATCH 5/14] memcg: free page_cgroup by RCU Message-Id: <20080822203457.d62e394d.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20080822202720.b7977aab.kamezawa.hiroyu@jp.fujitsu.com> References: <20080822202720.b7977aab.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: KAMEZAWA Hiroyuki Cc: "linux-mm@kvack.org" , "balbir@linux.vnet.ibm.com" , "nishimura@mxp.nes.nec.co.jp" List-ID: Freeing page_cgroup by RCU. This makes access to page->page_cgroup as RCU-safe. Signed-off-by: KAMEZAWA Hiroyuki --- mm/memcontrol.c | 44 ++++++++++++++++++++++++++++++++++++-------- 1 file changed, 36 insertions(+), 8 deletions(-) Index: mmtom-2.6.27-rc3+/mm/memcontrol.c =================================================================== --- mmtom-2.6.27-rc3+.orig/mm/memcontrol.c +++ mmtom-2.6.27-rc3+/mm/memcontrol.c @@ -588,19 +588,23 @@ unsigned long mem_cgroup_isolate_pages(u * Free obsolete page_cgroups which is linked to per-cpu drop list. */ -static void __free_obsolete_page_cgroup(void) +struct page_cgroup_rcu_work { + struct rcu_head head; + struct page_cgroup *list; +}; + +static void __free_obsolete_page_cgroup_cb(struct rcu_head *head) { struct mem_cgroup *memcg; struct page_cgroup *pc, *next; struct mem_cgroup_per_zone *mz, *page_mz; - struct mem_cgroup_sink_list *mcsl; + struct page_cgroup_rcu_work *work; unsigned long flags; - mcsl = &get_cpu_var(memcg_sink_list); - next = mcsl->next; - mcsl->next = NULL; - mcsl->count = 0; - put_cpu_var(memcg_sink_list); + + work = container_of(head, struct page_cgroup_rcu_work, head); + next = work->list; + kfree(work); mz = NULL; @@ -627,6 +631,26 @@ static void __free_obsolete_page_cgroup( local_irq_restore(flags); } +static int __free_obsolete_page_cgroup(void) +{ + struct page_cgroup_rcu_work *work; + struct mem_cgroup_sink_list *mcsl; + + work = kmalloc(sizeof(*work), GFP_ATOMIC); + if (!work) + return -ENOMEM; + INIT_RCU_HEAD(&work->head); + + mcsl = &get_cpu_var(memcg_sink_list); + work->list = mcsl->next; + mcsl->next = NULL; + mcsl->count = 0; + put_cpu_var(memcg_sink_list); + + call_rcu(&work->head, __free_obsolete_page_cgroup_cb); + return 0; +} + static void free_obsolete_page_cgroup(struct page_cgroup *pc) { int count; @@ -649,13 +673,17 @@ static DEFINE_MUTEX(memcg_force_drain_mu static void mem_cgroup_local_force_drain(struct work_struct *work) { - __free_obsolete_page_cgroup(); + int ret; + do { + ret = __free_obsolete_page_cgroup(); + } while (ret); } static void mem_cgroup_all_force_drain(void) { mutex_lock(&memcg_force_drain_mutex); schedule_on_each_cpu(mem_cgroup_local_force_drain); + synchronize_rcu(); mutex_unlock(&memcg_force_drain_mutex); } -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org