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[2620:137:e000::1:20]) by mx.google.com with ESMTP id ho8-20020a1709070e8800b0079b8cce1170si16873404ejc.950.2022.11.08.19.30.22; Tue, 08 Nov 2022 19:30:48 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=huawei.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229977AbiKIDXp (ORCPT + 99 others); Tue, 8 Nov 2022 22:23:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43100 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229546AbiKIDXn (ORCPT ); Tue, 8 Nov 2022 22:23:43 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 42F0C62E5; Tue, 8 Nov 2022 19:23:40 -0800 (PST) Received: from dggpeml500024.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4N6Vfj2XC0zmVkh; Wed, 9 Nov 2022 11:23:25 +0800 (CST) Received: from dggpeml100012.china.huawei.com (7.185.36.121) by dggpeml500024.china.huawei.com (7.185.36.10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Wed, 9 Nov 2022 11:23:38 +0800 Received: from localhost.localdomain (10.67.175.61) by dggpeml100012.china.huawei.com (7.185.36.121) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Wed, 9 Nov 2022 11:23:37 +0800 From: Zheng Yejian To: , CC: , , Subject: [PATCH] tracing: Optimize event type allocation with IDA Date: Wed, 9 Nov 2022 11:23:52 +0800 Message-ID: <20221109032352.254502-1-zhengyejian1@huawei.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-Originating-IP: [10.67.175.61] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpeml100012.china.huawei.com (7.185.36.121) X-CFilter-Loop: Reflected X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1748987698786584092?= X-GMAIL-MSGID: =?utf-8?q?1748987698786584092?= After commit 060fa5c83e67 ("tracing/events: reuse trace event ids after overflow"), trace events with dynamic type are linked up in list 'ftrace_event_list' through field 'trace_event.list'. Then when max event type number used up, it's possible to reuse type number of some freed one by traversing 'ftrace_event_list'. As instead, using IDA to manage available type numbers can make codes simpler and then the field 'trace_event.list' can be dropped. Since 'struct trace_event' is used in static tracepoints, drop 'trace_event.list' can make vmlinux smaller. Local test with about 2000 tracepoints, vmlinux reduced about 64KB: before：-rwxrwxr-x 1 root root 76669448 Nov 8 17:14 vmlinux after： -rwxrwxr-x 1 root root 76604176 Nov 8 17:15 vmlinux Signed-off-by: Zheng Yejian --- include/linux/trace_events.h | 1 - kernel/trace/trace_output.c | 65 +++++++++--------------------------- 2 files changed, 15 insertions(+), 51 deletions(-) diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index 20749bd9db71..bb2053246d6a 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -136,7 +136,6 @@ struct trace_event_functions { struct trace_event { struct hlist_node node; - struct list_head list; int type; struct trace_event_functions *funcs; }; diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index 67f47ea27921..314d175dee3a 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -21,8 +21,6 @@ DECLARE_RWSEM(trace_event_sem); static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly; -static int next_event_type = __TRACE_LAST_TYPE; - enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter) { struct trace_seq *s = &iter->seq; @@ -688,38 +686,23 @@ struct trace_event *ftrace_find_event(int type) return NULL; } -static LIST_HEAD(ftrace_event_list); +static DEFINE_IDA(trace_event_ida); -static int trace_search_list(struct list_head **list) +static void free_trace_event_type(int type) { - struct trace_event *e = NULL, *iter; - int next = __TRACE_LAST_TYPE; - - if (list_empty(&ftrace_event_list)) { - *list = &ftrace_event_list; - return next; - } + if (type >= __TRACE_LAST_TYPE) + ida_free(&trace_event_ida, type); +} - /* - * We used up all possible max events, - * lets see if somebody freed one. - */ - list_for_each_entry(iter, &ftrace_event_list, list) { - if (iter->type != next) { - e = iter; - break; - } - next++; - } +static int alloc_trace_event_type(void) +{ + int next; - /* Did we used up all 65 thousand events??? */ - if (next > TRACE_EVENT_TYPE_MAX) + /* Skip static defined type numbers */ + next = ida_alloc_range(&trace_event_ida, __TRACE_LAST_TYPE, + TRACE_EVENT_TYPE_MAX, GFP_KERNEL); + if (next < 0) return 0; - - if (e) - *list = &e->list; - else - *list = &ftrace_event_list; return next; } @@ -761,28 +744,10 @@ int register_trace_event(struct trace_event *event) if (WARN_ON(!event->funcs)) goto out; - INIT_LIST_HEAD(&event->list); - if (!event->type) { - struct list_head *list = NULL; - - if (next_event_type > TRACE_EVENT_TYPE_MAX) { - - event->type = trace_search_list(&list); - if (!event->type) - goto out; - - } else { - - event->type = next_event_type++; - list = &ftrace_event_list; - } - - if (WARN_ON(ftrace_find_event(event->type))) + event->type = alloc_trace_event_type(); + if (!event->type) goto out; - - list_add_tail(&event->list, list); - } else if (WARN(event->type > __TRACE_LAST_TYPE, "Need to add type to trace.h")) { goto out; @@ -819,7 +784,7 @@ EXPORT_SYMBOL_GPL(register_trace_event); int __unregister_trace_event(struct trace_event *event) { hlist_del(&event->node); - list_del(&event->list); + free_trace_event_type(event->type); return 0; }