From patchwork Tue Oct 11 07:11:25 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hou Tao X-Patchwork-Id: 13003710 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D28B2C4167B for ; Tue, 11 Oct 2022 06:45:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229631AbiJKGpv (ORCPT ); Tue, 11 Oct 2022 02:45:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48792 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229863AbiJKGpu (ORCPT ); Tue, 11 Oct 2022 02:45:50 -0400 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 606D277547; Mon, 10 Oct 2022 23:45:45 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4MmmSp5D4wzKFQP; Tue, 11 Oct 2022 14:43:22 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP4 (Coremail) with SMTP id gCh0CgD39sgQEUVj3FxfAA--.20636S4; Tue, 11 Oct 2022 14:45:38 +0800 (CST) From: Hou Tao To: bpf@vger.kernel.org Cc: Martin KaFai Lau , Andrii Nakryiko , Song Liu , Hao Luo , Yonghong Song , Alexei Starovoitov , Daniel Borkmann , KP Singh , "David S . Miller" , Jakub Kicinski , Stanislav Fomichev , Jiri Olsa , John Fastabend , "Paul E . McKenney" , Delyan Kratunov , rcu@vger.kernel.org, houtao1@huawei.com Subject: [PATCH bpf-next 0/3] Remove unnecessary RCU grace period chaining Date: Tue, 11 Oct 2022 15:11:25 +0800 Message-Id: <20221011071128.3470622-1-houtao@huaweicloud.com> X-Mailer: git-send-email 2.29.2 MIME-Version: 1.0 X-CM-TRANSID: gCh0CgD39sgQEUVj3FxfAA--.20636S4 X-Coremail-Antispam: 1UD129KBjvJXoW7CrW8WFy3XFWxGw15Ar1xGrg_yoW8Jw4rpF W8tFn8GFn5Ar4Sk3ZxZr4xGryUJws3G34xXFyFk34fA398AryDCr12qa45uF13K3ykAa42 vrn8Jw15G3Wqva7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUk2b4IE77IF4wAFF20E14v26ryj6rWUM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4 vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xIIjxv20xvEc7Cj xVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x 0267AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG 6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFV Cjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4IIrI8v6xkF7I0E8cxan2IY04v7MxAIw28I cxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2 IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVW8ZVWrXwCIc40Y0x0EwIxGrwCI 42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwCI42 IY6xAIw20EY4v20xvaj40_WFyUJVCq3wCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E 87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxUFDGOUUUUU X-CM-SenderInfo: xkrx3t3r6k3tpzhluzxrxghudrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org From: Hou Tao Hi, Now bpf uses RCU grace period chaining to wait for the completion of access from both sleepable and non-sleepable bpf program: calling call_rcu_tasks_trace() firstly to wait for a RCU-tasks-trace grace period, then in its callback calls call_rcu() or kfree_rcu() to wait for a normal RCU grace period. According to the implementation of RCU Tasks Trace, it inovkes ->postscan_func() to wait for one RCU-tasks-trace grace period and rcu_tasks_trace_postscan() inovkes synchronize_rcu() to wait for one normal RCU grace period in turn, so one RCU-tasks-trace grace period will imply one normal RCU grace period. And it also means there is no need to do call_rcu() or kfree_rcu() again in the callback of call_rcu_tasks_trace() in these grace period chains, so just remove the unnecessary call_rcu() or kfree_rcu() calls. Comments are always welcome. Hou Tao (3): bpf: Free elements after one RCU-tasks-trace grace period bpf: Free local storage memory after one RCU-tasks-trace grace period bpf: Free trace program array after one RCU-tasks-trace grace period kernel/bpf/bpf_local_storage.c | 10 ++++++++-- kernel/bpf/core.c | 5 ++++- kernel/bpf/memalloc.c | 17 ++++++----------- 3 files changed, 18 insertions(+), 14 deletions(-)