From patchwork Tue Oct 11 07:11:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hou Tao X-Patchwork-Id: 13003709 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 A9D62C43217 for ; Tue, 11 Oct 2022 06:45:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229854AbiJKGpu (ORCPT ); Tue, 11 Oct 2022 02:45:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48600 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229698AbiJKGpt (ORCPT ); Tue, 11 Oct 2022 02:45:49 -0400 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4634077542; Mon, 10 Oct 2022 23:45:41 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTP id 4MmmSs14nqz6PmRS; Tue, 11 Oct 2022 14:43:25 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP4 (Coremail) with SMTP id gCh0CgD39sgQEUVj3FxfAA--.20636S6; Tue, 11 Oct 2022 14:45:39 +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 2/3] bpf: Free local storage memory after one RCU-tasks-trace grace period Date: Tue, 11 Oct 2022 15:11:27 +0800 Message-Id: <20221011071128.3470622-3-houtao@huaweicloud.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20221011071128.3470622-1-houtao@huaweicloud.com> References: <20221011071128.3470622-1-houtao@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: gCh0CgD39sgQEUVj3FxfAA--.20636S6 X-Coremail-Antispam: 1UD129KBjvJXoW7uryrtFy8tr15Cw13WrWfXwb_yoW8AF4kpF yUXrn8Jr4Fya1ruanxGF4fAryDXw47Wr1UKFZ5A3yftrZxArWDWFnIkF1Uua43Gw4rWr4I vF90gF1UGw1UZFDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBYb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUXw A2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV W8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMc Ij6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_ Jr0_Gr1lF7xvr2IYc2Ij64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1l42xK82IYc2Ij64 vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8G jcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6rW5MIIYrxkI7VAKI48JMIIF0xvE2I x0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26F4j6r4UJwCI42IY6xAI w20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x 0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7IU1sa9DUUUUU== X-CM-SenderInfo: xkrx3t3r6k3tpzhluzxrxghudrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org From: Hou Tao Local storage map is accessible for both sleepable and normal bpf program, so its memory is freed by using both call_rcu_tasks_trace() and kfree_rcu() to wait for both RCU-tasks-trace grace period and RCU grace period to expire. However According to the current implementation of RCU-tasks-trace, one RCU-tasks-trace grace period waits for one RCU grace period, so there is no need to call kfree_rcu(), it is safe to call kfree() directly. Signed-off-by: Hou Tao --- kernel/bpf/bpf_local_storage.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 802fc15b0d73..18a2dd611635 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -84,20 +84,26 @@ bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner, return NULL; } +/* Now RCU Tasks grace period implies RCU grace period, so no need to call + * kfree_rcu(), just call kfree() directly. + */ void bpf_local_storage_free_rcu(struct rcu_head *rcu) { struct bpf_local_storage *local_storage; local_storage = container_of(rcu, struct bpf_local_storage, rcu); - kfree_rcu(local_storage, rcu); + kfree(local_storage); } +/* Now RCU Tasks grace period implies RCU grace period, so no need to call + * kfree_rcu(), just call kfree() directly. + */ static void bpf_selem_free_rcu(struct rcu_head *rcu) { struct bpf_local_storage_elem *selem; selem = container_of(rcu, struct bpf_local_storage_elem, rcu); - kfree_rcu(selem, rcu); + kfree(selem); } /* local_storage->lock must be held and selem->local_storage == local_storage.