From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.8 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 2D1717D2F0 for ; Tue, 27 Aug 2019 19:02:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730475AbfH0TCV (ORCPT ); Tue, 27 Aug 2019 15:02:21 -0400 Received: from mail-pg1-f194.google.com ([209.85.215.194]:36877 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731045AbfH0TCV (ORCPT ); Tue, 27 Aug 2019 15:02:21 -0400 Received: by mail-pg1-f194.google.com with SMTP id d1so13184296pgp.4 for ; Tue, 27 Aug 2019 12:02:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=message-id:from:to:cc:subject:date:in-reply-to:references :mime-version:content-transfer-encoding; bh=6hihGraNXlXP48d5Z6Hdgnows8/y28qoNHMvPTx99go=; b=aMSiz365cIlgtLZ4k3Wlpw4kwZQY561BfhFwUA9ddfaznbeRbp67pQyPtVNA4gPfF4 srl5Ro7SKyxaC9LxhxhmE3+UmEoF/8lRvIuLyjvKaHhzEzU+M8KJR5u/SApfcT/2TyqF nPMT1LFwjdhMxHpWETdIsyT17VH58e0OagaaA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:from:to:cc:subject:date:in-reply-to :references:mime-version:content-transfer-encoding; bh=6hihGraNXlXP48d5Z6Hdgnows8/y28qoNHMvPTx99go=; b=Cp8R/oiR3bOAyxNnkqBK3t2jSlSq/ha4WAWrwvrfTHOdAUkiNUKsS8M/UrmQYzmGjq HDe8MHmjZ3ejSFJzqeNiHMMKr2CfSLfzcTNbUMPGVXp6niEp+0JUPDpS6pT8mQCvzkyn L6VG4wMc93eKKLHkaWEku+eHYRd07aiEDslbPi/srKyDSJzVL4tD2wVdegKRKEld/4SN eldvcB6eYYEqrulD+8ppPfiahpXyFF/hW/TSVtgqaTzP4mMDXDYWjK++is5Z7VPxtJHC 9Bngw8Rz7/3k1eFAZHi5hktRMakUw86HbSCJgwEzEb01urXaOSb0BPO/RG7L/sT/a+yo u+dQ== X-Gm-Message-State: APjAAAUQxHnVzG7iTZBAdOj4U2O2isriDA8CFzL3MtVXme57J9pU8KOV g51PMLdTT0FRPilyLXatxJ3blQ== X-Google-Smtp-Source: APXvYqxsWWH8JYpBqrmPVso69JCv7ezyGHWFFN7S8Iy43W9I64XtOdpAl/AgVqQs62WRA1t4D5xvWg== X-Received: by 2002:a17:90b:8ca:: with SMTP id ds10mr155957pjb.139.1566932540256; Tue, 27 Aug 2019 12:02:20 -0700 (PDT) Received: from joelaf.cam.corp.google.com ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id k14sm33196pfi.98.2019.08.27.12.02.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Aug 2019 12:02:19 -0700 (PDT) Message-ID: <5d657e3b.1c69fb81.54250.01e2@mx.google.com> X-Google-Original-Message-ID: 15669324726162@cam.corp.google.com From: "Joel Fernandes (Google)" To: linux-kernel@vger.kernel.org Cc: "Joel Fernandes (Google)" , byungchul.park@lge.com, Josh Triplett , Lai Jiangshan , linux-doc@vger.kernel.org, Mathieu Desnoyers , "Paul E. McKenney" , rcu@vger.kernel.org, Steven Rostedt , kernel-team@android.com Subject: [PATCH 5/5] rcu: Remove kfree_call_rcu_nobatch() Date: Tue, 27 Aug 2019 15:01:59 -0400 X-Mailer: git-send-email 2.23.0.187.g17f5b7556c-goog In-Reply-To: 156693247224727@cam.corp.google.com References: 156693247224727@cam.corp.google.com MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org Now that kfree_rcu() special casing have been removed from tree RCU, remove kfree_call_rcu_nobatch() since it is not needed. Signed-off-by: Joel Fernandes (Google) --- .../admin-guide/kernel-parameters.txt | 4 --- include/linux/rcutiny.h | 5 --- include/linux/rcutree.h | 1 - kernel/rcu/rcuperf.c | 10 +----- kernel/rcu/tree.c | 33 ++++++++----------- 5 files changed, 14 insertions(+), 39 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 24fe8aefb12c..56be0e30100b 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3909,10 +3909,6 @@ Number of loops doing rcuperf.kfree_alloc_num number of allocations and frees. - rcuperf.kfree_no_batch= [KNL] - Use the non-batching (less efficient) version of kfree_rcu(). - This is useful for comparing with the batched version. - rcuperf.nreaders= [KNL] Set number of RCU readers. The value -1 selects N, where N is the number of CPUs. A value diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 949841f52ec5..7aa93afa5d8d 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -39,11 +39,6 @@ static inline void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func) call_rcu(head, func); } -static inline void kfree_call_rcu_nobatch(struct rcu_head *head, rcu_callback_t func) -{ - call_rcu(head, func); -} - void rcu_qs(void); static inline void rcu_softirq_qs(void) diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 961b7e05d141..0b68aa952f8b 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -34,7 +34,6 @@ static inline void rcu_virt_note_context_switch(int cpu) void synchronize_rcu_expedited(void); void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func); -void kfree_call_rcu_nobatch(struct rcu_head *head, rcu_callback_t func); void rcu_barrier(void); bool rcu_eqs_special_set(int cpu); diff --git a/kernel/rcu/rcuperf.c b/kernel/rcu/rcuperf.c index c1e25fd10f2a..da94b89cd531 100644 --- a/kernel/rcu/rcuperf.c +++ b/kernel/rcu/rcuperf.c @@ -593,7 +593,6 @@ rcu_perf_shutdown(void *arg) torture_param(int, kfree_nthreads, -1, "Number of threads running loops of kfree_rcu()."); torture_param(int, kfree_alloc_num, 8000, "Number of allocations and frees done in an iteration."); torture_param(int, kfree_loops, 10, "Number of loops doing kfree_alloc_num allocations and frees."); -torture_param(int, kfree_no_batch, 0, "Use the non-batching (slower) version of kfree_rcu()."); static struct task_struct **kfree_reader_tasks; static int kfree_nrealthreads; @@ -632,14 +631,7 @@ kfree_perf_thread(void *arg) if (!alloc_ptr) return -ENOMEM; - if (!kfree_no_batch) { - kfree_rcu(alloc_ptr, rh); - } else { - rcu_callback_t cb; - - cb = (rcu_callback_t)(unsigned long)offsetof(struct kfree_obj, rh); - kfree_call_rcu_nobatch(&(alloc_ptr->rh), cb); - } + kfree_rcu(alloc_ptr, rh); } cond_resched(); diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 12c17e10f2b4..c767973d62ac 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2777,8 +2777,10 @@ static void kfree_rcu_work(struct work_struct *work) rcu_lock_acquire(&rcu_callback_map); trace_rcu_invoke_kfree_callback(rcu_state.name, head, offset); - /* Could be possible to optimize with kfree_bulk in future */ - kfree((void *)head - offset); + if (!WARN_ON_ONCE(!__is_kfree_rcu_offset(offset))) { + /* Could be optimized with kfree_bulk() in future. */ + kfree((void *)head - offset); + } rcu_lock_release(&rcu_callback_map); cond_resched_tasks_rcu_qs(); @@ -2856,16 +2858,6 @@ static void kfree_rcu_monitor(struct work_struct *work) spin_unlock_irqrestore(&krcp->lock, flags); } -/* - * This version of kfree_call_rcu does not do batching of kfree_rcu() requests. - * Used only by rcuperf torture test for comparison with kfree_rcu_batch(). - */ -void kfree_call_rcu_nobatch(struct rcu_head *head, rcu_callback_t func) -{ - __call_rcu(head, func); -} -EXPORT_SYMBOL_GPL(kfree_call_rcu_nobatch); - /* * Queue a request for lazy invocation of kfree() after a grace period. * @@ -2885,12 +2877,6 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func) unsigned long flags; struct kfree_rcu_cpu *krcp; - /* kfree_call_rcu() batching requires timers to be up. If the scheduler - * is not yet up, just skip batching and do the non-batched version. - */ - if (rcu_scheduler_active != RCU_SCHEDULER_RUNNING) - return kfree_call_rcu_nobatch(head, func); - if (debug_rcu_head_queue(head)) { /* Probable double kfree_rcu() */ WARN_ONCE(1, "kfree_call_rcu(): Double-freed call. rcu_head %p\n", @@ -2909,8 +2895,15 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func) krcp->head = head; /* Schedule monitor for timely drain after KFREE_DRAIN_JIFFIES. */ - if (!xchg(&krcp->monitor_todo, true)) - schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES); + if (!xchg(&krcp->monitor_todo, true)) { + /* Scheduling the monitor requires scheduler/timers to be up, + * if it is not, just skip it. An eventual kfree_rcu() will + * kick it again. + */ + if ((rcu_scheduler_active == RCU_SCHEDULER_RUNNING)) { + schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES); + } + } spin_unlock(&krcp->lock); local_irq_restore(flags); -- 2.23.0.187.g17f5b7556c-goog