From mboxrd@z Thu Jan 1 00:00:00 1970 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 EFE63C433F5 for ; Sat, 14 May 2022 14:35:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233361AbiENOf3 (ORCPT ); Sat, 14 May 2022 10:35:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55570 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233357AbiENOf1 (ORCPT ); Sat, 14 May 2022 10:35:27 -0400 Received: from mail-qt1-x835.google.com (mail-qt1-x835.google.com [IPv6:2607:f8b0:4864:20::835]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 17724201A6 for ; Sat, 14 May 2022 07:35:26 -0700 (PDT) Received: by mail-qt1-x835.google.com with SMTP id hh4so9239133qtb.10 for ; Sat, 14 May 2022 07:35:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=kQmO86aj6VfDWI2cccfrc7HKv/pZDaVHtsdXoyk6k2c=; b=CYkDW4+nyP2lUNk/mKUt8bGlMdeAKobp0EyrAcfBlSEfJsK5/g6Ygi6zsXmRwIL+AJ vLuXjwM3+t3G0M3sp8JUj2EWUDBoZ+/BB0OkosnDWD70w7aYuE4vjdlzH5Y82qyHD3EM Wr+XBsehKBukP3AsXdP0Hqi49TjAkXcJoEePM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=kQmO86aj6VfDWI2cccfrc7HKv/pZDaVHtsdXoyk6k2c=; b=San9d5a4XXXWeEFDAVF2+I+SHYQ+PswPnnlhbeLFJgPCw5prEjrdHLpixkoGWvhPvv o8fLrNz6Dkx07Xt6YbpAzpjJP45R64ap4dr1l9OFF4XhbKUadKm+18D504pQyISoL8tv EkQWxOS3JICVXp+gAfGWYCL0YTGNsyGF0CQlBqbSOg77T541fEfcym3FBrCkqG6FJWv3 oeyO11nJP/uRe5XdUyTvRmhS/mhWTmiLjDH1ogOKEsVCQO14ZOAlRQSQwYmMdxxDur+c E1Ce9Aqqr6tvkGXhy3zxMux5546e/yP5/iwUNkm8ISeI5J1fgQqDBiIEt469Y9txY1P7 CTlQ== X-Gm-Message-State: AOAM533WMjUKfM7CltEfuBNsHPosJ9cNWWf4nB9BKT8l2Kf8tNZSIFD0 8vbH1a3+ubpaxL1ZF5GcLK9FXA== X-Google-Smtp-Source: ABdhPJwsJUtHsnapzhw2b++3EfwjMpkkKp2CC7ZVoBnqhZdUiBswGGnDVHkUsIBy397ik5bRHxp8zQ== X-Received: by 2002:ac8:5bce:0:b0:2f3:e20a:2fd2 with SMTP id b14-20020ac85bce000000b002f3e20a2fd2mr8846098qtb.455.1652538925220; Sat, 14 May 2022 07:35:25 -0700 (PDT) Received: from localhost (29.46.245.35.bc.googleusercontent.com. [35.245.46.29]) by smtp.gmail.com with ESMTPSA id d81-20020a379b54000000b006a10aa7908dsm2764445qke.38.2022.05.14.07.35.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 14 May 2022 07:35:24 -0700 (PDT) Date: Sat, 14 May 2022 14:35:24 +0000 From: Joel Fernandes To: Uladzislau Rezki Cc: rcu@vger.kernel.org, rushikesh.s.kadam@intel.com, neeraj.iitr10@gmail.com, frederic@kernel.org, paulmck@kernel.org, rostedt@goodmis.org Subject: Re: [RFC v1 12/14] rcu/kfree: remove useless monitor_todo flag Message-ID: References: <20220512030442.2530552-1-joel@joelfernandes.org> <20220512030442.2530552-13-joel@joelfernandes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org On Fri, May 13, 2022 at 04:53:05PM +0200, Uladzislau Rezki wrote: > > monitor_todo is not needed as the work struct already tracks if work is > > pending. Just use that to know if work is pending using > > delayed_work_pending() helper. > > > > Signed-off-by: Joel Fernandes (Google) > > --- > > kernel/rcu/tree.c | 22 +++++++--------------- > > 1 file changed, 7 insertions(+), 15 deletions(-) > > > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > > index 3baf29014f86..3828ac3bf1c4 100644 > > --- a/kernel/rcu/tree.c > > +++ b/kernel/rcu/tree.c > > @@ -3155,7 +3155,6 @@ struct kfree_rcu_cpu_work { > > * @krw_arr: Array of batches of kfree_rcu() objects waiting for a grace period > > * @lock: Synchronize access to this structure > > * @monitor_work: Promote @head to @head_free after KFREE_DRAIN_JIFFIES > > - * @monitor_todo: Tracks whether a @monitor_work delayed work is pending > > * @initialized: The @rcu_work fields have been initialized > > * @count: Number of objects for which GP not started > > * @bkvcache: > > @@ -3180,7 +3179,6 @@ struct kfree_rcu_cpu { > > struct kfree_rcu_cpu_work krw_arr[KFREE_N_BATCHES]; > > raw_spinlock_t lock; > > struct delayed_work monitor_work; > > - bool monitor_todo; > > bool initialized; > > int count; > > > > @@ -3416,9 +3414,7 @@ static void kfree_rcu_monitor(struct work_struct *work) > > // of the channels that is still busy we should rearm the > > // work to repeat an attempt. Because previous batches are > > // still in progress. > > - if (!krcp->bkvhead[0] && !krcp->bkvhead[1] && !krcp->head) > > - krcp->monitor_todo = false; > > - else > > + if (krcp->bkvhead[0] || krcp->bkvhead[1] || krcp->head) > > schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES); > > > > raw_spin_unlock_irqrestore(&krcp->lock, flags); > > @@ -3607,10 +3603,8 @@ void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func) > > > > // Set timer to drain after KFREE_DRAIN_JIFFIES. > > if (rcu_scheduler_active == RCU_SCHEDULER_RUNNING && > > - !krcp->monitor_todo) { > > - krcp->monitor_todo = true; > > + !delayed_work_pending(&krcp->monitor_work)) > > schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES); > > - } > > > > unlock_return: > > krc_this_cpu_unlock(krcp, flags); > > @@ -3685,14 +3679,12 @@ void __init kfree_rcu_scheduler_running(void) > > struct kfree_rcu_cpu *krcp = per_cpu_ptr(&krc, cpu); > > > > raw_spin_lock_irqsave(&krcp->lock, flags); > > - if ((!krcp->bkvhead[0] && !krcp->bkvhead[1] && !krcp->head) || > > - krcp->monitor_todo) { > > - raw_spin_unlock_irqrestore(&krcp->lock, flags); > > - continue; > > + if (krcp->bkvhead[0] || krcp->bkvhead[1] || krcp->head) { > > + if (delayed_work_pending(&krcp->monitor_work)) { > > + schedule_delayed_work_on(cpu, &krcp->monitor_work, > > + KFREE_DRAIN_JIFFIES); > > + } > > } > > - krcp->monitor_todo = true; > > - schedule_delayed_work_on(cpu, &krcp->monitor_work, > > - KFREE_DRAIN_JIFFIES); > > raw_spin_unlock_irqrestore(&krcp->lock, flags); > > } > > } > > -- > > > Looks good to me from the first glance, but let me know to have a look > at it more closely. Thanks, I appreciate it. - Joel