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 60C74C433F5 for ; Tue, 4 Oct 2022 11:41:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229959AbiJDLlt (ORCPT ); Tue, 4 Oct 2022 07:41:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49948 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229933AbiJDLlp (ORCPT ); Tue, 4 Oct 2022 07:41:45 -0400 Received: from mail-lf1-x136.google.com (mail-lf1-x136.google.com [IPv6:2a00:1450:4864:20::136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D8C74E60A; Tue, 4 Oct 2022 04:41:43 -0700 (PDT) Received: by mail-lf1-x136.google.com with SMTP id bp15so7244179lfb.13; Tue, 04 Oct 2022 04:41:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:from:to:cc:subject:date; bh=w6aHeemfKJ2dWcTzYlwuaWCnO1Xf4PrC8flGzPMZQ1M=; b=NbJYQKJTpScov9Li3/wLZxcfyjdtxdMmZYmv9rmuj4nq4DoP3pPLGgfpHCvF9thEB/ xd/jAB8eDpeYWAorhJA0uYQTrJRfHm2zJntLV0+G4AV7GO9fIFdpVWBDOm7l8rzjnEYc 0qomOBRSkwqvBUVzogvuwb4XbHRXTI9u21RZlPOs+UUsQf0utgPjiAuBIs08IWohrraq +mfN5IuOKD6fjgYPtK6It0kWWbjxsToYXeGdChRQFqVsB96FxlNmHNfk6ArQHyU5aXfs 2CWuhsnGN3EjRLP1399Mkqqze+w49UjIauB+AxBUYmhhGhr8Ab6uCVzJJi+ra0JNupYZ P2pw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:x-gm-message-state:from:to:cc:subject:date; bh=w6aHeemfKJ2dWcTzYlwuaWCnO1Xf4PrC8flGzPMZQ1M=; b=Pm/U++DwIXMEn4rTwc0VkJTNmv+1Hl0f4dWokzLvIaLkOP52Xc/nI5NwV9iU/rIwbh DID7kBIsj9hAyABQpMYPskbXVS+NbQtUAMFRHI7yZV/bCzweLI7QO1qo7IpA3rbC47OW ULrCTYit+zxTDIBp4bC53WIhXhl3oxAAV15DfKbth8b4WX+SWXr1nuIFzyGD+mrm9Ejf HmXPykmXD1qoyru4vzXr0OcyfgHL808QP6xAcxem1r0LRMEm/sXCvIPh63wnEYse/wel Abre9gMp1XCjhLvW1nECob+ggckRhjGlTV2HeGT9uwguRtTS5s4qlTMDBZ0Ikj7fdhJf Prfg== X-Gm-Message-State: ACrzQf29GCi5omGLxxOQqzlRMSyuj6znbLnt1/p3ijJmbxXvFwFF81dR 288XqS1f3Kny1iKE3iVHcnw= X-Google-Smtp-Source: AMsMyM7Vd22SsoCN43V1pttf2L8dkOi5cIiC7r4XGhGCc7WTovFNjcSMK8FQvvQFobbD5HZgvZih6g== X-Received: by 2002:a05:6512:6ce:b0:4a2:530a:33d0 with SMTP id u14-20020a05651206ce00b004a2530a33d0mr1027041lff.270.1664883701735; Tue, 04 Oct 2022 04:41:41 -0700 (PDT) Received: from pc636 (host-90-235-28-118.mobileonline.telia.com. [90.235.28.118]) by smtp.gmail.com with ESMTPSA id v2-20020ac25922000000b004949f7cbb6esm1882073lfi.79.2022.10.04.04.41.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Oct 2022 04:41:41 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Tue, 4 Oct 2022 13:41:38 +0200 To: paulmck@kernel.org, "Joel Fernandes (Google)" Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org, rushikesh.s.kadam@intel.com, urezki@gmail.com, neeraj.iitr10@gmail.com, frederic@kernel.org, paulmck@kernel.org, rostedt@goodmis.org, youssefesmat@google.com, surenb@google.com Subject: Re: [PATCH v7 02/11] rcu: Make call_rcu() lazy to save power Message-ID: References: <20221004024157.2470238-1-joel@joelfernandes.org> <20221004024157.2470238-3-joel@joelfernandes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221004024157.2470238-3-joel@joelfernandes.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("Check")); > rcu_nocb_lock_irqsave(rdp, flags); > lockdep_assert_held(&rdp->nocb_lock); > bypass_ncbs = rcu_cblist_n_cbs(&rdp->nocb_bypass); > - if (bypass_ncbs && > + lazy_ncbs = READ_ONCE(rdp->lazy_len); > + > + if (bypass_ncbs && (lazy_ncbs == bypass_ncbs) && > + (time_after(j, READ_ONCE(rdp->nocb_bypass_first) + jiffies_till_flush) || > + bypass_ncbs > 2 * qhimark)) { Do you know why we want double "qhimark" threshold? It is not only this place, there are several. I am asking because it is not expected by the user. -- Uladzsislau Rezki