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 X-Spam-Level: X-Spam-Status: No, score=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 13BB0C388F7 for ; Mon, 26 Oct 2020 00:32:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CCD2D223FD for ; Mon, 26 Oct 2020 00:32:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603672336; bh=1fHgtDwcojHqfa38+WinzLZz7ns0UEGRw+Xv9WxjUqU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=Pq9aX0gFXixjw2nakJ2bG4WxUJicGkn/XTAt4fdnrLiMuylv2Z4k8LVraHz75qpzm lAH0O7Ef1k2xdEh9jipXekTeChl3G/tYiFxdkVUkJTjAMMtYoz7La/dvHDR1XDZQ9z UplL9pJk+/YdoMvFK88UaqEcjzB7c9u7k9x9/otY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1420855AbgJZAcP (ORCPT ); Sun, 25 Oct 2020 20:32:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:40082 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1420846AbgJZAcP (ORCPT ); Sun, 25 Oct 2020 20:32:15 -0400 Received: from localhost (unknown [176.177.109.29]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6BF41223EA; Mon, 26 Oct 2020 00:32:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603672335; bh=1fHgtDwcojHqfa38+WinzLZz7ns0UEGRw+Xv9WxjUqU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=vy9K02XtGXOQ19O0GUpllZFIBUvHsEbMknzslJu8tRTgwcaMJ1jg8yPDN0fma0gOC l1k/epX1A8JHT5dcwimx5/L9yLUY2KMmcbk5/4JMR2irV1+CScaTtYuRdhuEIouWW9 4cIFjgTfg4tOIlCPHn4ZFXF/onrxqa4YNRNyZiuw= Date: Mon, 26 Oct 2020 01:32:12 +0100 From: Frederic Weisbecker To: "Joel Fernandes (Google)" Cc: linux-kernel@vger.kernel.org, Josh Triplett , Lai Jiangshan , Marco Elver , Mathieu Desnoyers , "Paul E. McKenney" , rcu@vger.kernel.org, Steven Rostedt , "Uladzislau Rezki (Sony)" , fweisbec@gmail.com, neeraj.iitr10@gmail.com Subject: Re: [PATCH v8 2/6] rcu/segcblist: Add counters to segcblist datastructure Message-ID: <20201026003212.GA104441@lothringen> References: <20201021190813.3005054-1-joel@joelfernandes.org> <20201021190813.3005054-3-joel@joelfernandes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201021190813.3005054-3-joel@joelfernandes.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 21, 2020 at 03:08:09PM -0400, Joel Fernandes (Google) wrote: > @@ -307,6 +317,7 @@ void rcu_segcblist_extract_done_cbs(struct rcu_segcblist *rsclp, > > if (!rcu_segcblist_ready_cbs(rsclp)) > return; /* Nothing to do. */ > + rclp->len = rcu_segcblist_get_seglen(rsclp, RCU_DONE_TAIL); I realize, doesn't it break the unsegmented count in srcu_invoke_callbacks() ? It still does rcu_segcblist_insert_count(), so it adds zero to rsclp->len which thus doesn't get cleared and probably keeps growing. At least srcu_barrier() relies on it. And module exit should warn. > *rclp->tail = rsclp->head; > WRITE_ONCE(rsclp->head, *rsclp->tails[RCU_DONE_TAIL]); > WRITE_ONCE(*rsclp->tails[RCU_DONE_TAIL], NULL); > @@ -314,6 +325,7 @@ void rcu_segcblist_extract_done_cbs(struct rcu_segcblist *rsclp, > for (i = RCU_CBLIST_NSEGS - 1; i >= RCU_DONE_TAIL; i--) > if (rsclp->tails[i] == rsclp->tails[RCU_DONE_TAIL]) > WRITE_ONCE(rsclp->tails[i], &rsclp->head); > + rcu_segcblist_set_seglen(rsclp, RCU_DONE_TAIL, 0); > } > > /* > @@ -330,11 +342,16 @@ void rcu_segcblist_extract_pend_cbs(struct rcu_segcblist *rsclp, > > if (!rcu_segcblist_pend_cbs(rsclp)) > return; /* Nothing to do. */ > + rclp->len = rcu_segcblist_get_seglen(rsclp, RCU_WAIT_TAIL) + > + rcu_segcblist_get_seglen(rsclp, RCU_NEXT_READY_TAIL) + > + rcu_segcblist_get_seglen(rsclp, RCU_NEXT_TAIL); > *rclp->tail = *rsclp->tails[RCU_DONE_TAIL]; > rclp->tail = rsclp->tails[RCU_NEXT_TAIL]; > WRITE_ONCE(*rsclp->tails[RCU_DONE_TAIL], NULL); > - for (i = RCU_DONE_TAIL + 1; i < RCU_CBLIST_NSEGS; i++) > + for (i = RCU_DONE_TAIL + 1; i < RCU_CBLIST_NSEGS; i++) { > WRITE_ONCE(rsclp->tails[i], rsclp->tails[RCU_DONE_TAIL]); > + rcu_segcblist_set_seglen(rsclp, i, 0); You seem to have forgotten the suggestion? rclp->len += rcu_segcblist_get_seglen(rsclp, i) Thanks.