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 7706EC6FD18 for ; Tue, 18 Apr 2023 12:08:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231526AbjDRMIt (ORCPT ); Tue, 18 Apr 2023 08:08:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42230 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230070AbjDRMId (ORCPT ); Tue, 18 Apr 2023 08:08:33 -0400 Received: from mail-lj1-x22b.google.com (mail-lj1-x22b.google.com [IPv6:2a00:1450:4864:20::22b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A7439B47B; Tue, 18 Apr 2023 05:05:15 -0700 (PDT) Received: by mail-lj1-x22b.google.com with SMTP id b9so1546781ljf.13; Tue, 18 Apr 2023 05:05:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1681819514; x=1684411514; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:from:to:cc:subject:date:message-id:reply-to; bh=46J6GzW9SMxNFr8fYJhfNVMAkEm/oWl1Dzn7CkJE/p4=; b=WPBDlfGOW6XlWFMWV5mqklvKP9LPXG3BW1vAhqkuHGDWo6sGPz9hUSHduvSSygVbTp l8NCkMm5UDOPogD8MzwlYIHueOvoILh0H+bOPvBHb4uDj576vlxS7VqLt9crV6TcNU/F 7Ldi28OFAQ3WaHw8nRXYxhrTPHxikbUHKgDkTsmgXRcbl29CUEjJi35AUJlAtC9Dre2U 3horpkcYuyEzk3tdlT3bd/4lDsSy0Hl4xieZQHax4RCpMcaC5nRQGHVGBzAoDkij+S2u kFle/FFxR2vlYYIotcOlOWnJxUj7NRwtgokIn3qvpSYsgEy0fr+5MslDr46bFaIsnDrw Mivw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1681819514; x=1684411514; 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 :message-id:reply-to; bh=46J6GzW9SMxNFr8fYJhfNVMAkEm/oWl1Dzn7CkJE/p4=; b=iqqGQEtbyVyfDuDoREbm97A8zMWd+f65RFJEDjfxfRVIzdplDdqXMFmKTLzHBOtzyN HgID0SV+ATHxbNtpLxvTUxvdZw29YsMC3b3cTeCeQySoq8OEmpA7q5nBOQEHWnLvHxyK U316/05JhpzV5nPcpTeiDW4FJmc5k3POp94uEIK1NNBt2IceW+pg9ccSzl+63KOhEujP iD1vJ7uLWzxocXq0fmsicpKMRXD4cF7XNKGzouDrG33d29dusbFHFpQ3Obzvz0pIemor WoMP/i44GkE1viJYSqk/wt0BAAlawAu33TV8Kn/aTgFDKOmAGXPdBlU6A5RsVaZWUOe3 mW5w== X-Gm-Message-State: AAQBX9f7CQKwdVITAfwTCxm4uw2LNHidBKQo79GfhaqPv/QmqrJh/jQK HXKLNMR9VwSZQJPGnXKbXAM= X-Google-Smtp-Source: AKy350avhTv+2hMQBXbqPTe3NHvXhZA5uEx+8kQfQXSzFvjJHY1HxupkwepTsTFBOEKKtV2stNW9rg== X-Received: by 2002:a2e:9a99:0:b0:2a8:a5fc:d0cd with SMTP id p25-20020a2e9a99000000b002a8a5fcd0cdmr644708lji.47.1681819513790; Tue, 18 Apr 2023 05:05:13 -0700 (PDT) Received: from pc636 (host-90-233-216-43.mobileonline.telia.com. [90.233.216.43]) by smtp.gmail.com with ESMTPSA id z22-20020a2e9b96000000b002a8c1462ecbsm1069879lji.137.2023.04.18.05.05.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 18 Apr 2023 05:05:13 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Tue, 18 Apr 2023 14:05:10 +0200 To: Zqiang Cc: urezki@gmail.com, paulmck@kernel.org, frederic@kernel.org, joel@joelfernandes.org, qiang.zhang1211@gmail.com, rcu@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] rcu/kvfree: Make drain_page_cache() call return directly if cache is disabled Message-ID: References: <20230418070259.1353785-1-qiang1.zhang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230418070259.1353785-1-qiang1.zhang@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 18, 2023 at 03:02:59PM +0800, Zqiang wrote: > If the rcu_min_cached_objs is set to zero at boot params, the > krcp->page_cache_work will not be triggered to fill page cache, > and the put_cached_bnode() also does not fill page cache, this > also means the krcp->bkvcache is always empty, so not need to > acquire unnecessary krcp->lock to get page from krcp->bkvcache, > this commit therefore make drain_page_cache() return directly if > the rcu_min_cached_objs is zero. > > Signed-off-by: Zqiang > --- > kernel/rcu/tree.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > index c8ba2be026fa..ce995fc1c644 100644 > --- a/kernel/rcu/tree.c > +++ b/kernel/rcu/tree.c > @@ -2924,6 +2924,9 @@ drain_page_cache(struct kfree_rcu_cpu *krcp) > struct llist_node *page_list, *pos, *n; > int freed = 0; > > + if (rcu_min_cached_objs) > + return 0; > + > Should we check for zero? -- Uladzislau Rezki