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 F179AC433FE for ; Thu, 3 Nov 2022 12:45:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231168AbiKCMo7 (ORCPT ); Thu, 3 Nov 2022 08:44:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60194 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230094AbiKCMoz (ORCPT ); Thu, 3 Nov 2022 08:44:55 -0400 Received: from mail-ej1-x635.google.com (mail-ej1-x635.google.com [IPv6:2a00:1450:4864:20::635]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C806F101EF; Thu, 3 Nov 2022 05:44:54 -0700 (PDT) Received: by mail-ej1-x635.google.com with SMTP id d26so4822390eje.10; Thu, 03 Nov 2022 05:44:54 -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:message-id:reply-to; bh=m1DVWcK/fPvxwYKjOU/YI+rXNMZdzDbCW84zWy8prE4=; b=H5fIzf9eK0AjkszI67lchy3AV48ysJKI18cu/KsnSygYiagzdB6hDcxlgV644EbUOf xWuKOLU8GHJDkJy4wjcIe6JNzEzbc+idLVlioTCdwuzQIFmB/cXPVV8RVHK+vfenkWSr gC2LPzyXDP5xn3nUgfJPCYPOqniYMH4ZovzOSevgIUEVjU2NMpj/TWittDGuN8zicnvX dgnVa29c/HMfcJ2krTNMdflND3jUIGd8epI21piYQUAS6LLnJuTRkWhxrUQXWpqEf8dl 4VhrnIRMC89N8vAp2ChrXfuTxpWgPmPIMVs40iZSt5D9ZZjqzMBQW6FtHllwn9wmu0d2 Ob4A== 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 :message-id:reply-to; bh=m1DVWcK/fPvxwYKjOU/YI+rXNMZdzDbCW84zWy8prE4=; b=0ewwAQJPZN1O0DmQ6hOTRKrquV7nVenYEoYSlmUqAZPKvgFa5Uy+a1lDplI0Af3mPB EXDSR98jgoZe1Wgq46pXwb7c2hsFNTJciMBC9V33p6WN4+vLrLBCjd4tuKsIz2yANuIF Wm5hQusvUKs0Wfi+LVO6zZIn3GlgURyC9EvypE8+zuV9W1SsPyc+VmHWPwdd3KFkRa60 d6Li+n+aNgDDGK+scrQyDhzq3CCiFW3f9oyfCwo6yjQTHqjqWfr2TEenaMB0adTnatys BTVf/Eqj0jQwvG2sAO0ypFs6BAZpeIwF5tNUWCodnoSc8Wpb3oddlwxldrq9bcVkhZno mKoQ== X-Gm-Message-State: ACrzQf0t8L843a463C1kHh1ll1Eu8+LMOZebHFkzcJ5xL8f2E1w0Ujlw 8fdTfe6yqMs/2bRGh1IkiPE= X-Google-Smtp-Source: AMsMyM5QaKNutgTeV3yG2v5UgXmJ9MxmPLRixJKR5Md9zyqeXWU6KmQDHm0pJmMonDg7w3EQmuQSPQ== X-Received: by 2002:a17:907:97d5:b0:7ac:5f72:6c1a with SMTP id js21-20020a17090797d500b007ac5f726c1amr28561297ejc.126.1667479493163; Thu, 03 Nov 2022 05:44:53 -0700 (PDT) Received: from pc638.lan ([155.137.26.201]) by smtp.gmail.com with ESMTPSA id p23-20020a056402155700b004615e1bbaf4sm460429edx.87.2022.11.03.05.44.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Nov 2022 05:44:52 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Thu, 3 Nov 2022 13:44:51 +0100 To: "Paul E. McKenney" Cc: Joel Fernandes , Uladzislau Rezki , rcu@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH RFC] rcu/kfree: Do not request RCU when not needed Message-ID: References: <20221102184911.GP5600@paulmck-ThinkPad-P17-Gen-1> <755B5ED1-653D-4E57-B114-77CDE10A9033@joelfernandes.org> <20221102202813.GR5600@paulmck-ThinkPad-P17-Gen-1> <20221102223516.GT5600@paulmck-ThinkPad-P17-Gen-1> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221102223516.GT5600@paulmck-ThinkPad-P17-Gen-1> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > > Though I am thinking, workqueue context is normally used to invoke > > code that can block, and would the issue you mentioned affect those as > > well, or affect RCU when those non-RCU work items block. So for > > example, when other things in the system that can queue things on the > > system_wq and block. (I might be throwing darts in the dark). > > > > To be safe, we can implement your suggestion which is basically a form > > of my initial patch. > > > > Should we add Tejun to the thread? > > Let's get organized first, but that would be a good thing. Or I could > reach out to Tejun internally. > > For but one thing to get organized about, maybe kfree_rcu() should be > using a workqueue with the WQ_MEM_RECLAIM flag set. > It can be as an option to consider. Because such workqueue has some special priority for better handling of memory releasing. I can have a look at it closer to see how kvfree_rcu() works if it goes with WQ_MEM_RECLAIM. -- Uladzislau Rezki