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=0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MALFORMED_FREEMAIL, 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 21037C2BB1D for ; Thu, 12 Mar 2020 09:56:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0200F20737 for ; Thu, 12 Mar 2020 09:56:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="VVrou6RJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726647AbgCLJ4M (ORCPT ); Thu, 12 Mar 2020 05:56:12 -0400 Received: from mail-wr1-f66.google.com ([209.85.221.66]:34172 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725268AbgCLJ4M (ORCPT ); Thu, 12 Mar 2020 05:56:12 -0400 Received: by mail-wr1-f66.google.com with SMTP id z15so6579649wrl.1 for ; Thu, 12 Mar 2020 02:56:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:date:to:cc:subject:in-reply-to:message-id:references :mime-version; bh=OgZKLTHeDttLbT/Br16mrT6HF82SkRK4UDqvqoYSVK8=; b=VVrou6RJ02jppAuZj5G6brHbhPI2wyw5PI/NdaHb7rQREgtAxNRKRJFmxciD/ERHD9 IF1zI5RJJG8RiCvyocn7d3op31iH9772k2BWpbwl65lOGP1lBdrZXkLd9Ni+uDstRdRk H17KBdKlOAvoedogTlH/A+K5KFYecDDOGcoVD6ipM/q3bkL5zGUyTXI0F6tfzr/AfCkC OKI6x/VYhd5A5OV6ZPpsORHuMTOeWjmCNNqQTINJkXPT5WC56bwJRmpBadaOpK2VkJ42 cOYA1GXaZB9I2x/6inAAjIgYuDzNOQ3WD6Gz3m2cq0cHf+G2VWE1kkiEop1SXiAQ+UpV v2LQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:to:cc:subject:in-reply-to:message-id :references:mime-version; bh=OgZKLTHeDttLbT/Br16mrT6HF82SkRK4UDqvqoYSVK8=; b=H415HKACRTn9X1H0DBLTrWpsyeUKeFs6BctaqukMBiiWjeUyY6M/eEElRhxH78vWEq ApfmUiARzUG68fm1Ektln7A0IHDyRMR2oqg8EJeQ1MYNOYdwpPMhYcJF/bal856h6O6e 3CBRrVs3811mt7lovmhZMGVUTRBq0BRRSGZB1qNVHtlPIe9yuUCMkct54uDyVJnCBztR OEET2BKEU7UjrYRuPHPWQdocIiIgjks3cqGoun9wG1flMtSKq0FmVYaCyBekI5f6ZYsJ XYs3qLUoVk/LGSSyA+9hdY/44gop/+rtFGbqngTe9pl3aZ84PutYVkAUY0nh3RIs9O8V fcTA== X-Gm-Message-State: ANhLgQ1aph8yxxAyR/lG6XL5yHGatRcVSPOithikPsmBgpYEYCzVLOZ8 C2ADw0D07h28AeLsIVubBQ== X-Google-Smtp-Source: ADFU+vtL5hIx2UE0FAWeqDWK7I9/59hEeOi0QLZYvUWEBU6Sj7CD5Xvdt6TJUqRekwYXOtEskpy4sQ== X-Received: by 2002:a5d:4386:: with SMTP id i6mr10157720wrq.412.1584006970772; Thu, 12 Mar 2020 02:56:10 -0700 (PDT) Received: from ninjahub.lan (host-2-102-15-144.as13285.net. [2.102.15.144]) by smtp.gmail.com with ESMTPSA id a26sm11998273wmm.18.2020.03.12.02.56.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Mar 2020 02:56:10 -0700 (PDT) From: Jules Irenge X-Google-Original-From: Jules Irenge Date: Thu, 12 Mar 2020 09:56:01 +0000 (GMT) To: Andrew Morton cc: Matthew Wilcox , Jules Irenge , boqun.feng@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] backing-dev: refactor wb_congested_put() In-Reply-To: <20200311200023.974009d9a5648b977d5168f6@linux-foundation.org> Message-ID: References: <20200312002156.49023-1-jbi.octave@gmail.com> <20200312002156.49023-2-jbi.octave@gmail.com> <20200311175919.30523d55b2e5307ba22bbdc0@linux-foundation.org> <20200312022948.GH22433@bombadil.infradead.org> <20200311200023.974009d9a5648b977d5168f6@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 11 Mar 2020, Andrew Morton wrote: > On Wed, 11 Mar 2020 19:29:48 -0700 Matthew Wilcox wrote: > > > On Wed, Mar 11, 2020 at 05:59:19PM -0700, Andrew Morton wrote: > > > hm, it's hard to get excited over this. Open-coding the > > > refcount_dec_and_lock_irqsave() internals at a callsite in order to > > > make sparse happy. > > > > > > Is there some other way, using __acquires (for example)? > > > > sparse is really bad at conditional lock acquisition. > > I can well imagine. > > > we have similar > > problems over the vfs. but we shouldn't be obfuscating our code to make > > the tool happy. > > Perhaps sparse needs a way of being directed to suppress checking > across a particular function. > > Thanks for the feedback, maybe this is a limitation for Sparse. I have experienced quite often this problem.