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[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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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.