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AJvYcCX1Tcm2UrTrmWIjGqgFbVV8scbrPULLT5rP1t2RoMMUQU/k3mjPQzPcVAr+xq9CDiRQkXynBLQkgIa8UzrPpsGoaa5Vj+Eoq0hHyxR4 X-Gm-Message-State: AOJu0Yz/u7QnwFT2nUCzWRM5iPVDCOQe7Z/jpz1HRmKyUh+Af9r0++5s Qlgk1G+aoxb/9b1NNQk8P/l83NqxeDFH81OUT3nURBBZpu/osW4apTn/gllM/Mg= X-Google-Smtp-Source: AGHT+IEpDI3SLb6DK8eESf91mbfRxTkqd15fvUPDNtPee/hawli5VCPVwcKmvtkaX2PmBdDDW5btOg== X-Received: by 2002:a17:90a:7e0e:b0:2a3:be48:23f3 with SMTP id i14-20020a17090a7e0e00b002a3be4823f3mr2885933pjl.4.1713452949760; Thu, 18 Apr 2024 08:09:09 -0700 (PDT) Received: from [192.168.1.150] ([198.8.77.194]) by smtp.gmail.com with ESMTPSA id s22-20020a17090aa11600b002ab664e5e17sm1547775pjp.1.2024.04.18.08.09.08 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 18 Apr 2024 08:09:09 -0700 (PDT) Message-ID: <362c3c63-6fd9-401c-9281-e2e0c7efc14a@kernel.dk> Date: Thu, 18 Apr 2024 09:09:07 -0600 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] completion: move blk_wait_io to kernel/sched/completion.c Content-Language: en-US To: Christoph Hellwig Cc: Mikulas Patocka , Peter Zijlstra , Mike Snitzer , Damien Le Moal , Ingo Molnar , Will Deacon , Waiman Long , Guangwu Zhang , dm-devel@lists.linux.dev, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org References: <31b118f3-bc8d-b18b-c4b9-e57d74a73f@redhat.com> <20240417175538.GP40213@noisy.programming.kicks-ass.net> <546473fd-ca4b-3c64-349d-cc739088b748@redhat.com> <5f3d434b-e05c-445f-bee5-2bb1f11a5946@kernel.dk> From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 4/18/24 8:46 AM, Christoph Hellwig wrote: > On Thu, Apr 18, 2024 at 08:30:14AM -0600, Jens Axboe wrote: >> It certainly is a hack/work-around, but unless there are a lot more that >> should be using something like this, I don't think adding extra core >> complexity in terms of a special task state (or per-task flag, at least >> that would be easier) is really warranted. > > Basically any kernel thread doing on-demand work has the same problem. > It just has an easier workaround hack, as the kernel threads can simply > claim to do an interruptible sleep to not trigger the softlockup > warnings. A kernel thread can just use TASK_INTERRUPTIBLE, as it doesn't take signals anyway. But yeah, I guess you could view that as a work-around as well. Outside of that, mostly only a block problem, where our sleep is always uninterruptible. Unless there are similar hacks elsewhere in the kernel that I'm not aware of? -- Jens Axboe