From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 99E0178C91; Tue, 22 Apr 2025 06:11:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745302320; cv=none; b=aRdwBMXoLAzOxd9a+sl/gcX6kH//tPRLdb+VgYYfPgy30MnmYpK7c7ROyw6FIJ5aaK/jbj3nJsi+8ZMTkV6aTeDXzsSy+foXhfnYvUIS1iNI1hojlMha2I5jofPRiSghuEz5X6eWjnGOhe88OQkokO16+sKcqh2VJa/L44syATs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745302320; c=relaxed/simple; bh=3U6SSAwI++1mMarBQrCnXaUsz8plHo4CysXh50ykFH4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Lj6MWyIFkyqxZWS7FBFjkF+LyJlh4RMwQ2O1fbEDKweuJYA0xuPt9VQqg1ruyJK0u+rQb/y680fvP5gWTCAb+Sg6VnH8QyBPzM5k4KRB0xjpqp2vvi5mtxGYMtSY16LFHkDb6ZuNZ0cvJkUqE7lCLMa+gOjuTaznej6qH8yPWtE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=IfJgyzCR; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="IfJgyzCR" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Transfer-Encoding :Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=i9IDz0JyHUWXPtjTKZlN6b5bZEngPXaM8Z/wmtOSlTc=; b=IfJgyzCRY3hexpQwQo3ixEoWxK /1LEeNL6/goAyEsYXJZAbBev1+aHqotUrm7a7BhLKJf3iUSS/ieq+qXhNpOo2p+/fwqN9oiMUjFmY zn4owcYOy9LwGIeVYYx0PQ4oD6vNIAgW+N19UTNCjhic8NNYpSzw2L8qbbbxIhQ9HgBbaCIWa9MYj h2f6u6/TMpt53ZqgT3xrq5Mjp8EdM7XDk473nrJ+b2fShwDOTd5+5MQf074BUnVG7Scdug5X6PoW1 5UsUEJP4sVyq2G5YWvSt/NUNAFVYsXf4x5RAUDS6aoATjL+ptGY2s9dLcBPFCtO55FvEl4Ea4G/G3 t7GpDpCg==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1u76rH-00000005vDV-1Qlj; Tue, 22 Apr 2025 06:11:51 +0000 Date: Mon, 21 Apr 2025 23:11:51 -0700 From: Christoph Hellwig To: Yu Kuai Cc: Christoph Hellwig , axboe@kernel.dk, xni@redhat.com, agk@redhat.com, snitzer@kernel.org, mpatocka@redhat.com, song@kernel.org, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, nadav.amit@gmail.com, ubizjak@gmail.com, cl@linux.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, dm-devel@lists.linux.dev, linux-raid@vger.kernel.org, yi.zhang@huawei.com, yangerkun@huawei.com, johnny.chenyi@huawei.com, "yukuai (C)" Subject: Re: [PATCH v2 1/5] block: cleanup and export bdev IO inflight APIs Message-ID: References: <20250418010941.667138-1-yukuai1@huaweicloud.com> <20250418010941.667138-2-yukuai1@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Mon, Apr 21, 2025 at 09:13:57PM +0800, Yu Kuai wrote: > > I'm not sure why this is needed or related, or even what additional > > distinction is added here. > > Because for rq-based device, there are two different stage, > blk_account_io_start() while allocating new rq, and > blk_mq_start_request() while issuing the rq to driver. > > When will we think the reqeust is inflight? For iostat, my anser is the > former one, because rq->start_time_ns is set here as well. And noted in > iostats api diskstats_show（/proc/diskstats) and part_stat_show > (/sys/block/sda/stat), inflight is get by part_in_flight, which is > different from disk sysfs api(/sys/block/sda/inflight). Trying to express this in a not very obvious function name isn't going to work very well. Documenting your findings in comments is much better. > > > > I'd just change this helper to call blk_mq_count_in_driver_rw for > > blk-mq devices and remove the conditional from the sysfs code instead. > > That gives us a much more robust and easier to understand API. > > Ok, and another separate patch, right? Yes.