From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (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 C088223A9BF for ; Mon, 11 Aug 2025 16:18:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.95.11.211 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754929083; cv=none; b=llQDYmjUB6susVVc5Y8cGOXwhQRaqKoI1i/1edkyYRAFbZqbKaHxDN/5WZlqfl2///2F9Qs1nkp7Ui6U3L3YK0VGxCKPzai17vEbu+PoDryaFd+NA1xKPFqRz5aAzvHHg8/+hUswwuUYFkjZCLOsXAS+Qzj7EJKkg8Nm5/MEDXQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754929083; c=relaxed/simple; bh=K6/7yPlwOZhquuul282eYeDj7tsyOIoAHqHzxkGfDwY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=FR5u2OBOr+Ef4mousQmxcuhMKrLQ2J2BMsD4P4APnjOb4Zaa6/mf4hvOnl/tuIwrOmjGpBJBaHbCiK0dzWiby8gy1msL0TOBnqTdo64taZ87qzpqEsjLUojVKsMgiv0xphGZFtrzxEHsitksnSOmgNPoya84LCPtNOaBh1WXHMs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de; spf=pass smtp.mailfrom=lst.de; arc=none smtp.client-ip=213.95.11.211 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lst.de Received: by verein.lst.de (Postfix, from userid 2407) id 57E0D68AA6; Mon, 11 Aug 2025 18:17:56 +0200 (CEST) Date: Mon, 11 Aug 2025 18:17:56 +0200 From: Christoph Hellwig To: Keith Busch Cc: Christoph Hellwig , Keith Busch , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, axboe@kernel.dk Subject: Re: [PATCH 1/2] block: accumulate segment page gaps per bio Message-ID: <20250811161756.GA25496@lst.de> References: <20250805195608.2379107-1-kbusch@meta.com> <20250806145621.GC20102@lst.de> <20250810143112.GA4860@lst.de> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) On Mon, Aug 11, 2025 at 09:27:18AM -0600, Keith Busch wrote: > I initially tried to copy the nsegs usage in the request, but there are > multiple places (iomap, xfs, and btrfs) that split to hardware limits > without a request, so I'm not sure where the result is supposed to go to > be referenced later. Or do those all call the same split function later > in the generic block layer, in which case it shouldn't matter if the > upper layers already called it? Yes, we'll always end up calling into __bio_split_to_limits in blk-mq, no matter if someone split before. The upper layer splits are only for zone append users that can't later be split, but __bio_split_to_limits is stilled called on them to count the segments and to assert that they don't need splitting.