From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailout1.samsung.com (mailout1.samsung.com [203.254.224.24]) (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 C33E91F1313 for ; Thu, 12 Jun 2025 06:24:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=203.254.224.24 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749709481; cv=none; b=WalEmlGayNn53tVxjsU/+yJ9IpZB/axaDPzCkQmsy59DCvfE/ZQVOmPAvFlQ+J4978dz7wTRCeQEjJVcCfUu2a6HG3D0n7vAWnmfTQ02hkQsxLnMfkbVpYCTeJC6VO6iRt6GGfmIGgkRamGgfqtSyB2+MFdFoCTLeuNeBGDTfEw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749709481; c=relaxed/simple; bh=/hmPVZcpOW3BoRGbrGLVszEJGz0BVeezTIFatC4dNyg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:From:In-Reply-To: Content-Type:References; b=tBZPb4xPZwbfdDr+aXREKwad2sadlMgAc7iuYrHReWO4T55b41afRXUXaYQWpIpYqoD6IWMH8XMeK30LdS4oylHxarak9INYCyBvkN1pGb6y+6Id6Or/0hdAmkJQS6/o/1aqnvD9PzKzfFZ5uFN4YZ9u8HfjoYS9WzIw++SiFJY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com; spf=pass smtp.mailfrom=samsung.com; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b=ZjFpl50f; arc=none smtp.client-ip=203.254.224.24 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=samsung.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b="ZjFpl50f" Received: from epcas5p1.samsung.com (unknown [182.195.41.39]) by mailout1.samsung.com (KnoxPortal) with ESMTP id 20250612062436epoutp01220eb2e5945ebc7fb38450b52abe044a~IN3_n1K5r2591525915epoutp01L for ; Thu, 12 Jun 2025 06:24:36 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout1.samsung.com 20250612062436epoutp01220eb2e5945ebc7fb38450b52abe044a~IN3_n1K5r2591525915epoutp01L DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1749709476; bh=UtPymdd8LPXoV15uEH9uSYo/uGh6AqBmwQzP/RMvyGU=; h=Date:Subject:To:Cc:From:In-Reply-To:References:From; b=ZjFpl50fvd9FHdWLEQl0C99J0G3ebipD+knz4D/naJG1SD3qF+48rISN9o/qClCDt Fh/Wj92/qq4XRVFP7H9oxHvU9ySM4/D/wqInr3yDJY09HsA5aVA/oeK3+iBEta1B68 j821rwWpkKc1Uew6P7nc2Jv2bsn5z3qFJC3RP80o= Received: from epsnrtp03.localdomain (unknown [182.195.42.155]) by epcas5p3.samsung.com (KnoxPortal) with ESMTPS id 20250612062434epcas5p340bce2c2519adc20e0d234883a45f900~IN388h_cH1502115021epcas5p3a; Thu, 12 Jun 2025 06:24:34 +0000 (GMT) Received: from epcas5p2.samsung.com (unknown [182.195.38.175]) by epsnrtp03.localdomain (Postfix) with ESMTP id 4bHsv44bdlz3hhT9; Thu, 12 Jun 2025 06:24:32 +0000 (GMT) Received: from epsmtip2.samsung.com (unknown [182.195.34.31]) by epcas5p1.samsung.com (KnoxPortal) with ESMTPA id 20250612062431epcas5p1eb2ce99af9b6aa2367d26b3db8804b73~IN36PhV6c3170231702epcas5p10; Thu, 12 Jun 2025 06:24:31 +0000 (GMT) Received: from [107.122.11.51] (unknown [107.122.11.51]) by epsmtip2.samsung.com (KnoxPortal) with ESMTPA id 20250612062430epsmtip23f092a27f487341f12eb593eb6b30b36~IN349aphG2969629696epsmtip2C; Thu, 12 Jun 2025 06:24:30 +0000 (GMT) Message-ID: Date: Thu, 12 Jun 2025 11:54:21 +0530 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/9] block: don't merge different kinds of P2P transfers in a single bio To: Christoph Hellwig , Jens Axboe Cc: Keith Busch , Sagi Grimberg , Chaitanya Kulkarni , Leon Romanovsky , Nitesh Shetty , Logan Gunthorpe , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org Content-Language: en-US From: Kanchan Joshi In-Reply-To: <20250610050713.2046316-2-hch@lst.de> Content-Transfer-Encoding: 7bit X-CMS-MailID: 20250612062431epcas5p1eb2ce99af9b6aa2367d26b3db8804b73 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" CMS-TYPE: 105P cpgsPolicy: CPGSC10-542,Y X-CFilter-Loop: Reflected X-CMS-RootMailID: 20250610050728epcas5p343c293cd81ffb03b6f12dabfcf2fd8d4 References: <20250610050713.2046316-1-hch@lst.de> <20250610050713.2046316-2-hch@lst.de> On 6/10/2025 10:36 AM, Christoph Hellwig wrote: > --- a/block/bio.c > +++ b/block/bio.c > @@ -930,8 +930,6 @@ static bool bvec_try_merge_page(struct bio_vec *bv, struct page *page, > return false; > if (xen_domain() && !xen_biovec_phys_mergeable(bv, page)) > return false; > - if (!zone_device_pages_have_same_pgmap(bv->bv_page, page)) > - return false; I did not understand the value of moving this out to its two callers (bio_add_page and bio_integrity_add_page). Since this check existed, I am a bit confused. The thing that patch title says - is not a new addition and used to happen earlier too? Or is this about setting REQ_NOMERGE in bio? Flagging P2P bio with the new flag REQ_P2PDMA seems preparatory work to optimize stuff in subsequent patches.