From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailout3.samsung.com (mailout3.samsung.com [203.254.224.33]) (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 D892748A8CC for ; Fri, 21 Aug 2026 12:33:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=203.254.224.33 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787315622; cv=none; b=LpSWkDIQGPlG2M1kleyIpIDjLkvEuRN82YzQQ/1C3HB5WhFTwRb2eDKImnN4uXxwB/1asD6kIB9bpGgFbxPfEXXTIzdXHFYMtlHtd37myxULAODGzMW4RYeJ+xOFKoatRBm3IDwOlvaWhWLKzNdxvDHr+BdVwT9HN6kt8fI68R4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787315622; c=relaxed/simple; bh=ExMBDFobXnMpp6RdVhm0dYjGLANPAQ4yQMEKSXVnyY0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:From:In-Reply-To: Content-Type:References; b=QZkYUdrtlE+crw97SE0FR8lbRY4F5yU2Q30M54n9Q2KwxLXUzPggv+acsZzKRiF1yDuEipJYGeUIEZPpruNXUNbq2Yvaop0mubuaLWcvSrdT3XWOHRM34yoztlGXrd/A/z5jntleGu4fsbggrocnlvFnMH0JejN6ONB2pmyf8sw= 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=o9kbQum0; arc=none smtp.client-ip=203.254.224.33 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="o9kbQum0" Received: from epcas5p2.samsung.com (unknown [182.195.41.40]) by mailout3.samsung.com (KnoxPortal) with ESMTP id 20260821123334epoutp036f8f671bbf34348ce7add7f796d44ad4~N0hT4hVI81819418194epoutp03E for ; Fri, 21 Aug 2026 12:33:34 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout3.samsung.com 20260821123334epoutp036f8f671bbf34348ce7add7f796d44ad4~N0hT4hVI81819418194epoutp03E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1787315614; bh=ODaDgCCYCUHp5n0OTjvR5sPE2vW6JgnD3H3aVJw7xl0=; h=Date:Subject:To:Cc:From:In-Reply-To:References:From; b=o9kbQum0UOIciTe1w+FMjdMqRXvY8anflXXhHzMGg27Ab2YuKiFWtBWaLGnuWBBU8 wCQYIhkf8/QT9F0Pg3KB4vl6jTMd+YRGySws7ri5ruxI1S1RXXe8LA4VzGgFKthsOV w32bX2trw5kmp7UorekJiSDQXPEek084L4a3dPW0= Received: from epsnrtp04.localdomain (unknown [182.195.42.156]) by epcas5p2.samsung.com (KnoxPortal) with ESMTPS id 20260821123334epcas5p2010e9c4ae5f4bac56498d380910a878b~N0hTTU-Da0398603986epcas5p27; Fri, 21 Aug 2026 12:33:34 +0000 (GMT) Received: from epcas5p1.samsung.com (unknown [182.195.38.88]) by epsnrtp04.localdomain (Postfix) with ESMTP id 4hRKV508qSz6B9m5; Fri, 21 Aug 2026 12:33:33 +0000 (GMT) Received: from epsmtip2.samsung.com (unknown [182.195.34.31]) by epcas5p2.samsung.com (KnoxPortal) with ESMTPA id 20260821123332epcas5p2b0a3d8c25ea3f8f148f16031818b9bdc~N0hRs26Kr1514515145epcas5p2P; Fri, 21 Aug 2026 12:33:32 +0000 (GMT) Received: from [107.122.11.51] (unknown [107.122.11.51]) by epsmtip2.samsung.com (KnoxPortal) with ESMTPA id 20260821123330epsmtip22fa01d534d6b61e2ad320efe56cf7b2e~N0hQBUPp32063620636epsmtip27; Fri, 21 Aug 2026 12:33:30 +0000 (GMT) Message-ID: Date: Fri, 21 Aug 2026 18:03:29 +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 v4 5/6] xfs: write stream based AG placement To: Christoph Hellwig Cc: brauner@kernel.org, djwong@kernel.org, dgc@kernel.org, jack@suse.cz, cem@kernel.org, axboe@kernel.dk, kbusch@kernel.org, ritesh.list@gmail.com, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, gost.dev@samsung.com Content-Language: en-US From: Kanchan Joshi In-Reply-To: <20260819072902.GA2332@lst.de> Content-Transfer-Encoding: 7bit X-CMS-MailID: 20260821123332epcas5p2b0a3d8c25ea3f8f148f16031818b9bdc 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: 20260717125638epcas5p2fb7128170d2443be3cfe1a7687d0c5fd References: <20260717125538.508925-1-joshi.k@samsung.com> <20260717125538.508925-6-joshi.k@samsung.com> <20260819072902.GA2332@lst.de> On 8/19/2026 12:59 PM, Christoph Hellwig wrote: > On Fri, Jul 17, 2026 at 06:25:37PM +0530, Kanchan Joshi wrote: >> If AGs are fewer than write streams, write streams are distributed into >> available AGs in round robin fashion. > > I think we should just limit the number of available write streams > to the number of AG, as otherwise we'll get into a bit of a mess. To confirm: given above quoting, for the other two cases (i.e., Streams <= AGs), are you open to stream-based AG-sets modulo inode hashing (that you suggested to skip in previous patch)? And is this point only for the case when Streams > AGs? This case can happen for hw streams, but for pure software streams, we will not hit this case because the filesystem determines the stream count based on the AG count. > And for the case of the hardware write streams query them in mkfs > to align the AG geometry to that. If this is only for the streams > AGs case, the filesystem can just clamp down to match, turning it into a 'streams = AGs' case. And that means no changes in mkfs. Is that fine? Related benefit is to skip tricky mkfs AG calculations right for future device sizes and varying stream counts.