From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 543671CDA3F; Fri, 15 Nov 2024 18:04:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731693850; cv=none; b=rAqIcITMHiCqErRmW0l3rs4XWH+0XYpQZwX/V1CDeO5SGMpj+gbVuTHnSOXSeX+ZlZE/jFIsqqa5EkvyN0k3uPMX6+s1xsSaHFO/5PKXXy6XTTk0vqPdDbwrPgyY6AOFg8YnJcgUnRxkhIV5xZquozt/PgQ9F9uRIcJ3wsSJVUQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731693850; c=relaxed/simple; bh=LPDOMZz6KV6iIi1jEYmzOnjPnCesxzIIxDTmzHaPhFo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=UfsToVQmLDqKiA/k4qrDywdSqNzEAaxdl88Z4bQsB0aebLohdh/Ju6R0yCUz+C2kfnG/MHkDyYUXLv0og3mv1bP9XQd2QB2T2F27MKNlXTdfBzOIDP6IC2HB8Tx3slP7Zljc0rpzJP7JXNXUVdlOAR9yIBrUZvYVcwc3nic6rPE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=mLRtysRU; arc=none smtp.client-ip=90.155.50.34 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=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="mLRtysRU" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=E2BNdGt9ER/nWRwbgvy7UUTAJ2vjHj29ke2nprS1nqE=; b=mLRtysRUSQWEXTgW0c4C6kFIrP 2DbechyxUleqgdzwz+N6MegMggR0Uyr3mTxTTI9dNesYFLPGVl+DtM7fVkThDaFww6S4A9Vtm9OAC T8Ux6eQr0HDmFTqJVmuhaBXyJ/hI1075TQBZUNQzmTW4xnN7twG4vu0Tmmfu2/KlQ5+Yjj5HhiTVo XH0D0+YvgPnm/I8BcYTadFTYdW5uHe9MrXEluzEVrszfaQOPKAFLW2IkbuXyqZzR/bojlfPXBZKfn isHFuCTBr9HyMXSo4fzJOn6H3Wg2h6FYNDpd0gzcoI70i77zpzW7XKbUZKlf2CZSvQclgdYJ+3qzR onR+8a5Q==; Received: from willy by casper.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1tC0fp-00000000AIu-1usX; Fri, 15 Nov 2024 18:04:01 +0000 Date: Fri, 15 Nov 2024 18:04:01 +0000 From: Matthew Wilcox To: Pavel Begunkov Cc: Christoph Hellwig , Anuj Gupta , axboe@kernel.dk, kbusch@kernel.org, martin.petersen@oracle.com, anuj1072538@gmail.com, brauner@kernel.org, jack@suse.cz, viro@zeniv.linux.org.uk, io-uring@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, gost.dev@samsung.com, linux-scsi@vger.kernel.org, vishak.g@samsung.com, linux-fsdevel@vger.kernel.org, Kanchan Joshi Subject: Re: [PATCH v9 06/11] io_uring: introduce attributes for read/write and PI support Message-ID: References: <20241114104517.51726-1-anuj20.g@samsung.com> <20241114104517.51726-7-anuj20.g@samsung.com> <20241114121632.GA3382@lst.de> <3fa101c9-1b38-426d-9d7c-8ed488035d4a@gmail.com> Precedence: bulk X-Mailing-List: io-uring@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: <3fa101c9-1b38-426d-9d7c-8ed488035d4a@gmail.com> On Thu, Nov 14, 2024 at 01:09:44PM +0000, Pavel Begunkov wrote: > With SQE128 it's also a problem that now all SQEs are 128 bytes regardless > of whether a particular request needs it or not, and the user will need > to zero them for each request. The way we handled this in NVMe was to use a bit in the command that was called (iirc) FUSED, which let you use two consecutive entries for a single command. Some variant on that could surely be used for io_uring. Perhaps a special opcode that says "the real opcode is here, and this is a two-slot command". Processing gets a little spicy when one slot is the last in the buffer and the next is the the first in the buffer, but that's a SMOP.