From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04D79C54EE9 for ; Wed, 28 Sep 2022 17:31:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234324AbiI1Rbb (ORCPT ); Wed, 28 Sep 2022 13:31:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234014AbiI1Rb0 (ORCPT ); Wed, 28 Sep 2022 13:31:26 -0400 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9AA087C1F9; Wed, 28 Sep 2022 10:31:24 -0700 (PDT) Received: by verein.lst.de (Postfix, from userid 2407) id 3B89D68BEB; Wed, 28 Sep 2022 19:31:21 +0200 (CEST) Date: Wed, 28 Sep 2022 19:31:21 +0200 From: Christoph Hellwig To: Kanchan Joshi Cc: axboe@kernel.dk, hch@lst.de, kbusch@kernel.org, io-uring@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, gost.dev@samsung.com Subject: Re: [PATCH for-next v10 5/7] block: factor out bio_map_get helper Message-ID: <20220928173121.GC17153@lst.de> References: <20220927173610.7794-1-joshi.k@samsung.com> <20220927173610.7794-6-joshi.k@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220927173610.7794-6-joshi.k@samsung.com> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Tue, Sep 27, 2022 at 11:06:08PM +0530, Kanchan Joshi wrote: > Move bio allocation logic from bio_map_user_iov to a new helper > bio_map_get. It is named so because functionality is opposite of what is > done inside bio_map_put. This is a prep patch. I'm still not a fan of using bio_sets for passthrough and would be much happier if we could drill down what the problems with the slab per-cpu allocator are, but it seems like I've lost that fight against Jens.. > +static struct bio *bio_map_get(struct request *rq, unsigned int nr_vecs, > gfp_t gfp_mask) But these names just seems rather misleading. Why not someting like blk_rq_map_bio_alloc and blk_mq_map_bio_put? Not really new in this code but a question to Jens: The existing bio_map_user_iov has no real upper bounds on the number of bios allocated, how does that fit with the very limited pool size of fs_bio_set?