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 X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39959C433B4 for ; Thu, 13 May 2021 11:26:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E84C9613F7 for ; Thu, 13 May 2021 11:26:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232431AbhEML1U (ORCPT ); Thu, 13 May 2021 07:27:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58612 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232340AbhEML1S (ORCPT ); Thu, 13 May 2021 07:27:18 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CAA59C06174A; Thu, 13 May 2021 04:26:08 -0700 (PDT) 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=r9oN4rAfYVkltFP1nqUdIrhELASwJQF3sOXiPvRVsQo=; b=hDwMX6WOwOcFiVtmwICnmhPT+f IgyOnHKvIq+Pt8H/edI/WB7n/lztayeU4Mzk9luE9yim4lGtdFWhPd4MY07tBJg2MZvZR2ckXCof4 zWZBjhX8kPT9Jk9x0alASXqpFgR4/srMCq88LEesSW6tVk1snu/PfnKfZkdRwFXESkppIx8+QjkX2 p/ob8iqQzdp5+tu3DFh+banaV3Mg1DYLsm3R5Albl0A2gMnDdfIGauty8LkIhxoQ/ofiSqlLxH/z5 4r+mo1P0pAsA+PNQ+U6Fi12UdEpMraXjpKw61260jrfn3HYoF8wqWmfnmm2nU5cjYKyFYwP483hTT M1fnf/IA==; Received: from hch by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lh9Qz-009NfE-A0; Thu, 13 May 2021 11:23:23 +0000 Date: Thu, 13 May 2021 12:23:17 +0100 From: Christoph Hellwig To: Changheun Lee Cc: alex_y_xu@yahoo.ca, yi.zhang@redhat.com, jaegeuk@kernel.org, bgoncalv@redhat.com, Johannes.Thumshirn@wdc.com, asml.silence@gmail.com, axboe@kernel.dk, bvanassche@acm.org, damien.lemoal@wdc.com, gregkh@linuxfoundation.org, hch@infradead.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, ming.lei@redhat.com, osandov@fb.com, patchwork-bot@kernel.org, tj@kernel.org, tom.leiming@gmail.com, jisoo2146.oh@samsung.com, junho89.kim@samsung.com, mj0123.lee@samsung.com, seunghwan.hyun@samsung.com, sookwan7.kim@samsung.com, woosung2.lee@samsung.com, yt0928.kim@samsung.com Subject: Re: [PATCH v10 0/1] bio: limit bio max size Message-ID: References: <20210513100205.17965-1-nanich.lee@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210513100205.17965-1-nanich.lee@samsung.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org FYI, I still think this whole limit is a bad idea, and instead we need to fix the algorithms to not waste time iterating over the bios again and again in non-optimal ways. I still haven't seen an answer if your original latency problems are reproducable with the iomap direct I/O implementation, and we've also not even started the work on making some of the common iterators less stupid.