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 7DEFBC4167B for ; Mon, 6 Nov 2023 04:54:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230269AbjKFEyk (ORCPT ); Sun, 5 Nov 2023 23:54:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45560 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229486AbjKFEyi (ORCPT ); Sun, 5 Nov 2023 23:54:38 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27806DB for ; Sun, 5 Nov 2023 20:53:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1699246429; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=J0xxS0GcTpI1/DgZckR1OrAQOwxzwiXZ07noMlU8lfM=; b=AEFJ7tT+HqXL6aYtCxTT6GUZC6eSpd9bEZLxn/7lUo7YmQKg7NQph9ZFHQAEAlfzwhiup5 RpkOFuuR0K0vYoharAdfuGv7xjsyrT0ckQZs9D8pF5+b/zjZiSQlVlpzByVWHPgbtMUcfg LO9xYuCreKnMuGBNIFqAPjO6TceUmZo= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-88-u2guWhx7NOmnhhSHkQuB-w-1; Sun, 05 Nov 2023 23:53:45 -0500 X-MC-Unique: u2guWhx7NOmnhhSHkQuB-w-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id CBCEB380628F; Mon, 6 Nov 2023 04:53:44 +0000 (UTC) Received: from fedora (unknown [10.72.120.4]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F11372166B26; Mon, 6 Nov 2023 04:53:35 +0000 (UTC) Date: Mon, 6 Nov 2023 12:53:31 +0800 From: Ming Lei To: Ed Tsai =?utf-8?B?KOiUoeWul+i7kik=?= Cc: Will Shiu =?utf-8?B?KOioseaBreeRnCk=?= , "linux-mediatek@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Peter Wang =?utf-8?B?KOeOi+S/oeWPiyk=?= , "linux-block@vger.kernel.org" , Alice Chao =?utf-8?B?KOi2meePruWdhyk=?= , wsd_upstream , "axboe@kernel.dk" , Casper Li =?utf-8?B?KOadjuS4reamrik=?= , Chun-Hung Wu =?utf-8?B?KOW3q+mnv+Wujyk=?= , Powen Kao =?utf-8?B?KOmrmOS8r+aWhyk=?= , Naomi Chu =?utf-8?B?KOacseipoOeUsCk=?= , "linux-arm-kernel@lists.infradead.org" , Stanley Chu =?utf-8?B?KOacseWOn+mZnik=?= , "matthias.bgg@gmail.com" , "angelogioacchino.delregno@collabora.com" , ming.lei@redhat.com Subject: Re: [PATCH 1/1] block: Check the queue limit before bio submitting Message-ID: References: <20231025092255.27930-1-ed.tsai@mediatek.com> <64db8f5406571c2f89b70f852eb411320201abe6.camel@mediatek.com> <2bc847a83849973b7658145f2efdda86cc47e3d5.camel@mediatek.com> <5ecedad658bf28abf9bbeeb70dcac09b4b404cf5.camel@mediatek.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <5ecedad658bf28abf9bbeeb70dcac09b4b404cf5.camel@mediatek.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.6 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 06, 2023 at 01:40:12AM +0000, Ed Tsai (蔡宗軒) wrote: > On Mon, 2023-11-06 at 09:33 +0800, Ed Tsai wrote: > > On Sat, 2023-11-04 at 11:43 +0800, Ming Lei wrote: ... > Sorry for missing out on my dd command. Here it is: > dd if=/data/test_file of=/dev/null bs=64m count=1 iflag=direct OK, thanks for the sharing. I understand the issue now, but not sure if it is one good idea to check queue limit in __bio_iov_iter_get_pages(): 1) bio->bi_bdev may not be set 2) what matters is actually bio's alignment, and bio size still can be big enough So I cooked one patch, and it should address your issue: diff --git a/block/bio.c b/block/bio.c index 816d412c06e9..7d982e74c65d 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1266,6 +1266,24 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) size -= trim; } + /* + * Try to make bio aligned with 128KB if there are pages left so we + * can avoid small bio in case of big chunk sequential IO + */ + if (iov_iter_count(iter)) { + unsigned curr_size = (bio->bi_iter.bi_size + size) & + ~((128U << 10) - 1); + if (curr_size <= bio->bi_iter.bi_size) { + ret = left = size; + goto revert; + } else { + curr_size -= bio->bi_iter.bi_size; + ret = size - curr_size; + iov_iter_revert(iter, ret); + size = curr_size; + } + } + if (unlikely(!size)) { ret = -EFAULT; goto out; @@ -1285,7 +1303,7 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) offset = 0; } - +revert: iov_iter_revert(iter, left); out: while (i < nr_pages) Thanks, Ming