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=-8.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 9D331C433DB for ; Wed, 23 Dec 2020 01:47:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6567022571 for ; Wed, 23 Dec 2020 01:47:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727172AbgLWBrk (ORCPT ); Tue, 22 Dec 2020 20:47:40 -0500 Received: from mail.kernel.org ([198.145.29.99]:36332 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726463AbgLWBrk (ORCPT ); Tue, 22 Dec 2020 20:47:40 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id A97992256F; Wed, 23 Dec 2020 01:46:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1608688019; bh=ZEPYdvs02rD2KFiANzUJPEVo2S5t5C+itOXnp/i/zBs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=ZJQ9hAgGrHx2BkzIRPPCqIiMxuD+51N6QSnpXoIBzSivbO+7FXnpECel/EmHvIM3c WPQ46mZazHTzwakVZe8i8zh7pcxng+OuiC+OyNSMxStLIfcDxChxGPzYysR34wuoJx vjXNk2zjoHeGmsnaCQZDo/XN9vsmI82PYeUXF6E4= Date: Tue, 22 Dec 2020 17:46:58 -0800 From: Andrew Morton To: Baoquan He Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, gopakumarr@vmware.com, rppt@kernel.org, david@redhat.com Subject: Re: [PATCH v2 0/5] Fix the incorrect memmep defer init handling and do some cleanup Message-Id: <20201222174658.a2d08ca723a20587467792d9@linux-foundation.org> In-Reply-To: <20201220082754.6900-1-bhe@redhat.com> References: <20201220082754.6900-1-bhe@redhat.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 20 Dec 2020 16:27:49 +0800 Baoquan He wrote: > VMware reported the performance regression during memmap_init() invocation. > And they bisected to commit 73a6e474cb376 ("mm: memmap_init: iterate over > memblock regions rather that check each PFN") causing it. > > https://lore.kernel.org/linux-mm/DM6PR05MB52921FF90FA01CC337DD23A1A4080@DM6PR05MB5292.namprd05.prod.outlook.com/ > > After investigation, it's caused by incorrect memmap init defer handling > in memmap_init_zone() after commit 73a6e474cb376. The current > memmap_init_zone() only handle one memory region of one zone, while > memmap_init() iterates over all its memory regions and pass them one by > one into memmap_init_zone() to handle. > > So in this patchset, patch 1/5 fixes the bug observed by VMware. Patch > 2~5/5 clean up codes. > accordingly. This series doesn't apply well to current mainline (plus, perhaps, material which I sent to Linus today). So please check all that against mainline in a day or so, refresh, retest and resend. Please separate the fix for the performance regression (1/5) into a single standalone patch, ready for -stable backporting. And then a separate 4-patch series with the cleanups for a 5.11 merge. Thanks.