From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932107AbcEWHcE (ORCPT ); Mon, 23 May 2016 03:32:04 -0400 Received: from mail-wm0-f68.google.com ([74.125.82.68]:34834 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752914AbcEWHcC (ORCPT ); Mon, 23 May 2016 03:32:02 -0400 Date: Mon, 23 May 2016 09:31:58 +0200 From: Michal Hocko To: "Shi, Yang" Cc: akpm@linux-foundation.org, iamjoonsoo.kim@lge.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linaro-kernel@lists.linaro.org Subject: Re: [v2 PATCH] mm: move page_ext_init after all struct pages are initialized Message-ID: <20160523073157.GD2278@dhcp22.suse.cz> References: <1463696006-31360-1-git-send-email-yang.shi@linaro.org> <20160520131649.GC5197@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 20-05-16 08:41:09, Shi, Yang wrote: > On 5/20/2016 6:16 AM, Michal Hocko wrote: > > On Thu 19-05-16 15:13:26, Yang Shi wrote: > > [...] > > > diff --git a/init/main.c b/init/main.c > > > index b3c6e36..2075faf 100644 > > > --- a/init/main.c > > > +++ b/init/main.c > > > @@ -606,7 +606,6 @@ asmlinkage __visible void __init start_kernel(void) > > > initrd_start = 0; > > > } > > > #endif > > > - page_ext_init(); > > > debug_objects_mem_init(); > > > kmemleak_init(); > > > setup_per_cpu_pageset(); > > > @@ -1004,6 +1003,8 @@ static noinline void __init kernel_init_freeable(void) > > > sched_init_smp(); > > > > > > page_alloc_init_late(); > > > + /* Initialize page ext after all struct pages are initializaed */ > > > + page_ext_init(); > > > > > > do_basic_setup(); > > > > I might be missing something but don't we have the same problem with > > CONFIG_FLATMEM? page_ext_init_flatmem is called way earlier. Or > > CONFIG_DEFERRED_STRUCT_PAGE_INIT is never enabled for CONFIG_FLATMEM? > > Yes, CONFIG_DEFERRED_STRUCT_PAGE_INIT depends on MEMORY_HOTPLUG which > depends on SPARSEMEM. So, this config is not valid for FLATMEM at all. Well config MEMORY_HOTPLUG bool "Allow for memory hot-add" depends on SPARSEMEM || X86_64_ACPI_NUMA depends on ARCH_ENABLE_MEMORY_HOTPLUG I wasn't really sure about X86_64_ACPI_NUMA dependency branch which depends on X86_64 && NUMA && ACPI && PCI and that didn't sound like SPARSEMEM only. If the FLATMEM shouldn't exist with CONFIG_DEFERRED_STRUCT_PAGE_INIT can we make that explicit please? -- Michal Hocko SUSE Labs