Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933043Ab3CSFrm (ORCPT ); Tue, 19 Mar 2013 01:47:42 -0400 Received: from mail-ia0-f175.google.com ([209.85.210.175]:51739 "EHLO mail-ia0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755227Ab3CSFrl (ORCPT ); Tue, 19 Mar 2013 01:47:41 -0400 MIME-Version: 1.0 In-Reply-To: <1363670161-9214-1-git-send-email-iamjoonsoo.kim@lge.com> References: <1363670161-9214-1-git-send-email-iamjoonsoo.kim@lge.com> Date: Mon, 18 Mar 2013 22:47:41 -0700 X-Google-Sender-Auth: 8OaGVA11QmUIQy5kfUPAbZJxsW4 Message-ID: Subject: Re: [PATCH 1/3] mm, nobootmem: fix wrong usage of max_low_pfn From: Yinghai Lu To: Joonsoo Kim Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Johannes Weiner , Jiang Liu Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1675 Lines: 51 On Mon, Mar 18, 2013 at 10:15 PM, Joonsoo Kim wrote: > max_low_pfn reflect the number of _pages_ in the system, > not the maximum PFN. You can easily find that fact in init_bootmem(). > So fix it. I'm confused. for x86, we have max_low_pfn defined in ... #ifdef CONFIG_X86_32 /* max_low_pfn get updated here */ find_low_pfn_range(); #else num_physpages = max_pfn; check_x2apic(); /* How many end-of-memory variables you have, grandma! */ /* need this before calling reserve_initrd */ if (max_pfn > (1UL<<(32 - PAGE_SHIFT))) max_low_pfn = e820_end_of_low_ram_pfn(); else max_low_pfn = max_pfn; and under max_low_pfn is bootmem. > > Additionally, if 'start_pfn == end_pfn', we don't need to go futher, > so change range check. > > Signed-off-by: Joonsoo Kim > > diff --git a/mm/nobootmem.c b/mm/nobootmem.c > index 5e07d36..4711e91 100644 > --- a/mm/nobootmem.c > +++ b/mm/nobootmem.c > @@ -110,9 +110,9 @@ static unsigned long __init __free_memory_core(phys_addr_t start, > { > unsigned long start_pfn = PFN_UP(start); > unsigned long end_pfn = min_t(unsigned long, > - PFN_DOWN(end), max_low_pfn); > + PFN_DOWN(end), min_low_pfn); what is min_low_pfn ? is it 0 for x86? Thanks Yinghai -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/