From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756133Ab2DQPzG (ORCPT ); Tue, 17 Apr 2012 11:55:06 -0400 Received: from cantor2.suse.de ([195.135.220.15]:60406 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753946Ab2DQPzE (ORCPT ); Tue, 17 Apr 2012 11:55:04 -0400 Date: Tue, 17 Apr 2012 17:55:02 +0200 From: Michal Hocko To: yinghai@kernel.org Cc: linux-mm@kvack.org, LKML Subject: Weirdness in __alloc_bootmem_node_high Message-ID: <20120417155502.GE22687@tiehlicka.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I just come across the following condition in __alloc_bootmem_node_high which I have hard times to understand. I guess it is a bug and we need something like the following. But, to be honest, I have no idea why we care about those 128MB above MAX_DMA32_PFN. --- mm/bootmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/bootmem.c b/mm/bootmem.c index 0131170..5adb072 100644 --- a/mm/bootmem.c +++ b/mm/bootmem.c @@ -737,7 +737,7 @@ void * __init __alloc_bootmem_node_high(pg_data_t *pgdat, unsigned long size, /* update goal according ...MAX_DMA32_PFN */ end_pfn = pgdat->node_start_pfn + pgdat->node_spanned_pages; - if (end_pfn > MAX_DMA32_PFN + (128 >> (20 - PAGE_SHIFT)) && + if (end_pfn > MAX_DMA32_PFN + (128 << (20 - PAGE_SHIFT)) && (goal >> PAGE_SHIFT) < MAX_DMA32_PFN) { void *ptr; unsigned long new_goal; -- 1.7.9.5 -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic