From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with ESMTP id 1D8566B004D for ; Tue, 18 Aug 2009 11:33:43 -0400 (EDT) Message-Id: <4A8AE5F50200007800010536@vpn.id2.novell.com> Date: Tue, 18 Aug 2009 16:33:41 +0100 From: "Jan Beulich" Subject: [PATCH] fix updating of num_physpages for hot plugged memory Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Sender: owner-linux-mm@kvack.org To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Rusty Russell List-ID: Sizing of memory allocations shouldn't depend on the number of physical pages found in a system, as that generally includes (perhaps a huge amount of) non-RAM pages. The amount of what actually is usable as storage should instead be used as a basis here. In line with that, the memory hotplug code should update num_physpages in a way that it retains its original (post-boot) meaning; in particular, decreasing the value should at best be done with great care - this patch doesn't try to ever decrease this value at all as it doesn't really seem meaningful to do so. Signed-off-by: Jan Beulich Acked-by: Rusty Russell --- mm/memory_hotplug.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- linux-2.6.31-rc6/mm/memory_hotplug.c 2009-08-18 15:31:56.0000000= 00 +0200 +++ 2.6.31-rc6-use-totalram_pages/mm/memory_hotplug.c 2009-08-17 = 15:21:19.000000000 +0200 @@ -339,8 +339,11 @@ EXPORT_SYMBOL_GPL(__remove_pages); =20 void online_page(struct page *page) { + unsigned long pfn =3D page_to_pfn(page); + totalram_pages++; - num_physpages++; + if (pfn >=3D num_physpages) + num_physpages =3D pfn + 1; =20 #ifdef CONFIG_HIGHMEM if (PageHighMem(page)) @@ -831,7 +834,6 @@ repeat: zone->present_pages -=3D offlined_pages; zone->zone_pgdat->node_present_pages -=3D offlined_pages; totalram_pages -=3D offlined_pages; - num_physpages -=3D offlined_pages; =20 setup_per_zone_wmarks(); calculate_zone_inactive_ratio(zone); -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org