From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id 2597C6B01E3 for ; Wed, 7 Apr 2010 12:30:03 -0400 (EDT) Message-ID: <4BBCB304.2050500@cs.helsinki.fi> Date: Wed, 07 Apr 2010 19:29:56 +0300 From: Pekka Enberg MIME-Version: 1.0 Subject: Re: [patch v2] slab: add memory hotplug support References: <20100226114136.GA16335@basil.fritz.box> <20100226155755.GE16335@basil.fritz.box> <20100305062002.GV8653@laptop> <20100309134633.GM8653@laptop> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: David Rientjes Cc: Nick Piggin , Andi Kleen , Christoph Lameter , linux-kernel@vger.kernel.org, linux-mm@kvack.org, haicheng.li@intel.com, KAMEZAWA Hiroyuki List-ID: David Rientjes wrote: > Slab lacks any memory hotplug support for nodes that are hotplugged > without cpus being hotplugged. This is possible at least on x86 > CONFIG_MEMORY_HOTPLUG_SPARSE kernels where SRAT entries are marked > ACPI_SRAT_MEM_HOT_PLUGGABLE and the regions of RAM represent a seperate > node. It can also be done manually by writing the start address to > /sys/devices/system/memory/probe for kernels that have > CONFIG_ARCH_MEMORY_PROBE set, which is how this patch was tested, and > then onlining the new memory region. > > When a node is hotadded, a nodelist for that node is allocated and > initialized for each slab cache. If this isn't completed due to a lack > of memory, the hotadd is aborted: we have a reasonable expectation that > kmalloc_node(nid) will work for all caches if nid is online and memory is > available. > > Since nodelists must be allocated and initialized prior to the new node's > memory actually being online, the struct kmem_list3 is allocated off-node > due to kmalloc_node()'s fallback. > > When an entire node would be offlined, its nodelists are subsequently > drained. If slab objects still exist and cannot be freed, the offline is > aborted. It is possible that objects will be allocated between this > drain and page isolation, so it's still possible that the offline will > still fail, however. > > Signed-off-by: David Rientjes I queued this up for 2.6.35. Thanks! -- 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