From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 20 May 2008 15:48:51 +0100 From: Andy Whitcroft Subject: Re: [PATCH] memory hotplug: fix early allocation handling Message-ID: <20080520144850.GO4146@shadowen.org> References: <20080520105145.GA24526@osiris.boeblingen.de.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080520105145.GA24526@osiris.boeblingen.de.ibm.com> Sender: owner-linux-mm@kvack.org Return-Path: To: Heiko Carstens Cc: Andrew Morton , Dave Hansen , Gerald Schaefer , KAMEZAWA Hiroyuki , Yasunori Goto , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Tue, May 20, 2008 at 12:51:45PM +0200, Heiko Carstens wrote: > From: Heiko Carstens > > Trying to add memory via add_memory() from within an initcall function > results in > > bootmem alloc of 163840 bytes failed! > Kernel panic - not syncing: Out of memory > > This is caused by zone_wait_table_init() which uses system_state to > decide if it should use the bootmem allocator or not. > When initcalls are handled the system_state is still SYSTEM_BOOTING > but the bootmem allocator doesn't work anymore. So the allocation > will fail. > > To fix this use slab_is_available() instead as indicator like we do > it everywhere else. > > Cc: Andy Whitcroft > Cc: Dave Hansen > Cc: Gerald Schaefer > Cc: KAMEZAWA Hiroyuki > Cc: Yasunori Goto > Signed-off-by: Heiko Carstens > --- > mm/page_alloc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > Index: linux-2.6/mm/page_alloc.c > =================================================================== > --- linux-2.6.orig/mm/page_alloc.c > +++ linux-2.6/mm/page_alloc.c > @@ -2804,7 +2804,7 @@ int zone_wait_table_init(struct zone *zo > alloc_size = zone->wait_table_hash_nr_entries > * sizeof(wait_queue_head_t); > > - if (system_state == SYSTEM_BOOTING) { > + if (!slab_is_available()) { > zone->wait_table = (wait_queue_head_t *) > alloc_bootmem_node(pgdat, alloc_size); > } else { It would be nice to be able to check that bootmem is enabled separatly from whether slab is available, as I am sure there is a time where neither is available during the change over. But the change looks reasonable as we cannot use vmalloc until slab is working. Reviewed-by: Andy Whitcroft -apw -- 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