From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 17 Apr 2008 20:14:32 -0700 From: Andrew Morton Subject: Re: [PATCH] memcgroup: check and initialize page->cgroup in memmap_init_zone Message-Id: <20080417201432.36b1c326.akpm@linux-foundation.org> In-Reply-To: <48080B86.7040200@cn.fujitsu.com> References: <48080706.50305@cn.fujitsu.com> <48080930.5090905@cn.fujitsu.com> <48080B86.7040200@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Shi Weihua Cc: Hiroyuki KAMEZAWA , balbir@linux.vnet.ibm.com, xemul@openvz.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, hugh@veritas.com List-ID: On Fri, 18 Apr 2008 10:46:30 +0800 Shi Weihua wrote: > When we test memory controller in Fujitsu PrimeQuest(arch: ia64), > the compiled kernel boots failed, the following message occured on > the telnet terminal. > ------------------------------------- > .......... > ELILO boot: Uncompressing Linux... done > Loading file initrd-2.6.25-rc9-00067-gb87e81e.img...done > _ (system freezed) > ------------------------------------- > > We found commit 9442ec9df40d952b0de185ae5638a74970388e01 > causes this boot failure by git-bisect. > And, we found the following change caused the boot failure. > ------------------------------------- > @@ -2528,7 +2535,6 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zon > set_page_links(page, zone, nid, pfn); > init_page_count(page); > reset_page_mapcount(page); > - page_assign_page_cgroup(page, NULL); > SetPageReserved(page); > > /* > ------------------------------------- > In this patch, the Author Hugh Dickins said > "...memmap_init_zone doesn't need it either, ... > Linux assumes pointers in zeroed structures are NULL pointers." > But it seems it's not always the case, so we should check and initialize > page->cgroup anyways. > > Signed-off-by: Shi Weihua > --- > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 402a504..506d4cf 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -2518,6 +2518,7 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone, > struct page *page; > unsigned long end_pfn = start_pfn + size; > unsigned long pfn; > + void *pc; > > for (pfn = start_pfn; pfn < end_pfn; pfn++) { > /* > @@ -2535,6 +2536,9 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone, > set_page_links(page, zone, nid, pfn); > init_page_count(page); > reset_page_mapcount(page); > + pc = page_get_page_cgroup(page); > + if (pc) > + page_reset_bad_cgroup(page); > SetPageReserved(page); > hm, fishy. Perhaps the architecture isn't zeroing the memmap arrays? Or perhaps that page was used and then later freed before we got to memmap_init_zone() and was freed with a non-zero ->page_cgroup. Which is unlikely given that page.page_cgroup was only just added and is only present if CONFIG_CGROUP_MEM_RES_CTLR. -- 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