From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: + powerpc-fix-code-for-reserved-memory-spanning-across-nodes.patch added to -mm tree Date: Thu, 25 Dec 2008 00:06:21 -0800 Message-ID: <200812250806.mBP86LPQ018399@imap1.linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:35681 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750952AbYLYIGa (ORCPT ); Thu, 25 Dec 2008 03:06:30 -0500 Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: mm-commits@vger.kernel.org Cc: chandru@in.ibm.com, benh@kernel.crashing.org, chandru@linux.vnet.ibm.com, paulus@samba.org The patch titled powerpc: fix code for reserved memory spanning across nodes has been added to the -mm tree. Its filename is powerpc-fix-code-for-reserved-memory-spanning-across-nodes.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: powerpc: fix code for reserved memory spanning across nodes From: Chandru When booted with crashkernel=224M@32M or any memory size less than this, the system boots properly. The following was the observation.. The system comes up with two nodes (0-256M and 256M-4GB). The crashkernel memory reservation spans across these two nodes. The mark_reserved_regions_for_nid() in arch/powerpc/mm/numa.c resizes the reserved part of the memory within it as: if (end_pfn > node_ar.end_pfn) reserve_size = (node_ar.end_pfn << PAGE_SHIFT) - (start_pfn << PAGE_SHIFT); but the reserve_bootmem_node() in mm/bootmem.c raises the pfn value of end end = PFN_UP(physaddr + size); This causes end to get a value past the last page in the 0-256M node. Again when reserve_bootmem_node() returns, mark_reserved_regions_for_nid() loops around to set the rest of the crashkernel memory in the next node as reserved. It references NODE_DATA(node_ar.nid) and this causes another 'Oops: kernel access of bad area' problem. The following changes made the system to boot with any amount of crashkernel memory size. Signed-off-by: Chandru S Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Signed-off-by: Andrew Morton --- arch/powerpc/mm/numa.c | 7 ++++--- mm/bootmem.c | 4 ++++ 2 files changed, 8 insertions(+), 3 deletions(-) diff -puN arch/powerpc/mm/numa.c~powerpc-fix-code-for-reserved-memory-spanning-across-nodes arch/powerpc/mm/numa.c --- a/arch/powerpc/mm/numa.c~powerpc-fix-code-for-reserved-memory-spanning-across-nodes +++ a/arch/powerpc/mm/numa.c @@ -995,10 +995,11 @@ void __init do_init_bootmem(void) start_pfn, end_pfn); free_bootmem_with_active_regions(nid, end_pfn); + } + + for_each_online_node(nid) { /* - * Be very careful about moving this around. Future - * calls to careful_allocation() depend on this getting - * done correctly. + * Be very careful about moving this around. */ mark_reserved_regions_for_nid(nid); sparse_memory_present_with_active_regions(nid); diff -puN mm/bootmem.c~powerpc-fix-code-for-reserved-memory-spanning-across-nodes mm/bootmem.c --- a/mm/bootmem.c~powerpc-fix-code-for-reserved-memory-spanning-across-nodes +++ a/mm/bootmem.c @@ -375,10 +375,14 @@ int __init reserve_bootmem_node(pg_data_ unsigned long size, int flags) { unsigned long start, end; + bootmem_data_t *bdata = pgdat->bdata; start = PFN_DOWN(physaddr); end = PFN_UP(physaddr + size); + if (end > bdata->node_low_pfn) + end = bdata->node_low_pfn; + return mark_bootmem_node(pgdat->bdata, start, end, 1, flags); } _ Patches currently in -mm which might be from chandru@in.ibm.com are powerpc-fix-code-for-reserved-memory-spanning-across-nodes.patch