Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932719Ab2HXOeN (ORCPT ); Fri, 24 Aug 2012 10:34:13 -0400 Received: from e23smtp07.au.ibm.com ([202.81.31.140]:54726 "EHLO e23smtp07.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756615Ab2HXOeL (ORCPT ); Fri, 24 Aug 2012 10:34:11 -0400 From: Wanpeng Li To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Michal Hocko , KAMEZAWA Hiroyuki , Minchan Kim , Andrew Morton , Gavin Shan , Wanpeng Li Subject: [PATCH 1/5] mm/memblock: truncate memblock if necessary Date: Fri, 24 Aug 2012 22:33:36 +0800 Message-Id: <1345818820-12102-1-git-send-email-liwanp@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.5.4 x-cbid: 12082414-0260-0000-0000-000001BD4DD7 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2153 Lines: 62 From: Gavin Shan While enforcing memory limit on current memblock layout, it is possible that we don't have to change the current memblock layout. For example, the enforced limited size is bigger than the maximal address of memory regions. Also, we don't have to change the memory layout while the enforced limited size is more than the accumulative size of all memory regions. The patch checks them and won't change current memblock layout for those cases, thus to reduce some overhead. Signed-off-by: Gavin Shan Signed-off-by: Wanpeng Li --- mm/memblock.c | 12 ++++++++---- 1 files changed, 8 insertions(+), 4 deletions(-) diff --git a/mm/memblock.c b/mm/memblock.c index 4d9393c..c1fbb12 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -844,14 +844,14 @@ void __init memblock_enforce_memory_limit(phys_addr_t limit) unsigned long i; phys_addr_t max_addr = (phys_addr_t)ULLONG_MAX; - if (!limit) + if (!limit || limit >= memblock_end_of_DRAM()) return; /* find out max address */ for (i = 0; i < memblock.memory.cnt; i++) { struct memblock_region *r = &memblock.memory.regions[i]; - if (limit <= r->size) { + if (limit < r->size) { max_addr = r->base + limit; break; } @@ -859,8 +859,12 @@ void __init memblock_enforce_memory_limit(phys_addr_t limit) } /* truncate both memory and reserved regions */ - __memblock_remove(&memblock.memory, max_addr, (phys_addr_t)ULLONG_MAX); - __memblock_remove(&memblock.reserved, max_addr, (phys_addr_t)ULLONG_MAX); + if (max_addr < (phys_addr_t)ULLONG_MAX) { + __memblock_remove(&memblock.memory, max_addr, + (phys_addr_t)ULLONG_MAX); + __memblock_remove(&memblock.reserved, max_addr, + (phys_addr_t)ULLONG_MAX); + } } static int __init_memblock memblock_search(struct memblock_type *type, phys_addr_t addr) -- 1.7.5.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/