From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx159.postini.com [74.125.245.159]) by kanga.kvack.org (Postfix) with SMTP id ABB336B0032 for ; Thu, 15 Aug 2013 14:04:13 -0400 (EDT) Message-ID: <520D1806.5040309@intel.com> Date: Thu, 15 Aug 2013 11:03:50 -0700 From: Dave Hansen MIME-Version: 1.0 Subject: Re: [PATCH 2/4] mm/sparse: introduce alloc_usemap_and_memmap References: <1376526703-2081-1-git-send-email-liwanp@linux.vnet.ibm.com> <1376526703-2081-2-git-send-email-liwanp@linux.vnet.ibm.com> In-Reply-To: <1376526703-2081-2-git-send-email-liwanp@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Wanpeng Li Cc: Andrew Morton , Rik van Riel , Dave Hansen , Fengguang Wu , Joonsoo Kim , Johannes Weiner , Tejun Heo , Yasuaki Ishimatsu , David Rientjes , KOSAKI Motohiro , Jiri Kosina , linux-mm@kvack.org, linux-kernel@vger.kernel.org On 08/14/2013 05:31 PM, Wanpeng Li wrote: > After commit 9bdac91424075("sparsemem: Put mem map for one node together."), > vmemmap for one node will be allocated together, its logic is similiar as > memory allocation for pageblock flags. This patch introduce alloc_usemap_and_memmap > to extract the same logic of memory alloction for pageblock flags and vmemmap. Shame on whoever copy-n-pasted that in the first place. > - > - for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) { > - struct mem_section *ms; > - > - if (!present_section_nr(pnum)) > - continue; > - ms = __nr_to_section(pnum); > - nodeid_begin = sparse_early_nid(ms); > - pnum_begin = pnum; > - break; > - } > - usemap_count = 1; > - for (pnum = pnum_begin + 1; pnum < NR_MEM_SECTIONS; pnum++) { > - struct mem_section *ms; > - int nodeid; > - > - if (!present_section_nr(pnum)) > - continue; > - ms = __nr_to_section(pnum); > - nodeid = sparse_early_nid(ms); > - if (nodeid == nodeid_begin) { > - usemap_count++; > - continue; > - } > - /* ok, we need to take cake of from pnum_begin to pnum - 1*/ > - sparse_early_usemaps_alloc_node(usemap_map, pnum_begin, pnum, > - usemap_count, nodeid_begin); > - /* new start, update count etc*/ > - nodeid_begin = nodeid; > - pnum_begin = pnum; > - usemap_count = 1; > - } > - /* ok, last chunk */ > - sparse_early_usemaps_alloc_node(usemap_map, pnum_begin, NR_MEM_SECTIONS, > - usemap_count, nodeid_begin); > + alloc_usemap_and_memmap(usemap_map, true); ... > + alloc_usemap_and_memmap((unsigned long **)map_map, false); > #endif Why does alloc_usemap_and_memmap() take an 'unsigned long **'? 'unsigned long' is for the usemap and 'struct page' is for the memmap. It's misleading to have it take an 'unsigned long **' and then just cast it over to a 'struct page **' internally. Also, what's the point of having a function that returns something in a double-pointer, but that doesn't use its return value? alloc_usemap_and_memmap() also needs a comment about what it's doing with that pointer and its other argument. -- 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