From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 53E9B6B0087 for ; Tue, 23 Nov 2010 19:25:51 -0500 (EST) Received: from m4.gw.fujitsu.co.jp ([10.0.50.74]) by fgwmail5.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id oAO0PmRN023289 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Wed, 24 Nov 2010 09:25:48 +0900 Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 02AAB45DE6F for ; Wed, 24 Nov 2010 09:25:48 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (s4.gw.fujitsu.co.jp [10.0.50.94]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id C746445DE60 for ; Wed, 24 Nov 2010 09:25:47 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 9E5D11DB8037 for ; Wed, 24 Nov 2010 09:25:47 +0900 (JST) Received: from m107.s.css.fujitsu.com (m107.s.css.fujitsu.com [10.249.87.107]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 339961DB8042 for ; Wed, 24 Nov 2010 09:25:47 +0900 (JST) Date: Wed, 24 Nov 2010 09:20:03 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH 3/4] alloc_contig_pages() allocate big chunk memory using migration Message-Id: <20101124092003.145e0c13.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <20101119171033.a8d9dc8f.kamezawa.hiroyu@jp.fujitsu.com> <20101119171528.32674ef4.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org To: Minchan Kim Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Bob Liu , fujita.tomonori@lab.ntt.co.jp, m.nazarewicz@samsung.com, pawel@osciak.com, andi.kleen@intel.com, felipe.contreras@gmail.com, "akpm@linux-foundation.org" , "kosaki.motohiro@jp.fujitsu.com" List-ID: On Mon, 22 Nov 2010 20:44:03 +0900 Minchan Kim wrote: > On Fri, Nov 19, 2010 at 5:15 PM, KAMEZAWA Hiroyuki > wrote: > > From: KAMEZAWA Hiroyuki > > > > Add an function to allocate contiguous memory larger than MAX_ORDER. > > The main difference between usual page allocator is that this uses > > memory offline technique (Isolate pages and migrate remaining pages.). > > > > I think this is not 100% solution because we can't avoid fragmentation, > > but we have kernelcore= boot option and can create MOVABLE zone. That > > helps us to allow allocate a contiguous range on demand. > > And later we can use compaction and reclaim, too. > So I think this approach is the way we have to go. > > > > > The new function is > > > > A alloc_contig_pages(base, end, nr_pages, alignment) > > > > This function will allocate contiguous pages of nr_pages from the range > > [base, end). If [base, end) is bigger than nr_pages, some pfn which > > meats alignment will be allocated. If alignment is smaller than MAX_ORDER, > > type meet > will fix. > > it will be raised to be MAX_ORDER. > > > > __alloc_contig_pages() has much more arguments. > > > > > > Some drivers allocates contig pages by bootmem or hiding some memory > > from the kernel at boot. But if contig pages are necessary only in some > > situation, kernelcore= boot option and using page migration is a choice. > > > > Changelog: 2010-11-19 > > A - removed no_search > > A - removed some drain_ functions because they are heavy. > > A - check -ENOMEM case > > > > Changelog: 2010-10-26 > > A - support gfp_t > > A - support zonelist/nodemask > > A - support [base, end) > > A - support alignment > > > > Signed-off-by: KAMEZAWA Hiroyuki > > --- > > A include/linux/page-isolation.h | A 15 ++ > > A mm/page_alloc.c A A A A A A A A | A 29 ++++ > > A mm/page_isolation.c A A A A A A | A 242 +++++++++++++++++++++++++++++++++++++++++ > > A 3 files changed, 286 insertions(+) > > > > Index: mmotm-1117/mm/page_isolation.c > > =================================================================== > > --- mmotm-1117.orig/mm/page_isolation.c > > +++ mmotm-1117/mm/page_isolation.c > > @@ -5,6 +5,7 @@ > > A #include > > A #include > > A #include > > +#include > > A #include > > A #include > > A #include > > @@ -396,3 +397,244 @@ retry: > > A A A A } > > A A A A return 0; > > A } > > + > > +/* > > + * Comparing caller specified [user_start, user_end) with physical memory layout > > + * [phys_start, phys_end). If no intersection is longer than nr_pages, return 1. > > + * If there is an intersection, return 0 and fill range in [*start, *end) > > I understand the goal of function. > But comment is rather awkward. > ok, I will rewrite. > > + */ > > +static int > > +__calc_search_range(unsigned long user_start, unsigned long user_end, > > Personally, I don't like the function name. > How about "__adjust_search_range"? > But I am not against this name strongly. :) > I will rename this. > > + A A A A A A A unsigned long nr_pages, > > + A A A A A A A unsigned long phys_start, unsigned long phys_end, > > + A A A A A A A unsigned long *start, unsigned long *end) > > +{ > > + A A A if ((user_start >= phys_end) || (user_end <= phys_start)) > > + A A A A A A A return 1; > > + A A A if (user_start <= phys_start) { > > + A A A A A A A *start = phys_start; > > + A A A A A A A *end = min(user_end, phys_end); > > + A A A } else { > > + A A A A A A A *start = user_start; > > + A A A A A A A *end = min(user_end, phys_end); > > + A A A } > > + A A A if (*end - *start < nr_pages) > > + A A A A A A A return 1; > > + A A A return 0; > > +} > > + > > + > > +/** > > + * __alloc_contig_pages - allocate a contiguous physical pages > > + * @base: the lowest pfn which caller wants. > > + * @end: A the highest pfn which caller wants. > > + * @nr_pages: the length of a chunk of pages to be allocated. > > the number of pages to be allocated. > ok. > > + * @align_order: alignment of start address of returned chunk in order. > > + * A Returned' page's order will be aligned to (1 << align_order).If smaller > > + * A than MAX_ORDER, it's raised to MAX_ORDER. > > + * @node: allocate near memory to the node, If -1, current node is used. > > + * @gfpflag: used to specify what zone the memory should be from. > > + * @nodemask: allocate memory within the nodemask. > > + * > > + * Search a memory range [base, end) and allocates physically contiguous > > + * pages. If end - base is larger than nr_pages, a chunk in [base, end) will > > + * be allocated > > + * > > + * This returns a page of the beginning of contiguous block. At failure, NULL > > + * is returned. > > + * > > + * Limitation: at allocation, nr_pages may be increased to be aligned to > > + * MAX_ORDER before searching a range. So, even if there is a enough chunk > > + * for nr_pages, it may not be able to be allocated. Extra tail pages of > > + * allocated chunk is returned to buddy allocator before returning the caller. > > + */ > > + > > +#define MIGRATION_RETRY A A A A (5) > > +struct page *__alloc_contig_pages(unsigned long base, unsigned long end, > > + A A A A A A A A A A A unsigned long nr_pages, int align_order, > > + A A A A A A A A A A A int node, gfp_t gfpflag, nodemask_t *mask) > > +{ > > + A A A unsigned long found, aligned_pages, start; > > + A A A struct page *ret = NULL; > > + A A A int migration_failed; > > + A A A unsigned long align_mask; > > + A A A struct zoneref *z; > > + A A A struct zone *zone; > > + A A A struct zonelist *zonelist; > > + A A A enum zone_type highzone_idx = gfp_zone(gfpflag); > > + A A A unsigned long zone_start, zone_end, rs, re, pos; > > + > > + A A A if (node == -1) > > + A A A A A A A node = numa_node_id(); > > + > > + A A A /* check unsupported flags */ > > + A A A if (gfpflag & __GFP_NORETRY) > > + A A A A A A A return NULL; > > + A A A if ((gfpflag & (__GFP_WAIT | __GFP_IO | __GFP_FS)) != > > + A A A A A A A (__GFP_WAIT | __GFP_IO | __GFP_FS)) > > + A A A A A A A return NULL; > > Why do we have to care about __GFP_IO|__GFP_FS? > If you consider compaction/reclaim later, I am OK. > because in page migration, we use GFP_HIGHUSER_MOVABLE now. > > + > > + A A A if (gfpflag & __GFP_THISNODE) > > + A A A A A A A zonelist = &NODE_DATA(node)->node_zonelists[1]; > > + A A A else > > + A A A A A A A zonelist = &NODE_DATA(node)->node_zonelists[0]; > > + A A A /* > > + A A A A * Base/nr_page/end should be aligned to MAX_ORDER > > + A A A A */ > > + A A A found = 0; > > + > > + A A A if (align_order < MAX_ORDER) > > + A A A A A A A align_order = MAX_ORDER; > > + > > + A A A align_mask = (1 << align_order) - 1; > > + A A A /* > > + A A A A * We allocates MAX_ORDER aligned pages and cut tail pages later. > > + A A A A */ > > + A A A aligned_pages = ALIGN(nr_pages, (1 << MAX_ORDER)); > > + A A A /* > > + A A A A * If end - base == nr_pages, we can't search range. base must be > > + A A A A * aligned. > > + A A A A */ > > + A A A if ((end - base == nr_pages) && (base & align_mask)) > > + A A A A A A A return NULL; > > + > > + A A A base = ALIGN(base, (1 << align_order)); > > + A A A if ((end <= base) || (end - base < aligned_pages)) > > + A A A A A A A return NULL; > > + > > + A A A /* > > + A A A A * searching contig memory range within [pos, end). > > + A A A A * pos is updated at migration failure to find next chunk in zone. > > + A A A A * pos is reset to the base at searching next zone. > > + A A A A * (see for_each_zone_zonelist_nodemask in mmzone.h) > > + A A A A * > > + A A A A * Note: we cannot assume zones/nodes are in linear memory layout. > > + A A A A */ > > + A A A z = first_zones_zonelist(zonelist, highzone_idx, mask, &zone); > > + A A A pos = base; > > +retry: > > + A A A if (!zone) > > + A A A A A A A return NULL; > > + > > + A A A zone_start = ALIGN(zone->zone_start_pfn, 1 << align_order); > > + A A A zone_end = zone->zone_start_pfn + zone->spanned_pages; > > + > > + A A A /* check [pos, end) is in this zone. */ > > + A A A if ((pos >= end) || > > + A A A A A A (__calc_search_range(pos, end, aligned_pages, > > + A A A A A A A A A A A zone_start, zone_end, &rs, &re))) { > > +next_zone: > > + A A A A A A A /* go to the next zone */ > > + A A A A A A A z = next_zones_zonelist(++z, highzone_idx, mask, &zone); > > + A A A A A A A /* reset the pos */ > > + A A A A A A A pos = base; > > + A A A A A A A goto retry; > > + A A A } > > + A A A /* [pos, end) is trimmed to [rs, re) in this zone. */ > > + A A A pos = rs; > > The 'pos' doesn't used any more at below. > Ah, yes. I'll check this was for what and remove this. Thanks, -Kame -- 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org