Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752748Ab0GNHuv (ORCPT ); Wed, 14 Jul 2010 03:50:51 -0400 Received: from mailout1.samsung.com ([203.254.224.24]:46637 "EHLO mailout1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752341Ab0GNHuq (ORCPT ); Wed, 14 Jul 2010 03:50:46 -0400 Date: Wed, 14 Jul 2010 16:50:25 +0900 From: Kukjin Kim Subject: RE: [RFC] Tight check of pfn_valid on sparsemem In-reply-to: <20100714092301.69e7e628.kamezawa.hiroyu@jp.fujitsu.com> To: "'KAMEZAWA Hiroyuki'" , "'Minchan Kim'" Cc: "'Dave Hansen'" , "'Johannes Weiner'" , linux@arm.linux.org.uk, "'Yinghai Lu'" , "'H. Peter Anvin'" , "'Andrew Morton'" , "'Shaohua Li'" , "'Yakui Zhao'" , linux-kernel@vger.kernel.org, linux-mm@kvack.org, arm-kernel@lists.infradead.org, "'Mel Gorman'" Message-id: <000e01cb2329$3d8c5770$b8a50650$%kim@samsung.com> MIME-version: 1.0 X-Mailer: Microsoft Office Outlook 12.0 Content-type: text/plain; charset=us-ascii Content-language: ko Content-transfer-encoding: 7BIT Thread-index: Acsi62u2Lyw0fe1cT2u5zvkt64draQABwSHA References: <20100712155348.GA2815@barrios-desktop> <20100713093006.GB14504@cmpxchg.org> <20100713154335.GB2815@barrios-desktop> <1279038933.10995.9.camel@nimitz> <20100713164423.GC2815@barrios-desktop> <20100714092301.69e7e628.kamezawa.hiroyu@jp.fujitsu.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5599 Lines: 181 KAMEZAWA Hiroyuki wrote: > > On Wed, 14 Jul 2010 01:44:23 +0900 > Minchan Kim wrote: > > > > If you _really_ can't make the section size smaller, and the vast > > > majority of the sections are fully populated, you could hack something > > > in. We could, for instance, have a global list that's mostly readonly > > > which tells you which sections need to be have their sizes closely > > > inspected. That would work OK if, for instance, you only needed to > > > check a couple of memory sections in the system. It'll start to suck if > > > you made the lists very long. > > > > Thanks for advise. As I say, I hope Russell accept 16M section. > > Hi, Thanks for your inputs. > > It seems what I needed was good sleep.... > How about this if 16M section is not acceptable ? > > == NOT TESTED AT ALL, EVEN NOT COMPILED == Yeah... Couldn't build with s5pv210_defconfig when used mmotm tree, And couldn't apply your patch against latest mainline 35-rc5. Could you please remake your patch against mainline 35-rc5? Or...please let me know how I can test on my board(smdkv210). > > register address of mem_section to memmap itself's page struct's pg->private > field. > This means the page is used for memmap of the section. > Otherwise, the page is used for other purpose and memmap has a hole. > > --- > arch/arm/mm/init.c | 11 ++++++++++- > include/linux/mmzone.h | 19 ++++++++++++++++++- > mm/sparse.c | 37 > +++++++++++++++++++++++++++++++++++++ > 3 files changed, 65 insertions(+), 2 deletions(-) > > Index: mmotm-2.6.35-0701/include/linux/mmzone.h > ============================================================= > ====== > --- mmotm-2.6.35-0701.orig/include/linux/mmzone.h > +++ mmotm-2.6.35-0701/include/linux/mmzone.h > @@ -1047,11 +1047,28 @@ static inline struct mem_section *__pfn_ > return __nr_to_section(pfn_to_section_nr(pfn)); > } > > +#ifdef CONFIG_SPARSEMEM_HAS_PIT > +void mark_memmap_pit(unsigned long start, unsigned long end, bool valid); > +static inline int page_valid(struct mem_section *ms, unsigned long pfn) > +{ > + struct page *page = pfn_to_page(pfn); > + struct page *__pg = virt_to_page(page); > + return __pg->private == ms; > +} > +#else > +static inline int page_valid(struct mem_section *ms, unsigned long pfn) > +{ > + return 1; > +} > +#endif > + > static inline int pfn_valid(unsigned long pfn) > { > + struct mem_section *ms; > if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) > return 0; > - return valid_section(__nr_to_section(pfn_to_section_nr(pfn))); > + ms = __nr_to_section(pfn_to_section_nr(pfn)); > + return valid_section(ms) && page_valid(ms, pfn); > } > > static inline int pfn_present(unsigned long pfn) > Index: mmotm-2.6.35-0701/mm/sparse.c > ============================================================= > ====== > --- mmotm-2.6.35-0701.orig/mm/sparse.c > +++ mmotm-2.6.35-0701/mm/sparse.c > @@ -615,6 +615,43 @@ void __init sparse_init(void) > free_bootmem(__pa(usemap_map), size); > } > > +#ifdef CONFIT_SPARSEMEM_HAS_PIT > +/* > + * Fill memmap's pg->private with a pointer to mem_section. > + * pfn_valid() will check this later. (see include/linux/mmzone.h) > + * The caller should call > + * mark_memmap_pit(start, end, true) # for all allocated mem_map > + * and, after that, > + * mark_memmap_pit(start, end, false) # for all pits in mem_map. > + * please see usage in ARM. > + */ > +void mark_memmap_pit(unsigned long start, unsigned long end, bool valid) > +{ > + struct mem_section *ms; > + unsigned long pos, next; > + struct page *pg; > + void *memmap, *end; > + unsigned long mapsize = sizeof(struct page) * PAGES_PER_SECTION; > + > + for (pos = start; > + pos < end; pos = next) { > + next = (pos + PAGES_PER_SECTION) & > PAGE_SECTION_MASK; > + ms = __pfn_to_section(pos); > + if (!valid_section(ms)) > + continue; > + for (memmap = pfn_to_page(pfn), end = pfn_to_page(next-1); > + memmap != end + 1; > + memmap += PAGE_SIZE) { > + pg = virt_to_page(memmap); > + if (valid) > + pg->private = ms; > + else > + pg->private = NULL; > + } > + } > +} > +#endif > + > #ifdef CONFIG_MEMORY_HOTPLUG > #ifdef CONFIG_SPARSEMEM_VMEMMAP > static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid, > Index: mmotm-2.6.35-0701/arch/arm/mm/init.c > ============================================================= > ====== > --- mmotm-2.6.35-0701.orig/arch/arm/mm/init.c > +++ mmotm-2.6.35-0701/arch/arm/mm/init.c > @@ -234,6 +234,13 @@ static void __init arm_bootmem_free(stru > arch_adjust_zones(zone_size, zhole_size); > > free_area_init_node(0, zone_size, min, zhole_size); > + > +#ifdef CONFIG_SPARSEMEM > + for_each_bank(i, mi) { > + mark_memmap_pit(bank_start_pfn(mi->bank[i]), > + bank_end_pfn(mi->bank[i]), true); > + } > +#endif > } > > #ifndef CONFIG_SPARSEMEM > @@ -386,8 +393,10 @@ free_memmap(unsigned long start_pfn, uns > * If there are free pages between these, > * free the section of the memmap array. > */ > - if (pg < pgend) > + if (pg < pgend) { > + mark_memap_pit(pg >> PAGE_SHIFT, pgend >> PAGE_SHIFT, > false); > free_bootmem(pg, pgend - pg); > + } > } > > /* Thanks. Best regards, Kgene. -- Kukjin Kim , Senior Engineer, SW Solution Development Team, Samsung Electronics Co., Ltd. -- 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/