From patchwork Wed Jul 18 10:16:41 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yasuaki Ishimatsu X-Patchwork-Id: 171636 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [IPv6:::1]) by ozlabs.org (Postfix) with ESMTP id 93B9B2C077E for ; Wed, 18 Jul 2012 20:17:29 +1000 (EST) Received: from fgwmail5.fujitsu.co.jp (fgwmail5.fujitsu.co.jp [192.51.44.35]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 403D32C034E for ; Wed, 18 Jul 2012 20:17:04 +1000 (EST) Received: from m2.gw.fujitsu.co.jp (unknown [10.0.50.72]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id 88B0E3EE0BC for ; Wed, 18 Jul 2012 19:17:02 +0900 (JST) Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 61DFD45DE50 for ; Wed, 18 Jul 2012 19:17:02 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 48E9245DE4E for ; Wed, 18 Jul 2012 19:17:02 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 2ED3DE38002 for ; Wed, 18 Jul 2012 19:17:02 +0900 (JST) Received: from g01jpexchyt07.g01.fujitsu.local (g01jpexchyt07.g01.fujitsu.local [10.128.194.46]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id CCDE3E18004 for ; Wed, 18 Jul 2012 19:17:01 +0900 (JST) Received: from [127.0.0.1] (10.124.101.33) by g01jpexchyt07.g01.fujitsu.local (10.128.194.46) with Microsoft SMTP Server id 14.2.309.2; Wed, 18 Jul 2012 19:16:57 +0900 X-SecurityPolicyCheck: OK by SHieldMailChecker v1.7.4 Message-ID: <50068D09.1050704@jp.fujitsu.com> Date: Wed, 18 Jul 2012 19:16:41 +0900 From: Yasuaki Ishimatsu User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:13.0) Gecko/20120614 Thunderbird/13.0.1 MIME-Version: 1.0 To: , , , Subject: [RFC PATCH v4 11/13] memory-hotplug : free memmap of sparse-vmemmap References: <50068974.1070409@jp.fujitsu.com> In-Reply-To: <50068974.1070409@jp.fujitsu.com> Cc: len.brown@intel.com, wency@cn.fujitsu.com, paulus@samba.org, minchan.kim@gmail.com, kosaki.motohiro@jp.fujitsu.com, rientjes@google.com, cl@linux.com, akpm@linux-foundation.org, liuj97@gmail.com X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" All pages of virtual mapping in removed memory cannot be freed, since some pages used as PGD/PUD includes not only removed memory but also other memory. So the patch checks whether page can be freed or not. How to check whether page can be freed or not? 1. When removing memory, the page structs of the revmoved memory are filled with 0FD. 2. All page structs are filled with 0xFD on PT/PMD, PT/PMD can be cleared. In this case, the page used as PT/PMD can be freed. Applying patch, __remove_section() of CONFIG_SPARSEMEM_VMEMMAP is integrated into one. So __remove_section() of CONFIG_SPARSEMEM_VMEMMAP is deleted. CC: David Rientjes CC: Jiang Liu CC: Len Brown CC: Benjamin Herrenschmidt CC: Paul Mackerras CC: Christoph Lameter Cc: Minchan Kim CC: Andrew Morton CC: KOSAKI Motohiro CC: Wen Congyang Signed-off-by: Yasuaki Ishimatsu --- arch/x86/mm/init_64.c | 121 ++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/mm.h | 2 mm/memory_hotplug.c | 19 ------- mm/sparse.c | 5 +- 4 files changed, 128 insertions(+), 19 deletions(-) Index: linux-3.5-rc6/include/linux/mm.h =================================================================== --- linux-3.5-rc6.orig/include/linux/mm.h 2012-07-18 18:01:28.000000000 +0900 +++ linux-3.5-rc6/include/linux/mm.h 2012-07-18 18:03:05.551168773 +0900 @@ -1588,6 +1588,8 @@ int vmemmap_populate(struct page *start_ void vmemmap_populate_print_last(void); void register_page_bootmem_memmap(unsigned long section_nr, struct page *map, unsigned long size); +void vmemmap_kfree(struct page *memmpa, unsigned long nr_pages); +void vmemmap_free_bootmem(struct page *memmpa, unsigned long nr_pages); enum mf_flags { MF_COUNT_INCREASED = 1 << 0, Index: linux-3.5-rc6/mm/sparse.c =================================================================== --- linux-3.5-rc6.orig/mm/sparse.c 2012-07-18 17:59:25.000000000 +0900 +++ linux-3.5-rc6/mm/sparse.c 2012-07-18 18:03:05.553168749 +0900 @@ -614,12 +614,13 @@ static inline struct page *kmalloc_secti /* This will make the necessary allocations eventually. */ return sparse_mem_map_populate(pnum, nid); } -static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages) +static void __kfree_section_memmap(struct page *page, unsigned long nr_pages) { - return; /* XXX: Not implemented yet */ + vmemmap_kfree(page, nr_pages); } static void free_map_bootmem(struct page *page, unsigned long nr_pages) { + vmemmap_free_bootmem(page, nr_pages); } #else static struct page *__kmalloc_section_memmap(unsigned long nr_pages) Index: linux-3.5-rc6/arch/x86/mm/init_64.c =================================================================== --- linux-3.5-rc6.orig/arch/x86/mm/init_64.c 2012-07-18 18:01:28.000000000 +0900 +++ linux-3.5-rc6/arch/x86/mm/init_64.c 2012-07-18 18:03:05.564168611 +0900 @@ -978,6 +978,127 @@ vmemmap_populate(struct page *start_page return 0; } +#define PAGE_INUSE 0xFD + +unsigned long find_and_clear_pte_page(unsigned long addr, unsigned long end, + struct page **pp, int *page_size) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + void *page_addr; + unsigned long next; + + *pp = NULL; + + pgd = pgd_offset_k(addr); + if (pgd_none(*pgd)) + return pgd_addr_end(addr, end); + + pud = pud_offset(pgd, addr); + if (pud_none(*pud)) + return pud_addr_end(addr,end); + + if (!cpu_has_pse) { + next = (addr + PAGE_SIZE) & PAGE_MASK; + pmd = pmd_offset(pud, addr); + if (pmd_none(*pmd)) + return next; + + pte = pte_offset_kernel(pmd, addr); + if (pte_none(*pte)) + return next; + + *page_size = PAGE_SIZE; + *pp = pte_page(*pte); + } else { + next = pmd_addr_end(addr, end); + + pmd = pmd_offset(pud, addr); + if (pmd_none(*pmd)) + return next; + + *page_size = PMD_SIZE; + *pp = pmd_page(*pmd); + } + + /* + * Removed page structs are filled with 0xFD. + */ + memset((void *)addr, PAGE_INUSE, next - addr); + + page_addr = page_address(*pp); + + /* + * Check the page is filled with 0xFD or not. + * memchr_inv() returns the address. In this case, we cannot + * clear PTE/PUD entry, since the page is used by other. + * So we cannot also free the page. + * + * memchr_inv() returns NULL. In this case, we can clear + * PTE/PUD entry, since the page is not used by other. + * So we can also free the page. + */ + if (memchr_inv(page_addr, PAGE_INUSE, *page_size)) { + *pp = NULL; + return next; + } + + if (!cpu_has_pse) + pte_clear(&init_mm, addr, pte); + else + pmd_clear(pmd); + + return next; +} + +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages) +{ + unsigned long addr = (unsigned long)memmap; + unsigned long end = (unsigned long)(memmap + nr_pages); + unsigned long next; + struct page *page; + int page_size; + + for (; addr < end; addr = next) { + page = NULL; + page_size = 0; + next = find_and_clear_pte_page(addr, end, &page, &page_size); + if (!page) + continue; + + free_pages((unsigned long)page_address(page), + get_order(page_size)); + __flush_tlb_one((unsigned long)page_address(page)); + } + +} + +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages) +{ + unsigned long addr = (unsigned long)memmap; + unsigned long end = (unsigned long)(memmap + nr_pages); + unsigned long next; + struct page *page; + int page_size; + unsigned long magic; + + for (; addr < end; addr = next) { + page = NULL; + page_size = 0; + next = find_and_clear_pte_page(addr, end, &page, &page_size); + if (!page) + continue; + + magic = (unsigned long) page->lru.next; + if (magic == SECTION_INFO) + put_page_bootmem(page); + flush_tlb_kernel_range(addr, end); + } + +} + void register_page_bootmem_memmap(unsigned long section_nr, struct page *start_page, unsigned long size) { Index: linux-3.5-rc6/mm/memory_hotplug.c =================================================================== --- linux-3.5-rc6.orig/mm/memory_hotplug.c 2012-07-18 18:01:28.000000000 +0900 +++ linux-3.5-rc6/mm/memory_hotplug.c 2012-07-18 18:25:11.036597977 +0900 @@ -300,7 +300,6 @@ static int __meminit __add_section(int n return register_new_memory(nid, __pfn_to_section(phys_start_pfn)); } -#ifdef CONFIG_SPARSEMEM_VMEMMAP static int __remove_section(struct zone *zone, struct mem_section *ms) { int ret = -EINVAL; @@ -309,29 +308,15 @@ static int __remove_section(struct zone return ret; ret = unregister_memory_section(ms); - - return ret; -} -#else -static int __remove_section(struct zone *zone, struct mem_section *ms) -{ - unsigned long flags; - struct pglist_data *pgdat = zone->zone_pgdat; - int ret = -EINVAL; - - if (!valid_section(ms)) - return ret; - - ret = unregister_memory_section(ms); if (ret) return ret; pgdat_resize_lock(pgdat, &flags); sparse_remove_one_section(zone, ms); pgdat_resize_unlock(pgdat, &flags); - return 0; + + return ret; } -#endif /* * Reasonably generic function for adding memory. It is