From patchwork Wed Jun 5 21:57:54 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 10977951 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CAE0C1398 for ; Wed, 5 Jun 2019 22:12:14 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B90EE202A5 for ; Wed, 5 Jun 2019 22:12:14 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id AD661285DB; Wed, 5 Jun 2019 22:12:14 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 74793202A5 for ; Wed, 5 Jun 2019 22:12:13 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 678212128DD5F; Wed, 5 Jun 2019 15:12:13 -0700 (PDT) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=134.134.136.126; helo=mga18.intel.com; envelope-from=dan.j.williams@intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 327972128DD56 for ; Wed, 5 Jun 2019 15:12:11 -0700 (PDT) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Jun 2019 15:12:10 -0700 X-ExtLoop1: 1 Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by orsmga003.jf.intel.com with ESMTP; 05 Jun 2019 15:12:10 -0700 Subject: [PATCH v9 01/12] mm/sparsemem: Introduce struct mem_section_usage From: Dan Williams To: akpm@linux-foundation.org Date: Wed, 05 Jun 2019 14:57:54 -0700 Message-ID: <155977187407.2443951.16503493275720588454.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <155977186863.2443951.9036044808311959913.stgit@dwillia2-desk3.amr.corp.intel.com> References: <155977186863.2443951.9036044808311959913.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-2-gc94f MIME-Version: 1.0 X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mhocko@suse.com, Pavel Tatashin , linux-nvdimm@lists.01.org, Benjamin Herrenschmidt , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Paul Mackerras , Michael Ellerman , Vlastimil Babka , osalvador@suse.de Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP Towards enabling memory hotplug to track partial population of a section, introduce 'struct mem_section_usage'. A pointer to a 'struct mem_section_usage' instance replaces the existing pointer to a 'pageblock_flags' bitmap. Effectively it adds one more 'unsigned long' beyond the 'pageblock_flags' (usemap) allocation to house a new 'subsection_map' bitmap. The new bitmap enables the memory hot{plug,remove} implementation to act on incremental sub-divisions of a section. The default SUBSECTION_SHIFT is chosen to keep the 'subsection_map' no larger than a single 'unsigned long' on the major architectures. Alternatively an architecture can define ARCH_SUBSECTION_SHIFT to override the default PMD_SHIFT. Note that PowerPC needs to use ARCH_SUBSECTION_SHIFT to workaround PMD_SHIFT being a non-constant expression on PowerPC. The primary motivation for this functionality is to support platforms that mix "System RAM" and "Persistent Memory" within a single section, or multiple PMEM ranges with different mapping lifetimes within a single section. The section restriction for hotplug has caused an ongoing saga of hacks and bugs for devm_memremap_pages() users. Beyond the fixups to teach existing paths how to retrieve the 'usemap' from a section, and updates to usemap allocation path, there are no expected behavior changes. Cc: Michal Hocko Cc: Vlastimil Babka Cc: Logan Gunthorpe Cc: Oscar Salvador Cc: Pavel Tatashin Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Signed-off-by: Dan Williams Reviewed-by: Oscar Salvador Reviewed-by: Wei Yang --- arch/powerpc/include/asm/sparsemem.h | 3 + include/linux/mmzone.h | 48 +++++++++++++++++++- mm/memory_hotplug.c | 18 ++++---- mm/page_alloc.c | 2 - mm/sparse.c | 81 +++++++++++++++++----------------- 5 files changed, 99 insertions(+), 53 deletions(-) diff --git a/arch/powerpc/include/asm/sparsemem.h b/arch/powerpc/include/asm/sparsemem.h index 3192d454a733..1aa3c9303bf8 100644 --- a/arch/powerpc/include/asm/sparsemem.h +++ b/arch/powerpc/include/asm/sparsemem.h @@ -10,6 +10,9 @@ */ #define SECTION_SIZE_BITS 24 +/* Reflect the largest possible PMD-size as the subsection-size constant */ +#define ARCH_SUBSECTION_SHIFT 24 + #endif /* CONFIG_SPARSEMEM */ #ifdef CONFIG_MEMORY_HOTPLUG diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 427b79c39b3c..ac163f2f274f 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1161,6 +1161,44 @@ static inline unsigned long section_nr_to_pfn(unsigned long sec) #define SECTION_ALIGN_UP(pfn) (((pfn) + PAGES_PER_SECTION - 1) & PAGE_SECTION_MASK) #define SECTION_ALIGN_DOWN(pfn) ((pfn) & PAGE_SECTION_MASK) +/* + * SUBSECTION_SHIFT must be constant since it is used to declare + * subsection_map and related bitmaps without triggering the generation + * of variable-length arrays. The most natural size for a subsection is + * a PMD-page. For architectures that do not have a constant PMD-size + * ARCH_SUBSECTION_SHIFT can be set to a constant max size, or otherwise + * fallback to 2MB. + */ +#if defined(ARCH_SUBSECTION_SHIFT) +#define SUBSECTION_SHIFT (ARCH_SUBSECTION_SHIFT) +#elif defined(PMD_SHIFT) +#define SUBSECTION_SHIFT (PMD_SHIFT) +#else +/* + * Memory hotplug enabled platforms avoid this default because they + * either define ARCH_SUBSECTION_SHIFT, or PMD_SHIFT is a constant, but + * this is kept as a backstop to allow compilation on + * !ARCH_ENABLE_MEMORY_HOTPLUG archs. + */ +#define SUBSECTION_SHIFT 21 +#endif + +#define PFN_SUBSECTION_SHIFT (SUBSECTION_SHIFT - PAGE_SHIFT) +#define PAGES_PER_SUBSECTION (1UL << PFN_SUBSECTION_SHIFT) +#define PAGE_SUBSECTION_MASK ((~(PAGES_PER_SUBSECTION-1))) + +#if SUBSECTION_SHIFT > SECTION_SIZE_BITS +#error Subsection size exceeds section size +#else +#define SUBSECTIONS_PER_SECTION (1UL << (SECTION_SIZE_BITS - SUBSECTION_SHIFT)) +#endif + +struct mem_section_usage { + DECLARE_BITMAP(subsection_map, SUBSECTIONS_PER_SECTION); + /* See declaration of similar field in struct zone */ + unsigned long pageblock_flags[0]; +}; + struct page; struct page_ext; struct mem_section { @@ -1178,8 +1216,7 @@ struct mem_section { */ unsigned long section_mem_map; - /* See declaration of similar field in struct zone */ - unsigned long *pageblock_flags; + struct mem_section_usage *usage; #ifdef CONFIG_PAGE_EXTENSION /* * If SPARSEMEM, pgdat doesn't have page_ext pointer. We use @@ -1210,6 +1247,11 @@ extern struct mem_section **mem_section; extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]; #endif +static inline unsigned long *section_to_usemap(struct mem_section *ms) +{ + return ms->usage->pageblock_flags; +} + static inline struct mem_section *__nr_to_section(unsigned long nr) { #ifdef CONFIG_SPARSEMEM_EXTREME @@ -1221,7 +1263,7 @@ static inline struct mem_section *__nr_to_section(unsigned long nr) return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK]; } extern int __section_nr(struct mem_section* ms); -extern unsigned long usemap_size(void); +extern size_t mem_section_usage_size(void); /* * We use the lower bits of the mem_map pointer to store diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index a88c5f334e5a..7b963c2d3a0d 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -166,9 +166,10 @@ void put_page_bootmem(struct page *page) #ifndef CONFIG_SPARSEMEM_VMEMMAP static void register_page_bootmem_info_section(unsigned long start_pfn) { - unsigned long *usemap, mapsize, section_nr, i; + unsigned long mapsize, section_nr, i; struct mem_section *ms; struct page *page, *memmap; + struct mem_section_usage *usage; section_nr = pfn_to_section_nr(start_pfn); ms = __nr_to_section(section_nr); @@ -188,10 +189,10 @@ static void register_page_bootmem_info_section(unsigned long start_pfn) for (i = 0; i < mapsize; i++, page++) get_page_bootmem(section_nr, page, SECTION_INFO); - usemap = ms->pageblock_flags; - page = virt_to_page(usemap); + usage = ms->usage; + page = virt_to_page(usage); - mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT; + mapsize = PAGE_ALIGN(mem_section_usage_size()) >> PAGE_SHIFT; for (i = 0; i < mapsize; i++, page++) get_page_bootmem(section_nr, page, MIX_SECTION_INFO); @@ -200,9 +201,10 @@ static void register_page_bootmem_info_section(unsigned long start_pfn) #else /* CONFIG_SPARSEMEM_VMEMMAP */ static void register_page_bootmem_info_section(unsigned long start_pfn) { - unsigned long *usemap, mapsize, section_nr, i; + unsigned long mapsize, section_nr, i; struct mem_section *ms; struct page *page, *memmap; + struct mem_section_usage *usage; section_nr = pfn_to_section_nr(start_pfn); ms = __nr_to_section(section_nr); @@ -211,10 +213,10 @@ static void register_page_bootmem_info_section(unsigned long start_pfn) register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION); - usemap = ms->pageblock_flags; - page = virt_to_page(usemap); + usage = ms->usage; + page = virt_to_page(usage); - mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT; + mapsize = PAGE_ALIGN(mem_section_usage_size()) >> PAGE_SHIFT; for (i = 0; i < mapsize; i++, page++) get_page_bootmem(section_nr, page, MIX_SECTION_INFO); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index c061f66c2d0c..c6d8224d792e 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -404,7 +404,7 @@ static inline unsigned long *get_pageblock_bitmap(struct page *page, unsigned long pfn) { #ifdef CONFIG_SPARSEMEM - return __pfn_to_section(pfn)->pageblock_flags; + return section_to_usemap(__pfn_to_section(pfn)); #else return page_zone(page)->pageblock_flags; #endif /* CONFIG_SPARSEMEM */ diff --git a/mm/sparse.c b/mm/sparse.c index 1552c855d62a..71da15cc7432 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -288,33 +288,31 @@ struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pn static void __meminit sparse_init_one_section(struct mem_section *ms, unsigned long pnum, struct page *mem_map, - unsigned long *pageblock_bitmap) + struct mem_section_usage *usage) { ms->section_mem_map &= ~SECTION_MAP_MASK; ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) | SECTION_HAS_MEM_MAP; - ms->pageblock_flags = pageblock_bitmap; + ms->usage = usage; } -unsigned long usemap_size(void) +static unsigned long usemap_size(void) { return BITS_TO_LONGS(SECTION_BLOCKFLAGS_BITS) * sizeof(unsigned long); } -#ifdef CONFIG_MEMORY_HOTPLUG -static unsigned long *__kmalloc_section_usemap(void) +size_t mem_section_usage_size(void) { - return kmalloc(usemap_size(), GFP_KERNEL); + return sizeof(struct mem_section_usage) + usemap_size(); } -#endif /* CONFIG_MEMORY_HOTPLUG */ #ifdef CONFIG_MEMORY_HOTREMOVE -static unsigned long * __init +static struct mem_section_usage * __init sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat, unsigned long size) { + struct mem_section_usage *usage; unsigned long goal, limit; - unsigned long *p; int nid; /* * A page may contain usemaps for other sections preventing the @@ -330,15 +328,16 @@ sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat, limit = goal + (1UL << PA_SECTION_SHIFT); nid = early_pfn_to_nid(goal >> PAGE_SHIFT); again: - p = memblock_alloc_try_nid(size, SMP_CACHE_BYTES, goal, limit, nid); - if (!p && limit) { + usage = memblock_alloc_try_nid(size, SMP_CACHE_BYTES, goal, limit, nid); + if (!usage && limit) { limit = 0; goto again; } - return p; + return usage; } -static void __init check_usemap_section_nr(int nid, unsigned long *usemap) +static void __init check_usemap_section_nr(int nid, + struct mem_section_usage *usage) { unsigned long usemap_snr, pgdat_snr; static unsigned long old_usemap_snr; @@ -352,7 +351,7 @@ static void __init check_usemap_section_nr(int nid, unsigned long *usemap) old_pgdat_snr = NR_MEM_SECTIONS; } - usemap_snr = pfn_to_section_nr(__pa(usemap) >> PAGE_SHIFT); + usemap_snr = pfn_to_section_nr(__pa(usage) >> PAGE_SHIFT); pgdat_snr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT); if (usemap_snr == pgdat_snr) return; @@ -380,14 +379,15 @@ static void __init check_usemap_section_nr(int nid, unsigned long *usemap) usemap_snr, pgdat_snr, nid); } #else -static unsigned long * __init +static struct mem_section_usage * __init sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat, unsigned long size) { return memblock_alloc_node(size, SMP_CACHE_BYTES, pgdat->node_id); } -static void __init check_usemap_section_nr(int nid, unsigned long *usemap) +static void __init check_usemap_section_nr(int nid, + struct mem_section_usage *usage) { } #endif /* CONFIG_MEMORY_HOTREMOVE */ @@ -474,14 +474,13 @@ static void __init sparse_init_nid(int nid, unsigned long pnum_begin, unsigned long pnum_end, unsigned long map_count) { - unsigned long pnum, usemap_longs, *usemap; + struct mem_section_usage *usage; + unsigned long pnum; struct page *map; - usemap_longs = BITS_TO_LONGS(SECTION_BLOCKFLAGS_BITS); - usemap = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nid), - usemap_size() * - map_count); - if (!usemap) { + usage = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nid), + mem_section_usage_size() * map_count); + if (!usage) { pr_err("%s: node[%d] usemap allocation failed", __func__, nid); goto failed; } @@ -497,9 +496,9 @@ static void __init sparse_init_nid(int nid, unsigned long pnum_begin, pnum_begin = pnum; goto failed; } - check_usemap_section_nr(nid, usemap); - sparse_init_one_section(__nr_to_section(pnum), pnum, map, usemap); - usemap += usemap_longs; + check_usemap_section_nr(nid, usage); + sparse_init_one_section(__nr_to_section(pnum), pnum, map, usage); + usage = (void *) usage + mem_section_usage_size(); } sparse_buffer_fini(); return; @@ -697,9 +696,9 @@ int __meminit sparse_add_one_section(int nid, unsigned long start_pfn, struct vmem_altmap *altmap) { unsigned long section_nr = pfn_to_section_nr(start_pfn); + struct mem_section_usage *usage; struct mem_section *ms; struct page *memmap; - unsigned long *usemap; int ret; /* @@ -713,8 +712,8 @@ int __meminit sparse_add_one_section(int nid, unsigned long start_pfn, memmap = kmalloc_section_memmap(section_nr, nid, altmap); if (!memmap) return -ENOMEM; - usemap = __kmalloc_section_usemap(); - if (!usemap) { + usage = kzalloc(mem_section_usage_size(), GFP_KERNEL); + if (!usage) { __kfree_section_memmap(memmap, altmap); return -ENOMEM; } @@ -732,11 +731,11 @@ int __meminit sparse_add_one_section(int nid, unsigned long start_pfn, page_init_poison(memmap, sizeof(struct page) * PAGES_PER_SECTION); section_mark_present(ms); - sparse_init_one_section(ms, section_nr, memmap, usemap); + sparse_init_one_section(ms, section_nr, memmap, usage); out: if (ret < 0) { - kfree(usemap); + kfree(usage); __kfree_section_memmap(memmap, altmap); } return ret; @@ -772,20 +771,20 @@ static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages) } #endif -static void free_section_usemap(struct page *memmap, unsigned long *usemap, - struct vmem_altmap *altmap) +static void free_section_usage(struct page *memmap, + struct mem_section_usage *usage, struct vmem_altmap *altmap) { - struct page *usemap_page; + struct page *usage_page; - if (!usemap) + if (!usage) return; - usemap_page = virt_to_page(usemap); + usage_page = virt_to_page(usage); /* * Check to see if allocation came from hot-plug-add */ - if (PageSlab(usemap_page) || PageCompound(usemap_page)) { - kfree(usemap); + if (PageSlab(usage_page) || PageCompound(usage_page)) { + kfree(usage); if (memmap) __kfree_section_memmap(memmap, altmap); return; @@ -804,18 +803,18 @@ void sparse_remove_one_section(struct mem_section *ms, unsigned long map_offset, struct vmem_altmap *altmap) { struct page *memmap = NULL; - unsigned long *usemap = NULL; + struct mem_section_usage *usage = NULL; if (ms->section_mem_map) { - usemap = ms->pageblock_flags; + usage = ms->usage; memmap = sparse_decode_mem_map(ms->section_mem_map, __section_nr(ms)); ms->section_mem_map = 0; - ms->pageblock_flags = NULL; + ms->usage = NULL; } clear_hwpoisoned_pages(memmap + map_offset, PAGES_PER_SECTION - map_offset); - free_section_usemap(memmap, usemap, altmap); + free_section_usage(memmap, usage, altmap); } #endif /* CONFIG_MEMORY_HOTPLUG */