From patchwork Wed Jun 5 21:58:42 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 10977981 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 0AB986C5 for ; Wed, 5 Jun 2019 22:13:04 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id ECD7921BED for ; Wed, 5 Jun 2019 22:13:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E07E22890A; Wed, 5 Jun 2019 22:13:03 +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=unavailable version=3.3.1 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E91AD21BED for ; Wed, 5 Jun 2019 22:13:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D89AF6B0277; Wed, 5 Jun 2019 18:13:01 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id D38606B0278; Wed, 5 Jun 2019 18:13:01 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C4EE06B0279; Wed, 5 Jun 2019 18:13:01 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from mail-pl1-f200.google.com (mail-pl1-f200.google.com [209.85.214.200]) by kanga.kvack.org (Postfix) with ESMTP id 8843F6B0277 for ; Wed, 5 Jun 2019 18:13:01 -0400 (EDT) Received: by mail-pl1-f200.google.com with SMTP id q2so179102plr.19 for ; Wed, 05 Jun 2019 15:13:01 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:subject:from :to:cc:date:message-id:in-reply-to:references:user-agent :mime-version:content-transfer-encoding; bh=iSwXzQQbTQrIqHqiTk0MZs9qCXr7kdVRZXlzTAF7W04=; b=dnl+oF0CHZ45unWqa2qOXFJcO4OcExft3TKMf84KPats3TJ/n9FA6mP330gS22vO7+ e9XTKkpLvxKgI4WDjYHyAb4lcvknUqJDVSlVilF3EGw+t9XgM1fpC9ccG/pm0W9SCMis TJbMl2ccK6q3km6f6mjH8NAvX20mxtyqKhpWPVuNVbrLeXMvFpa5HrxLMUJbXR6wnzmh 1O8HtezLLLDFW6acpgYaAa47bPrkH++4d53mwz+bHrLhg4NqjTyDypGkODZxB6mFUQv8 YtZbH5c762HLDo1IU7R6hKOGIBXpW2F1+YZojBf1MHPAlHrw4EFRn1fTrYuEMziyZt/m cQPQ== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of dan.j.williams@intel.com designates 134.134.136.20 as permitted sender) smtp.mailfrom=dan.j.williams@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com X-Gm-Message-State: APjAAAW2722t1+dMLghRobw+fzPRhp0l1e0LfwcjCtyEcaW4Qr8bv1Tw A6Ybu7jZUspSiDTBZT7gU3qhzed+57M3T5p0PzKlrQXo4UyTLZq59gA9J57Z1Mh/BRpBtXYpkFA pp/lj554pKUpY9Ft11rv4rGaa+sE8nDOOwUMAMoag8lgcSOTj/Fqz2D4APQOvx/Z0JA== X-Received: by 2002:a17:902:a986:: with SMTP id bh6mr45103546plb.100.1559772781001; Wed, 05 Jun 2019 15:13:01 -0700 (PDT) X-Google-Smtp-Source: APXvYqzAJELr1MWYX3fJ/K1EHVkweJjKVoZRsKnYebwHJshL4fk0STMxhTKhCTo6kM55ZiUnNIoJ X-Received: by 2002:a17:902:a986:: with SMTP id bh6mr45103427plb.100.1559772779878; Wed, 05 Jun 2019 15:12:59 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1559772779; cv=none; d=google.com; s=arc-20160816; b=s+k9Jsv082mJaf9jORfpxcXiNKNSoUslHfGFyZL9735BUCd55Qsk4b781BzB19hbLJ w3fOX0e506rWmBdjjQ7ZFq4owNYNyhcUSaEJJd45pDWVp+20zDPSfdgqmGT8wsLL5FbO 3k6KZM0FADYqR4EfLflctVAyGpqTIeZg5kGToQzFw9XWqvJzTX47eVMU4xttOXRjsUqg yMt9qtgoY+6+eAWBJyXORiQxpTwJxKiJ0wDksbIRj1ftby54DgrQaOqub/jh8wuInUS+ ABJBuguN7c22XOwrkCpUHOOrm14uQtRVHbaqiJs2ulwlbrNskaEzPYcJc6R4UuYFvQ7m YtyA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:mime-version:user-agent:references :in-reply-to:message-id:date:cc:to:from:subject; bh=iSwXzQQbTQrIqHqiTk0MZs9qCXr7kdVRZXlzTAF7W04=; b=GvwzAMrmo61U//s1UgyzsQZP777Zfk0ihr8YmVS0cTSXZIpV9slVro17UmNdSMMeLy hoEZJq17MmYpolPCsmAdXwbGV/b3ZZWn936nVdSG5TuO51bp8+WsyiwR8npZHRigs34r 76DbO503347a46nlN84tqGjRn+uiweDj9KbmwBXGaKXYPDq0OyrruF0EGyUGAbBwCNpg r3Za0icf88MXDaTH0ihKaqgsh5SfrT+q+0/TISnwmHyjfILkvLUvdDx1Z2miWHnQF1+j 1wDeJ+qQnL8WqzvH8NtLYPd99gf5ID/8hsF2RuL/+KeluQPIZ9ljUDiqvmPi4tcaSpKJ kVYA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of dan.j.williams@intel.com designates 134.134.136.20 as permitted sender) smtp.mailfrom=dan.j.williams@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: from mga02.intel.com (mga02.intel.com. [134.134.136.20]) by mx.google.com with ESMTPS id t1si127205pgh.406.2019.06.05.15.12.59 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 05 Jun 2019 15:12:59 -0700 (PDT) Received-SPF: pass (google.com: domain of dan.j.williams@intel.com designates 134.134.136.20 as permitted sender) client-ip=134.134.136.20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of dan.j.williams@intel.com designates 134.134.136.20 as permitted sender) smtp.mailfrom=dan.j.williams@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Jun 2019 15:12:59 -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 15:12:59 -0700 Subject: [PATCH v9 08/12] mm/sparsemem: Support sub-section hotplug From: Dan Williams To: akpm@linux-foundation.org Cc: Michal Hocko , Vlastimil Babka , Logan Gunthorpe , Oscar Salvador , Pavel Tatashin , linux-mm@kvack.org, linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org, osalvador@suse.de, mhocko@suse.com Date: Wed, 05 Jun 2019 14:58:42 -0700 Message-ID: <155977192280.2443951.13941265207662462739.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-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: X-Virus-Scanned: ClamAV using ClamSMTP The libnvdimm sub-system has suffered a series of hacks and broken workarounds for the memory-hotplug implementation's awkward section-aligned (128MB) granularity. For example the following backtrace is emitted when attempting arch_add_memory() with physical address ranges that intersect 'System RAM' (RAM) with 'Persistent Memory' (PMEM) within a given section: WARNING: CPU: 0 PID: 558 at kernel/memremap.c:300 devm_memremap_pages+0x3b5/0x4c0 devm_memremap_pages attempted on mixed region [mem 0x200000000-0x2fbffffff flags 0x200] [..] Call Trace: dump_stack+0x86/0xc3 __warn+0xcb/0xf0 warn_slowpath_fmt+0x5f/0x80 devm_memremap_pages+0x3b5/0x4c0 __wrap_devm_memremap_pages+0x58/0x70 [nfit_test_iomap] pmem_attach_disk+0x19a/0x440 [nd_pmem] Recently it was discovered that the problem goes beyond RAM vs PMEM collisions as some platform produce PMEM vs PMEM collisions within a given section. The libnvdimm workaround for that case revealed that the libnvdimm section-alignment-padding implementation has been broken for a long while. A fix for that long-standing breakage introduces as many problems as it solves as it would require a backward-incompatible change to the namespace metadata interpretation. Instead of that dubious route [1], address the root problem in the memory-hotplug implementation. [1]: https://lore.kernel.org/r/155000671719.348031.2347363160141119237.stgit@dwillia2-desk3.amr.corp.intel.com Cc: Michal Hocko Cc: Vlastimil Babka Cc: Logan Gunthorpe Cc: Oscar Salvador Cc: Pavel Tatashin Signed-off-by: Dan Williams Reviewed-by: Oscar Salvador --- include/linux/memory_hotplug.h | 2 mm/memory_hotplug.c | 7 - mm/page_alloc.c | 2 mm/sparse.c | 225 +++++++++++++++++++++++++++------------- 4 files changed, 155 insertions(+), 81 deletions(-) diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index 3ab0282b4fe5..0b8a5e5ef2da 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -350,7 +350,7 @@ extern void move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn, extern bool is_memblock_offlined(struct memory_block *mem); extern int sparse_add_section(int nid, unsigned long pfn, unsigned long nr_pages, struct vmem_altmap *altmap); -extern void sparse_remove_one_section(struct mem_section *ms, +extern void sparse_remove_section(struct mem_section *ms, unsigned long pfn, unsigned long nr_pages, unsigned long map_offset, struct vmem_altmap *altmap); extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map, diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 399bf78bccc5..8188be7a9edb 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -255,13 +255,10 @@ void __init register_page_bootmem_info_node(struct pglist_data *pgdat) static int __meminit __add_section(int nid, unsigned long pfn, unsigned long nr_pages, struct vmem_altmap *altmap) { - int ret; - if (pfn_valid(pfn)) return -EEXIST; - ret = sparse_add_section(nid, pfn, nr_pages, altmap); - return ret < 0 ? ret : 0; + return sparse_add_section(nid, pfn, nr_pages, altmap); } static int check_pfn_span(unsigned long pfn, unsigned long nr_pages, @@ -541,7 +538,7 @@ static void __remove_section(struct zone *zone, unsigned long pfn, return; __remove_zone(zone, pfn, nr_pages); - sparse_remove_one_section(ms, pfn, nr_pages, map_offset, altmap); + sparse_remove_section(ms, pfn, nr_pages, map_offset, altmap); } /** diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 5dff3f49a372..af260cc469cd 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5915,7 +5915,7 @@ void __ref memmap_init_zone_device(struct zone *zone, * pfn out of zone. * * Please note that MEMMAP_HOTPLUG path doesn't clear memmap - * because this is done early in sparse_add_one_section + * because this is done early in section_activate() */ if (!(pfn & (pageblock_nr_pages - 1))) { set_pageblock_migratetype(page, MIGRATE_MOVABLE); diff --git a/mm/sparse.c b/mm/sparse.c index f65206deaf49..d83bac5d1324 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -83,8 +83,15 @@ static int __meminit sparse_index_init(unsigned long section_nr, int nid) unsigned long root = SECTION_NR_TO_ROOT(section_nr); struct mem_section *section; + /* + * An existing section is possible in the sub-section hotplug + * case. First hot-add instantiates, follow-on hot-add reuses + * the existing section. + * + * The mem_hotplug_lock resolves the apparent race below. + */ if (mem_section[root]) - return -EEXIST; + return 0; section = sparse_index_alloc(nid); if (!section) @@ -325,6 +332,15 @@ static void __meminit sparse_init_one_section(struct mem_section *ms, unsigned long pnum, struct page *mem_map, struct mem_section_usage *usage) { + /* + * Given that SPARSEMEM_VMEMMAP=y supports sub-section hotplug, + * ->section_mem_map can not be guaranteed to point to a full + * section's worth of memory. The field is only valid / used + * in the SPARSEMEM_VMEMMAP=n case. + */ + if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP)) + mem_map = NULL; + ms->section_mem_map &= ~SECTION_MAP_MASK; ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) | SECTION_HAS_MEM_MAP; @@ -726,10 +742,131 @@ static void free_map_bootmem(struct page *memmap) } #endif /* CONFIG_SPARSEMEM_VMEMMAP */ +static bool is_early_section(struct mem_section *ms) +{ + struct page *usage_page; + + usage_page = virt_to_page(ms->usage); + if (PageSlab(usage_page) || PageCompound(usage_page)) + return false; + else + return true; +} + +static void section_deactivate(unsigned long pfn, unsigned long nr_pages, + struct vmem_altmap *altmap) +{ + DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 }; + DECLARE_BITMAP(tmp, SUBSECTIONS_PER_SECTION) = { 0 }; + struct mem_section *ms = __pfn_to_section(pfn); + bool early_section = is_early_section(ms); + struct page *memmap = NULL; + unsigned long *subsection_map = ms->usage + ? &ms->usage->subsection_map[0] : NULL; + + subsection_mask_set(map, pfn, nr_pages); + if (subsection_map) + bitmap_and(tmp, map, subsection_map, SUBSECTIONS_PER_SECTION); + + if (WARN(!subsection_map || !bitmap_equal(tmp, map, SUBSECTIONS_PER_SECTION), + "section already deactivated (%#lx + %ld)\n", + pfn, nr_pages)) + return; + + /* + * There are 3 cases to handle across two configurations + * (SPARSEMEM_VMEMMAP={y,n}): + * + * 1/ deactivation of a partial hot-added section (only possible + * in the SPARSEMEM_VMEMMAP=y case). + * a/ section was present at memory init + * b/ section was hot-added post memory init + * 2/ deactivation of a complete hot-added section + * 3/ deactivation of a complete section from memory init + * + * For 1/, when subsection_map does not empty we will not be + * freeing the usage map, but still need to free the vmemmap + * range. + * + * For 2/ and 3/ the SPARSEMEM_VMEMMAP={y,n} cases are unified + */ + bitmap_xor(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION); + if (bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION)) { + unsigned long section_nr = pfn_to_section_nr(pfn); + + if (!early_section) { + kfree(ms->usage); + ms->usage = NULL; + } + memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); + ms->section_mem_map = sparse_encode_mem_map(NULL, section_nr); + } + + if (early_section && memmap) + free_map_bootmem(memmap); + else + depopulate_section_memmap(pfn, nr_pages, altmap); +} + +static struct page * __meminit section_activate(int nid, unsigned long pfn, + unsigned long nr_pages, struct vmem_altmap *altmap) +{ + DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 }; + struct mem_section *ms = __pfn_to_section(pfn); + struct mem_section_usage *usage = NULL; + unsigned long *subsection_map; + struct page *memmap; + int rc = 0; + + subsection_mask_set(map, pfn, nr_pages); + + if (!ms->usage) { + usage = kzalloc(mem_section_usage_size(), GFP_KERNEL); + if (!usage) + return ERR_PTR(-ENOMEM); + ms->usage = usage; + } + subsection_map = &ms->usage->subsection_map[0]; + + if (bitmap_empty(map, SUBSECTIONS_PER_SECTION)) + rc = -EINVAL; + else if (bitmap_intersects(map, subsection_map, SUBSECTIONS_PER_SECTION)) + rc = -EEXIST; + else + bitmap_or(subsection_map, map, subsection_map, + SUBSECTIONS_PER_SECTION); + + if (rc) { + if (usage) + ms->usage = NULL; + kfree(usage); + return ERR_PTR(rc); + } + + /* + * The early init code does not consider partially populated + * initial sections, it simply assumes that memory will never be + * referenced. If we hot-add memory into such a section then we + * do not need to populate the memmap and can simply reuse what + * is already there. + */ + if (nr_pages < PAGES_PER_SECTION && is_early_section(ms)) + return pfn_to_page(pfn); + + memmap = populate_section_memmap(pfn, nr_pages, nid, altmap); + if (!memmap) { + section_deactivate(pfn, nr_pages, altmap); + return ERR_PTR(-ENOMEM); + } + + return memmap; +} + /** - * sparse_add_one_section - add a memory section + * sparse_add_section - add a memory section, or populate an existing one * @nid: The node to add section on * @start_pfn: start pfn of the memory range + * @nr_pages: number of pfns to add in the section * @altmap: device page map * * This is only intended for hotplug. @@ -743,50 +880,29 @@ int __meminit sparse_add_section(int nid, unsigned long start_pfn, unsigned long nr_pages, 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; int ret; - /* - * no locking for this, because it does its own - * plus, it does a kmalloc - */ ret = sparse_index_init(section_nr, nid); - if (ret < 0 && ret != -EEXIST) + if (ret < 0) return ret; - ret = 0; - memmap = populate_section_memmap(start_pfn, PAGES_PER_SECTION, nid, - altmap); - if (!memmap) - return -ENOMEM; - usage = kzalloc(mem_section_usage_size(), GFP_KERNEL); - if (!usage) { - depopulate_section_memmap(start_pfn, PAGES_PER_SECTION, altmap); - return -ENOMEM; - } - ms = __pfn_to_section(start_pfn); - if (ms->section_mem_map & SECTION_MARKED_PRESENT) { - ret = -EEXIST; - goto out; - } + memmap = section_activate(nid, start_pfn, nr_pages, altmap); + if (IS_ERR(memmap)) + return PTR_ERR(memmap); /* * Poison uninitialized struct pages in order to catch invalid flags * combinations. */ - page_init_poison(memmap, sizeof(struct page) * PAGES_PER_SECTION); + page_init_poison(pfn_to_page(start_pfn), sizeof(struct page) * nr_pages); + ms = __pfn_to_section(start_pfn); section_mark_present(ms); - sparse_init_one_section(ms, section_nr, memmap, usage); + sparse_init_one_section(ms, section_nr, memmap, ms->usage); -out: - if (ret < 0) { - kfree(usage); - depopulate_section_memmap(start_pfn, PAGES_PER_SECTION, altmap); - } - return ret; + return 0; } #ifdef CONFIG_MEMORY_FAILURE @@ -819,51 +935,12 @@ static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages) } #endif -static void free_section_usage(struct page *memmap, - struct mem_section_usage *usage, unsigned long pfn, - unsigned long nr_pages, struct vmem_altmap *altmap) -{ - struct page *usage_page; - - if (!usage) - return; - - usage_page = virt_to_page(usage); - /* - * Check to see if allocation came from hot-plug-add - */ - if (PageSlab(usage_page) || PageCompound(usage_page)) { - kfree(usage); - if (memmap) - depopulate_section_memmap(pfn, nr_pages, altmap); - return; - } - - /* - * The usemap came from bootmem. This is packed with other usemaps - * on the section which has pgdat at boot time. Just keep it as is now. - */ - - if (memmap) - free_map_bootmem(memmap); -} - -void sparse_remove_one_section(struct mem_section *ms, unsigned long pfn, +void sparse_remove_section(struct mem_section *ms, unsigned long pfn, unsigned long nr_pages, unsigned long map_offset, struct vmem_altmap *altmap) { - struct page *memmap = NULL; - struct mem_section_usage *usage = NULL; - - if (ms->section_mem_map) { - usage = ms->usage; - memmap = sparse_decode_mem_map(ms->section_mem_map, - __section_nr(ms)); - ms->section_mem_map = 0; - ms->usage = NULL; - } - - clear_hwpoisoned_pages(memmap + map_offset, nr_pages - map_offset); - free_section_usage(memmap, usage, pfn, nr_pages, altmap); + clear_hwpoisoned_pages(pfn_to_page(pfn) + map_offset, + nr_pages - map_offset); + section_deactivate(pfn, nr_pages, altmap); } #endif /* CONFIG_MEMORY_HOTPLUG */