From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 305C6C04AB3 for ; Mon, 27 May 2019 10:21:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E2E1320859 for ; Mon, 27 May 2019 10:21:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726302AbfE0KVl (ORCPT ); Mon, 27 May 2019 06:21:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53634 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725814AbfE0KVl (ORCPT ); Mon, 27 May 2019 06:21:41 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B950D30832F4; Mon, 27 May 2019 10:21:37 +0000 (UTC) Received: from [10.36.117.89] (ovpn-117-89.ams2.redhat.com [10.36.117.89]) by smtp.corp.redhat.com (Postfix) with ESMTP id A771D19C58; Mon, 27 May 2019 10:21:24 +0000 (UTC) Subject: Re: [PATCH V4 4/4] arm64/mm: Enable memory hot remove To: Anshuman Khandual , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, akpm@linux-foundation.org, catalin.marinas@arm.com, will.deacon@arm.com Cc: mark.rutland@arm.com, mhocko@suse.com, ira.weiny@intel.com, cai@lca.pw, logang@deltatee.com, james.morse@arm.com, cpandya@codeaurora.org, arunks@codeaurora.org, dan.j.williams@intel.com, mgorman@techsingularity.net, osalvador@suse.de, ard.biesheuvel@arm.com References: <1558329516-10445-1-git-send-email-anshuman.khandual@arm.com> <1558329516-10445-5-git-send-email-anshuman.khandual@arm.com> From: David Hildenbrand Openpgp: preference=signencrypt Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwX4EEwECACgFAljj9eoCGwMFCQlmAYAGCwkI BwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEE3eEPcA/4Na5IIP/3T/FIQMxIfNzZshIq687qgG 8UbspuE/YSUDdv7r5szYTK6KPTlqN8NAcSfheywbuYD9A4ZeSBWD3/NAVUdrCaRP2IvFyELj xoMvfJccbq45BxzgEspg/bVahNbyuBpLBVjVWwRtFCUEXkyazksSv8pdTMAs9IucChvFmmq3 jJ2vlaz9lYt/lxN246fIVceckPMiUveimngvXZw21VOAhfQ+/sofXF8JCFv2mFcBDoa7eYob s0FLpmqFaeNRHAlzMWgSsP80qx5nWWEvRLdKWi533N2vC/EyunN3HcBwVrXH4hxRBMco3jvM m8VKLKao9wKj82qSivUnkPIwsAGNPdFoPbgghCQiBjBe6A75Z2xHFrzo7t1jg7nQfIyNC7ez MZBJ59sqA9EDMEJPlLNIeJmqslXPjmMFnE7Mby/+335WJYDulsRybN+W5rLT5aMvhC6x6POK z55fMNKrMASCzBJum2Fwjf/VnuGRYkhKCqqZ8gJ3OvmR50tInDV2jZ1DQgc3i550T5JDpToh dPBxZocIhzg+MBSRDXcJmHOx/7nQm3iQ6iLuwmXsRC6f5FbFefk9EjuTKcLMvBsEx+2DEx0E UnmJ4hVg7u1PQ+2Oy+Lh/opK/BDiqlQ8Pz2jiXv5xkECvr/3Sv59hlOCZMOaiLTTjtOIU7Tq 7ut6OL64oAq+zsFNBFXLn5EBEADn1959INH2cwYJv0tsxf5MUCghCj/CA/lc/LMthqQ773ga uB9mN+F1rE9cyyXb6jyOGn+GUjMbnq1o121Vm0+neKHUCBtHyseBfDXHA6m4B3mUTWo13nid 0e4AM71r0DS8+KYh6zvweLX/LL5kQS9GQeT+QNroXcC1NzWbitts6TZ+IrPOwT1hfB4WNC+X 2n4AzDqp3+ILiVST2DT4VBc11Gz6jijpC/KI5Al8ZDhRwG47LUiuQmt3yqrmN63V9wzaPhC+ xbwIsNZlLUvuRnmBPkTJwwrFRZvwu5GPHNndBjVpAfaSTOfppyKBTccu2AXJXWAE1Xjh6GOC 8mlFjZwLxWFqdPHR1n2aPVgoiTLk34LR/bXO+e0GpzFXT7enwyvFFFyAS0Nk1q/7EChPcbRb hJqEBpRNZemxmg55zC3GLvgLKd5A09MOM2BrMea+l0FUR+PuTenh2YmnmLRTro6eZ/qYwWkC u8FFIw4pT0OUDMyLgi+GI1aMpVogTZJ70FgV0pUAlpmrzk/bLbRkF3TwgucpyPtcpmQtTkWS gDS50QG9DR/1As3LLLcNkwJBZzBG6PWbvcOyrwMQUF1nl4SSPV0LLH63+BrrHasfJzxKXzqg rW28CTAE2x8qi7e/6M/+XXhrsMYG+uaViM7n2je3qKe7ofum3s4vq7oFCPsOgwARAQABwsFl BBgBAgAPBQJVy5+RAhsMBQkJZgGAAAoJEE3eEPcA/4NagOsP/jPoIBb/iXVbM+fmSHOjEshl KMwEl/m5iLj3iHnHPVLBUWrXPdS7iQijJA/VLxjnFknhaS60hkUNWexDMxVVP/6lbOrs4bDZ NEWDMktAeqJaFtxackPszlcpRVkAs6Msn9tu8hlvB517pyUgvuD7ZS9gGOMmYwFQDyytpepo YApVV00P0u3AaE0Cj/o71STqGJKZxcVhPaZ+LR+UCBZOyKfEyq+ZN311VpOJZ1IvTExf+S/5 lqnciDtbO3I4Wq0ArLX1gs1q1XlXLaVaA3yVqeC8E7kOchDNinD3hJS4OX0e1gdsx/e6COvy qNg5aL5n0Kl4fcVqM0LdIhsubVs4eiNCa5XMSYpXmVi3HAuFyg9dN+x8thSwI836FoMASwOl C7tHsTjnSGufB+D7F7ZBT61BffNBBIm1KdMxcxqLUVXpBQHHlGkbwI+3Ye+nE6HmZH7IwLwV W+Ajl7oYF+jeKaH4DZFtgLYGLtZ1LDwKPjX7VAsa4Yx7S5+EBAaZGxK510MjIx6SGrZWBrrV TEvdV00F2MnQoeXKzD7O4WFbL55hhyGgfWTHwZ457iN9SgYi1JLPqWkZB0JRXIEtjd4JEQcx +8Umfre0Xt4713VxMygW0PnQt5aSQdMD58jHFxTk092mU+yIHj5LeYgvwSgZN4airXk5yRXl SE+xAvmumFBY Organization: Red Hat GmbH Message-ID: Date: Mon, 27 May 2019 12:21:23 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.44]); Mon, 27 May 2019 10:21:41 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 27.05.19 10:09, Anshuman Khandual wrote: > > > On 05/21/2019 03:50 PM, David Hildenbrand wrote: >> On 20.05.19 07:18, Anshuman Khandual wrote: >>> The arch code for hot-remove must tear down portions of the linear map and >>> vmemmap corresponding to memory being removed. In both cases the page >>> tables mapping these regions must be freed, and when sparse vmemmap is in >>> use the memory backing the vmemmap must also be freed. >>> >>> This patch adds a new remove_pagetable() helper which can be used to tear >>> down either region, and calls it from vmemmap_free() and >>> ___remove_pgd_mapping(). The sparse_vmap argument determines whether the >>> backing memory will be freed. >>> >>> While freeing intermediate level page table pages bail out if any of it's >>> entries are still valid. This can happen for partially filled kernel page >>> table either from a previously attempted failed memory hot add or while >>> removing an address range which does not span the entire page table page >>> range. >>> >>> The vmemmap region may share levels of table with the vmalloc region. Take >>> the kernel ptl so that we can safely free potentially-shared tables. >>> >>> While here update arch_add_memory() to handle __add_pages() failures by >>> just unmapping recently added kernel linear mapping. Now enable memory hot >>> remove on arm64 platforms by default with ARCH_ENABLE_MEMORY_HOTREMOVE. >>> >>> This implementation is overall inspired from kernel page table tear down >>> procedure on X86 architecture. >>> >>> Signed-off-by: Anshuman Khandual >>> --- >>> arch/arm64/Kconfig | 3 + >>> arch/arm64/mm/mmu.c | 212 +++++++++++++++++++++++++++++++++++++++++++++++++++- >>> 2 files changed, 213 insertions(+), 2 deletions(-) >>> >>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig >>> index 4780eb7..ce24427 100644 >>> --- a/arch/arm64/Kconfig >>> +++ b/arch/arm64/Kconfig >>> @@ -267,6 +267,9 @@ config HAVE_GENERIC_GUP >>> config ARCH_ENABLE_MEMORY_HOTPLUG >>> def_bool y >>> >>> +config ARCH_ENABLE_MEMORY_HOTREMOVE >>> + def_bool y >>> + >>> config SMP >>> def_bool y >>> >>> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c >>> index a1bfc44..0cf0d41 100644 >>> --- a/arch/arm64/mm/mmu.c >>> +++ b/arch/arm64/mm/mmu.c >>> @@ -733,6 +733,187 @@ int kern_addr_valid(unsigned long addr) >>> >>> return pfn_valid(pte_pfn(pte)); >>> } >>> + >>> +#ifdef CONFIG_MEMORY_HOTPLUG >>> +static void free_hotplug_page_range(struct page *page, ssize_t size) >>> +{ >>> + WARN_ON(PageReserved(page)); >>> + free_pages((unsigned long)page_address(page), get_order(size)); >>> +} >>> + >>> +static void free_hotplug_pgtable_page(struct page *page) >>> +{ >>> + free_hotplug_page_range(page, PAGE_SIZE); >>> +} >>> + >>> +static void free_pte_table(pte_t *ptep, pmd_t *pmdp, unsigned long addr) >>> +{ >>> + struct page *page; >>> + int i; >>> + >>> + for (i = 0; i < PTRS_PER_PTE; i++) { >>> + if (!pte_none(ptep[i])) >>> + return; >>> + } >>> + >>> + page = pmd_page(READ_ONCE(*pmdp)); >>> + pmd_clear(pmdp); >>> + __flush_tlb_kernel_pgtable(addr); >>> + free_hotplug_pgtable_page(page); >>> +} >>> + >>> +static void free_pmd_table(pmd_t *pmdp, pud_t *pudp, unsigned long addr) >>> +{ >>> + struct page *page; >>> + int i; >>> + >>> + if (CONFIG_PGTABLE_LEVELS <= 2) >>> + return; >>> + >>> + for (i = 0; i < PTRS_PER_PMD; i++) { >>> + if (!pmd_none(pmdp[i])) >>> + return; >>> + } >>> + >>> + page = pud_page(READ_ONCE(*pudp)); >>> + pud_clear(pudp); >>> + __flush_tlb_kernel_pgtable(addr); >>> + free_hotplug_pgtable_page(page); >>> +} >>> + >>> +static void free_pud_table(pud_t *pudp, pgd_t *pgdp, unsigned long addr) >>> +{ >>> + struct page *page; >>> + int i; >>> + >>> + if (CONFIG_PGTABLE_LEVELS <= 3) >>> + return; >>> + >>> + for (i = 0; i < PTRS_PER_PUD; i++) { >>> + if (!pud_none(pudp[i])) >>> + return; >>> + } >>> + >>> + page = pgd_page(READ_ONCE(*pgdp)); >>> + pgd_clear(pgdp); >>> + __flush_tlb_kernel_pgtable(addr); >>> + free_hotplug_pgtable_page(page); >>> +} >>> + >>> +static void >>> +remove_pte_table(pmd_t *pmdp, unsigned long addr, >>> + unsigned long end, bool sparse_vmap) >>> +{ >>> + struct page *page; >>> + pte_t *ptep, pte; >>> + unsigned long start = addr; >>> + >>> + for (; addr < end; addr += PAGE_SIZE) { >>> + ptep = pte_offset_kernel(pmdp, addr); >>> + pte = READ_ONCE(*ptep); >>> + >>> + if (pte_none(pte)) >>> + continue; >>> + >>> + WARN_ON(!pte_present(pte)); >>> + if (sparse_vmap) { >>> + page = pte_page(pte); >>> + free_hotplug_page_range(page, PAGE_SIZE); >>> + } >>> + pte_clear(&init_mm, addr, ptep); >>> + } >>> + flush_tlb_kernel_range(start, end); >>> +} >>> + >>> +static void >>> +remove_pmd_table(pud_t *pudp, unsigned long addr, >>> + unsigned long end, bool sparse_vmap) >>> +{ >>> + unsigned long next; >>> + struct page *page; >>> + pte_t *ptep_base; >>> + pmd_t *pmdp, pmd; >>> + >>> + for (; addr < end; addr = next) { >>> + next = pmd_addr_end(addr, end); >>> + pmdp = pmd_offset(pudp, addr); >>> + pmd = READ_ONCE(*pmdp); >>> + >>> + if (pmd_none(pmd)) >>> + continue; >>> + >>> + WARN_ON(!pmd_present(pmd)); >>> + if (pmd_sect(pmd)) { >>> + if (sparse_vmap) { >>> + page = pmd_page(pmd); >>> + free_hotplug_page_range(page, PMD_SIZE); >>> + } >>> + pmd_clear(pmdp); >>> + continue; >>> + } >>> + ptep_base = pte_offset_kernel(pmdp, 0UL); >>> + remove_pte_table(pmdp, addr, next, sparse_vmap); >>> + free_pte_table(ptep_base, pmdp, addr); >>> + } >>> +} >>> + >>> +static void >>> +remove_pud_table(pgd_t *pgdp, unsigned long addr, >>> + unsigned long end, bool sparse_vmap) >>> +{ >>> + unsigned long next; >>> + struct page *page; >>> + pmd_t *pmdp_base; >>> + pud_t *pudp, pud; >>> + >>> + for (; addr < end; addr = next) { >>> + next = pud_addr_end(addr, end); >>> + pudp = pud_offset(pgdp, addr); >>> + pud = READ_ONCE(*pudp); >>> + >>> + if (pud_none(pud)) >>> + continue; >>> + >>> + WARN_ON(!pud_present(pud)); >>> + if (pud_sect(pud)) { >>> + if (sparse_vmap) { >>> + page = pud_page(pud); >>> + free_hotplug_page_range(page, PUD_SIZE); >>> + } >>> + pud_clear(pudp); >>> + continue; >>> + } >>> + pmdp_base = pmd_offset(pudp, 0UL); >>> + remove_pmd_table(pudp, addr, next, sparse_vmap); >>> + free_pmd_table(pmdp_base, pudp, addr); >>> + } >>> +} >>> + >>> +static void >>> +remove_pagetable(unsigned long start, unsigned long end, bool sparse_vmap) >>> +{ >>> + unsigned long addr, next; >>> + pud_t *pudp_base; >>> + pgd_t *pgdp, pgd; >>> + >>> + spin_lock(&init_mm.page_table_lock); >>> + for (addr = start; addr < end; addr = next) { >>> + next = pgd_addr_end(addr, end); >>> + pgdp = pgd_offset_k(addr); >>> + pgd = READ_ONCE(*pgdp); >>> + >>> + if (pgd_none(pgd)) >>> + continue; >>> + >>> + WARN_ON(!pgd_present(pgd)); >>> + pudp_base = pud_offset(pgdp, 0UL); >>> + remove_pud_table(pgdp, addr, next, sparse_vmap); >>> + free_pud_table(pudp_base, pgdp, addr); >>> + } >>> + spin_unlock(&init_mm.page_table_lock); >>> +} >>> +#endif >>> + >>> #ifdef CONFIG_SPARSEMEM_VMEMMAP >>> #if !ARM64_SWAPPER_USES_SECTION_MAPS >>> int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, >>> @@ -780,6 +961,9 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, >>> void vmemmap_free(unsigned long start, unsigned long end, >>> struct vmem_altmap *altmap) >>> { >>> +#ifdef CONFIG_MEMORY_HOTPLUG >>> + remove_pagetable(start, end, true); >>> +#endif >>> } >>> #endif /* CONFIG_SPARSEMEM_VMEMMAP */ >>> >>> @@ -1070,10 +1254,16 @@ int p4d_free_pud_page(p4d_t *p4d, unsigned long addr) >>> } >>> >>> #ifdef CONFIG_MEMORY_HOTPLUG >>> +static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size) >>> +{ >>> + WARN_ON(pgdir != init_mm.pgd); >>> + remove_pagetable(start, start + size, false); >>> +} >>> + >>> int arch_add_memory(int nid, u64 start, u64 size, >>> struct mhp_restrictions *restrictions) >>> { >>> - int flags = 0; >>> + int ret, flags = 0; >>> >>> if (rodata_full || debug_pagealloc_enabled()) >>> flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; >>> @@ -1081,7 +1271,25 @@ int arch_add_memory(int nid, u64 start, u64 size, >>> __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), >>> size, PAGE_KERNEL, __pgd_pgtable_alloc, flags); >>> >>> - return __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, >>> + ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, >>> restrictions); >>> + if (ret) >>> + __remove_pgd_mapping(swapper_pg_dir, >>> + __phys_to_virt(start), size); >> >> Nit: Indentation of the parameters looks really weird. >> >>> + return ret; >>> +} >>> + >>> +#ifdef CONFIG_MEMORY_HOTREMOVE >>> +void arch_remove_memory(int nid, u64 start, u64 size, >>> + struct vmem_altmap *altmap) >>> +{ >>> + unsigned long start_pfn = start >> PAGE_SHIFT; >>> + unsigned long nr_pages = size >> PAGE_SHIFT; >>> + struct zone *zone = page_zone(pfn_to_page(start_pfn)); >>> + >>> + __remove_pages(zone, start_pfn, nr_pages, altmap); >>> + __remove_pgd_mapping(swapper_pg_dir, >>> + __phys_to_virt(start), size); >> >> Dito, indentation of the parameters. >> >> For these two changes (arch_*_memory) >> >> Acked-by: David Hildenbrand > > Thanks David. The following change on this patch should fix the indentation > problem. If there are no other comments I will incorporate this and re-spin > the series once more. > > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 0cf0d41..a87ba18 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -1273,9 +1273,10 @@ int arch_add_memory(int nid, u64 start, u64 size, > > ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, > restrictions); > - if (ret) > - __remove_pgd_mapping(swapper_pg_dir, > - __phys_to_virt(start), size); > + if (!ret) > + return ret; > + > + __remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size); you can leave the old code, just make sure the start of all parameters on new lines are aligned, that seemed to be not the case if (ret) __remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size); ............................^ > return ret; > } > > @@ -1288,8 +1289,7 @@ void arch_remove_memory(int nid, u64 start, u64 size, > struct zone *zone = page_zone(pfn_to_page(start_pfn)); > > __remove_pages(zone, start_pfn, nr_pages, altmap); > - __remove_pgd_mapping(swapper_pg_dir, > - __phys_to_virt(start), size); > + __remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size); > } > #endif > #endif > -- Thanks, David / dhildenb