Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935008AbcLOGUK (ORCPT ); Thu, 15 Dec 2016 01:20:10 -0500 Received: from szxga01-in.huawei.com ([58.251.152.64]:23656 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752693AbcLOGUI (ORCPT ); Thu, 15 Dec 2016 01:20:08 -0500 Message-ID: <58523598.3080902@huawei.com> Date: Thu, 15 Dec 2016 14:18:00 +0800 From: Xishi Qiu User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: Maciej Bielski CC: , , , , , Subject: Re: [RFC PATCH] Memory hotplug support for arm64 platform References: <1481717765-31186-1-git-send-email-m.bielski@virtualopensystems.com> In-Reply-To: <1481717765-31186-1-git-send-email-m.bielski@virtualopensystems.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.25.179] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3161 Lines: 105 On 2016/12/14 20:16, Maciej Bielski wrote: > > > -#ifdef CONFIG_MEMORY_HOTREMOVE > -int arch_remove_memory(u64 start, u64 size) > -{ > - unsigned long start_pfn = start >> PAGE_SHIFT; > - unsigned long nr_pages = size >> PAGE_SHIFT; > - struct zone *zone; > - int ret; > + SetPageReserved(pfn_to_page(pfn)); > + } Hi Maciej, Why we need to set reserved here? I think the new pages are already reserved in __add_zone() -> memmap_init_zone(), right? Thanks, Xishi Qiu > > - zone = page_zone(pfn_to_page(start_pfn)); > - ret = __remove_pages(zone, start_pfn, nr_pages); > if (ret) > - pr_warn("%s: Problem encountered in __remove_pages() ret=%d\n", > + pr_warn("%s: Problem encountered in __add_pages() ret=%d\n", > __func__, ret); > > return ret; > } > #endif > -#endif > > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 05615a3..9efa7d1 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -493,6 +493,30 @@ void __init paging_init(void) > SWAPPER_DIR_SIZE - PAGE_SIZE); > } > > +#ifdef CONFIG_MEMORY_HOTPLUG > +/* > + * hotplug_paging() is used by memory hotplug to build new page tables > + * for hot added memory. > + */ > +void hotplug_paging(phys_addr_t start, phys_addr_t size) > +{ > + phys_addr_t pgd_phys = pgd_pgtable_alloc(); > + pgd_t *pgd = pgd_set_fixmap(pgd_phys); > + > + memcpy(pgd, swapper_pg_dir, PAGE_SIZE); > + > + __create_pgd_mapping(pgd, start, __phys_to_virt(start), size, > + PAGE_KERNEL, pgd_pgtable_alloc, false); > + > + cpu_replace_ttbr1(__va(pgd_phys)); > + memcpy(swapper_pg_dir, pgd, PAGE_SIZE); > + cpu_replace_ttbr1(swapper_pg_dir); > + > + pgd_clear_fixmap(); > + memblock_free(pgd_phys, PAGE_SIZE); > +} > +#endif > + > /* > * Check whether a kernel address is valid (derived from arch/x86/). > */ > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > index 5b759c9..5f78257 100644 > --- a/include/linux/memblock.h > +++ b/include/linux/memblock.h > @@ -92,6 +92,7 @@ int memblock_mark_hotplug(phys_addr_t base, phys_addr_t size); > int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size); > int memblock_mark_mirror(phys_addr_t base, phys_addr_t size); > int memblock_mark_nomap(phys_addr_t base, phys_addr_t size); > +int memblock_clear_nomap(phys_addr_t base, phys_addr_t size); > ulong choose_memblock_flags(void); > > /* Low level functions */ > diff --git a/mm/memblock.c b/mm/memblock.c > index 7608bc3..05e7676 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -814,6 +814,16 @@ int __init_memblock memblock_mark_nomap(phys_addr_t base, phys_addr_t size) > } > > /** > + * memblock_clear_nomap - Clear a flag of MEMBLOCK_NOMAP memory region > + * @base: the base phys addr of the region > + * @size: the size of the region > + */ > +int __init_memblock memblock_clear_nomap(phys_addr_t base, phys_addr_t size) > +{ > + return memblock_setclr_flag(base, size, 0, MEMBLOCK_NOMAP); > +} > + > +/** > * __next_reserved_mem_region - next function for for_each_reserved_region() > * @idx: pointer to u64 loop variable > * @out_start: ptr to phys_addr_t for start address of the region, can be %NULL