Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754223AbdCPPOH (ORCPT ); Thu, 16 Mar 2017 11:14:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46754 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753067AbdCPPMP (ORCPT ); Thu, 16 Mar 2017 11:12:15 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com CC9DD7AE90 Authentication-Results: ext-mx01.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx01.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=jglisse@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com CC9DD7AE90 From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= To: akpm@linux-foundation.org, , linux-mm@kvack.org Cc: John Hubbard , Naoya Horiguchi , David Nellans , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Evgeny Baskakov , Mark Hairgrove , Sherry Cheung , Subhash Gutti Subject: [HMM 09/16] mm/hmm: heterogeneous memory management (HMM for short) Date: Thu, 16 Mar 2017 12:05:28 -0400 Message-Id: <1489680335-6594-10-git-send-email-jglisse@redhat.com> In-Reply-To: <1489680335-6594-1-git-send-email-jglisse@redhat.com> References: <1489680335-6594-1-git-send-email-jglisse@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Thu, 16 Mar 2017 15:04:01 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 11440 Lines: 362 HMM provides 3 separate types of functionality: - Mirroring: synchronize CPU page table and device page table - Device memory: allocating struct page for device memory - Migration: migrating regular memory to device memory This patch introduces some common helpers and definitions to all of those 3 functionality. Signed-off-by: Jérôme Glisse Signed-off-by: Evgeny Baskakov Signed-off-by: John Hubbard Signed-off-by: Mark Hairgrove Signed-off-by: Sherry Cheung Signed-off-by: Subhash Gutti --- MAINTAINERS | 7 +++ include/linux/hmm.h | 153 +++++++++++++++++++++++++++++++++++++++++++++++ include/linux/mm_types.h | 5 ++ kernel/fork.c | 2 + mm/Kconfig | 4 ++ mm/Makefile | 1 + mm/hmm.c | 81 +++++++++++++++++++++++++ 7 files changed, 253 insertions(+) create mode 100644 include/linux/hmm.h create mode 100644 mm/hmm.c diff --git a/MAINTAINERS b/MAINTAINERS index c776906..af37f7c 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -5964,6 +5964,13 @@ S: Supported F: drivers/scsi/hisi_sas/ F: Documentation/devicetree/bindings/scsi/hisilicon-sas.txt +HMM - Heterogeneous Memory Management +M: Jérôme Glisse +L: linux-mm@kvack.org +S: Maintained +F: mm/hmm* +F: include/linux/hmm* + HOST AP DRIVER M: Jouni Malinen L: linux-wireless@vger.kernel.org diff --git a/include/linux/hmm.h b/include/linux/hmm.h new file mode 100644 index 0000000..9fb6767 --- /dev/null +++ b/include/linux/hmm.h @@ -0,0 +1,153 @@ +/* + * Copyright 2013 Red Hat Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * Authors: Jérôme Glisse + */ +/* + * HMM provides 3 separate types of functionality: + * - Mirroring: synchronize CPU page table and device page table + * - Device memory: allocating struct pages for device memory + * - Migration: migrating regular memory to device memory + * + * Each can be used independently from the others. + * + * + * Mirroring: + * + * HMM provides helpers to mirror a process address space on a device. For this, + * it provides several helpers to order device page table updates with respect + * to CPU page table updates. The requirement is that for any given virtual + * address the CPU and device page table cannot point to different physical + * pages. It uses the mmu_notifier API behind the scenes. + * + * Device memory: + * + * HMM provides helpers to help leverage device memory. Device memory is, at any + * given time, either CPU-addressable like regular memory, or completely + * unaddressable. In both cases the device memory is associated with dedicated + * struct pages (which are allocated as if for hotplugged memory). Device memory + * management is under the responsibility of the device driver. HMM only + * allocates and initializes the struct pages associated with the device memory, + * by hotplugging a ZONE_DEVICE memory range. + * + * Allocating struct pages for device memory allows us to use device memory + * almost like regular CPU memory. Unlike regular memory, however, it cannot be + * added to the lru, nor can any memory allocation can use device memory + * directly. Device memory will only end up in use by a process if the device + * driver migrates some of the process memory from regular memory to device + * memory. + * + * Migration: + * + * The existing memory migration mechanism (mm/migrate.c) does not allow using + * anything other than the CPU to copy from source to destination memory. + * Moreover, existing code does not provide a way to migrate based on a virtual + * address range. Existing code only supports struct-page-based migration. Also, + * the migration flow does not allow for graceful failure at intermediate stages + * of the migration process. + * + * HMM solves all of the above, by providing a simple API: + * + * hmm_vma_migrate(ops, vma, src_pfns, dst_pfns, start, end, private); + * + * finalize_and_map(). The first, alloc_and_copy(), allocates the destination + * memory and initializes it using source memory. Migration can fail at this + * point, and the device driver then has a place to abort the migration. The + * finalize_and_map() callback allows the device driver to know which pages + * were successfully migrated and which were not. + * + * This can easily be used outside of the original HMM use case. + * + * + * This header file contain all the APIs related to hmm_vma_migrate. Additional + * detailed documentation may be found below. + */ +#ifndef LINUX_HMM_H +#define LINUX_HMM_H + +#include + +#if IS_ENABLED(CONFIG_HMM) + + +/* + * hmm_pfn_t - HMM use its own pfn type to keep several flags per page + * + * Flags: + * HMM_PFN_VALID: pfn is valid + * HMM_PFN_WRITE: CPU page table have the write permission set + */ +typedef unsigned long hmm_pfn_t; + +#define HMM_PFN_VALID (1 << 0) +#define HMM_PFN_WRITE (1 << 1) +#define HMM_PFN_SHIFT 2 + +/* + * hmm_pfn_to_page() - return struct page pointed to by a valid hmm_pfn_t + * @pfn: hmm_pfn_t to convert to struct page + * Returns: struct page pointer if pfn is a valid hmm_pfn_t, NULL otherwise + * + * If the hmm_pfn_t is valid (ie valid flag set) then return the struct page + * matching the pfn value store in the hmm_pfn_t. Otherwise return NULL. + */ +static inline struct page *hmm_pfn_to_page(hmm_pfn_t pfn) +{ + if (!(pfn & HMM_PFN_VALID)) + return NULL; + return pfn_to_page(pfn >> HMM_PFN_SHIFT); +} + +/* + * hmm_pfn_to_pfn() - return pfn value store in a hmm_pfn_t + * @pfn: hmm_pfn_t to extract pfn from + * Returns: pfn value if hmm_pfn_t is valid, -1UL otherwise + */ +static inline unsigned long hmm_pfn_to_pfn(hmm_pfn_t pfn) +{ + if (!(pfn & HMM_PFN_VALID)) + return -1UL; + return (pfn >> HMM_PFN_SHIFT); +} + +/* + * hmm_pfn_from_page() - create a valid hmm_pfn_t value from struct page + * @page: struct page pointer for which to create the hmm_pfn_t + * Returns: valid hmm_pfn_t for the page + */ +static inline hmm_pfn_t hmm_pfn_from_page(struct page *page) +{ + return (page_to_pfn(page) << HMM_PFN_SHIFT) | HMM_PFN_VALID; +} + +/* + * hmm_pfn_from_pfn() - create a valid hmm_pfn_t value from pfn + * @pfn: pfn value for which to create the hmm_pfn_t + * Returns: valid hmm_pfn_t for the pfn + */ +static inline hmm_pfn_t hmm_pfn_from_pfn(unsigned long pfn) +{ + return (pfn << HMM_PFN_SHIFT) | HMM_PFN_VALID; +} + + +/* Below are for HMM internal use only! Not to be used by device driver! */ +void hmm_mm_destroy(struct mm_struct *mm); + +#else /* IS_ENABLED(CONFIG_HMM) */ + +/* Below are for HMM internal use only! Not to be used by device driver! */ +static inline void hmm_mm_destroy(struct mm_struct *mm) {} + +#endif /* IS_ENABLED(CONFIG_HMM) */ +#endif /* LINUX_HMM_H */ diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index f60f45f..81068ce 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -23,6 +23,7 @@ struct address_space; struct mem_cgroup; +struct hmm; /* * Each physical page in the system has a struct page associated with @@ -495,6 +496,10 @@ struct mm_struct { atomic_long_t hugetlb_usage; #endif struct work_struct async_put_work; +#if IS_ENABLED(CONFIG_HMM) + /* HMM need to track few things per mm */ + struct hmm *hmm; +#endif }; extern struct mm_struct init_mm; diff --git a/kernel/fork.c b/kernel/fork.c index 6c463c80..1f8d612 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -37,6 +37,7 @@ #include #include #include +#include #include #include #include @@ -863,6 +864,7 @@ void __mmdrop(struct mm_struct *mm) BUG_ON(mm == &init_mm); mm_free_pgd(mm); destroy_context(mm); + hmm_mm_destroy(mm); mmu_notifier_mm_destroy(mm); check_mm(mm); put_user_ns(mm->user_ns); diff --git a/mm/Kconfig b/mm/Kconfig index 9502315..fe8ad24 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -289,6 +289,10 @@ config MIGRATION config ARCH_ENABLE_HUGEPAGE_MIGRATION bool +config HMM + bool + depends on MMU + config PHYS_ADDR_T_64BIT def_bool 64BIT || ARCH_PHYS_ADDR_T_64BIT diff --git a/mm/Makefile b/mm/Makefile index 026f6a8..9eb4121 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -75,6 +75,7 @@ obj-$(CONFIG_FAILSLAB) += failslab.o obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o obj-$(CONFIG_MEMTEST) += memtest.o obj-$(CONFIG_MIGRATION) += migrate.o +obj-$(CONFIG_HMM) += hmm.o obj-$(CONFIG_QUICKLIST) += quicklist.o obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o khugepaged.o obj-$(CONFIG_PAGE_COUNTER) += page_counter.o diff --git a/mm/hmm.c b/mm/hmm.c new file mode 100644 index 0000000..ed3a847 --- /dev/null +++ b/mm/hmm.c @@ -0,0 +1,81 @@ +/* + * Copyright 2013 Red Hat Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * Authors: Jérôme Glisse + */ +/* + * Refer to include/linux/hmm.h for information about heterogeneous memory + * management or HMM for short. + */ +#include +#include +#include +#include + +/* + * struct hmm - HMM per mm struct + * + * @mm: mm struct this HMM struct is bound to + */ +struct hmm { + struct mm_struct *mm; +}; + +/* + * hmm_register - register HMM against an mm (HMM internal) + * + * @mm: mm struct to attach to + * + * This is not intended to be used directly by device drivers. It allocates an + * HMM struct if mm does not have one, and initializes it. + */ +static struct hmm *hmm_register(struct mm_struct *mm) +{ + if (!mm->hmm) { + struct hmm *hmm = NULL; + + hmm = kmalloc(sizeof(*hmm), GFP_KERNEL); + if (!hmm) + return NULL; + hmm->mm = mm; + + spin_lock(&mm->page_table_lock); + if (!mm->hmm) + mm->hmm = hmm; + else + kfree(hmm); + spin_unlock(&mm->page_table_lock); + } + + /* + * The hmm struct can only be freed once the mm_struct goes away, + * hence we should always have pre-allocated an new hmm struct + * above. + */ + return mm->hmm; +} + +void hmm_mm_destroy(struct mm_struct *mm) +{ + struct hmm *hmm; + + /* + * We should not need to lock here as no one should be able to register + * a new HMM while an mm is being destroy. But just to be safe ... + */ + spin_lock(&mm->page_table_lock); + hmm = mm->hmm; + mm->hmm = NULL; + spin_unlock(&mm->page_table_lock); + kfree(hmm); +} -- 2.4.11