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![Matthew Wilcox](/assets/img/avatar_default.png)
Let's stop working on the private field and use an explicit swap field. We have to move the swp_entry_t typedef. Link: https://lkml.kernel.org/r/20230821160849.531668-3-david@redhat.com Signed-off-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Chris Li <chrisl@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
1375 lines
43 KiB
C
1375 lines
43 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_MM_TYPES_H
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#define _LINUX_MM_TYPES_H
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#include <linux/mm_types_task.h>
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#include <linux/auxvec.h>
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#include <linux/kref.h>
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#include <linux/list.h>
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#include <linux/spinlock.h>
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#include <linux/rbtree.h>
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#include <linux/maple_tree.h>
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#include <linux/rwsem.h>
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#include <linux/completion.h>
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#include <linux/cpumask.h>
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#include <linux/uprobes.h>
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#include <linux/rcupdate.h>
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#include <linux/page-flags-layout.h>
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#include <linux/workqueue.h>
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#include <linux/seqlock.h>
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#include <linux/percpu_counter.h>
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#include <asm/mmu.h>
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#ifndef AT_VECTOR_SIZE_ARCH
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#define AT_VECTOR_SIZE_ARCH 0
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#endif
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#define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))
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#define INIT_PASID 0
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struct address_space;
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struct mem_cgroup;
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/*
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* Each physical page in the system has a struct page associated with
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* it to keep track of whatever it is we are using the page for at the
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* moment. Note that we have no way to track which tasks are using
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* a page, though if it is a pagecache page, rmap structures can tell us
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* who is mapping it.
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*
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* If you allocate the page using alloc_pages(), you can use some of the
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* space in struct page for your own purposes. The five words in the main
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* union are available, except for bit 0 of the first word which must be
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* kept clear. Many users use this word to store a pointer to an object
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* which is guaranteed to be aligned. If you use the same storage as
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* page->mapping, you must restore it to NULL before freeing the page.
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*
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* If your page will not be mapped to userspace, you can also use the four
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* bytes in the mapcount union, but you must call page_mapcount_reset()
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* before freeing it.
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*
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* If you want to use the refcount field, it must be used in such a way
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* that other CPUs temporarily incrementing and then decrementing the
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* refcount does not cause problems. On receiving the page from
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* alloc_pages(), the refcount will be positive.
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*
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* If you allocate pages of order > 0, you can use some of the fields
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* in each subpage, but you may need to restore some of their values
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* afterwards.
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*
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* SLUB uses cmpxchg_double() to atomically update its freelist and counters.
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* That requires that freelist & counters in struct slab be adjacent and
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* double-word aligned. Because struct slab currently just reinterprets the
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* bits of struct page, we align all struct pages to double-word boundaries,
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* and ensure that 'freelist' is aligned within struct slab.
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*/
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#ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
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#define _struct_page_alignment __aligned(2 * sizeof(unsigned long))
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#else
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#define _struct_page_alignment __aligned(sizeof(unsigned long))
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#endif
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struct page {
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unsigned long flags; /* Atomic flags, some possibly
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* updated asynchronously */
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/*
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* Five words (20/40 bytes) are available in this union.
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* WARNING: bit 0 of the first word is used for PageTail(). That
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* means the other users of this union MUST NOT use the bit to
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* avoid collision and false-positive PageTail().
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*/
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union {
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struct { /* Page cache and anonymous pages */
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/**
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* @lru: Pageout list, eg. active_list protected by
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* lruvec->lru_lock. Sometimes used as a generic list
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* by the page owner.
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*/
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union {
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struct list_head lru;
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/* Or, for the Unevictable "LRU list" slot */
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struct {
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/* Always even, to negate PageTail */
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void *__filler;
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/* Count page's or folio's mlocks */
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unsigned int mlock_count;
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};
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/* Or, free page */
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struct list_head buddy_list;
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struct list_head pcp_list;
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};
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/* See page-flags.h for PAGE_MAPPING_FLAGS */
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struct address_space *mapping;
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union {
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pgoff_t index; /* Our offset within mapping. */
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unsigned long share; /* share count for fsdax */
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};
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/**
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* @private: Mapping-private opaque data.
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* Usually used for buffer_heads if PagePrivate.
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* Used for swp_entry_t if PageSwapCache.
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* Indicates order in the buddy system if PageBuddy.
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*/
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unsigned long private;
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};
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struct { /* page_pool used by netstack */
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/**
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* @pp_magic: magic value to avoid recycling non
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* page_pool allocated pages.
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*/
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unsigned long pp_magic;
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struct page_pool *pp;
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unsigned long _pp_mapping_pad;
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unsigned long dma_addr;
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union {
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/**
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* dma_addr_upper: might require a 64-bit
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* value on 32-bit architectures.
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*/
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unsigned long dma_addr_upper;
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/**
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* For frag page support, not supported in
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* 32-bit architectures with 64-bit DMA.
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*/
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atomic_long_t pp_frag_count;
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};
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};
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struct { /* Tail pages of compound page */
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unsigned long compound_head; /* Bit zero is set */
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};
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struct { /* ZONE_DEVICE pages */
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/** @pgmap: Points to the hosting device page map. */
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struct dev_pagemap *pgmap;
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void *zone_device_data;
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/*
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* ZONE_DEVICE private pages are counted as being
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* mapped so the next 3 words hold the mapping, index,
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* and private fields from the source anonymous or
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* page cache page while the page is migrated to device
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* private memory.
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* ZONE_DEVICE MEMORY_DEVICE_FS_DAX pages also
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* use the mapping, index, and private fields when
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* pmem backed DAX files are mapped.
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*/
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};
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/** @rcu_head: You can use this to free a page by RCU. */
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struct rcu_head rcu_head;
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};
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union { /* This union is 4 bytes in size. */
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/*
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* If the page can be mapped to userspace, encodes the number
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* of times this page is referenced by a page table.
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*/
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atomic_t _mapcount;
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/*
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* If the page is neither PageSlab nor mappable to userspace,
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* the value stored here may help determine what this page
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* is used for. See page-flags.h for a list of page types
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* which are currently stored here.
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*/
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unsigned int page_type;
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};
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/* Usage count. *DO NOT USE DIRECTLY*. See page_ref.h */
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atomic_t _refcount;
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#ifdef CONFIG_MEMCG
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unsigned long memcg_data;
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#endif
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/*
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* On machines where all RAM is mapped into kernel address space,
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* we can simply calculate the virtual address. On machines with
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* highmem some memory is mapped into kernel virtual memory
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* dynamically, so we need a place to store that address.
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* Note that this field could be 16 bits on x86 ... ;)
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*
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* Architectures with slow multiplication can define
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* WANT_PAGE_VIRTUAL in asm/page.h
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*/
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#if defined(WANT_PAGE_VIRTUAL)
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void *virtual; /* Kernel virtual address (NULL if
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not kmapped, ie. highmem) */
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#endif /* WANT_PAGE_VIRTUAL */
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#ifdef CONFIG_KMSAN
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/*
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* KMSAN metadata for this page:
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* - shadow page: every bit indicates whether the corresponding
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* bit of the original page is initialized (0) or not (1);
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* - origin page: every 4 bytes contain an id of the stack trace
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* where the uninitialized value was created.
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*/
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struct page *kmsan_shadow;
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struct page *kmsan_origin;
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#endif
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#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
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int _last_cpupid;
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#endif
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} _struct_page_alignment;
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/*
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* struct encoded_page - a nonexistent type marking this pointer
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*
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* An 'encoded_page' pointer is a pointer to a regular 'struct page', but
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* with the low bits of the pointer indicating extra context-dependent
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* information. Not super-common, but happens in mmu_gather and mlock
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* handling, and this acts as a type system check on that use.
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*
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* We only really have two guaranteed bits in general, although you could
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* play with 'struct page' alignment (see CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
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* for more.
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*
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* Use the supplied helper functions to endcode/decode the pointer and bits.
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*/
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struct encoded_page;
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#define ENCODE_PAGE_BITS 3ul
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static __always_inline struct encoded_page *encode_page(struct page *page, unsigned long flags)
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{
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BUILD_BUG_ON(flags > ENCODE_PAGE_BITS);
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return (struct encoded_page *)(flags | (unsigned long)page);
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}
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static inline unsigned long encoded_page_flags(struct encoded_page *page)
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{
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return ENCODE_PAGE_BITS & (unsigned long)page;
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}
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static inline struct page *encoded_page_ptr(struct encoded_page *page)
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{
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return (struct page *)(~ENCODE_PAGE_BITS & (unsigned long)page);
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}
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/*
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* A swap entry has to fit into a "unsigned long", as the entry is hidden
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* in the "index" field of the swapper address space.
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*/
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typedef struct {
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unsigned long val;
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} swp_entry_t;
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/**
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* struct folio - Represents a contiguous set of bytes.
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* @flags: Identical to the page flags.
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* @lru: Least Recently Used list; tracks how recently this folio was used.
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* @mlock_count: Number of times this folio has been pinned by mlock().
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* @mapping: The file this page belongs to, or refers to the anon_vma for
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* anonymous memory.
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* @index: Offset within the file, in units of pages. For anonymous memory,
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* this is the index from the beginning of the mmap.
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* @private: Filesystem per-folio data (see folio_attach_private()).
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* @swap: Used for swp_entry_t if folio_test_swapcache().
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* @_mapcount: Do not access this member directly. Use folio_mapcount() to
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* find out how many times this folio is mapped by userspace.
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* @_refcount: Do not access this member directly. Use folio_ref_count()
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* to find how many references there are to this folio.
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* @memcg_data: Memory Control Group data.
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* @_entire_mapcount: Do not use directly, call folio_entire_mapcount().
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* @_nr_pages_mapped: Do not use directly, call folio_mapcount().
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* @_pincount: Do not use directly, call folio_maybe_dma_pinned().
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* @_folio_nr_pages: Do not use directly, call folio_nr_pages().
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* @_hugetlb_subpool: Do not use directly, use accessor in hugetlb.h.
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* @_hugetlb_cgroup: Do not use directly, use accessor in hugetlb_cgroup.h.
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* @_hugetlb_cgroup_rsvd: Do not use directly, use accessor in hugetlb_cgroup.h.
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* @_hugetlb_hwpoison: Do not use directly, call raw_hwp_list_head().
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* @_deferred_list: Folios to be split under memory pressure.
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*
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* A folio is a physically, virtually and logically contiguous set
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* of bytes. It is a power-of-two in size, and it is aligned to that
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* same power-of-two. It is at least as large as %PAGE_SIZE. If it is
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* in the page cache, it is at a file offset which is a multiple of that
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* power-of-two. It may be mapped into userspace at an address which is
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* at an arbitrary page offset, but its kernel virtual address is aligned
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* to its size.
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*/
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struct folio {
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/* private: don't document the anon union */
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union {
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struct {
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/* public: */
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unsigned long flags;
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union {
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struct list_head lru;
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/* private: avoid cluttering the output */
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struct {
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void *__filler;
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/* public: */
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unsigned int mlock_count;
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/* private: */
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};
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/* public: */
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};
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struct address_space *mapping;
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pgoff_t index;
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union {
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void *private;
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swp_entry_t swap;
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};
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atomic_t _mapcount;
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atomic_t _refcount;
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#ifdef CONFIG_MEMCG
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unsigned long memcg_data;
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#endif
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/* private: the union with struct page is transitional */
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};
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struct page page;
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};
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union {
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struct {
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unsigned long _flags_1;
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unsigned long _head_1;
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unsigned long _folio_avail;
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/* public: */
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atomic_t _entire_mapcount;
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atomic_t _nr_pages_mapped;
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atomic_t _pincount;
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#ifdef CONFIG_64BIT
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unsigned int _folio_nr_pages;
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#endif
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/* private: the union with struct page is transitional */
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};
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struct page __page_1;
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};
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union {
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struct {
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unsigned long _flags_2;
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unsigned long _head_2;
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/* public: */
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void *_hugetlb_subpool;
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void *_hugetlb_cgroup;
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void *_hugetlb_cgroup_rsvd;
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void *_hugetlb_hwpoison;
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/* private: the union with struct page is transitional */
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};
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struct {
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unsigned long _flags_2a;
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unsigned long _head_2a;
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/* public: */
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struct list_head _deferred_list;
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/* private: the union with struct page is transitional */
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};
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struct page __page_2;
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};
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};
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#define FOLIO_MATCH(pg, fl) \
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static_assert(offsetof(struct page, pg) == offsetof(struct folio, fl))
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FOLIO_MATCH(flags, flags);
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FOLIO_MATCH(lru, lru);
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FOLIO_MATCH(mapping, mapping);
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FOLIO_MATCH(compound_head, lru);
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FOLIO_MATCH(index, index);
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FOLIO_MATCH(private, private);
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FOLIO_MATCH(_mapcount, _mapcount);
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FOLIO_MATCH(_refcount, _refcount);
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#ifdef CONFIG_MEMCG
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FOLIO_MATCH(memcg_data, memcg_data);
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#endif
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#undef FOLIO_MATCH
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#define FOLIO_MATCH(pg, fl) \
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static_assert(offsetof(struct folio, fl) == \
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offsetof(struct page, pg) + sizeof(struct page))
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FOLIO_MATCH(flags, _flags_1);
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FOLIO_MATCH(compound_head, _head_1);
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#undef FOLIO_MATCH
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#define FOLIO_MATCH(pg, fl) \
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static_assert(offsetof(struct folio, fl) == \
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offsetof(struct page, pg) + 2 * sizeof(struct page))
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FOLIO_MATCH(flags, _flags_2);
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FOLIO_MATCH(compound_head, _head_2);
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FOLIO_MATCH(flags, _flags_2a);
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FOLIO_MATCH(compound_head, _head_2a);
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#undef FOLIO_MATCH
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/**
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* struct ptdesc - Memory descriptor for page tables.
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* @__page_flags: Same as page flags. Unused for page tables.
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* @pt_rcu_head: For freeing page table pages.
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* @pt_list: List of used page tables. Used for s390 and x86.
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* @_pt_pad_1: Padding that aliases with page's compound head.
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* @pmd_huge_pte: Protected by ptdesc->ptl, used for THPs.
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* @__page_mapping: Aliases with page->mapping. Unused for page tables.
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* @pt_mm: Used for x86 pgds.
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* @pt_frag_refcount: For fragmented page table tracking. Powerpc and s390 only.
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* @_pt_pad_2: Padding to ensure proper alignment.
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* @ptl: Lock for the page table.
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* @__page_type: Same as page->page_type. Unused for page tables.
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* @_refcount: Same as page refcount. Used for s390 page tables.
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* @pt_memcg_data: Memcg data. Tracked for page tables here.
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*
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* This struct overlays struct page for now. Do not modify without a good
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* understanding of the issues.
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*/
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struct ptdesc {
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unsigned long __page_flags;
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union {
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struct rcu_head pt_rcu_head;
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struct list_head pt_list;
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struct {
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unsigned long _pt_pad_1;
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pgtable_t pmd_huge_pte;
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};
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};
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unsigned long __page_mapping;
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union {
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struct mm_struct *pt_mm;
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atomic_t pt_frag_refcount;
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};
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union {
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unsigned long _pt_pad_2;
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#if ALLOC_SPLIT_PTLOCKS
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spinlock_t *ptl;
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#else
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spinlock_t ptl;
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#endif
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};
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unsigned int __page_type;
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atomic_t _refcount;
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#ifdef CONFIG_MEMCG
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unsigned long pt_memcg_data;
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#endif
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};
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#define TABLE_MATCH(pg, pt) \
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static_assert(offsetof(struct page, pg) == offsetof(struct ptdesc, pt))
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TABLE_MATCH(flags, __page_flags);
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TABLE_MATCH(compound_head, pt_list);
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TABLE_MATCH(compound_head, _pt_pad_1);
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TABLE_MATCH(mapping, __page_mapping);
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TABLE_MATCH(rcu_head, pt_rcu_head);
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TABLE_MATCH(page_type, __page_type);
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TABLE_MATCH(_refcount, _refcount);
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#ifdef CONFIG_MEMCG
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TABLE_MATCH(memcg_data, pt_memcg_data);
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#endif
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#undef TABLE_MATCH
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static_assert(sizeof(struct ptdesc) <= sizeof(struct page));
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#define ptdesc_page(pt) (_Generic((pt), \
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const struct ptdesc *: (const struct page *)(pt), \
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struct ptdesc *: (struct page *)(pt)))
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#define ptdesc_folio(pt) (_Generic((pt), \
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const struct ptdesc *: (const struct folio *)(pt), \
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struct ptdesc *: (struct folio *)(pt)))
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#define page_ptdesc(p) (_Generic((p), \
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const struct page *: (const struct ptdesc *)(p), \
|
|
struct page *: (struct ptdesc *)(p)))
|
|
|
|
/*
|
|
* Used for sizing the vmemmap region on some architectures
|
|
*/
|
|
#define STRUCT_PAGE_MAX_SHIFT (order_base_2(sizeof(struct page)))
|
|
|
|
#define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK)
|
|
#define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE)
|
|
|
|
/*
|
|
* page_private can be used on tail pages. However, PagePrivate is only
|
|
* checked by the VM on the head page. So page_private on the tail pages
|
|
* should be used for data that's ancillary to the head page (eg attaching
|
|
* buffer heads to tail pages after attaching buffer heads to the head page)
|
|
*/
|
|
#define page_private(page) ((page)->private)
|
|
|
|
static inline void set_page_private(struct page *page, unsigned long private)
|
|
{
|
|
page->private = private;
|
|
}
|
|
|
|
static inline void *folio_get_private(struct folio *folio)
|
|
{
|
|
return folio->private;
|
|
}
|
|
|
|
struct page_frag_cache {
|
|
void * va;
|
|
#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
|
|
__u16 offset;
|
|
__u16 size;
|
|
#else
|
|
__u32 offset;
|
|
#endif
|
|
/* we maintain a pagecount bias, so that we dont dirty cache line
|
|
* containing page->_refcount every time we allocate a fragment.
|
|
*/
|
|
unsigned int pagecnt_bias;
|
|
bool pfmemalloc;
|
|
};
|
|
|
|
typedef unsigned long vm_flags_t;
|
|
|
|
/*
|
|
* A region containing a mapping of a non-memory backed file under NOMMU
|
|
* conditions. These are held in a global tree and are pinned by the VMAs that
|
|
* map parts of them.
|
|
*/
|
|
struct vm_region {
|
|
struct rb_node vm_rb; /* link in global region tree */
|
|
vm_flags_t vm_flags; /* VMA vm_flags */
|
|
unsigned long vm_start; /* start address of region */
|
|
unsigned long vm_end; /* region initialised to here */
|
|
unsigned long vm_top; /* region allocated to here */
|
|
unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */
|
|
struct file *vm_file; /* the backing file or NULL */
|
|
|
|
int vm_usage; /* region usage count (access under nommu_region_sem) */
|
|
bool vm_icache_flushed : 1; /* true if the icache has been flushed for
|
|
* this region */
|
|
};
|
|
|
|
#ifdef CONFIG_USERFAULTFD
|
|
#define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, })
|
|
struct vm_userfaultfd_ctx {
|
|
struct userfaultfd_ctx *ctx;
|
|
};
|
|
#else /* CONFIG_USERFAULTFD */
|
|
#define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {})
|
|
struct vm_userfaultfd_ctx {};
|
|
#endif /* CONFIG_USERFAULTFD */
|
|
|
|
struct anon_vma_name {
|
|
struct kref kref;
|
|
/* The name needs to be at the end because it is dynamically sized. */
|
|
char name[];
|
|
};
|
|
|
|
struct vma_lock {
|
|
struct rw_semaphore lock;
|
|
};
|
|
|
|
struct vma_numab_state {
|
|
unsigned long next_scan;
|
|
unsigned long next_pid_reset;
|
|
unsigned long access_pids[2];
|
|
};
|
|
|
|
/*
|
|
* This struct describes a virtual memory area. There is one of these
|
|
* per VM-area/task. A VM area is any part of the process virtual memory
|
|
* space that has a special rule for the page-fault handlers (ie a shared
|
|
* library, the executable area etc).
|
|
*/
|
|
struct vm_area_struct {
|
|
/* The first cache line has the info for VMA tree walking. */
|
|
|
|
union {
|
|
struct {
|
|
/* VMA covers [vm_start; vm_end) addresses within mm */
|
|
unsigned long vm_start;
|
|
unsigned long vm_end;
|
|
};
|
|
#ifdef CONFIG_PER_VMA_LOCK
|
|
struct rcu_head vm_rcu; /* Used for deferred freeing. */
|
|
#endif
|
|
};
|
|
|
|
struct mm_struct *vm_mm; /* The address space we belong to. */
|
|
pgprot_t vm_page_prot; /* Access permissions of this VMA. */
|
|
|
|
/*
|
|
* Flags, see mm.h.
|
|
* To modify use vm_flags_{init|reset|set|clear|mod} functions.
|
|
*/
|
|
union {
|
|
const vm_flags_t vm_flags;
|
|
vm_flags_t __private __vm_flags;
|
|
};
|
|
|
|
#ifdef CONFIG_PER_VMA_LOCK
|
|
/*
|
|
* Can only be written (using WRITE_ONCE()) while holding both:
|
|
* - mmap_lock (in write mode)
|
|
* - vm_lock->lock (in write mode)
|
|
* Can be read reliably while holding one of:
|
|
* - mmap_lock (in read or write mode)
|
|
* - vm_lock->lock (in read or write mode)
|
|
* Can be read unreliably (using READ_ONCE()) for pessimistic bailout
|
|
* while holding nothing (except RCU to keep the VMA struct allocated).
|
|
*
|
|
* This sequence counter is explicitly allowed to overflow; sequence
|
|
* counter reuse can only lead to occasional unnecessary use of the
|
|
* slowpath.
|
|
*/
|
|
int vm_lock_seq;
|
|
struct vma_lock *vm_lock;
|
|
|
|
/* Flag to indicate areas detached from the mm->mm_mt tree */
|
|
bool detached;
|
|
#endif
|
|
|
|
/*
|
|
* For areas with an address space and backing store,
|
|
* linkage into the address_space->i_mmap interval tree.
|
|
*
|
|
*/
|
|
struct {
|
|
struct rb_node rb;
|
|
unsigned long rb_subtree_last;
|
|
} shared;
|
|
|
|
/*
|
|
* A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
|
|
* list, after a COW of one of the file pages. A MAP_SHARED vma
|
|
* can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
|
|
* or brk vma (with NULL file) can only be in an anon_vma list.
|
|
*/
|
|
struct list_head anon_vma_chain; /* Serialized by mmap_lock &
|
|
* page_table_lock */
|
|
struct anon_vma *anon_vma; /* Serialized by page_table_lock */
|
|
|
|
/* Function pointers to deal with this struct. */
|
|
const struct vm_operations_struct *vm_ops;
|
|
|
|
/* Information about our backing store: */
|
|
unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
|
|
units */
|
|
struct file * vm_file; /* File we map to (can be NULL). */
|
|
void * vm_private_data; /* was vm_pte (shared mem) */
|
|
|
|
#ifdef CONFIG_ANON_VMA_NAME
|
|
/*
|
|
* For private and shared anonymous mappings, a pointer to a null
|
|
* terminated string containing the name given to the vma, or NULL if
|
|
* unnamed. Serialized by mmap_lock. Use anon_vma_name to access.
|
|
*/
|
|
struct anon_vma_name *anon_name;
|
|
#endif
|
|
#ifdef CONFIG_SWAP
|
|
atomic_long_t swap_readahead_info;
|
|
#endif
|
|
#ifndef CONFIG_MMU
|
|
struct vm_region *vm_region; /* NOMMU mapping region */
|
|
#endif
|
|
#ifdef CONFIG_NUMA
|
|
struct mempolicy *vm_policy; /* NUMA policy for the VMA */
|
|
#endif
|
|
#ifdef CONFIG_NUMA_BALANCING
|
|
struct vma_numab_state *numab_state; /* NUMA Balancing state */
|
|
#endif
|
|
struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
|
|
} __randomize_layout;
|
|
|
|
#ifdef CONFIG_SCHED_MM_CID
|
|
struct mm_cid {
|
|
u64 time;
|
|
int cid;
|
|
};
|
|
#endif
|
|
|
|
struct kioctx_table;
|
|
struct mm_struct {
|
|
struct {
|
|
/*
|
|
* Fields which are often written to are placed in a separate
|
|
* cache line.
|
|
*/
|
|
struct {
|
|
/**
|
|
* @mm_count: The number of references to &struct
|
|
* mm_struct (@mm_users count as 1).
|
|
*
|
|
* Use mmgrab()/mmdrop() to modify. When this drops to
|
|
* 0, the &struct mm_struct is freed.
|
|
*/
|
|
atomic_t mm_count;
|
|
} ____cacheline_aligned_in_smp;
|
|
|
|
struct maple_tree mm_mt;
|
|
#ifdef CONFIG_MMU
|
|
unsigned long (*get_unmapped_area) (struct file *filp,
|
|
unsigned long addr, unsigned long len,
|
|
unsigned long pgoff, unsigned long flags);
|
|
#endif
|
|
unsigned long mmap_base; /* base of mmap area */
|
|
unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */
|
|
#ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES
|
|
/* Base addresses for compatible mmap() */
|
|
unsigned long mmap_compat_base;
|
|
unsigned long mmap_compat_legacy_base;
|
|
#endif
|
|
unsigned long task_size; /* size of task vm space */
|
|
pgd_t * pgd;
|
|
|
|
#ifdef CONFIG_MEMBARRIER
|
|
/**
|
|
* @membarrier_state: Flags controlling membarrier behavior.
|
|
*
|
|
* This field is close to @pgd to hopefully fit in the same
|
|
* cache-line, which needs to be touched by switch_mm().
|
|
*/
|
|
atomic_t membarrier_state;
|
|
#endif
|
|
|
|
/**
|
|
* @mm_users: The number of users including userspace.
|
|
*
|
|
* Use mmget()/mmget_not_zero()/mmput() to modify. When this
|
|
* drops to 0 (i.e. when the task exits and there are no other
|
|
* temporary reference holders), we also release a reference on
|
|
* @mm_count (which may then free the &struct mm_struct if
|
|
* @mm_count also drops to 0).
|
|
*/
|
|
atomic_t mm_users;
|
|
|
|
#ifdef CONFIG_SCHED_MM_CID
|
|
/**
|
|
* @pcpu_cid: Per-cpu current cid.
|
|
*
|
|
* Keep track of the currently allocated mm_cid for each cpu.
|
|
* The per-cpu mm_cid values are serialized by their respective
|
|
* runqueue locks.
|
|
*/
|
|
struct mm_cid __percpu *pcpu_cid;
|
|
/*
|
|
* @mm_cid_next_scan: Next mm_cid scan (in jiffies).
|
|
*
|
|
* When the next mm_cid scan is due (in jiffies).
|
|
*/
|
|
unsigned long mm_cid_next_scan;
|
|
#endif
|
|
#ifdef CONFIG_MMU
|
|
atomic_long_t pgtables_bytes; /* size of all page tables */
|
|
#endif
|
|
int map_count; /* number of VMAs */
|
|
|
|
spinlock_t page_table_lock; /* Protects page tables and some
|
|
* counters
|
|
*/
|
|
/*
|
|
* With some kernel config, the current mmap_lock's offset
|
|
* inside 'mm_struct' is at 0x120, which is very optimal, as
|
|
* its two hot fields 'count' and 'owner' sit in 2 different
|
|
* cachelines, and when mmap_lock is highly contended, both
|
|
* of the 2 fields will be accessed frequently, current layout
|
|
* will help to reduce cache bouncing.
|
|
*
|
|
* So please be careful with adding new fields before
|
|
* mmap_lock, which can easily push the 2 fields into one
|
|
* cacheline.
|
|
*/
|
|
struct rw_semaphore mmap_lock;
|
|
|
|
struct list_head mmlist; /* List of maybe swapped mm's. These
|
|
* are globally strung together off
|
|
* init_mm.mmlist, and are protected
|
|
* by mmlist_lock
|
|
*/
|
|
#ifdef CONFIG_PER_VMA_LOCK
|
|
/*
|
|
* This field has lock-like semantics, meaning it is sometimes
|
|
* accessed with ACQUIRE/RELEASE semantics.
|
|
* Roughly speaking, incrementing the sequence number is
|
|
* equivalent to releasing locks on VMAs; reading the sequence
|
|
* number can be part of taking a read lock on a VMA.
|
|
*
|
|
* Can be modified under write mmap_lock using RELEASE
|
|
* semantics.
|
|
* Can be read with no other protection when holding write
|
|
* mmap_lock.
|
|
* Can be read with ACQUIRE semantics if not holding write
|
|
* mmap_lock.
|
|
*/
|
|
int mm_lock_seq;
|
|
#endif
|
|
|
|
|
|
unsigned long hiwater_rss; /* High-watermark of RSS usage */
|
|
unsigned long hiwater_vm; /* High-water virtual memory usage */
|
|
|
|
unsigned long total_vm; /* Total pages mapped */
|
|
unsigned long locked_vm; /* Pages that have PG_mlocked set */
|
|
atomic64_t pinned_vm; /* Refcount permanently increased */
|
|
unsigned long data_vm; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */
|
|
unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */
|
|
unsigned long stack_vm; /* VM_STACK */
|
|
unsigned long def_flags;
|
|
|
|
/**
|
|
* @write_protect_seq: Locked when any thread is write
|
|
* protecting pages mapped by this mm to enforce a later COW,
|
|
* for instance during page table copying for fork().
|
|
*/
|
|
seqcount_t write_protect_seq;
|
|
|
|
spinlock_t arg_lock; /* protect the below fields */
|
|
|
|
unsigned long start_code, end_code, start_data, end_data;
|
|
unsigned long start_brk, brk, start_stack;
|
|
unsigned long arg_start, arg_end, env_start, env_end;
|
|
|
|
unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
|
|
|
|
struct percpu_counter rss_stat[NR_MM_COUNTERS];
|
|
|
|
struct linux_binfmt *binfmt;
|
|
|
|
/* Architecture-specific MM context */
|
|
mm_context_t context;
|
|
|
|
unsigned long flags; /* Must use atomic bitops to access */
|
|
|
|
#ifdef CONFIG_AIO
|
|
spinlock_t ioctx_lock;
|
|
struct kioctx_table __rcu *ioctx_table;
|
|
#endif
|
|
#ifdef CONFIG_MEMCG
|
|
/*
|
|
* "owner" points to a task that is regarded as the canonical
|
|
* user/owner of this mm. All of the following must be true in
|
|
* order for it to be changed:
|
|
*
|
|
* current == mm->owner
|
|
* current->mm != mm
|
|
* new_owner->mm == mm
|
|
* new_owner->alloc_lock is held
|
|
*/
|
|
struct task_struct __rcu *owner;
|
|
#endif
|
|
struct user_namespace *user_ns;
|
|
|
|
/* store ref to file /proc/<pid>/exe symlink points to */
|
|
struct file __rcu *exe_file;
|
|
#ifdef CONFIG_MMU_NOTIFIER
|
|
struct mmu_notifier_subscriptions *notifier_subscriptions;
|
|
#endif
|
|
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
|
|
pgtable_t pmd_huge_pte; /* protected by page_table_lock */
|
|
#endif
|
|
#ifdef CONFIG_NUMA_BALANCING
|
|
/*
|
|
* numa_next_scan is the next time that PTEs will be remapped
|
|
* PROT_NONE to trigger NUMA hinting faults; such faults gather
|
|
* statistics and migrate pages to new nodes if necessary.
|
|
*/
|
|
unsigned long numa_next_scan;
|
|
|
|
/* Restart point for scanning and remapping PTEs. */
|
|
unsigned long numa_scan_offset;
|
|
|
|
/* numa_scan_seq prevents two threads remapping PTEs. */
|
|
int numa_scan_seq;
|
|
#endif
|
|
/*
|
|
* An operation with batched TLB flushing is going on. Anything
|
|
* that can move process memory needs to flush the TLB when
|
|
* moving a PROT_NONE mapped page.
|
|
*/
|
|
atomic_t tlb_flush_pending;
|
|
#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
|
|
/* See flush_tlb_batched_pending() */
|
|
atomic_t tlb_flush_batched;
|
|
#endif
|
|
struct uprobes_state uprobes_state;
|
|
#ifdef CONFIG_PREEMPT_RT
|
|
struct rcu_head delayed_drop;
|
|
#endif
|
|
#ifdef CONFIG_HUGETLB_PAGE
|
|
atomic_long_t hugetlb_usage;
|
|
#endif
|
|
struct work_struct async_put_work;
|
|
|
|
#ifdef CONFIG_IOMMU_SVA
|
|
u32 pasid;
|
|
#endif
|
|
#ifdef CONFIG_KSM
|
|
/*
|
|
* Represent how many pages of this process are involved in KSM
|
|
* merging (not including ksm_zero_pages).
|
|
*/
|
|
unsigned long ksm_merging_pages;
|
|
/*
|
|
* Represent how many pages are checked for ksm merging
|
|
* including merged and not merged.
|
|
*/
|
|
unsigned long ksm_rmap_items;
|
|
/*
|
|
* Represent how many empty pages are merged with kernel zero
|
|
* pages when enabling KSM use_zero_pages.
|
|
*/
|
|
unsigned long ksm_zero_pages;
|
|
#endif /* CONFIG_KSM */
|
|
#ifdef CONFIG_LRU_GEN
|
|
struct {
|
|
/* this mm_struct is on lru_gen_mm_list */
|
|
struct list_head list;
|
|
/*
|
|
* Set when switching to this mm_struct, as a hint of
|
|
* whether it has been used since the last time per-node
|
|
* page table walkers cleared the corresponding bits.
|
|
*/
|
|
unsigned long bitmap;
|
|
#ifdef CONFIG_MEMCG
|
|
/* points to the memcg of "owner" above */
|
|
struct mem_cgroup *memcg;
|
|
#endif
|
|
} lru_gen;
|
|
#endif /* CONFIG_LRU_GEN */
|
|
} __randomize_layout;
|
|
|
|
/*
|
|
* The mm_cpumask needs to be at the end of mm_struct, because it
|
|
* is dynamically sized based on nr_cpu_ids.
|
|
*/
|
|
unsigned long cpu_bitmap[];
|
|
};
|
|
|
|
#define MM_MT_FLAGS (MT_FLAGS_ALLOC_RANGE | MT_FLAGS_LOCK_EXTERN | \
|
|
MT_FLAGS_USE_RCU)
|
|
extern struct mm_struct init_mm;
|
|
|
|
/* Pointer magic because the dynamic array size confuses some compilers. */
|
|
static inline void mm_init_cpumask(struct mm_struct *mm)
|
|
{
|
|
unsigned long cpu_bitmap = (unsigned long)mm;
|
|
|
|
cpu_bitmap += offsetof(struct mm_struct, cpu_bitmap);
|
|
cpumask_clear((struct cpumask *)cpu_bitmap);
|
|
}
|
|
|
|
/* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
|
|
static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
|
|
{
|
|
return (struct cpumask *)&mm->cpu_bitmap;
|
|
}
|
|
|
|
#ifdef CONFIG_LRU_GEN
|
|
|
|
struct lru_gen_mm_list {
|
|
/* mm_struct list for page table walkers */
|
|
struct list_head fifo;
|
|
/* protects the list above */
|
|
spinlock_t lock;
|
|
};
|
|
|
|
void lru_gen_add_mm(struct mm_struct *mm);
|
|
void lru_gen_del_mm(struct mm_struct *mm);
|
|
#ifdef CONFIG_MEMCG
|
|
void lru_gen_migrate_mm(struct mm_struct *mm);
|
|
#endif
|
|
|
|
static inline void lru_gen_init_mm(struct mm_struct *mm)
|
|
{
|
|
INIT_LIST_HEAD(&mm->lru_gen.list);
|
|
mm->lru_gen.bitmap = 0;
|
|
#ifdef CONFIG_MEMCG
|
|
mm->lru_gen.memcg = NULL;
|
|
#endif
|
|
}
|
|
|
|
static inline void lru_gen_use_mm(struct mm_struct *mm)
|
|
{
|
|
/*
|
|
* When the bitmap is set, page reclaim knows this mm_struct has been
|
|
* used since the last time it cleared the bitmap. So it might be worth
|
|
* walking the page tables of this mm_struct to clear the accessed bit.
|
|
*/
|
|
WRITE_ONCE(mm->lru_gen.bitmap, -1);
|
|
}
|
|
|
|
#else /* !CONFIG_LRU_GEN */
|
|
|
|
static inline void lru_gen_add_mm(struct mm_struct *mm)
|
|
{
|
|
}
|
|
|
|
static inline void lru_gen_del_mm(struct mm_struct *mm)
|
|
{
|
|
}
|
|
|
|
#ifdef CONFIG_MEMCG
|
|
static inline void lru_gen_migrate_mm(struct mm_struct *mm)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
static inline void lru_gen_init_mm(struct mm_struct *mm)
|
|
{
|
|
}
|
|
|
|
static inline void lru_gen_use_mm(struct mm_struct *mm)
|
|
{
|
|
}
|
|
|
|
#endif /* CONFIG_LRU_GEN */
|
|
|
|
struct vma_iterator {
|
|
struct ma_state mas;
|
|
};
|
|
|
|
#define VMA_ITERATOR(name, __mm, __addr) \
|
|
struct vma_iterator name = { \
|
|
.mas = { \
|
|
.tree = &(__mm)->mm_mt, \
|
|
.index = __addr, \
|
|
.node = MAS_START, \
|
|
}, \
|
|
}
|
|
|
|
static inline void vma_iter_init(struct vma_iterator *vmi,
|
|
struct mm_struct *mm, unsigned long addr)
|
|
{
|
|
mas_init(&vmi->mas, &mm->mm_mt, addr);
|
|
}
|
|
|
|
#ifdef CONFIG_SCHED_MM_CID
|
|
|
|
enum mm_cid_state {
|
|
MM_CID_UNSET = -1U, /* Unset state has lazy_put flag set. */
|
|
MM_CID_LAZY_PUT = (1U << 31),
|
|
};
|
|
|
|
static inline bool mm_cid_is_unset(int cid)
|
|
{
|
|
return cid == MM_CID_UNSET;
|
|
}
|
|
|
|
static inline bool mm_cid_is_lazy_put(int cid)
|
|
{
|
|
return !mm_cid_is_unset(cid) && (cid & MM_CID_LAZY_PUT);
|
|
}
|
|
|
|
static inline bool mm_cid_is_valid(int cid)
|
|
{
|
|
return !(cid & MM_CID_LAZY_PUT);
|
|
}
|
|
|
|
static inline int mm_cid_set_lazy_put(int cid)
|
|
{
|
|
return cid | MM_CID_LAZY_PUT;
|
|
}
|
|
|
|
static inline int mm_cid_clear_lazy_put(int cid)
|
|
{
|
|
return cid & ~MM_CID_LAZY_PUT;
|
|
}
|
|
|
|
/* Accessor for struct mm_struct's cidmask. */
|
|
static inline cpumask_t *mm_cidmask(struct mm_struct *mm)
|
|
{
|
|
unsigned long cid_bitmap = (unsigned long)mm;
|
|
|
|
cid_bitmap += offsetof(struct mm_struct, cpu_bitmap);
|
|
/* Skip cpu_bitmap */
|
|
cid_bitmap += cpumask_size();
|
|
return (struct cpumask *)cid_bitmap;
|
|
}
|
|
|
|
static inline void mm_init_cid(struct mm_struct *mm)
|
|
{
|
|
int i;
|
|
|
|
for_each_possible_cpu(i) {
|
|
struct mm_cid *pcpu_cid = per_cpu_ptr(mm->pcpu_cid, i);
|
|
|
|
pcpu_cid->cid = MM_CID_UNSET;
|
|
pcpu_cid->time = 0;
|
|
}
|
|
cpumask_clear(mm_cidmask(mm));
|
|
}
|
|
|
|
static inline int mm_alloc_cid(struct mm_struct *mm)
|
|
{
|
|
mm->pcpu_cid = alloc_percpu(struct mm_cid);
|
|
if (!mm->pcpu_cid)
|
|
return -ENOMEM;
|
|
mm_init_cid(mm);
|
|
return 0;
|
|
}
|
|
|
|
static inline void mm_destroy_cid(struct mm_struct *mm)
|
|
{
|
|
free_percpu(mm->pcpu_cid);
|
|
mm->pcpu_cid = NULL;
|
|
}
|
|
|
|
static inline unsigned int mm_cid_size(void)
|
|
{
|
|
return cpumask_size();
|
|
}
|
|
#else /* CONFIG_SCHED_MM_CID */
|
|
static inline void mm_init_cid(struct mm_struct *mm) { }
|
|
static inline int mm_alloc_cid(struct mm_struct *mm) { return 0; }
|
|
static inline void mm_destroy_cid(struct mm_struct *mm) { }
|
|
static inline unsigned int mm_cid_size(void)
|
|
{
|
|
return 0;
|
|
}
|
|
#endif /* CONFIG_SCHED_MM_CID */
|
|
|
|
struct mmu_gather;
|
|
extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm);
|
|
extern void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm);
|
|
extern void tlb_finish_mmu(struct mmu_gather *tlb);
|
|
|
|
struct vm_fault;
|
|
|
|
/**
|
|
* typedef vm_fault_t - Return type for page fault handlers.
|
|
*
|
|
* Page fault handlers return a bitmask of %VM_FAULT values.
|
|
*/
|
|
typedef __bitwise unsigned int vm_fault_t;
|
|
|
|
/**
|
|
* enum vm_fault_reason - Page fault handlers return a bitmask of
|
|
* these values to tell the core VM what happened when handling the
|
|
* fault. Used to decide whether a process gets delivered SIGBUS or
|
|
* just gets major/minor fault counters bumped up.
|
|
*
|
|
* @VM_FAULT_OOM: Out Of Memory
|
|
* @VM_FAULT_SIGBUS: Bad access
|
|
* @VM_FAULT_MAJOR: Page read from storage
|
|
* @VM_FAULT_HWPOISON: Hit poisoned small page
|
|
* @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded
|
|
* in upper bits
|
|
* @VM_FAULT_SIGSEGV: segmentation fault
|
|
* @VM_FAULT_NOPAGE: ->fault installed the pte, not return page
|
|
* @VM_FAULT_LOCKED: ->fault locked the returned page
|
|
* @VM_FAULT_RETRY: ->fault blocked, must retry
|
|
* @VM_FAULT_FALLBACK: huge page fault failed, fall back to small
|
|
* @VM_FAULT_DONE_COW: ->fault has fully handled COW
|
|
* @VM_FAULT_NEEDDSYNC: ->fault did not modify page tables and needs
|
|
* fsync() to complete (for synchronous page faults
|
|
* in DAX)
|
|
* @VM_FAULT_COMPLETED: ->fault completed, meanwhile mmap lock released
|
|
* @VM_FAULT_HINDEX_MASK: mask HINDEX value
|
|
*
|
|
*/
|
|
enum vm_fault_reason {
|
|
VM_FAULT_OOM = (__force vm_fault_t)0x000001,
|
|
VM_FAULT_SIGBUS = (__force vm_fault_t)0x000002,
|
|
VM_FAULT_MAJOR = (__force vm_fault_t)0x000004,
|
|
VM_FAULT_HWPOISON = (__force vm_fault_t)0x000010,
|
|
VM_FAULT_HWPOISON_LARGE = (__force vm_fault_t)0x000020,
|
|
VM_FAULT_SIGSEGV = (__force vm_fault_t)0x000040,
|
|
VM_FAULT_NOPAGE = (__force vm_fault_t)0x000100,
|
|
VM_FAULT_LOCKED = (__force vm_fault_t)0x000200,
|
|
VM_FAULT_RETRY = (__force vm_fault_t)0x000400,
|
|
VM_FAULT_FALLBACK = (__force vm_fault_t)0x000800,
|
|
VM_FAULT_DONE_COW = (__force vm_fault_t)0x001000,
|
|
VM_FAULT_NEEDDSYNC = (__force vm_fault_t)0x002000,
|
|
VM_FAULT_COMPLETED = (__force vm_fault_t)0x004000,
|
|
VM_FAULT_HINDEX_MASK = (__force vm_fault_t)0x0f0000,
|
|
};
|
|
|
|
/* Encode hstate index for a hwpoisoned large page */
|
|
#define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16))
|
|
#define VM_FAULT_GET_HINDEX(x) (((__force unsigned int)(x) >> 16) & 0xf)
|
|
|
|
#define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | \
|
|
VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON | \
|
|
VM_FAULT_HWPOISON_LARGE | VM_FAULT_FALLBACK)
|
|
|
|
#define VM_FAULT_RESULT_TRACE \
|
|
{ VM_FAULT_OOM, "OOM" }, \
|
|
{ VM_FAULT_SIGBUS, "SIGBUS" }, \
|
|
{ VM_FAULT_MAJOR, "MAJOR" }, \
|
|
{ VM_FAULT_HWPOISON, "HWPOISON" }, \
|
|
{ VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \
|
|
{ VM_FAULT_SIGSEGV, "SIGSEGV" }, \
|
|
{ VM_FAULT_NOPAGE, "NOPAGE" }, \
|
|
{ VM_FAULT_LOCKED, "LOCKED" }, \
|
|
{ VM_FAULT_RETRY, "RETRY" }, \
|
|
{ VM_FAULT_FALLBACK, "FALLBACK" }, \
|
|
{ VM_FAULT_DONE_COW, "DONE_COW" }, \
|
|
{ VM_FAULT_NEEDDSYNC, "NEEDDSYNC" }, \
|
|
{ VM_FAULT_COMPLETED, "COMPLETED" }
|
|
|
|
struct vm_special_mapping {
|
|
const char *name; /* The name, e.g. "[vdso]". */
|
|
|
|
/*
|
|
* If .fault is not provided, this points to a
|
|
* NULL-terminated array of pages that back the special mapping.
|
|
*
|
|
* This must not be NULL unless .fault is provided.
|
|
*/
|
|
struct page **pages;
|
|
|
|
/*
|
|
* If non-NULL, then this is called to resolve page faults
|
|
* on the special mapping. If used, .pages is not checked.
|
|
*/
|
|
vm_fault_t (*fault)(const struct vm_special_mapping *sm,
|
|
struct vm_area_struct *vma,
|
|
struct vm_fault *vmf);
|
|
|
|
int (*mremap)(const struct vm_special_mapping *sm,
|
|
struct vm_area_struct *new_vma);
|
|
};
|
|
|
|
enum tlb_flush_reason {
|
|
TLB_FLUSH_ON_TASK_SWITCH,
|
|
TLB_REMOTE_SHOOTDOWN,
|
|
TLB_LOCAL_SHOOTDOWN,
|
|
TLB_LOCAL_MM_SHOOTDOWN,
|
|
TLB_REMOTE_SEND_IPI,
|
|
NR_TLB_FLUSH_REASONS,
|
|
};
|
|
|
|
/**
|
|
* enum fault_flag - Fault flag definitions.
|
|
* @FAULT_FLAG_WRITE: Fault was a write fault.
|
|
* @FAULT_FLAG_MKWRITE: Fault was mkwrite of existing PTE.
|
|
* @FAULT_FLAG_ALLOW_RETRY: Allow to retry the fault if blocked.
|
|
* @FAULT_FLAG_RETRY_NOWAIT: Don't drop mmap_lock and wait when retrying.
|
|
* @FAULT_FLAG_KILLABLE: The fault task is in SIGKILL killable region.
|
|
* @FAULT_FLAG_TRIED: The fault has been tried once.
|
|
* @FAULT_FLAG_USER: The fault originated in userspace.
|
|
* @FAULT_FLAG_REMOTE: The fault is not for current task/mm.
|
|
* @FAULT_FLAG_INSTRUCTION: The fault was during an instruction fetch.
|
|
* @FAULT_FLAG_INTERRUPTIBLE: The fault can be interrupted by non-fatal signals.
|
|
* @FAULT_FLAG_UNSHARE: The fault is an unsharing request to break COW in a
|
|
* COW mapping, making sure that an exclusive anon page is
|
|
* mapped after the fault.
|
|
* @FAULT_FLAG_ORIG_PTE_VALID: whether the fault has vmf->orig_pte cached.
|
|
* We should only access orig_pte if this flag set.
|
|
* @FAULT_FLAG_VMA_LOCK: The fault is handled under VMA lock.
|
|
*
|
|
* About @FAULT_FLAG_ALLOW_RETRY and @FAULT_FLAG_TRIED: we can specify
|
|
* whether we would allow page faults to retry by specifying these two
|
|
* fault flags correctly. Currently there can be three legal combinations:
|
|
*
|
|
* (a) ALLOW_RETRY and !TRIED: this means the page fault allows retry, and
|
|
* this is the first try
|
|
*
|
|
* (b) ALLOW_RETRY and TRIED: this means the page fault allows retry, and
|
|
* we've already tried at least once
|
|
*
|
|
* (c) !ALLOW_RETRY and !TRIED: this means the page fault does not allow retry
|
|
*
|
|
* The unlisted combination (!ALLOW_RETRY && TRIED) is illegal and should never
|
|
* be used. Note that page faults can be allowed to retry for multiple times,
|
|
* in which case we'll have an initial fault with flags (a) then later on
|
|
* continuous faults with flags (b). We should always try to detect pending
|
|
* signals before a retry to make sure the continuous page faults can still be
|
|
* interrupted if necessary.
|
|
*
|
|
* The combination FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE is illegal.
|
|
* FAULT_FLAG_UNSHARE is ignored and treated like an ordinary read fault when
|
|
* applied to mappings that are not COW mappings.
|
|
*/
|
|
enum fault_flag {
|
|
FAULT_FLAG_WRITE = 1 << 0,
|
|
FAULT_FLAG_MKWRITE = 1 << 1,
|
|
FAULT_FLAG_ALLOW_RETRY = 1 << 2,
|
|
FAULT_FLAG_RETRY_NOWAIT = 1 << 3,
|
|
FAULT_FLAG_KILLABLE = 1 << 4,
|
|
FAULT_FLAG_TRIED = 1 << 5,
|
|
FAULT_FLAG_USER = 1 << 6,
|
|
FAULT_FLAG_REMOTE = 1 << 7,
|
|
FAULT_FLAG_INSTRUCTION = 1 << 8,
|
|
FAULT_FLAG_INTERRUPTIBLE = 1 << 9,
|
|
FAULT_FLAG_UNSHARE = 1 << 10,
|
|
FAULT_FLAG_ORIG_PTE_VALID = 1 << 11,
|
|
FAULT_FLAG_VMA_LOCK = 1 << 12,
|
|
};
|
|
|
|
typedef unsigned int __bitwise zap_flags_t;
|
|
|
|
/*
|
|
* FOLL_PIN and FOLL_LONGTERM may be used in various combinations with each
|
|
* other. Here is what they mean, and how to use them:
|
|
*
|
|
*
|
|
* FIXME: For pages which are part of a filesystem, mappings are subject to the
|
|
* lifetime enforced by the filesystem and we need guarantees that longterm
|
|
* users like RDMA and V4L2 only establish mappings which coordinate usage with
|
|
* the filesystem. Ideas for this coordination include revoking the longterm
|
|
* pin, delaying writeback, bounce buffer page writeback, etc. As FS DAX was
|
|
* added after the problem with filesystems was found FS DAX VMAs are
|
|
* specifically failed. Filesystem pages are still subject to bugs and use of
|
|
* FOLL_LONGTERM should be avoided on those pages.
|
|
*
|
|
* In the CMA case: long term pins in a CMA region would unnecessarily fragment
|
|
* that region. And so, CMA attempts to migrate the page before pinning, when
|
|
* FOLL_LONGTERM is specified.
|
|
*
|
|
* FOLL_PIN indicates that a special kind of tracking (not just page->_refcount,
|
|
* but an additional pin counting system) will be invoked. This is intended for
|
|
* anything that gets a page reference and then touches page data (for example,
|
|
* Direct IO). This lets the filesystem know that some non-file-system entity is
|
|
* potentially changing the pages' data. In contrast to FOLL_GET (whose pages
|
|
* are released via put_page()), FOLL_PIN pages must be released, ultimately, by
|
|
* a call to unpin_user_page().
|
|
*
|
|
* FOLL_PIN is similar to FOLL_GET: both of these pin pages. They use different
|
|
* and separate refcounting mechanisms, however, and that means that each has
|
|
* its own acquire and release mechanisms:
|
|
*
|
|
* FOLL_GET: get_user_pages*() to acquire, and put_page() to release.
|
|
*
|
|
* FOLL_PIN: pin_user_pages*() to acquire, and unpin_user_pages to release.
|
|
*
|
|
* FOLL_PIN and FOLL_GET are mutually exclusive for a given function call.
|
|
* (The underlying pages may experience both FOLL_GET-based and FOLL_PIN-based
|
|
* calls applied to them, and that's perfectly OK. This is a constraint on the
|
|
* callers, not on the pages.)
|
|
*
|
|
* FOLL_PIN should be set internally by the pin_user_pages*() APIs, never
|
|
* directly by the caller. That's in order to help avoid mismatches when
|
|
* releasing pages: get_user_pages*() pages must be released via put_page(),
|
|
* while pin_user_pages*() pages must be released via unpin_user_page().
|
|
*
|
|
* Please see Documentation/core-api/pin_user_pages.rst for more information.
|
|
*/
|
|
|
|
enum {
|
|
/* check pte is writable */
|
|
FOLL_WRITE = 1 << 0,
|
|
/* do get_page on page */
|
|
FOLL_GET = 1 << 1,
|
|
/* give error on hole if it would be zero */
|
|
FOLL_DUMP = 1 << 2,
|
|
/* get_user_pages read/write w/o permission */
|
|
FOLL_FORCE = 1 << 3,
|
|
/*
|
|
* if a disk transfer is needed, start the IO and return without waiting
|
|
* upon it
|
|
*/
|
|
FOLL_NOWAIT = 1 << 4,
|
|
/* do not fault in pages */
|
|
FOLL_NOFAULT = 1 << 5,
|
|
/* check page is hwpoisoned */
|
|
FOLL_HWPOISON = 1 << 6,
|
|
/* don't do file mappings */
|
|
FOLL_ANON = 1 << 7,
|
|
/*
|
|
* FOLL_LONGTERM indicates that the page will be held for an indefinite
|
|
* time period _often_ under userspace control. This is in contrast to
|
|
* iov_iter_get_pages(), whose usages are transient.
|
|
*/
|
|
FOLL_LONGTERM = 1 << 8,
|
|
/* split huge pmd before returning */
|
|
FOLL_SPLIT_PMD = 1 << 9,
|
|
/* allow returning PCI P2PDMA pages */
|
|
FOLL_PCI_P2PDMA = 1 << 10,
|
|
/* allow interrupts from generic signals */
|
|
FOLL_INTERRUPTIBLE = 1 << 11,
|
|
/*
|
|
* Always honor (trigger) NUMA hinting faults.
|
|
*
|
|
* FOLL_WRITE implicitly honors NUMA hinting faults because a
|
|
* PROT_NONE-mapped page is not writable (exceptions with FOLL_FORCE
|
|
* apply). get_user_pages_fast_only() always implicitly honors NUMA
|
|
* hinting faults.
|
|
*/
|
|
FOLL_HONOR_NUMA_FAULT = 1 << 12,
|
|
|
|
/* See also internal only FOLL flags in mm/internal.h */
|
|
};
|
|
|
|
#endif /* _LINUX_MM_TYPES_H */
|