![Richard Kennedy](/assets/img/avatar_default.png)
Reorder mm_struct to remove 16 bytes of alignment padding on 64 bit builds. On my config this shrinks mm_struct by enough to fit in one fewer cache lines and allows more objects per slab in mm_struct kmem_cache under SLUB. slabinfo before patch :- Sizes (bytes) Slabs -------------------------------- Object : 848 Total : 9 SlabObj: 896 Full : 2 SlabSiz: 16384 Partial: 5 Loss : 48 CpuSlab: 2 Align : 64 Objects: 18 slabinfo after :- Sizes (bytes) Slabs -------------------------------- Object : 832 Total : 7 SlabObj: 832 Full : 2 SlabSiz: 16384 Partial: 3 Loss : 0 CpuSlab: 2 Align : 64 Objects: 19 Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
326 lines
9.9 KiB
C
326 lines
9.9 KiB
C
#ifndef _LINUX_MM_TYPES_H
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#define _LINUX_MM_TYPES_H
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#include <linux/auxvec.h>
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#include <linux/types.h>
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#include <linux/threads.h>
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#include <linux/list.h>
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#include <linux/spinlock.h>
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#include <linux/prio_tree.h>
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#include <linux/rbtree.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/page-debug-flags.h>
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#include <asm/page.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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struct address_space;
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#define USE_SPLIT_PTLOCKS (NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS)
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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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struct page {
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unsigned long flags; /* Atomic flags, some possibly
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* updated asynchronously */
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atomic_t _count; /* Usage count, see below. */
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union {
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atomic_t _mapcount; /* Count of ptes mapped in mms,
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* to show when page is mapped
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* & limit reverse map searches.
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*/
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struct { /* SLUB */
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u16 inuse;
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u16 objects;
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};
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};
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union {
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struct {
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unsigned long private; /* Mapping-private opaque data:
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* usually used for buffer_heads
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* if PagePrivate set; used for
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* swp_entry_t if PageSwapCache;
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* indicates order in the buddy
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* system if PG_buddy is set.
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*/
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struct address_space *mapping; /* If low bit clear, points to
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* inode address_space, or NULL.
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* If page mapped as anonymous
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* memory, low bit is set, and
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* it points to anon_vma object:
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* see PAGE_MAPPING_ANON below.
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*/
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};
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#if USE_SPLIT_PTLOCKS
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spinlock_t ptl;
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#endif
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struct kmem_cache *slab; /* SLUB: Pointer to slab */
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struct page *first_page; /* Compound tail pages */
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};
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union {
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pgoff_t index; /* Our offset within mapping. */
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void *freelist; /* SLUB: freelist req. slab lock */
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};
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struct list_head lru; /* Pageout list, eg. active_list
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* protected by zone->lru_lock !
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*/
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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_WANT_PAGE_DEBUG_FLAGS
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unsigned long debug_flags; /* Use atomic bitops on this */
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#endif
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#ifdef CONFIG_KMEMCHECK
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/*
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* kmemcheck wants to track the status of each byte in a page; this
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* is a pointer to such a status block. NULL if not tracked.
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*/
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void *shadow;
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#endif
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};
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/*
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* A region containing a mapping of a non-memory backed file under NOMMU
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* conditions. These are held in a global tree and are pinned by the VMAs that
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* map parts of them.
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*/
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struct vm_region {
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struct rb_node vm_rb; /* link in global region tree */
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unsigned long vm_flags; /* VMA vm_flags */
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unsigned long vm_start; /* start address of region */
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unsigned long vm_end; /* region initialised to here */
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unsigned long vm_top; /* region allocated to here */
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unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */
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struct file *vm_file; /* the backing file or NULL */
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int vm_usage; /* region usage count (access under nommu_region_sem) */
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bool vm_icache_flushed : 1; /* true if the icache has been flushed for
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* this region */
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};
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/*
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* This struct defines a memory VMM memory area. There is one of these
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* per VM-area/task. A VM area is any part of the process virtual memory
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* space that has a special rule for the page-fault handlers (ie a shared
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* library, the executable area etc).
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*/
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struct vm_area_struct {
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struct mm_struct * vm_mm; /* The address space we belong to. */
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unsigned long vm_start; /* Our start address within vm_mm. */
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unsigned long vm_end; /* The first byte after our end address
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within vm_mm. */
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/* linked list of VM areas per task, sorted by address */
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struct vm_area_struct *vm_next, *vm_prev;
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pgprot_t vm_page_prot; /* Access permissions of this VMA. */
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unsigned long vm_flags; /* Flags, see mm.h. */
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struct rb_node vm_rb;
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/*
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* For areas with an address space and backing store,
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* linkage into the address_space->i_mmap prio tree, or
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* linkage to the list of like vmas hanging off its node, or
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* linkage of vma in the address_space->i_mmap_nonlinear list.
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*/
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union {
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struct {
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struct list_head list;
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void *parent; /* aligns with prio_tree_node parent */
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struct vm_area_struct *head;
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} vm_set;
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struct raw_prio_tree_node prio_tree_node;
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} shared;
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/*
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* A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
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* list, after a COW of one of the file pages. A MAP_SHARED vma
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* can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
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* or brk vma (with NULL file) can only be in an anon_vma list.
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*/
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struct list_head anon_vma_chain; /* Serialized by mmap_sem &
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* page_table_lock */
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struct anon_vma *anon_vma; /* Serialized by page_table_lock */
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/* Function pointers to deal with this struct. */
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const struct vm_operations_struct *vm_ops;
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/* Information about our backing store: */
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unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
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units, *not* PAGE_CACHE_SIZE */
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struct file * vm_file; /* File we map to (can be NULL). */
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void * vm_private_data; /* was vm_pte (shared mem) */
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unsigned long vm_truncate_count;/* truncate_count or restart_addr */
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#ifndef CONFIG_MMU
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struct vm_region *vm_region; /* NOMMU mapping region */
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#endif
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#ifdef CONFIG_NUMA
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struct mempolicy *vm_policy; /* NUMA policy for the VMA */
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#endif
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};
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struct core_thread {
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struct task_struct *task;
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struct core_thread *next;
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};
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struct core_state {
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atomic_t nr_threads;
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struct core_thread dumper;
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struct completion startup;
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};
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enum {
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MM_FILEPAGES,
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MM_ANONPAGES,
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MM_SWAPENTS,
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NR_MM_COUNTERS
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};
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#if USE_SPLIT_PTLOCKS && defined(CONFIG_MMU)
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#define SPLIT_RSS_COUNTING
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struct mm_rss_stat {
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atomic_long_t count[NR_MM_COUNTERS];
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};
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/* per-thread cached information, */
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struct task_rss_stat {
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int events; /* for synchronization threshold */
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int count[NR_MM_COUNTERS];
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};
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#else /* !USE_SPLIT_PTLOCKS */
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struct mm_rss_stat {
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unsigned long count[NR_MM_COUNTERS];
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};
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#endif /* !USE_SPLIT_PTLOCKS */
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struct mm_struct {
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struct vm_area_struct * mmap; /* list of VMAs */
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struct rb_root mm_rb;
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struct vm_area_struct * mmap_cache; /* last find_vma result */
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#ifdef CONFIG_MMU
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unsigned long (*get_unmapped_area) (struct file *filp,
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unsigned long addr, unsigned long len,
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unsigned long pgoff, unsigned long flags);
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void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
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#endif
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unsigned long mmap_base; /* base of mmap area */
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unsigned long task_size; /* size of task vm space */
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unsigned long cached_hole_size; /* if non-zero, the largest hole below free_area_cache */
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unsigned long free_area_cache; /* first hole of size cached_hole_size or larger */
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pgd_t * pgd;
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atomic_t mm_users; /* How many users with user space? */
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atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */
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int map_count; /* number of VMAs */
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spinlock_t page_table_lock; /* Protects page tables and some counters */
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struct rw_semaphore mmap_sem;
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struct list_head mmlist; /* List of maybe swapped mm's. These are globally strung
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* together off init_mm.mmlist, and are protected
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* by mmlist_lock
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*/
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unsigned long hiwater_rss; /* High-watermark of RSS usage */
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unsigned long hiwater_vm; /* High-water virtual memory usage */
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unsigned long total_vm, locked_vm, shared_vm, exec_vm;
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unsigned long stack_vm, reserved_vm, def_flags, nr_ptes;
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unsigned long start_code, end_code, start_data, end_data;
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unsigned long start_brk, brk, start_stack;
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unsigned long arg_start, arg_end, env_start, env_end;
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unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
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/*
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* Special counters, in some configurations protected by the
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* page_table_lock, in other configurations by being atomic.
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*/
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struct mm_rss_stat rss_stat;
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struct linux_binfmt *binfmt;
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cpumask_t cpu_vm_mask;
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/* Architecture-specific MM context */
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mm_context_t context;
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/* Swap token stuff */
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/*
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* Last value of global fault stamp as seen by this process.
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* In other words, this value gives an indication of how long
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* it has been since this task got the token.
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* Look at mm/thrash.c
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*/
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unsigned int faultstamp;
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unsigned int token_priority;
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unsigned int last_interval;
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/* How many tasks sharing this mm are OOM_DISABLE */
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atomic_t oom_disable_count;
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unsigned long flags; /* Must use atomic bitops to access the bits */
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struct core_state *core_state; /* coredumping support */
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#ifdef CONFIG_AIO
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spinlock_t ioctx_lock;
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struct hlist_head ioctx_list;
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#endif
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#ifdef CONFIG_MM_OWNER
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/*
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* "owner" points to a task that is regarded as the canonical
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* user/owner of this mm. All of the following must be true in
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* order for it to be changed:
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*
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* current == mm->owner
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* current->mm != mm
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* new_owner->mm == mm
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* new_owner->alloc_lock is held
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*/
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struct task_struct __rcu *owner;
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#endif
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#ifdef CONFIG_PROC_FS
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/* store ref to file /proc/<pid>/exe symlink points to */
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struct file *exe_file;
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unsigned long num_exe_file_vmas;
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#endif
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#ifdef CONFIG_MMU_NOTIFIER
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struct mmu_notifier_mm *mmu_notifier_mm;
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#endif
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#ifdef CONFIG_TRANSPARENT_HUGEPAGE
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pgtable_t pmd_huge_pte; /* protected by page_table_lock */
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#endif
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};
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/* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
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#define mm_cpumask(mm) (&(mm)->cpu_vm_mask)
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#endif /* _LINUX_MM_TYPES_H */
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