mm_types_task.h

 1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef _LINUX_MM_TYPES_TASK_H
 3#define _LINUX_MM_TYPES_TASK_H
 4
 5/*
 6 * Here are the definitions of the MM data types that are embedded in 'struct task_struct'.
 7 *
 8 * (These are defined separately to decouple sched.h from mm_types.h as much as possible.)
 9 */
10
11#include <linux/align.h>
12#include <linux/types.h>
13
14#include <asm/page.h>
15
16#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
17#include <asm/tlbbatch.h>
18#endif
19
20#define ALLOC_SPLIT_PTLOCKS	(SPINLOCK_SIZE > BITS_PER_LONG/8)
21
22/*
23 * When updating this, please also update struct resident_page_types[] in
24 * kernel/fork.c
25 */
26enum {
27	MM_FILEPAGES,	/* Resident file mapping pages */
28	MM_ANONPAGES,	/* Resident anonymous pages */
29	MM_SWAPENTS,	/* Anonymous swap entries */
30	MM_SHMEMPAGES,	/* Resident shared memory pages */
31	NR_MM_COUNTERS
32};
33
34struct page;
35
36struct page_frag {
37	struct page *page;
38#if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
39	__u32 offset;
40	__u32 size;
41#else
42	__u16 offset;
43	__u16 size;
44#endif
45};
46
47#define PAGE_FRAG_CACHE_MAX_SIZE	__ALIGN_MASK(32768, ~PAGE_MASK)
48#define PAGE_FRAG_CACHE_MAX_ORDER	get_order(PAGE_FRAG_CACHE_MAX_SIZE)
49struct page_frag_cache {
50	/* encoded_page consists of the virtual address, pfmemalloc bit and
51	 * order of a page.
52	 */
53	unsigned long encoded_page;
54
55	/* we maintain a pagecount bias, so that we dont dirty cache line
56	 * containing page->_refcount every time we allocate a fragment.
57	 */
58#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) && (BITS_PER_LONG <= 32)
59	__u16 offset;
60	__u16 pagecnt_bias;
61#else
62	__u32 offset;
63	__u32 pagecnt_bias;
64#endif
65};
66
67/* Track pages that require TLB flushes */
68struct tlbflush_unmap_batch {
69#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
70	/*
71	 * The arch code makes the following promise: generic code can modify a
72	 * PTE, then call arch_tlbbatch_add_pending() (which internally provides
73	 * all needed barriers), then call arch_tlbbatch_flush(), and the entries
74	 * will be flushed on all CPUs by the time that arch_tlbbatch_flush()
75	 * returns.
76	 */
77	struct arch_tlbflush_unmap_batch arch;
78
79	/* True if a flush is needed. */
80	bool flush_required;
81
82	/*
83	 * If true then the PTE was dirty when unmapped. The entry must be
84	 * flushed before IO is initiated or a stale TLB entry potentially
85	 * allows an update without redirtying the page.
86	 */
87	bool writable;
88#endif
89};
90
91#endif /* _LINUX_MM_TYPES_TASK_H */