source: trunk/kernel/mm/page.h @ 1

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1/*
2 * page.h - physical page descriptor and related operations
3 *
4 * Authors Ghassan Almalles (2008,2009,2010,2011,2012)
5 *         Alain Greiner    (2016)
6 *
7 * Copyright (c) UPMC Sorbonne Universites
8 *
9 * This file is part of ALMOS-MKH.
10 *
11 * ALMOS-MKH is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; version 2.0 of the License.
14 *
15 * ALMOS-MKH is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
22 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
23 */
24
25#ifndef _PAGE_H_
26#define _PAGE_H_
27
28#include <almos_config.h>
29#include <hal_types.h>
30#include <spinlock.h>
31#include <list.h>
32#include <slist.h>
33#include <xlist.h>
34
35/***   Forward declarations   ***/
36
37struct mapper_s;
38 
39/*************************************************************************************
40 * This  defines the flags that can be attached to a physical page.
41 ************************************************************************************/
42
43#define PG_INIT             0x0001     // page descriptor has been initialised
44#define PG_RESERVED         0x0002     // cannot be allocated by PPM
45#define PG_FREE             0x0004     // page can be allocated by PPM
46#define PG_INLOAD           0x0008     // on-going load from disk
47#define PG_IO_ERR           0x0010     // mapper signals a read/write access error
48#define PG_BUFFER           0x0020     // used in blockio.c
49#define PG_DIRTY            0x0040     // page has been written
50#define PG_LOCKED       0x0080     // page is locked
51
52#define PG_ALL          0xFFFF     // All flags
53
54/*************************************************************************************
55 * This structure defines a physical page descriptor.
56 * Size is 60 bytes for a 32 bits core...
57 ************************************************************************************/
58
59typedef struct page_s
60{
61    uint16_t          flags;          /*! flags defined above                  (2)  */
62    uint16_t          order;          /*! log2( number of 4Kbytes pages)       (2)  */
63
64    struct mapper_s * mapper;         /*! local pointer on associated mapper   (4)  */
65    uint32_t          index;          /*! page index in mapper                 (4)  */
66 
67        union                             /*!                                      (4)  */
68        {
69                uint32_t      private;        /*! TODO ??? [AG]                             */
70                void        * data;           /*! TODO ??? [AG]                             */
71                slist_entry_t root;           /*! TODO ??? [AG]                             */
72        };
73
74        list_entry_t      list;           /*! for both dirty pages and free pages  (8)  */ 
75
76    xlist_entry_t     wait_root;      /*! root of list of waiting threads      (16) */
77
78        uint32_t          refcount;       /*! reference counter                    (4)  */
79        spinlock_t        lock;           /*! only used to set the PG_LOCKED flag  (16) */
80}
81page_t;
82
83/*************************************************************************************
84 * This function initializes one page descriptor.
85 * @ page    : pointer to page descriptor
86 ************************************************************************************/
87inline void page_init( page_t * page );
88
89/*************************************************************************************
90 * This function set one or several flags in page descriptor flags.
91 * @ page    : pointer to page descriptor.
92 * @ value   : all non zero bits in value will be set.
93 ************************************************************************************/
94inline void page_set_flag( page_t   * page,
95                           uint16_t   value );
96
97/*************************************************************************************
98 * This function reset one or several flags in page descriptor flags.
99 * @ page    : pointer to page descriptor.
100 * @ value   : all non zero bits in value will be cleared.
101 ************************************************************************************/
102inline void page_clear_flag( page_t   * page,
103                             uint16_t   value );
104
105/*************************************************************************************
106 * This function test the value of one or several flags in page descriptor flags.
107 * @ page    : pointer to page descriptor.
108 * @ value   : all non zero bits will be tested.
109 * @ returns true if at least one non zero bit in value is set / false otherwise.
110 ************************************************************************************/
111inline bool_t page_is_flag( page_t   * page,
112                            uint16_t   value );
113
114/*************************************************************************************
115 * This function synchronizes (i.e. update the disk) all dirty pages in a cluster.
116 * It scan the PPM dirty list, that should be empty when this operation is completed.
117 ************************************************************************************/
118void sync_all_pages();
119
120/*************************************************************************************
121 * This function set the PG_DIRTY flag in the page descriptor,
122 * and register the page in the dirty list in PPM.
123 * @ page     : pointer on page descriptor.
124 * @ returns true if page was not dirty / returns false if page was dirty
125 ************************************************************************************/
126bool_t page_do_dirty( page_t * page );
127
128/*************************************************************************************
129 * This function reset the PG_DIRTY flag in the page descriptor,
130 * and remove the page from the dirty list in PPM.
131 * @ page     : pointer on page descriptor.
132 * @ returns true if page was dirty / returns false if page was not dirty
133 ************************************************************************************/
134bool_t page_undo_dirty( page_t * page );
135
136/*************************************************************************************
137 * This function makes a local copy of the content of a src page  to a dst page.
138 * @ dst      : pointer on destination page descriptor.
139 * @ src      : pointer on source page descriptor.
140 ************************************************************************************/
141void page_copy( page_t * dst,
142                page_t * src );
143
144/*************************************************************************************
145 * This function reset to 0 all bytes in a given page.
146 * @ page     : pointer on page descriptor.
147 ************************************************************************************/
148void page_zero( page_t * page );
149
150/*************************************************************************************
151 * This blocking function set the PG_LOCKED flag on the page.
152 * It deschedule if the page has already been locked by another thread,
153 * and returns only when the flag has been successfully set.
154 * @ page     : pointer on page descriptor.
155 ************************************************************************************/
156void page_lock( page_t * page );
157
158/*************************************************************************************
159 * This blocking function reset the PG_LOCKED flag on the page, if there is no
160 * other waiting thread. IF there is waiting thread(s), it activates the first
161 * waiting thread without modifying the PG_LOCKED flag.
162 * @ page     : pointer on page descriptor.
163 ************************************************************************************/
164void page_unlock( page_t * page );
165
166/*************************************************************************************
167 * This blocking function atomically increment the page refcount.
168 * @ page     : pointer on page descriptor.
169 ************************************************************************************/
170inline void page_refcount_up( page_t * page );
171
172/*************************************************************************************
173 * This blocking function atomically decrement the page refcount.
174 * @ page     : pointer on page descriptor.
175 ************************************************************************************/
176inline void page_refcount_down( page_t * page );
177
178/*************************************************************************************
179 * This function display the values contained in a page descriptor.
180 ************************************************************************************/
181void page_print( page_t * page );
182
183
184#endif  /* _PAGE_H_ */
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