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git.proxmox.com Git - mirror_ubuntu-zesty-kernel.git/blob - mm/fadvise.c
4 * Copyright (C) 2002, Linus Torvalds
6 * 11Jan2003 Andrew Morton
10 #include <linux/kernel.h>
11 #include <linux/file.h>
14 #include <linux/pagemap.h>
15 #include <linux/backing-dev.h>
16 #include <linux/pagevec.h>
17 #include <linux/fadvise.h>
18 #include <linux/writeback.h>
19 #include <linux/syscalls.h>
20 #include <linux/swap.h>
22 #include <asm/unistd.h>
25 * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
26 * deactivate the pages and clear PG_Referenced.
28 SYSCALL_DEFINE4(fadvise64_64
, int, fd
, loff_t
, offset
, loff_t
, len
, int, advice
)
30 struct fd f
= fdget(fd
);
31 struct address_space
*mapping
;
32 struct backing_dev_info
*bdi
;
33 loff_t endbyte
; /* inclusive */
36 unsigned long nrpages
;
42 if (S_ISFIFO(file_inode(f
.file
)->i_mode
)) {
47 mapping
= f
.file
->f_mapping
;
48 if (!mapping
|| len
< 0) {
53 if (mapping
->a_ops
->get_xip_mem
) {
55 case POSIX_FADV_NORMAL
:
56 case POSIX_FADV_RANDOM
:
57 case POSIX_FADV_SEQUENTIAL
:
58 case POSIX_FADV_WILLNEED
:
59 case POSIX_FADV_NOREUSE
:
60 case POSIX_FADV_DONTNEED
:
61 /* no bad return value, but ignore advice */
69 /* Careful about overflows. Len == 0 means "as much as possible" */
70 endbyte
= offset
+ len
;
71 if (!len
|| endbyte
< len
)
74 endbyte
--; /* inclusive */
76 bdi
= inode_to_bdi(mapping
->host
);
79 case POSIX_FADV_NORMAL
:
80 f
.file
->f_ra
.ra_pages
= bdi
->ra_pages
;
81 spin_lock(&f
.file
->f_lock
);
82 f
.file
->f_mode
&= ~FMODE_RANDOM
;
83 spin_unlock(&f
.file
->f_lock
);
85 case POSIX_FADV_RANDOM
:
86 spin_lock(&f
.file
->f_lock
);
87 f
.file
->f_mode
|= FMODE_RANDOM
;
88 spin_unlock(&f
.file
->f_lock
);
90 case POSIX_FADV_SEQUENTIAL
:
91 f
.file
->f_ra
.ra_pages
= bdi
->ra_pages
* 2;
92 spin_lock(&f
.file
->f_lock
);
93 f
.file
->f_mode
&= ~FMODE_RANDOM
;
94 spin_unlock(&f
.file
->f_lock
);
96 case POSIX_FADV_WILLNEED
:
97 /* First and last PARTIAL page! */
98 start_index
= offset
>> PAGE_CACHE_SHIFT
;
99 end_index
= endbyte
>> PAGE_CACHE_SHIFT
;
101 /* Careful about overflow on the "+1" */
102 nrpages
= end_index
- start_index
+ 1;
107 * Ignore return value because fadvise() shall return
108 * success even if filesystem can't retrieve a hint,
110 force_page_cache_readahead(mapping
, f
.file
, start_index
,
113 case POSIX_FADV_NOREUSE
:
115 case POSIX_FADV_DONTNEED
:
116 if (!bdi_write_congested(bdi
))
117 __filemap_fdatawrite_range(mapping
, offset
, endbyte
,
121 * First and last FULL page! Partial pages are deliberately
122 * preserved on the expectation that it is better to preserve
123 * needed memory than to discard unneeded memory.
125 start_index
= (offset
+(PAGE_CACHE_SIZE
-1)) >> PAGE_CACHE_SHIFT
;
126 end_index
= (endbyte
>> PAGE_CACHE_SHIFT
);
128 if (end_index
>= start_index
) {
129 unsigned long count
= invalidate_mapping_pages(mapping
,
130 start_index
, end_index
);
133 * If fewer pages were invalidated than expected then
134 * it is possible that some of the pages were on
135 * a per-cpu pagevec for a remote CPU. Drain all
136 * pagevecs and try again.
138 if (count
< (end_index
- start_index
+ 1)) {
140 invalidate_mapping_pages(mapping
, start_index
,
153 #ifdef __ARCH_WANT_SYS_FADVISE64
155 SYSCALL_DEFINE4(fadvise64
, int, fd
, loff_t
, offset
, size_t, len
, int, advice
)
157 return sys_fadvise64_64(fd
, offset
, len
, advice
);