/[pkg-src]/trunk/kernel26-magellan/patches-2.6.17-r6/0027-2.6.17-mm-filesize_dependant_lru_cache_add.patch |
Annotation of /trunk/kernel26-magellan/patches-2.6.17-r6/0027-2.6.17-mm-filesize_dependant_lru_cache_add.patch
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Revision 105 -
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Sun Mar 11 16:17:56 2007 UTC (17 years, 6 months ago) by niro
File size: 7698 byte(s)
Sun Mar 11 16:17:56 2007 UTC (17 years, 6 months ago) by niro
File size: 7698 byte(s)
2.6.17-magellan-r6
1 | niro | 105 | When reading from large files through the generic file read functions into |
2 | page cache we can detect when a file is so large that it is unlikely to be | ||
3 | fully cached in ram. | ||
4 | |||
5 | Add a tunable /proc/sys/vm/tail_largefiles that puts them at the tail of the | ||
6 | inactive list to minimise their harm on present mapped pages and pagecache | ||
7 | and enable it by default. | ||
8 | |||
9 | Signed-off-by: Con Kolivas <kernel@kolivas.org> | ||
10 | |||
11 | --- | ||
12 | Documentation/filesystems/proc.txt | 8 ++++++ | ||
13 | Documentation/sysctl/vm.txt | 2 - | ||
14 | include/linux/sysctl.h | 1 | ||
15 | include/linux/writeback.h | 2 + | ||
16 | kernel/sysctl.c | 9 +++++++ | ||
17 | mm/filemap.c | 47 +++++++++++++++++++++++++++++++++++-- | ||
18 | mm/page-writeback.c | 2 - | ||
19 | mm/swap.c | 3 -- | ||
20 | 8 files changed, 68 insertions(+), 6 deletions(-) | ||
21 | |||
22 | Index: linux-ck-dev/include/linux/writeback.h | ||
23 | =================================================================== | ||
24 | --- linux-ck-dev.orig/include/linux/writeback.h 2006-06-18 15:20:10.000000000 +1000 | ||
25 | +++ linux-ck-dev/include/linux/writeback.h 2006-06-18 15:25:25.000000000 +1000 | ||
26 | @@ -85,6 +85,8 @@ void laptop_io_completion(void); | ||
27 | void laptop_sync_completion(void); | ||
28 | void throttle_vm_writeout(void); | ||
29 | |||
30 | +extern long total_pages; | ||
31 | + | ||
32 | /* These are exported to sysctl. */ | ||
33 | extern int dirty_background_ratio; | ||
34 | extern int vm_dirty_ratio; | ||
35 | Index: linux-ck-dev/mm/filemap.c | ||
36 | =================================================================== | ||
37 | --- linux-ck-dev.orig/mm/filemap.c 2006-06-18 15:20:10.000000000 +1000 | ||
38 | +++ linux-ck-dev/mm/filemap.c 2006-06-18 15:25:25.000000000 +1000 | ||
39 | @@ -434,6 +434,16 @@ int add_to_page_cache_lru(struct page *p | ||
40 | return ret; | ||
41 | } | ||
42 | |||
43 | +int add_to_page_cache_lru_tail(struct page *page, | ||
44 | + struct address_space *mapping, pgoff_t offset, gfp_t gfp_mask) | ||
45 | +{ | ||
46 | + int ret = add_to_page_cache(page, mapping, offset, gfp_mask); | ||
47 | + | ||
48 | + if (ret == 0) | ||
49 | + lru_cache_add_tail(page); | ||
50 | + return ret; | ||
51 | +} | ||
52 | + | ||
53 | #ifdef CONFIG_NUMA | ||
54 | struct page *page_cache_alloc(struct address_space *x) | ||
55 | { | ||
56 | @@ -783,6 +793,28 @@ grab_cache_page_nowait(struct address_sp | ||
57 | EXPORT_SYMBOL(grab_cache_page_nowait); | ||
58 | |||
59 | /* | ||
60 | + * Sysctl which determines whether we should read from large files to the | ||
61 | + * tail of the inactive lru list. | ||
62 | + */ | ||
63 | +int vm_tail_largefiles __read_mostly = 1; | ||
64 | + | ||
65 | +/* | ||
66 | + * This examines how large in pages a file size is and returns 1 if it is | ||
67 | + * more than half the unmapped ram. Avoid doing read_page_state which is | ||
68 | + * expensive unless we already know it is likely to be large enough. | ||
69 | + */ | ||
70 | +static int large_isize(unsigned long nr_pages) | ||
71 | +{ | ||
72 | + if (nr_pages * 6 > total_pages) { | ||
73 | + unsigned long unmapped_ram = total_pages - read_page_state(nr_mapped); | ||
74 | + | ||
75 | + if (nr_pages * 2 > unmapped_ram) | ||
76 | + return 1; | ||
77 | + } | ||
78 | + return 0; | ||
79 | +} | ||
80 | + | ||
81 | +/* | ||
82 | * This is a generic file read routine, and uses the | ||
83 | * mapping->a_ops->readpage() function for the actual low-level | ||
84 | * stuff. | ||
85 | @@ -982,8 +1014,19 @@ no_cached_page: | ||
86 | goto out; | ||
87 | } | ||
88 | } | ||
89 | - error = add_to_page_cache_lru(cached_page, mapping, | ||
90 | - index, GFP_KERNEL); | ||
91 | + | ||
92 | + /* | ||
93 | + * If we know the file is large we add the pages read to the | ||
94 | + * end of the lru as we're unlikely to be able to cache the | ||
95 | + * whole file in ram so make those pages the first to be | ||
96 | + * dropped if not referenced soon. | ||
97 | + */ | ||
98 | + if (vm_tail_largefiles && large_isize(end_index)) | ||
99 | + error = add_to_page_cache_lru_tail(cached_page, | ||
100 | + mapping, index, GFP_KERNEL); | ||
101 | + else | ||
102 | + error = add_to_page_cache_lru(cached_page, mapping, | ||
103 | + index, GFP_KERNEL); | ||
104 | if (error) { | ||
105 | if (error == -EEXIST) | ||
106 | goto find_page; | ||
107 | Index: linux-ck-dev/mm/page-writeback.c | ||
108 | =================================================================== | ||
109 | --- linux-ck-dev.orig/mm/page-writeback.c 2006-06-18 15:25:22.000000000 +1000 | ||
110 | +++ linux-ck-dev/mm/page-writeback.c 2006-06-18 15:25:25.000000000 +1000 | ||
111 | @@ -45,7 +45,7 @@ | ||
112 | */ | ||
113 | static long ratelimit_pages = 32; | ||
114 | |||
115 | -static long total_pages; /* The total number of pages in the machine. */ | ||
116 | +long total_pages __read_mostly; /* The total number of pages in the machine. */ | ||
117 | static int dirty_exceeded __cacheline_aligned_in_smp; /* Dirty mem may be over limit */ | ||
118 | |||
119 | /* | ||
120 | Index: linux-ck-dev/mm/swap.c | ||
121 | =================================================================== | ||
122 | --- linux-ck-dev.orig/mm/swap.c 2006-06-18 15:24:48.000000000 +1000 | ||
123 | +++ linux-ck-dev/mm/swap.c 2006-06-18 15:25:25.000000000 +1000 | ||
124 | @@ -416,8 +416,7 @@ void __pagevec_lru_add_active(struct pag | ||
125 | |||
126 | /* | ||
127 | * Function used uniquely to put pages back to the lru at the end of the | ||
128 | - * inactive list to preserve the lru order. Currently only used by swap | ||
129 | - * prefetch. | ||
130 | + * inactive list to preserve the lru order. | ||
131 | */ | ||
132 | void fastcall lru_cache_add_tail(struct page *page) | ||
133 | { | ||
134 | Index: linux-ck-dev/include/linux/sysctl.h | ||
135 | =================================================================== | ||
136 | --- linux-ck-dev.orig/include/linux/sysctl.h 2006-06-18 15:24:58.000000000 +1000 | ||
137 | +++ linux-ck-dev/include/linux/sysctl.h 2006-06-18 15:25:25.000000000 +1000 | ||
138 | @@ -191,6 +191,7 @@ enum | ||
139 | VM_ZONE_RECLAIM_INTERVAL=32, /* time period to wait after reclaim failure */ | ||
140 | VM_SWAP_PREFETCH=33, /* swap prefetch */ | ||
141 | VM_HARDMAPLIMIT=34, /* Make mapped a hard limit */ | ||
142 | + VM_TAIL_LARGEFILES=35, /* Read large files to lru tail */ | ||
143 | }; | ||
144 | |||
145 | |||
146 | Index: linux-ck-dev/kernel/sysctl.c | ||
147 | =================================================================== | ||
148 | --- linux-ck-dev.orig/kernel/sysctl.c 2006-06-18 15:24:58.000000000 +1000 | ||
149 | +++ linux-ck-dev/kernel/sysctl.c 2006-06-18 15:25:25.000000000 +1000 | ||
150 | @@ -73,6 +73,7 @@ extern int printk_ratelimit_burst; | ||
151 | extern int pid_max_min, pid_max_max; | ||
152 | extern int sysctl_drop_caches; | ||
153 | extern int percpu_pagelist_fraction; | ||
154 | +extern int vm_tail_largefiles; | ||
155 | |||
156 | #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86) | ||
157 | int unknown_nmi_panic; | ||
158 | @@ -809,6 +810,14 @@ static ctl_table vm_table[] = { | ||
159 | .mode = 0644, | ||
160 | .proc_handler = &proc_dointvec, | ||
161 | }, | ||
162 | + { | ||
163 | + .ctl_name = VM_TAIL_LARGEFILES, | ||
164 | + .procname = "tail_largefiles", | ||
165 | + .data = &vm_tail_largefiles, | ||
166 | + .maxlen = sizeof(int), | ||
167 | + .mode = 0644, | ||
168 | + .proc_handler = &proc_dointvec, | ||
169 | + }, | ||
170 | #ifdef CONFIG_HUGETLB_PAGE | ||
171 | { | ||
172 | .ctl_name = VM_HUGETLB_PAGES, | ||
173 | Index: linux-ck-dev/Documentation/filesystems/proc.txt | ||
174 | =================================================================== | ||
175 | --- linux-ck-dev.orig/Documentation/filesystems/proc.txt 2006-06-18 15:20:10.000000000 +1000 | ||
176 | +++ linux-ck-dev/Documentation/filesystems/proc.txt 2006-06-18 15:25:25.000000000 +1000 | ||
177 | @@ -1318,6 +1318,14 @@ To free pagecache, dentries and inodes: | ||
178 | As this is a non-destructive operation and dirty objects are not freeable, the | ||
179 | user should run `sync' first. | ||
180 | |||
181 | +tail_largefiles | ||
182 | +--------------- | ||
183 | + | ||
184 | +When enabled reads from large files to the tail end of the inactive lru list. | ||
185 | +This means that any cache from reading large files is dropped very quickly, | ||
186 | +preventing loss of mapped ram and useful pagecache when large files are read. | ||
187 | +This does, however, make caching less effective when working with large files. | ||
188 | + | ||
189 | |||
190 | 2.5 /proc/sys/dev - Device specific parameters | ||
191 | ---------------------------------------------- | ||
192 | Index: linux-ck-dev/Documentation/sysctl/vm.txt | ||
193 | =================================================================== | ||
194 | --- linux-ck-dev.orig/Documentation/sysctl/vm.txt 2006-06-18 15:24:58.000000000 +1000 | ||
195 | +++ linux-ck-dev/Documentation/sysctl/vm.txt 2006-06-18 15:25:25.000000000 +1000 | ||
196 | @@ -37,7 +37,7 @@ Currently, these files are in /proc/sys/ | ||
197 | |||
198 | dirty_ratio, dirty_background_ratio, dirty_expire_centisecs, | ||
199 | dirty_writeback_centisecs, vfs_cache_pressure, laptop_mode, | ||
200 | -block_dump, swap_token_timeout, drop-caches: | ||
201 | +block_dump, swap_token_timeout, drop-caches, tail_largefiles: | ||
202 | |||
203 | See Documentation/filesystems/proc.txt | ||
204 |