Commit | Line | Data |
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5d1ea48b | 1 | #include <linux/swap_cgroup.h> |
4c821042 | 2 | #include <linux/vmalloc.h> |
5d1ea48b | 3 | #include <linux/mm.h> |
27a7faa0 | 4 | |
5d1ea48b | 5 | #include <linux/swapops.h> /* depends on mm.h include */ |
27a7faa0 KH |
6 | |
7 | static DEFINE_MUTEX(swap_cgroup_mutex); | |
8 | struct swap_cgroup_ctrl { | |
9 | struct page **map; | |
10 | unsigned long length; | |
e9e58a4e | 11 | spinlock_t lock; |
27a7faa0 KH |
12 | }; |
13 | ||
61600f57 | 14 | static struct swap_cgroup_ctrl swap_cgroup_ctrl[MAX_SWAPFILES]; |
27a7faa0 | 15 | |
27a7faa0 | 16 | struct swap_cgroup { |
a3b2d692 | 17 | unsigned short id; |
27a7faa0 KH |
18 | }; |
19 | #define SC_PER_PAGE (PAGE_SIZE/sizeof(struct swap_cgroup)) | |
27a7faa0 KH |
20 | |
21 | /* | |
22 | * SwapCgroup implements "lookup" and "exchange" operations. | |
23 | * In typical usage, this swap_cgroup is accessed via memcg's charge/uncharge | |
24 | * against SwapCache. At swap_free(), this is accessed directly from swap. | |
25 | * | |
26 | * This means, | |
27 | * - we have no race in "exchange" when we're accessed via SwapCache because | |
28 | * SwapCache(and its swp_entry) is under lock. | |
29 | * - When called via swap_free(), there is no user of this entry and no race. | |
30 | * Then, we don't need lock around "exchange". | |
31 | * | |
32 | * TODO: we can push these buffers out to HIGHMEM. | |
33 | */ | |
34 | ||
35 | /* | |
36 | * allocate buffer for swap_cgroup. | |
37 | */ | |
38 | static int swap_cgroup_prepare(int type) | |
39 | { | |
40 | struct page *page; | |
41 | struct swap_cgroup_ctrl *ctrl; | |
42 | unsigned long idx, max; | |
43 | ||
27a7faa0 KH |
44 | ctrl = &swap_cgroup_ctrl[type]; |
45 | ||
46 | for (idx = 0; idx < ctrl->length; idx++) { | |
47 | page = alloc_page(GFP_KERNEL | __GFP_ZERO); | |
48 | if (!page) | |
49 | goto not_enough_page; | |
50 | ctrl->map[idx] = page; | |
ef707629 YZ |
51 | |
52 | if (!(idx % SWAP_CLUSTER_MAX)) | |
53 | cond_resched(); | |
27a7faa0 KH |
54 | } |
55 | return 0; | |
56 | not_enough_page: | |
57 | max = idx; | |
58 | for (idx = 0; idx < max; idx++) | |
59 | __free_page(ctrl->map[idx]); | |
60 | ||
61 | return -ENOMEM; | |
62 | } | |
63 | ||
9fb4b7cc BL |
64 | static struct swap_cgroup *lookup_swap_cgroup(swp_entry_t ent, |
65 | struct swap_cgroup_ctrl **ctrlp) | |
66 | { | |
67 | pgoff_t offset = swp_offset(ent); | |
68 | struct swap_cgroup_ctrl *ctrl; | |
69 | struct page *mappage; | |
c09ff089 | 70 | struct swap_cgroup *sc; |
9fb4b7cc BL |
71 | |
72 | ctrl = &swap_cgroup_ctrl[swp_type(ent)]; | |
73 | if (ctrlp) | |
74 | *ctrlp = ctrl; | |
75 | ||
76 | mappage = ctrl->map[offset / SC_PER_PAGE]; | |
c09ff089 HD |
77 | sc = page_address(mappage); |
78 | return sc + offset % SC_PER_PAGE; | |
9fb4b7cc BL |
79 | } |
80 | ||
02491447 DN |
81 | /** |
82 | * swap_cgroup_cmpxchg - cmpxchg mem_cgroup's id for this swp_entry. | |
dad7557e | 83 | * @ent: swap entry to be cmpxchged |
02491447 DN |
84 | * @old: old id |
85 | * @new: new id | |
86 | * | |
87 | * Returns old id at success, 0 at failure. | |
25985edc | 88 | * (There is no mem_cgroup using 0 as its id) |
02491447 DN |
89 | */ |
90 | unsigned short swap_cgroup_cmpxchg(swp_entry_t ent, | |
91 | unsigned short old, unsigned short new) | |
92 | { | |
02491447 | 93 | struct swap_cgroup_ctrl *ctrl; |
02491447 | 94 | struct swap_cgroup *sc; |
e9e58a4e KH |
95 | unsigned long flags; |
96 | unsigned short retval; | |
02491447 | 97 | |
9fb4b7cc | 98 | sc = lookup_swap_cgroup(ent, &ctrl); |
02491447 | 99 | |
e9e58a4e KH |
100 | spin_lock_irqsave(&ctrl->lock, flags); |
101 | retval = sc->id; | |
102 | if (retval == old) | |
103 | sc->id = new; | |
02491447 | 104 | else |
e9e58a4e KH |
105 | retval = 0; |
106 | spin_unlock_irqrestore(&ctrl->lock, flags); | |
107 | return retval; | |
02491447 DN |
108 | } |
109 | ||
27a7faa0 KH |
110 | /** |
111 | * swap_cgroup_record - record mem_cgroup for this swp_entry. | |
112 | * @ent: swap entry to be recorded into | |
dad7557e | 113 | * @id: mem_cgroup to be recorded |
27a7faa0 | 114 | * |
a3b2d692 KH |
115 | * Returns old value at success, 0 at failure. |
116 | * (Of course, old value can be 0.) | |
27a7faa0 | 117 | */ |
a3b2d692 | 118 | unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id) |
27a7faa0 | 119 | { |
27a7faa0 | 120 | struct swap_cgroup_ctrl *ctrl; |
27a7faa0 | 121 | struct swap_cgroup *sc; |
a3b2d692 | 122 | unsigned short old; |
e9e58a4e | 123 | unsigned long flags; |
27a7faa0 | 124 | |
9fb4b7cc | 125 | sc = lookup_swap_cgroup(ent, &ctrl); |
27a7faa0 | 126 | |
e9e58a4e KH |
127 | spin_lock_irqsave(&ctrl->lock, flags); |
128 | old = sc->id; | |
129 | sc->id = id; | |
130 | spin_unlock_irqrestore(&ctrl->lock, flags); | |
27a7faa0 KH |
131 | |
132 | return old; | |
133 | } | |
134 | ||
135 | /** | |
9fb4b7cc | 136 | * lookup_swap_cgroup_id - lookup mem_cgroup id tied to swap entry |
27a7faa0 KH |
137 | * @ent: swap entry to be looked up. |
138 | * | |
b3ff8a2f | 139 | * Returns ID of mem_cgroup at success. 0 at failure. (0 is invalid ID) |
27a7faa0 | 140 | */ |
9fb4b7cc | 141 | unsigned short lookup_swap_cgroup_id(swp_entry_t ent) |
27a7faa0 | 142 | { |
9fb4b7cc | 143 | return lookup_swap_cgroup(ent, NULL)->id; |
27a7faa0 KH |
144 | } |
145 | ||
146 | int swap_cgroup_swapon(int type, unsigned long max_pages) | |
147 | { | |
148 | void *array; | |
149 | unsigned long array_size; | |
150 | unsigned long length; | |
151 | struct swap_cgroup_ctrl *ctrl; | |
152 | ||
153 | if (!do_swap_account) | |
154 | return 0; | |
155 | ||
33278f7f | 156 | length = DIV_ROUND_UP(max_pages, SC_PER_PAGE); |
27a7faa0 KH |
157 | array_size = length * sizeof(void *); |
158 | ||
8c1fec1b | 159 | array = vzalloc(array_size); |
27a7faa0 KH |
160 | if (!array) |
161 | goto nomem; | |
162 | ||
27a7faa0 KH |
163 | ctrl = &swap_cgroup_ctrl[type]; |
164 | mutex_lock(&swap_cgroup_mutex); | |
165 | ctrl->length = length; | |
166 | ctrl->map = array; | |
e9e58a4e | 167 | spin_lock_init(&ctrl->lock); |
27a7faa0 KH |
168 | if (swap_cgroup_prepare(type)) { |
169 | /* memory shortage */ | |
170 | ctrl->map = NULL; | |
171 | ctrl->length = 0; | |
27a7faa0 | 172 | mutex_unlock(&swap_cgroup_mutex); |
6a5b18d2 | 173 | vfree(array); |
27a7faa0 KH |
174 | goto nomem; |
175 | } | |
176 | mutex_unlock(&swap_cgroup_mutex); | |
177 | ||
27a7faa0 KH |
178 | return 0; |
179 | nomem: | |
1170532b JP |
180 | pr_info("couldn't allocate enough memory for swap_cgroup\n"); |
181 | pr_info("swap_cgroup can be disabled by swapaccount=0 boot option\n"); | |
27a7faa0 KH |
182 | return -ENOMEM; |
183 | } | |
184 | ||
185 | void swap_cgroup_swapoff(int type) | |
186 | { | |
6a5b18d2 NK |
187 | struct page **map; |
188 | unsigned long i, length; | |
27a7faa0 KH |
189 | struct swap_cgroup_ctrl *ctrl; |
190 | ||
191 | if (!do_swap_account) | |
192 | return; | |
193 | ||
194 | mutex_lock(&swap_cgroup_mutex); | |
195 | ctrl = &swap_cgroup_ctrl[type]; | |
6a5b18d2 NK |
196 | map = ctrl->map; |
197 | length = ctrl->length; | |
198 | ctrl->map = NULL; | |
199 | ctrl->length = 0; | |
200 | mutex_unlock(&swap_cgroup_mutex); | |
201 | ||
202 | if (map) { | |
203 | for (i = 0; i < length; i++) { | |
204 | struct page *page = map[i]; | |
27a7faa0 KH |
205 | if (page) |
206 | __free_page(page); | |
460bcec8 DR |
207 | if (!(i % SWAP_CLUSTER_MAX)) |
208 | cond_resched(); | |
27a7faa0 | 209 | } |
6a5b18d2 | 210 | vfree(map); |
27a7faa0 | 211 | } |
27a7faa0 | 212 | } |