4 * Copyright (c) 2012 Samsung Electronics Co., Ltd.
5 * http://www.samsung.com/
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 #define GC_THREAD_NAME "f2fs_gc_task"
12 #define GC_THREAD_MIN_WB_PAGES 1 /*
13 * a threshold to determine
14 * whether IO subsystem is idle
17 #define GC_THREAD_MIN_SLEEP_TIME 10000 /* milliseconds */
18 #define GC_THREAD_MAX_SLEEP_TIME 30000
19 #define GC_THREAD_NOGC_SLEEP_TIME 10000
20 #define LIMIT_INVALID_BLOCK 40 /* percentage over total user space */
21 #define LIMIT_FREE_BLOCK 40 /* percentage over invalid + free space */
23 /* Search max. number of dirty segments to select a victim segment */
24 #define MAX_VICTIM_SEARCH 20
35 struct f2fs_gc_kthread
{
36 struct task_struct
*f2fs_gc_task
;
37 wait_queue_head_t gc_wait_queue_head
;
41 struct list_head list
;
48 static inline block_t
free_user_blocks(struct f2fs_sb_info
*sbi
)
50 if (free_segments(sbi
) < overprovision_segments(sbi
))
53 return (free_segments(sbi
) - overprovision_segments(sbi
))
54 << sbi
->log_blocks_per_seg
;
57 static inline block_t
limit_invalid_user_blocks(struct f2fs_sb_info
*sbi
)
59 return (long)(sbi
->user_block_count
* LIMIT_INVALID_BLOCK
) / 100;
62 static inline block_t
limit_free_user_blocks(struct f2fs_sb_info
*sbi
)
64 block_t reclaimable_user_blocks
= sbi
->user_block_count
-
65 written_block_count(sbi
);
66 return (long)(reclaimable_user_blocks
* LIMIT_FREE_BLOCK
) / 100;
69 static inline long increase_sleep_time(long wait
)
71 wait
+= GC_THREAD_MIN_SLEEP_TIME
;
72 if (wait
> GC_THREAD_MAX_SLEEP_TIME
)
73 wait
= GC_THREAD_MAX_SLEEP_TIME
;
77 static inline long decrease_sleep_time(long wait
)
79 wait
-= GC_THREAD_MIN_SLEEP_TIME
;
80 if (wait
<= GC_THREAD_MIN_SLEEP_TIME
)
81 wait
= GC_THREAD_MIN_SLEEP_TIME
;
85 static inline bool has_enough_invalid_blocks(struct f2fs_sb_info
*sbi
)
87 block_t invalid_user_blocks
= sbi
->user_block_count
-
88 written_block_count(sbi
);
90 * Background GC is triggered with the following condition.
91 * 1. There are a number of invalid blocks.
92 * 2. There is not enough free space.
94 if (invalid_user_blocks
> limit_invalid_user_blocks(sbi
) &&
95 free_user_blocks(sbi
) < limit_free_user_blocks(sbi
))
100 static inline int is_idle(struct f2fs_sb_info
*sbi
)
102 struct block_device
*bdev
= sbi
->sb
->s_bdev
;
103 struct request_queue
*q
= bdev_get_queue(bdev
);
104 struct request_list
*rl
= &q
->root_rl
;
105 return !(rl
->count
[BLK_RW_SYNC
]) && !(rl
->count
[BLK_RW_ASYNC
]);
108 static inline bool should_do_checkpoint(struct f2fs_sb_info
*sbi
)
110 unsigned int pages_per_sec
= sbi
->segs_per_sec
*
111 (1 << sbi
->log_blocks_per_seg
);
112 int node_secs
= ((get_pages(sbi
, F2FS_DIRTY_NODES
) + pages_per_sec
- 1)
113 >> sbi
->log_blocks_per_seg
) / sbi
->segs_per_sec
;
114 int dent_secs
= ((get_pages(sbi
, F2FS_DIRTY_DENTS
) + pages_per_sec
- 1)
115 >> sbi
->log_blocks_per_seg
) / sbi
->segs_per_sec
;
116 return free_sections(sbi
) <= (node_secs
+ 2 * dent_secs
+ 2);