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_MIN_WB_PAGES 1 /*
12 * a threshold to determine
13 * whether IO subsystem is idle
16 #define DEF_GC_THREAD_MIN_SLEEP_TIME 30000 /* milliseconds */
17 #define DEF_GC_THREAD_MAX_SLEEP_TIME 60000
18 #define DEF_GC_THREAD_NOGC_SLEEP_TIME 300000 /* wait 5 min */
19 #define LIMIT_INVALID_BLOCK 40 /* percentage over total user space */
20 #define LIMIT_FREE_BLOCK 40 /* percentage over invalid + free space */
22 /* Search max. number of dirty segments to select a victim segment */
23 #define MAX_VICTIM_SEARCH 20
25 struct f2fs_gc_kthread {
26 struct task_struct *f2fs_gc_task;
27 wait_queue_head_t gc_wait_queue_head;
29 /* for gc sleep time */
30 unsigned int min_sleep_time;
31 unsigned int max_sleep_time;
32 unsigned int no_gc_sleep_time;
36 struct list_head list;
43 static inline block_t free_user_blocks(struct f2fs_sb_info *sbi)
45 if (free_segments(sbi) < overprovision_segments(sbi))
48 return (free_segments(sbi) - overprovision_segments(sbi))
49 << sbi->log_blocks_per_seg;
52 static inline block_t limit_invalid_user_blocks(struct f2fs_sb_info *sbi)
54 return (long)(sbi->user_block_count * LIMIT_INVALID_BLOCK) / 100;
57 static inline block_t limit_free_user_blocks(struct f2fs_sb_info *sbi)
59 block_t reclaimable_user_blocks = sbi->user_block_count -
60 written_block_count(sbi);
61 return (long)(reclaimable_user_blocks * LIMIT_FREE_BLOCK) / 100;
64 static inline long increase_sleep_time(struct f2fs_gc_kthread *gc_th, long wait)
66 if (wait == gc_th->no_gc_sleep_time)
69 wait += gc_th->min_sleep_time;
70 if (wait > gc_th->max_sleep_time)
71 wait = gc_th->max_sleep_time;
75 static inline long decrease_sleep_time(struct f2fs_gc_kthread *gc_th, long wait)
77 if (wait == gc_th->no_gc_sleep_time)
78 wait = gc_th->max_sleep_time;
80 wait -= gc_th->min_sleep_time;
81 if (wait <= gc_th->min_sleep_time)
82 wait = gc_th->min_sleep_time;
86 static inline bool has_enough_invalid_blocks(struct f2fs_sb_info *sbi)
88 block_t invalid_user_blocks = sbi->user_block_count -
89 written_block_count(sbi);
91 * Background GC is triggered with the following condition.
92 * 1. There are a number of invalid blocks.
93 * 2. There is not enough free space.
95 if (invalid_user_blocks > limit_invalid_user_blocks(sbi) &&
96 free_user_blocks(sbi) < limit_free_user_blocks(sbi))
101 static inline int is_idle(struct f2fs_sb_info *sbi)
103 struct block_device *bdev = sbi->sb->s_bdev;
104 struct request_queue *q = bdev_get_queue(bdev);
105 struct request_list *rl = &q->root_rl;
106 return !(rl->count[BLK_RW_SYNC]) && !(rl->count[BLK_RW_ASYNC]);