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 GC_THREAD_MIN_SLEEP_TIME 10000 /* milliseconds */
17 #define GC_THREAD_MAX_SLEEP_TIME 30000
18 #define GC_THREAD_NOGC_SLEEP_TIME 10000
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
34 struct f2fs_gc_kthread {
35 struct task_struct *f2fs_gc_task;
36 wait_queue_head_t gc_wait_queue_head;
40 struct list_head list;
47 static inline block_t free_user_blocks(struct f2fs_sb_info *sbi)
49 if (free_segments(sbi) < overprovision_segments(sbi))
52 return (free_segments(sbi) - overprovision_segments(sbi))
53 << sbi->log_blocks_per_seg;
56 static inline block_t limit_invalid_user_blocks(struct f2fs_sb_info *sbi)
58 return (long)(sbi->user_block_count * LIMIT_INVALID_BLOCK) / 100;
61 static inline block_t limit_free_user_blocks(struct f2fs_sb_info *sbi)
63 block_t reclaimable_user_blocks = sbi->user_block_count -
64 written_block_count(sbi);
65 return (long)(reclaimable_user_blocks * LIMIT_FREE_BLOCK) / 100;
68 static inline long increase_sleep_time(long wait)
70 wait += GC_THREAD_MIN_SLEEP_TIME;
71 if (wait > GC_THREAD_MAX_SLEEP_TIME)
72 wait = GC_THREAD_MAX_SLEEP_TIME;
76 static inline long decrease_sleep_time(long wait)
78 wait -= GC_THREAD_MIN_SLEEP_TIME;
79 if (wait <= GC_THREAD_MIN_SLEEP_TIME)
80 wait = GC_THREAD_MIN_SLEEP_TIME;
84 static inline bool has_enough_invalid_blocks(struct f2fs_sb_info *sbi)
86 block_t invalid_user_blocks = sbi->user_block_count -
87 written_block_count(sbi);
89 * Background GC is triggered with the following condition.
90 * 1. There are a number of invalid blocks.
91 * 2. There is not enough free space.
93 if (invalid_user_blocks > limit_invalid_user_blocks(sbi) &&
94 free_user_blocks(sbi) < limit_free_user_blocks(sbi))
99 static inline int is_idle(struct f2fs_sb_info *sbi)
101 struct block_device *bdev = sbi->sb->s_bdev;
102 struct request_queue *q = bdev_get_queue(bdev);
103 struct request_list *rl = &q->root_rl;
104 return !(rl->count[BLK_RW_SYNC]) && !(rl->count[BLK_RW_ASYNC]);
107 static inline bool should_do_checkpoint(struct f2fs_sb_info *sbi)
109 int node_secs = get_blocktype_secs(sbi, F2FS_DIRTY_NODES);
110 int dent_secs = get_blocktype_secs(sbi, F2FS_DIRTY_DENTS);
111 return free_sections(sbi) <= (node_secs + 2 * dent_secs + 2);