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 DEF_MAX_VICTIM_SEARCH 4096 /* covers 8GB */
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;
34 /* for changing gc mode */
38 struct gc_inode_list {
39 struct list_head ilist;
40 struct radix_tree_root iroot;
43 extern struct kmem_cache *inode_entry_slab;
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(struct f2fs_gc_kthread *gc_th, long wait)
71 if (wait == gc_th->no_gc_sleep_time)
74 wait += gc_th->min_sleep_time;
75 if (wait > gc_th->max_sleep_time)
76 wait = gc_th->max_sleep_time;
80 static inline long decrease_sleep_time(struct f2fs_gc_kthread *gc_th, long wait)
82 if (wait == gc_th->no_gc_sleep_time)
83 wait = gc_th->max_sleep_time;
85 wait -= gc_th->min_sleep_time;
86 if (wait <= gc_th->min_sleep_time)
87 wait = gc_th->min_sleep_time;
91 static inline bool has_enough_invalid_blocks(struct f2fs_sb_info *sbi)
93 block_t invalid_user_blocks = sbi->user_block_count -
94 written_block_count(sbi);
96 * Background GC is triggered with the following conditions.
97 * 1. There are a number of invalid blocks.
98 * 2. There is not enough free space.
100 if (invalid_user_blocks > limit_invalid_user_blocks(sbi) &&
101 free_user_blocks(sbi) < limit_free_user_blocks(sbi))
106 static inline int is_idle(struct f2fs_sb_info *sbi)
108 struct block_device *bdev = sbi->sb->s_bdev;
109 struct request_queue *q = bdev_get_queue(bdev);
110 struct request_list *rl = &q->root_rl;
111 return !(rl->count[BLK_RW_SYNC]) && !(rl->count[BLK_RW_ASYNC]);