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
]);