1 /*
2  * fs/f2fs/gc.h
3  *
4  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
5  *             http://www.samsung.com/
6  *
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.
10  */
11 #define GC_THREAD_MIN_WB_PAGES		1	/*
12 						 * a threshold to determine
13 						 * whether IO subsystem is idle
14 						 * or not
15 						 */
16 #define DEF_GC_THREAD_URGENT_SLEEP_TIME	500	/* 500 ms */
17 #define DEF_GC_THREAD_MIN_SLEEP_TIME	30000	/* milliseconds */
18 #define DEF_GC_THREAD_MAX_SLEEP_TIME	60000
19 #define DEF_GC_THREAD_NOGC_SLEEP_TIME	300000	/* wait 5 min */
20 #define LIMIT_INVALID_BLOCK	40 /* percentage over total user space */
21 #define LIMIT_FREE_BLOCK	40 /* percentage over invalid + free space */
22 
23 #define DEF_GC_FAILED_PINNED_FILES	2048
24 
25 /* Search max. number of dirty segments to select a victim segment */
26 #define DEF_MAX_VICTIM_SEARCH 4096 /* covers 8GB */
27 
28 struct f2fs_gc_kthread {
29 	struct task_struct *f2fs_gc_task;
30 	wait_queue_head_t gc_wait_queue_head;
31 
32 	/* for gc sleep time */
33 	unsigned int urgent_sleep_time;
34 	unsigned int min_sleep_time;
35 	unsigned int max_sleep_time;
36 	unsigned int no_gc_sleep_time;
37 
38 	/* for changing gc mode */
39 	unsigned int gc_wake;
40 };
41 
42 struct gc_inode_list {
43 	struct list_head ilist;
44 	struct radix_tree_root iroot;
45 };
46 
47 /*
48  * inline functions
49  */
free_user_blocks(struct f2fs_sb_info * sbi)50 static inline block_t free_user_blocks(struct f2fs_sb_info *sbi)
51 {
52 	if (free_segments(sbi) < overprovision_segments(sbi))
53 		return 0;
54 	else
55 		return (free_segments(sbi) - overprovision_segments(sbi))
56 			<< sbi->log_blocks_per_seg;
57 }
58 
limit_invalid_user_blocks(struct f2fs_sb_info * sbi)59 static inline block_t limit_invalid_user_blocks(struct f2fs_sb_info *sbi)
60 {
61 	return (long)(sbi->user_block_count * LIMIT_INVALID_BLOCK) / 100;
62 }
63 
limit_free_user_blocks(struct f2fs_sb_info * sbi)64 static inline block_t limit_free_user_blocks(struct f2fs_sb_info *sbi)
65 {
66 	block_t reclaimable_user_blocks = sbi->user_block_count -
67 		written_block_count(sbi);
68 	return (long)(reclaimable_user_blocks * LIMIT_FREE_BLOCK) / 100;
69 }
70 
increase_sleep_time(struct f2fs_gc_kthread * gc_th,unsigned int * wait)71 static inline void increase_sleep_time(struct f2fs_gc_kthread *gc_th,
72 							unsigned int *wait)
73 {
74 	unsigned int min_time = gc_th->min_sleep_time;
75 	unsigned int max_time = gc_th->max_sleep_time;
76 
77 	if (*wait == gc_th->no_gc_sleep_time)
78 		return;
79 
80 	if ((long long)*wait + (long long)min_time > (long long)max_time)
81 		*wait = max_time;
82 	else
83 		*wait += min_time;
84 }
85 
decrease_sleep_time(struct f2fs_gc_kthread * gc_th,unsigned int * wait)86 static inline void decrease_sleep_time(struct f2fs_gc_kthread *gc_th,
87 							unsigned int *wait)
88 {
89 	unsigned int min_time = gc_th->min_sleep_time;
90 
91 	if (*wait == gc_th->no_gc_sleep_time)
92 		*wait = gc_th->max_sleep_time;
93 
94 	if ((long long)*wait - (long long)min_time < (long long)min_time)
95 		*wait = min_time;
96 	else
97 		*wait -= min_time;
98 }
99 
has_enough_invalid_blocks(struct f2fs_sb_info * sbi)100 static inline bool has_enough_invalid_blocks(struct f2fs_sb_info *sbi)
101 {
102 	block_t invalid_user_blocks = sbi->user_block_count -
103 					written_block_count(sbi);
104 	/*
105 	 * Background GC is triggered with the following conditions.
106 	 * 1. There are a number of invalid blocks.
107 	 * 2. There is not enough free space.
108 	 */
109 	if (invalid_user_blocks > limit_invalid_user_blocks(sbi) &&
110 			free_user_blocks(sbi) < limit_free_user_blocks(sbi))
111 		return true;
112 	return false;
113 }
114