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_NAME "f2fs_gc_task" 12 #define GC_THREAD_MIN_WB_PAGES 1 /* 13 * a threshold to determine 14 * whether IO subsystem is idle 15 * or not 16 */ 17 #define GC_THREAD_MIN_SLEEP_TIME 10000 /* milliseconds */ 18 #define GC_THREAD_MAX_SLEEP_TIME 30000 19 #define GC_THREAD_NOGC_SLEEP_TIME 10000 20 #define LIMIT_INVALID_BLOCK 40 /* percentage over total user space */ 21 #define LIMIT_FREE_BLOCK 40 /* percentage over invalid + free space */ 22 23 /* Search max. number of dirty segments to select a victim segment */ 24 #define MAX_VICTIM_SEARCH 20 25 26 enum { 27 GC_NONE = 0, 28 GC_ERROR, 29 GC_OK, 30 GC_NEXT, 31 GC_BLOCKED, 32 GC_DONE, 33 }; 34 35 struct f2fs_gc_kthread { 36 struct task_struct *f2fs_gc_task; 37 wait_queue_head_t gc_wait_queue_head; 38 }; 39 40 struct inode_entry { 41 struct list_head list; 42 struct inode *inode; 43 }; 44 45 /* 46 * inline functions 47 */ 48 static inline block_t free_user_blocks(struct f2fs_sb_info *sbi) 49 { 50 if (free_segments(sbi) < overprovision_segments(sbi)) 51 return 0; 52 else 53 return (free_segments(sbi) - overprovision_segments(sbi)) 54 << sbi->log_blocks_per_seg; 55 } 56 57 static inline block_t limit_invalid_user_blocks(struct f2fs_sb_info *sbi) 58 { 59 return (long)(sbi->user_block_count * LIMIT_INVALID_BLOCK) / 100; 60 } 61 62 static inline block_t limit_free_user_blocks(struct f2fs_sb_info *sbi) 63 { 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; 67 } 68 69 static inline long increase_sleep_time(long wait) 70 { 71 wait += GC_THREAD_MIN_SLEEP_TIME; 72 if (wait > GC_THREAD_MAX_SLEEP_TIME) 73 wait = GC_THREAD_MAX_SLEEP_TIME; 74 return wait; 75 } 76 77 static inline long decrease_sleep_time(long wait) 78 { 79 wait -= GC_THREAD_MIN_SLEEP_TIME; 80 if (wait <= GC_THREAD_MIN_SLEEP_TIME) 81 wait = GC_THREAD_MIN_SLEEP_TIME; 82 return wait; 83 } 84 85 static inline bool has_enough_invalid_blocks(struct f2fs_sb_info *sbi) 86 { 87 block_t invalid_user_blocks = sbi->user_block_count - 88 written_block_count(sbi); 89 /* 90 * Background GC is triggered with the following condition. 91 * 1. There are a number of invalid blocks. 92 * 2. There is not enough free space. 93 */ 94 if (invalid_user_blocks > limit_invalid_user_blocks(sbi) && 95 free_user_blocks(sbi) < limit_free_user_blocks(sbi)) 96 return true; 97 return false; 98 } 99 100 static inline int is_idle(struct f2fs_sb_info *sbi) 101 { 102 struct block_device *bdev = sbi->sb->s_bdev; 103 struct request_queue *q = bdev_get_queue(bdev); 104 struct request_list *rl = &q->root_rl; 105 return !(rl->count[BLK_RW_SYNC]) && !(rl->count[BLK_RW_ASYNC]); 106 } 107 108 static inline bool should_do_checkpoint(struct f2fs_sb_info *sbi) 109 { 110 unsigned int pages_per_sec = sbi->segs_per_sec * 111 (1 << sbi->log_blocks_per_seg); 112 int node_secs = ((get_pages(sbi, F2FS_DIRTY_NODES) + pages_per_sec - 1) 113 >> sbi->log_blocks_per_seg) / sbi->segs_per_sec; 114 int dent_secs = ((get_pages(sbi, F2FS_DIRTY_DENTS) + pages_per_sec - 1) 115 >> sbi->log_blocks_per_seg) / sbi->segs_per_sec; 116 return free_sections(sbi) <= (node_secs + 2 * dent_secs + 2); 117 } 118