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 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 */ 21 22 /* Search max. number of dirty segments to select a victim segment */ 23 #define MAX_VICTIM_SEARCH 20 24 25 struct f2fs_gc_kthread { 26 struct task_struct *f2fs_gc_task; 27 wait_queue_head_t gc_wait_queue_head; 28 }; 29 30 struct inode_entry { 31 struct list_head list; 32 struct inode *inode; 33 }; 34 35 /* 36 * inline functions 37 */ 38 static inline block_t free_user_blocks(struct f2fs_sb_info *sbi) 39 { 40 if (free_segments(sbi) < overprovision_segments(sbi)) 41 return 0; 42 else 43 return (free_segments(sbi) - overprovision_segments(sbi)) 44 << sbi->log_blocks_per_seg; 45 } 46 47 static inline block_t limit_invalid_user_blocks(struct f2fs_sb_info *sbi) 48 { 49 return (long)(sbi->user_block_count * LIMIT_INVALID_BLOCK) / 100; 50 } 51 52 static inline block_t limit_free_user_blocks(struct f2fs_sb_info *sbi) 53 { 54 block_t reclaimable_user_blocks = sbi->user_block_count - 55 written_block_count(sbi); 56 return (long)(reclaimable_user_blocks * LIMIT_FREE_BLOCK) / 100; 57 } 58 59 static inline long increase_sleep_time(long wait) 60 { 61 wait += GC_THREAD_MIN_SLEEP_TIME; 62 if (wait > GC_THREAD_MAX_SLEEP_TIME) 63 wait = GC_THREAD_MAX_SLEEP_TIME; 64 return wait; 65 } 66 67 static inline long decrease_sleep_time(long wait) 68 { 69 wait -= GC_THREAD_MIN_SLEEP_TIME; 70 if (wait <= GC_THREAD_MIN_SLEEP_TIME) 71 wait = GC_THREAD_MIN_SLEEP_TIME; 72 return wait; 73 } 74 75 static inline bool has_enough_invalid_blocks(struct f2fs_sb_info *sbi) 76 { 77 block_t invalid_user_blocks = sbi->user_block_count - 78 written_block_count(sbi); 79 /* 80 * Background GC is triggered with the following condition. 81 * 1. There are a number of invalid blocks. 82 * 2. There is not enough free space. 83 */ 84 if (invalid_user_blocks > limit_invalid_user_blocks(sbi) && 85 free_user_blocks(sbi) < limit_free_user_blocks(sbi)) 86 return true; 87 return false; 88 } 89 90 static inline int is_idle(struct f2fs_sb_info *sbi) 91 { 92 struct block_device *bdev = sbi->sb->s_bdev; 93 struct request_queue *q = bdev_get_queue(bdev); 94 struct request_list *rl = &q->root_rl; 95 return !(rl->count[BLK_RW_SYNC]) && !(rl->count[BLK_RW_ASYNC]); 96 } 97