fs/f2fs/gc.h

   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_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 */
  21
  22 /*
  23  * with this macro, we can control the max time we do garbage collection,
  24  * when user triggers batch mode gc by ioctl.
  25  */
  26 #define F2FS_BATCH_GC_MAX_NUM           16
  27
  28 /* Search max. number of dirty segments to select a victim segment */
  29 #define DEF_MAX_VICTIM_SEARCH 4096 /* covers 8GB */
  30
  31 struct f2fs_gc_kthread {
  32         struct task_struct *f2fs_gc_task;
  33         wait_queue_head_t gc_wait_queue_head;
  34
  35         /* for gc sleep time */
  36         unsigned int min_sleep_time;
  37         unsigned int max_sleep_time;
  38         unsigned int no_gc_sleep_time;
  39
  40         /* for changing gc mode */
  41         unsigned int gc_idle;
  42 };
  43
  44 struct gc_inode_list {
  45         struct list_head ilist;
  46         struct radix_tree_root iroot;
  47 };
  48
  49 /*
  50  * inline functions
  51  */
  52 static inline block_t free_user_blocks(struct f2fs_sb_info *sbi)
  53 {
  54         if (free_segments(sbi) < overprovision_segments(sbi))
  55                 return 0;
  56         else
  57                 return (free_segments(sbi) - overprovision_segments(sbi))
  58                         << sbi->log_blocks_per_seg;
  59 }
  60
  61 static inline block_t limit_invalid_user_blocks(struct f2fs_sb_info *sbi)
  62 {
  63         return (long)(sbi->user_block_count * LIMIT_INVALID_BLOCK) / 100;
  64 }
  65
  66 static inline block_t limit_free_user_blocks(struct f2fs_sb_info *sbi)
  67 {
  68         block_t reclaimable_user_blocks = sbi->user_block_count -
  69                 written_block_count(sbi);
  70         return (long)(reclaimable_user_blocks * LIMIT_FREE_BLOCK) / 100;
  71 }
  72
  73 static inline void increase_sleep_time(struct f2fs_gc_kthread *gc_th,
  74                                                                 long *wait)
  75 {
  76         if (*wait == gc_th->no_gc_sleep_time)
  77                 return;
  78
  79         *wait += gc_th->min_sleep_time;
  80         if (*wait > gc_th->max_sleep_time)
  81                 *wait = gc_th->max_sleep_time;
  82 }
  83
  84 static inline void decrease_sleep_time(struct f2fs_gc_kthread *gc_th,
  85                                                                 long *wait)
  86 {
  87         if (*wait == gc_th->no_gc_sleep_time)
  88                 *wait = gc_th->max_sleep_time;
  89
  90         *wait -= gc_th->min_sleep_time;
  91         if (*wait <= gc_th->min_sleep_time)
  92                 *wait = gc_th->min_sleep_time;
  93 }
  94
  95 static inline bool has_enough_invalid_blocks(struct f2fs_sb_info *sbi)
  96 {
  97         block_t invalid_user_blocks = sbi->user_block_count -
  98                                         written_block_count(sbi);
  99         /*
 100          * Background GC is triggered with the following conditions.
 101          * 1. There are a number of invalid blocks.
 102          * 2. There is not enough free space.
 103          */
 104         if (invalid_user_blocks > limit_invalid_user_blocks(sbi) &&
 105                         free_user_blocks(sbi) < limit_free_user_blocks(sbi))
 106                 return true;
 107         return false;
 108 }
 109
 110 static inline int is_idle(struct f2fs_sb_info *sbi)
 111 {
 112         struct block_device *bdev = sbi->sb->s_bdev;
 113         struct request_queue *q = bdev_get_queue(bdev);
 114         struct request_list *rl = &q->root_rl;
 115         return !(rl->count[BLK_RW_SYNC]) && !(rl->count[BLK_RW_ASYNC]);
 116 }