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_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 /* Search max. number of dirty segments to select a victim segment */
  24 #define DEF_MAX_VICTIM_SEARCH 4096 /* covers 8GB */
  25
  26 struct f2fs_gc_kthread {
  27         struct task_struct *f2fs_gc_task;
  28         wait_queue_head_t gc_wait_queue_head;
  29
  30         /* for gc sleep time */
  31         unsigned int urgent_sleep_time;
  32         unsigned int min_sleep_time;
  33         unsigned int max_sleep_time;
  34         unsigned int no_gc_sleep_time;
  35
  36         /* for changing gc mode */
  37         unsigned int gc_idle;
  38         unsigned int gc_urgent;
  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  */
  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
  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
  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
  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
  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
 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 }