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 #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_idle;
  40         unsigned int gc_urgent;
  41         unsigned int gc_wake;
  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                                                         unsigned int *wait)
  75 {
  76         unsigned int min_time = gc_th->min_sleep_time;
  77         unsigned int max_time = gc_th->max_sleep_time;
  78
  79         if (*wait == gc_th->no_gc_sleep_time)
  80                 return;
  81
  82         if ((long long)*wait + (long long)min_time > (long long)max_time)
  83                 *wait = max_time;
  84         else
  85                 *wait += min_time;
  86 }
  87
  88 static inline void decrease_sleep_time(struct f2fs_gc_kthread *gc_th,
  89                                                         unsigned int *wait)
  90 {
  91         unsigned int min_time = gc_th->min_sleep_time;
  92
  93         if (*wait == gc_th->no_gc_sleep_time)
  94                 *wait = gc_th->max_sleep_time;
  95
  96         if ((long long)*wait - (long long)min_time < (long long)min_time)
  97                 *wait = min_time;
  98         else
  99                 *wait -= min_time;
 100 }
 101
 102 static inline bool has_enough_invalid_blocks(struct f2fs_sb_info *sbi)
 103 {
 104         block_t invalid_user_blocks = sbi->user_block_count -
 105                                         written_block_count(sbi);
 106         /*
 107          * Background GC is triggered with the following conditions.
 108          * 1. There are a number of invalid blocks.
 109          * 2. There is not enough free space.
 110          */
 111         if (invalid_user_blocks > limit_invalid_user_blocks(sbi) &&
 112                         free_user_blocks(sbi) < limit_free_user_blocks(sbi))
 113                 return true;
 114         return false;
 115 }