/* SPDX-License-Identifier: GPL-2.0 */

  /*

   * fs/f2fs/gc.h
   *
   * Copyright (c) 2012 Samsung Electronics Co., Ltd.
   *             http://www.samsung.com/

   */

  #define GC_THREAD_MIN_WB_PAGES		1	/*
  						 * a threshold to determine
  						 * whether IO subsystem is idle
  						 * or not
  						 */

  #define DEF_GC_THREAD_URGENT_SLEEP_TIME	500	/* 500 ms */

  #define DEF_GC_THREAD_MIN_SLEEP_TIME	30000	/* milliseconds */
  #define DEF_GC_THREAD_MAX_SLEEP_TIME	60000
  #define DEF_GC_THREAD_NOGC_SLEEP_TIME	300000	/* wait 5 min */

  
  /* choose candidates from sections which has age of more than 7 days */
  #define DEF_GC_THREAD_AGE_THRESHOLD		(60 * 60 * 24 * 7)
  #define DEF_GC_THREAD_CANDIDATE_RATIO		20	/* select 20% oldest sections as candidates */
  #define DEF_GC_THREAD_MAX_CANDIDATE_COUNT	10	/* select at most 10 sections as candidates */
  #define DEF_GC_THREAD_AGE_WEIGHT		60	/* age weight */
  #define DEFAULT_ACCURACY_CLASS			10000	/* accuracy class */

  #define LIMIT_INVALID_BLOCK	40 /* percentage over total user space */
  #define LIMIT_FREE_BLOCK	40 /* percentage over invalid + free space */

  #define DEF_GC_FAILED_PINNED_FILES	2048

  /* Search max. number of dirty segments to select a victim segment */

  #define DEF_MAX_VICTIM_SEARCH 4096 /* covers 8GB */

  struct f2fs_gc_kthread {
  	struct task_struct *f2fs_gc_task;
  	wait_queue_head_t gc_wait_queue_head;

  
  	/* for gc sleep time */

  	unsigned int urgent_sleep_time;

  	unsigned int min_sleep_time;
  	unsigned int max_sleep_time;
  	unsigned int no_gc_sleep_time;

  
  	/* for changing gc mode */

  	unsigned int gc_wake;

  };

  struct gc_inode_list {
  	struct list_head ilist;
  	struct radix_tree_root iroot;
  };

  struct victim_info {
  	unsigned long long mtime;	/* mtime of section */
  	unsigned int segno;		/* section No. */
  };
  
  struct victim_entry {
  	struct rb_node rb_node;		/* rb node located in rb-tree */
  	union {
  		struct {
  			unsigned long long mtime;	/* mtime of section */
  			unsigned int segno;		/* segment No. */
  		};
  		struct victim_info vi;	/* victim info */
  	};
  	struct list_head list;
  };

  /*

   * inline functions
   */

  
  /*
   * On a Zoned device zone-capacity can be less than zone-size and if
   * zone-capacity is not aligned to f2fs segment size(2MB), then the segment
   * starting just before zone-capacity has some blocks spanning across the
   * zone-capacity, these blocks are not usable.
   * Such spanning segments can be in free list so calculate the sum of usable
   * blocks in currently free segments including normal and spanning segments.
   */
  static inline block_t free_segs_blk_count_zoned(struct f2fs_sb_info *sbi)
  {
  	block_t free_seg_blks = 0;
  	struct free_segmap_info *free_i = FREE_I(sbi);
  	int j;
  
  	spin_lock(&free_i->segmap_lock);
  	for (j = 0; j < MAIN_SEGS(sbi); j++)
  		if (!test_bit(j, free_i->free_segmap))
  			free_seg_blks += f2fs_usable_blks_in_seg(sbi, j);
  	spin_unlock(&free_i->segmap_lock);
  
  	return free_seg_blks;
  }
  
  static inline block_t free_segs_blk_count(struct f2fs_sb_info *sbi)
  {
  	if (f2fs_sb_has_blkzoned(sbi))
  		return free_segs_blk_count_zoned(sbi);
  
  	return free_segments(sbi) << sbi->log_blocks_per_seg;
  }

  static inline block_t free_user_blocks(struct f2fs_sb_info *sbi)
  {

  	block_t free_blks, ovp_blks;
  
  	free_blks = free_segs_blk_count(sbi);
  	ovp_blks = overprovision_segments(sbi) << sbi->log_blocks_per_seg;
  
  	if (free_blks < ovp_blks)

  		return 0;

  
  	return free_blks - ovp_blks;

  }
  
  static inline block_t limit_invalid_user_blocks(struct f2fs_sb_info *sbi)
  {
  	return (long)(sbi->user_block_count * LIMIT_INVALID_BLOCK) / 100;
  }
  
  static inline block_t limit_free_user_blocks(struct f2fs_sb_info *sbi)
  {
  	block_t reclaimable_user_blocks = sbi->user_block_count -
  		written_block_count(sbi);
  	return (long)(reclaimable_user_blocks * LIMIT_FREE_BLOCK) / 100;
  }

  static inline void increase_sleep_time(struct f2fs_gc_kthread *gc_th,

  							unsigned int *wait)

  {

  	unsigned int min_time = gc_th->min_sleep_time;
  	unsigned int max_time = gc_th->max_sleep_time;

  	if (*wait == gc_th->no_gc_sleep_time)
  		return;

  	if ((long long)*wait + (long long)min_time > (long long)max_time)
  		*wait = max_time;
  	else
  		*wait += min_time;

  }

  static inline void decrease_sleep_time(struct f2fs_gc_kthread *gc_th,

  							unsigned int *wait)

  {

  	unsigned int min_time = gc_th->min_sleep_time;

  	if (*wait == gc_th->no_gc_sleep_time)
  		*wait = gc_th->max_sleep_time;

  	if ((long long)*wait - (long long)min_time < (long long)min_time)
  		*wait = min_time;
  	else
  		*wait -= min_time;

  }
  
  static inline bool has_enough_invalid_blocks(struct f2fs_sb_info *sbi)
  {
  	block_t invalid_user_blocks = sbi->user_block_count -
  					written_block_count(sbi);
  	/*

  	 * Background GC is triggered with the following conditions.

  	 * 1. There are a number of invalid blocks.
  	 * 2. There is not enough free space.
  	 */
  	if (invalid_user_blocks > limit_invalid_user_blocks(sbi) &&
  			free_user_blocks(sbi) < limit_free_user_blocks(sbi))
  		return true;
  	return false;
  }