mirror of
https://github.com/torvalds/linux.git
synced 2024-11-30 16:11:38 +00:00
b1c57c1caa
Previously during SSR and GC, the maximum number of retrials to find a victim
segment was hard-coded by MAX_VICTIM_SEARCH, 4096 by default.
This number makes an effect on IO locality, when SSR mode is activated, which
results in performance fluctuation on some low-end devices.
If max_victim_search = 4, the victim will be searched like below.
("D" represents a dirty segment, and "*" indicates a selected victim segment.)
D1 D2 D3 D4 D5 D6 D7 D8 D9
[ * ]
[ * ]
[ * ]
[ ....]
This patch adds a sysfs entry to control the number dynamically through:
/sys/fs/f2fs/$dev/max_victim_search
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
111 lines
3.0 KiB
C
111 lines
3.0 KiB
C
/*
|
|
* fs/f2fs/gc.h
|
|
*
|
|
* Copyright (c) 2012 Samsung Electronics Co., Ltd.
|
|
* http://www.samsung.com/
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
#define GC_THREAD_MIN_WB_PAGES 1 /*
|
|
* a threshold to determine
|
|
* whether IO subsystem is idle
|
|
* or not
|
|
*/
|
|
#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 */
|
|
#define LIMIT_INVALID_BLOCK 40 /* percentage over total user space */
|
|
#define LIMIT_FREE_BLOCK 40 /* percentage over invalid + free space */
|
|
|
|
/* 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 min_sleep_time;
|
|
unsigned int max_sleep_time;
|
|
unsigned int no_gc_sleep_time;
|
|
|
|
/* for changing gc mode */
|
|
unsigned int gc_idle;
|
|
};
|
|
|
|
struct inode_entry {
|
|
struct list_head list;
|
|
struct inode *inode;
|
|
};
|
|
|
|
/*
|
|
* inline functions
|
|
*/
|
|
static inline block_t free_user_blocks(struct f2fs_sb_info *sbi)
|
|
{
|
|
if (free_segments(sbi) < overprovision_segments(sbi))
|
|
return 0;
|
|
else
|
|
return (free_segments(sbi) - overprovision_segments(sbi))
|
|
<< sbi->log_blocks_per_seg;
|
|
}
|
|
|
|
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 long increase_sleep_time(struct f2fs_gc_kthread *gc_th, long wait)
|
|
{
|
|
if (wait == gc_th->no_gc_sleep_time)
|
|
return wait;
|
|
|
|
wait += gc_th->min_sleep_time;
|
|
if (wait > gc_th->max_sleep_time)
|
|
wait = gc_th->max_sleep_time;
|
|
return wait;
|
|
}
|
|
|
|
static inline long decrease_sleep_time(struct f2fs_gc_kthread *gc_th, long wait)
|
|
{
|
|
if (wait == gc_th->no_gc_sleep_time)
|
|
wait = gc_th->max_sleep_time;
|
|
|
|
wait -= gc_th->min_sleep_time;
|
|
if (wait <= gc_th->min_sleep_time)
|
|
wait = gc_th->min_sleep_time;
|
|
return wait;
|
|
}
|
|
|
|
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 condition.
|
|
* 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;
|
|
}
|
|
|
|
static inline int is_idle(struct f2fs_sb_info *sbi)
|
|
{
|
|
struct block_device *bdev = sbi->sb->s_bdev;
|
|
struct request_queue *q = bdev_get_queue(bdev);
|
|
struct request_list *rl = &q->root_rl;
|
|
return !(rl->count[BLK_RW_SYNC]) && !(rl->count[BLK_RW_ASYNC]);
|
|
}
|