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Commit d2dc095f authored by Namjae Jeon's avatar Namjae Jeon Committed by Jaegeuk Kim
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f2fs: add sysfs entries to select the gc policy 



Add sysfs entry gc_idle to control the gc policy. Where
gc_idle = 1 corresponds to selecting a cost benefit approach,
while gc_idle = 2 corresponds to selecting a greedy approach
to garbage collection. The selection is mutually exclusive one
approach will work at any point. If gc_idle = 0, then this
option is disabled.

Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: default avatarNamjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: default avatarPankaj Kumar <pankaj.km@samsung.com>
Reviewed-by: default avatarGu Zheng <guz.fnst@cn.fujitsu.com>
[Jaegeuk Kim: change the select_gc_type() flow slightly]
Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
parent b59d0bae

Documentation/ABI/testing/sysfs-fs-f2fs

+6 −0
Original line number Diff line number Diff line
@@ -18,3 +18,9 @@ Contact: "Namjae Jeon" <namjae.jeon@samsung.com> 
Description:

		 Controls the default sleep time for gc_thread. Time

		 is in milliseconds.



What:		/sys/fs/f2fs/<disk>/gc_idle

Date:		July 2013

Contact:	"Namjae Jeon" <namjae.jeon@samsung.com>

Description:

		 Controls the victim selection policy for garbage collection.

Documentation/filesystems/f2fs.txt

+6 −0
Original line number Diff line number Diff line
@@ -158,6 +158,12 @@ Files in /sys/fs/f2fs/<devname> 
                              time for the garbage collection thread. Time is

                              in milliseconds.



 gc_idle                      This parameter controls the selection of victim

                              policy for garbage collection. Setting gc_idle = 0

                              (default) will disable this option. Setting

                              gc_idle = 1 will select the Cost Benefit approach

                              & setting gc_idle = 2 will select the greedy aproach.



================================================================================

USAGE

================================================================================

fs/f2fs/gc.c

+13 −3
Original line number Diff line number Diff line
@@ -106,6 +106,8 @@ int start_gc_thread(struct f2fs_sb_info *sbi) 
	gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;

	gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;



	gc_th->gc_idle = 0;



	sbi->gc_thread = gc_th;

	init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);

	sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
@@ -130,9 +132,17 @@ void stop_gc_thread(struct f2fs_sb_info *sbi) 
	sbi->gc_thread = NULL;

}



static int select_gc_type(int gc_type)

static int select_gc_type(struct f2fs_gc_kthread *gc_th, int gc_type)

{

	return (gc_type == BG_GC) ? GC_CB : GC_GREEDY;

	int gc_mode = (gc_type == BG_GC) ? GC_CB : GC_GREEDY;



	if (gc_th && gc_th->gc_idle) {

		if (gc_th->gc_idle == 1)

			gc_mode = GC_CB;

		else if (gc_th->gc_idle == 2)

			gc_mode = GC_GREEDY;

	}

	return gc_mode;

}



static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
@@ -145,7 +155,7 @@ static void select_policy(struct f2fs_sb_info *sbi, int gc_type, 
		p->dirty_segmap = dirty_i->dirty_segmap[type];

		p->ofs_unit = 1;

	} else {

		p->gc_mode = select_gc_type(gc_type);

		p->gc_mode = select_gc_type(sbi->gc_thread, gc_type);

		p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];

		p->ofs_unit = sbi->segs_per_sec;

	}

fs/f2fs/gc.h

+3 −0
Original line number Diff line number Diff line
@@ -30,6 +30,9 @@ struct f2fs_gc_kthread { 
	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 {

fs/f2fs/super.c

+2 −0
Original line number Diff line number Diff line
@@ -148,12 +148,14 @@ static struct f2fs_attr f2fs_attr_##_name = { \ 
F2FS_RW_ATTR(gc_min_sleep_time, min_sleep_time);

F2FS_RW_ATTR(gc_max_sleep_time, max_sleep_time);

F2FS_RW_ATTR(gc_no_gc_sleep_time, no_gc_sleep_time);

F2FS_RW_ATTR(gc_idle, gc_idle);



#define ATTR_LIST(name) (&f2fs_attr_##name.attr)

static struct attribute *f2fs_attrs[] = {

	ATTR_LIST(gc_min_sleep_time),

	ATTR_LIST(gc_max_sleep_time),

	ATTR_LIST(gc_no_gc_sleep_time),

	ATTR_LIST(gc_idle),

	NULL,

};