linux-kernel - Re: [f2fs-dev] [PATCH v2] f2fs: add gc_boost_gc

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Message-ID: <aIeoEmbeloGR6zdV@google.com>
Date: Mon, 28 Jul 2025 16:40:50 +0000
From: Jaegeuk Kim <jaegeuk@...nel.org>
To: Chao Yu <chao@...nel.org>
Cc: Daeho Jeong <daeho43@...il.com>, linux-kernel@...r.kernel.org,
	linux-f2fs-devel@...ts.sourceforge.net, kernel-team@...roid.com,
	Daeho Jeong <daehojeong@...gle.com>
Subject: Re: [f2fs-dev] [PATCH v2] f2fs: add gc_boost_gc_greedy sysfs node

On 07/22, Chao Yu wrote:
> On 7/19/25 05:50, Daeho Jeong wrote:
> > From: Daeho Jeong <daehojeong@...gle.com>
> > 
> > Add this to control GC algorithm for boost GC.
> > 
> > Signed-off-by: Daeho Jeong <daehojeong@...gle.com>
> > ---
> > v2: use GC_GREEDY instead of 1
> > ---
> >  Documentation/ABI/testing/sysfs-fs-f2fs |  8 +++++++-
> >  fs/f2fs/gc.c                            |  3 ++-
> >  fs/f2fs/gc.h                            |  1 +
> >  fs/f2fs/sysfs.c                         | 16 ++++++++++++++++
> >  4 files changed, 26 insertions(+), 2 deletions(-)
> > 
> > diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
> > index 931c1f63aa2e..2158055cd9d1 100644
> > --- a/Documentation/ABI/testing/sysfs-fs-f2fs
> > +++ b/Documentation/ABI/testing/sysfs-fs-f2fs
> > @@ -866,6 +866,12 @@ What:		/sys/fs/f2fs/<disk>/gc_boost_gc_multiple
> >  Date:		June 2025
> >  Contact:	"Daeho Jeong" <daehojeong@...gle.com>
> >  Description:	Set a multiplier for the background GC migration window when F2FS GC is
> > -		boosted.
> > +		boosted. the range should be from 1 to the segment count in a section.
> >  		Default: 5
> >  
> > +What:		/sys/fs/f2fs/<disk>/gc_boost_gc_greedy
> > +Date:		June 2025
> > +Contact:	"Daeho Jeong" <daehojeong@...gle.com>
> > +Description:	Control GC algorithm for boost GC. 0: cost benefit, 1: greedy
> > +		Default: 1
> > +
> > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> > index de7e59bc0906..0d7703e7f9e0 100644
> > --- a/fs/f2fs/gc.c
> > +++ b/fs/f2fs/gc.c
> > @@ -141,7 +141,7 @@ static int gc_thread_func(void *data)
> >  					FOREGROUND : BACKGROUND);
> >  
> >  		sync_mode = (F2FS_OPTION(sbi).bggc_mode == BGGC_MODE_SYNC) ||
> > -				gc_control.one_time;
> > +			(gc_control.one_time && gc_th->boost_gc_greedy);
> >  
> >  		/* foreground GC was been triggered via f2fs_balance_fs() */
> >  		if (foreground)
> > @@ -198,6 +198,7 @@ int f2fs_start_gc_thread(struct f2fs_sb_info *sbi)
> >  	gc_th->urgent_sleep_time = DEF_GC_THREAD_URGENT_SLEEP_TIME;
> >  	gc_th->valid_thresh_ratio = DEF_GC_THREAD_VALID_THRESH_RATIO;
> >  	gc_th->boost_gc_multiple = BOOST_GC_MULTIPLE;
> > +	gc_th->boost_gc_greedy = GC_GREEDY;
> >  
> >  	if (f2fs_sb_has_blkzoned(sbi)) {
> >  		gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME_ZONED;
> > diff --git a/fs/f2fs/gc.h b/fs/f2fs/gc.h
> > index efa1968810a0..1a2e7a84b59f 100644
> > --- a/fs/f2fs/gc.h
> > +++ b/fs/f2fs/gc.h
> > @@ -69,6 +69,7 @@ struct f2fs_gc_kthread {
> >  	unsigned int boost_zoned_gc_percent;
> >  	unsigned int valid_thresh_ratio;
> >  	unsigned int boost_gc_multiple;
> > +	unsigned int boost_gc_greedy;
> >  };
> >  
> >  struct gc_inode_list {
> > diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> > index b0270b1c939c..3a52f51ee3c6 100644
> > --- a/fs/f2fs/sysfs.c
> > +++ b/fs/f2fs/sysfs.c
> > @@ -824,6 +824,20 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
> >  		return count;
> >  	}
> >  
> > +	if (!strcmp(a->attr.name, "gc_boost_gc_multiple")) {
> > +		if (t < 1 || t > SEGS_PER_SEC(sbi))
> > +			return -EINVAL;
> > +		sbi->gc_thread->boost_gc_multiple = (unsigned int)t;
> > +		return count;
> > +	}
> 
> This check should be in ("f2fs: add gc_boost_gc_multiple sysfs node"), right?

Applied with the fix.

> 
> Thanks,
> 
> > +
> > +	if (!strcmp(a->attr.name, "gc_boost_gc_greedy")) {
> > +		if (t > GC_GREEDY)
> > +			return -EINVAL;
> > +		sbi->gc_thread->boost_gc_greedy = (unsigned int)t;
> > +		return count;
> > +	}
> > +
> >  	*ui = (unsigned int)t;
> >  
> >  	return count;
> > @@ -1051,6 +1065,7 @@ GC_THREAD_RW_ATTR(gc_no_zoned_gc_percent, no_zoned_gc_percent);
> >  GC_THREAD_RW_ATTR(gc_boost_zoned_gc_percent, boost_zoned_gc_percent);
> >  GC_THREAD_RW_ATTR(gc_valid_thresh_ratio, valid_thresh_ratio);
> >  GC_THREAD_RW_ATTR(gc_boost_gc_multiple, boost_gc_multiple);
> > +GC_THREAD_RW_ATTR(gc_boost_gc_greedy, boost_gc_greedy);
> >  
> >  /* SM_INFO ATTR */
> >  SM_INFO_RW_ATTR(reclaim_segments, rec_prefree_segments);
> > @@ -1222,6 +1237,7 @@ static struct attribute *f2fs_attrs[] = {
> >  	ATTR_LIST(gc_boost_zoned_gc_percent),
> >  	ATTR_LIST(gc_valid_thresh_ratio),
> >  	ATTR_LIST(gc_boost_gc_multiple),
> > +	ATTR_LIST(gc_boost_gc_greedy),
> >  	ATTR_LIST(gc_idle),
> >  	ATTR_LIST(gc_urgent),
> >  	ATTR_LIST(reclaim_segments),
>