[PATCH 1/5] f2fs: add mount option for segment allocation policy

[PATCH 1/5] f2fs: add mount option for segment allocation policy

[Jaegeuk Kim]

This patch adds an mount option, "alloc_mode=%s" having two options, "default"
and "reuse".

In "alloc_mode=reuse" case, f2fs starts to allocate segments from 0'th segment
all the time to reassign segments. It'd be useful for small-sized eMMC parts.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/f2fs.h    |  8 ++++++++
 fs/f2fs/segment.c |  5 +++++
 fs/f2fs/super.c   | 24 ++++++++++++++++++++++++
 3 files changed, 37 insertions(+)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 4e79a7b6f2e9..1ed17ec682ef 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1043,6 +1043,11 @@ enum {
 	WHINT_MODE_FS,		/* pass down hints with F2FS policy */
 };
 
+enum {
+	ALLOC_MODE_DEFAULT,	/* stay default */
+	ALLOC_MODE_REUSE,	/* reuse segments as much as possible */
+};
+
 struct f2fs_sb_info {
 	struct super_block *sb;			/* pointer to VFS super block */
 	struct proc_dir_entry *s_proc;		/* proc entry */
@@ -1229,6 +1234,9 @@ struct f2fs_sb_info {
 #endif
 	/* For which write hints are passed down to block layer */
 	int whint_mode;
+
+	/* segment allocation policy */
+	int alloc_mode;
 };
 
 #ifdef CONFIG_F2FS_FAULT_INJECTION
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 0646d5de8cd0..5e5e2936a26a 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2170,6 +2170,11 @@ static unsigned int __get_next_segno(struct f2fs_sb_info *sbi, int type)
 
 	if (SIT_I(sbi)->last_victim[ALLOC_NEXT])
 		return SIT_I(sbi)->last_victim[ALLOC_NEXT];
+
+	/* find segments from 0 to reuse freed segments */
+	if (sbi->alloc_mode == ALLOC_MODE_REUSE)
+		return 0;
+
 	return CURSEG_I(sbi, type)->segno;
 }
 
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 2e4f5673d65d..b7c0bdd1e532 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -130,6 +130,7 @@ enum {
 	Opt_jqfmt_vfsv0,
 	Opt_jqfmt_vfsv1,
 	Opt_whint,
+	Opt_alloc,
 	Opt_err,
 };
 
@@ -184,6 +185,7 @@ static match_table_t f2fs_tokens = {
 	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
 	{Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
 	{Opt_whint, "whint_mode=%s"},
+	{Opt_alloc, "alloc_mode=%s"},
 	{Opt_err, NULL},
 };
 
@@ -700,6 +702,23 @@ static int parse_options(struct super_block *sb, char *options)
 			}
 			kfree(name);
 			break;
+		case Opt_alloc:
+			name = match_strdup(&args[0]);
+			if (!name)
+				return -ENOMEM;
+
+			if (strlen(name) == 7 &&
+					!strncmp(name, "default", 7)) {
+				sbi->alloc_mode = ALLOC_MODE_DEFAULT;
+			} else if (strlen(name) == 5 &&
+					!strncmp(name, "reuse", 5)) {
+				sbi->alloc_mode = ALLOC_MODE_REUSE;
+			} else {
+				kfree(name);
+				return -EINVAL;
+			}
+			kfree(name);
+			break;
 		default:
 			f2fs_msg(sb, KERN_ERR,
 				"Unrecognized mount option \"%s\" or missing value",
@@ -1264,6 +1283,10 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
 	else if (sbi->whint_mode == WHINT_MODE_FS)
 		seq_printf(seq, ",whint_mode=%s", "fs-based");
 
+	if (sbi->alloc_mode == ALLOC_MODE_DEFAULT)
+		seq_printf(seq, ",alloc_mode=%s", "default");
+	else if (sbi->alloc_mode == ALLOC_MODE_REUSE)
+		seq_printf(seq, ",alloc_mode=%s", "reuse");
 	return 0;
 }
 
@@ -1273,6 +1296,7 @@ static void default_options(struct f2fs_sb_info *sbi)
 	sbi->active_logs = NR_CURSEG_TYPE;
 	sbi->inline_xattr_size = DEFAULT_INLINE_XATTR_ADDRS;
 	sbi->whint_mode = WHINT_MODE_OFF;
+	sbi->alloc_mode = ALLOC_MODE_DEFAULT;
 
 	set_opt(sbi, BG_GC);
 	set_opt(sbi, INLINE_XATTR);
-- 
2.15.0.531.g2ccb3012c9-goog

[PATCH 2/5] f2fs: add auto tuning for small devices

[Jaegeuk Kim]

If f2fs is running on top of very small devices, it's worth to avoid abusing
free LBAs. In order to achieve that, this patch introduces some parameter
tuning.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/segment.h |  2 ++
 fs/f2fs/super.c   | 14 ++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index f11c4bc82c78..dbb774aaf387 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -596,6 +596,8 @@ static inline int utilization(struct f2fs_sb_info *sbi)
 #define DEF_MIN_FSYNC_BLOCKS	8
 #define DEF_MIN_HOT_BLOCKS	16
 
+#define SMALL_VOLUME_SEGMENTS	(16 * 512)	/* 16GB */
+
 enum {
 	F2FS_IPU_FORCE,
 	F2FS_IPU_SSR,
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index b7c0bdd1e532..9515c10eebad 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2512,6 +2512,18 @@ static int f2fs_scan_devices(struct f2fs_sb_info *sbi)
 	return 0;
 }
 
+static void f2fs_tuning_parameters(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_sm_info *sm_i = SM_I(sbi);
+
+	/* adjust parameters according to the volume size */
+	if (sm_i->main_segments <= SMALL_VOLUME_SEGMENTS) {
+		sbi->alloc_mode = ALLOC_MODE_REUSE;
+		sm_i->dcc_info->discard_granularity = 1;
+		sm_i->ipu_policy = 1 << F2FS_IPU_FORCE;
+	}
+}
+
 static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 {
 	struct f2fs_sb_info *sbi;
@@ -2864,6 +2876,8 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 
 	f2fs_join_shrinker(sbi);
 
+	f2fs_tuning_parameters(sbi);
+
 	f2fs_msg(sbi->sb, KERN_NOTICE, "Mounted with checkpoint version = %llx",
 				cur_cp_version(F2FS_CKPT(sbi)));
 	f2fs_update_time(sbi, CP_TIME);
-- 
2.15.0.531.g2ccb3012c9-goog

Re: [PATCH 2/5] f2fs: add auto tuning for small devices

[Chao Yu]

On 2018/2/27 1:47, Jaegeuk Kim wrote:
> If f2fs is running on top of very small devices, it's worth to avoid abusing
> free LBAs. In order to achieve that, this patch introduces some parameter
> tuning.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Reviewed-by: Chao Yu <yuchao0@huawei.com>

Thanks,

[PATCH 3/5] f2fs: set readdir_ra by default

[Jaegeuk Kim]

It gives general readdir improvement.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/super.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 9515c10eebad..425eb4f6654a 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1297,6 +1297,7 @@ static void default_options(struct f2fs_sb_info *sbi)
 	sbi->inline_xattr_size = DEFAULT_INLINE_XATTR_ADDRS;
 	sbi->whint_mode = WHINT_MODE_OFF;
 	sbi->alloc_mode = ALLOC_MODE_DEFAULT;
+	sbi->readdir_ra = 1;
 
 	set_opt(sbi, BG_GC);
 	set_opt(sbi, INLINE_XATTR);
-- 
2.15.0.531.g2ccb3012c9-goog

Re: [PATCH 3/5] f2fs: set readdir_ra by default

[Chao Yu]

On 2018/2/27 1:47, Jaegeuk Kim wrote:
> It gives general readdir improvement.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Reviewed-by: Chao Yu <yuchao0@huawei.com>

Thanks,

[PATCH 4/5] f2fs: issue discard aggressively in the gc_urgent mode

[Jaegeuk Kim]

This patch avoids to skip discard commands when user sets gc_urgent mode.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/segment.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 5e5e2936a26a..bda2ad048ea0 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1727,7 +1727,7 @@ void init_discard_policy(struct discard_policy *dpolicy,
 	} else if (discard_type == DPOLICY_FORCE) {
 		dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME;
 		dpolicy->max_interval = DEF_MAX_DISCARD_ISSUE_TIME;
-		dpolicy->io_aware = true;
+		dpolicy->io_aware = false;
 	} else if (discard_type == DPOLICY_FSTRIM) {
 		dpolicy->io_aware = false;
 	} else if (discard_type == DPOLICY_UMOUNT) {
-- 
2.15.0.531.g2ccb3012c9-goog

Re: [PATCH 4/5] f2fs: issue discard aggressively in the gc_urgent mode

[Chao Yu]

On 2018/2/27 1:47, Jaegeuk Kim wrote:
> This patch avoids to skip discard commands when user sets gc_urgent mode.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Reviewed-by: Chao Yu <yuchao0@huawei.com>

Thanks,

Re: [PATCH 4/5] f2fs: issue discard aggressively in the gc_urgent mode

[Jaegeuk Kim]

Change log from v1:
- relax more to issue discard commands

This patch avoids to skip discard commands when user sets gc_urgent mode.

Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/segment.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 5e5e2936a26a..1e3dd3de4ecc 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1411,12 +1411,11 @@ static int issue_discard_thread(void *data)
 		if (kthread_should_stop())
 			return 0;
 
-		if (dcc->discard_wake) {
+		if (dcc->discard_wake)
 			dcc->discard_wake = 0;
-			if (sbi->gc_thread && sbi->gc_thread->gc_urgent)
-				init_discard_policy(&dpolicy,
-							DPOLICY_FORCE, 1);
-		}
+
+		if (sbi->gc_thread && sbi->gc_thread->gc_urgent)
+			init_discard_policy(&dpolicy, DPOLICY_FORCE, 1);
 
 		sb_start_intwrite(sbi->sb);
 
@@ -1727,7 +1726,7 @@ void init_discard_policy(struct discard_policy *dpolicy,
 	} else if (discard_type == DPOLICY_FORCE) {
 		dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME;
 		dpolicy->max_interval = DEF_MAX_DISCARD_ISSUE_TIME;
-		dpolicy->io_aware = true;
+		dpolicy->io_aware = false;
 	} else if (discard_type == DPOLICY_FSTRIM) {
 		dpolicy->io_aware = false;
 	} else if (discard_type == DPOLICY_UMOUNT) {
-- 
2.15.0.531.g2ccb3012c9-goog

[PATCH 5/5] f2fs: don't stop GC if GC is contended

[Jaegeuk Kim]

Let's do GC as much as possible, while gc_urgent is set.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/gc.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index b9d93fd532a9..bc9420ce2275 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -76,14 +76,15 @@ static int gc_thread_func(void *data)
 		 * invalidated soon after by user update or deletion.
 		 * So, I'd like to wait some time to collect dirty segments.
 		 */
-		if (!mutex_trylock(&sbi->gc_mutex))
-			goto next;
-
 		if (gc_th->gc_urgent) {
 			wait_ms = gc_th->urgent_sleep_time;
+			mutex_lock(&sbi->gc_mutex);
 			goto do_gc;
 		}
 
+		if (!mutex_trylock(&sbi->gc_mutex))
+			goto next;
+
 		if (!is_idle(sbi)) {
 			increase_sleep_time(gc_th, &wait_ms);
 			mutex_unlock(&sbi->gc_mutex);
-- 
2.15.0.531.g2ccb3012c9-goog

Re: [PATCH 5/5] f2fs: don't stop GC if GC is contended

[Chao Yu]

On 2018/2/27 1:47, Jaegeuk Kim wrote:
> Let's do GC as much as possible, while gc_urgent is set.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Reviewed-by: Chao Yu <yuchao0@huawei.com>

Thanks,

Re: [PATCH 1/5] f2fs: add mount option for segment allocation policy

[Chao Yu]

Hi Jaegeuk,

On 2018/2/27 1:47, Jaegeuk Kim wrote:
> This patch adds an mount option, "alloc_mode=%s" having two options, "default"
> and "reuse".
> 
> In "alloc_mode=reuse" case, f2fs starts to allocate segments from 0'th segment
> all the time to reassign segments. It'd be useful for small-sized eMMC parts.

We needs to add Doc for this mount option. ;)

Thanks,

Re: [PATCH 1/5 v2] f2fs: add mount option for segment allocation policy

[Jaegeuk Kim]

Change log from v1:
 - add doc :)

This patch adds an mount option, "alloc_mode=%s" having two options, "default"
and "reuse".

In "alloc_mode=reuse" case, f2fs starts to allocate segments from 0'th segment
all the time to reassign segments. It'd be useful for small-sized eMMC parts.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 Documentation/filesystems/f2fs.txt |  2 ++
 fs/f2fs/f2fs.h                     |  8 ++++++++
 fs/f2fs/segment.c                  |  5 +++++
 fs/f2fs/super.c                    | 24 ++++++++++++++++++++++++
 4 files changed, 39 insertions(+)

diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
index 0caf7da0a532..0409c47584ea 100644
--- a/Documentation/filesystems/f2fs.txt
+++ b/Documentation/filesystems/f2fs.txt
@@ -180,6 +180,8 @@ whint_mode=%s          Control which write hints are passed down to block
                        down hints. In "user-based" mode, f2fs tries to pass
                        down hints given by users. And in "fs-based" mode, f2fs
                        passes down hints with its policy.
+alloc_mode=%s          Adjust block allocation policy, which supports "reuse"
+                       and "default".
 
 ================================================================================
 DEBUGFS ENTRIES
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index f68ece08b5a2..d1bfdf691afc 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1043,6 +1043,11 @@ enum {
 	WHINT_MODE_FS,		/* pass down hints with F2FS policy */
 };
 
+enum {
+	ALLOC_MODE_DEFAULT,	/* stay default */
+	ALLOC_MODE_REUSE,	/* reuse segments as much as possible */
+};
+
 struct f2fs_sb_info {
 	struct super_block *sb;			/* pointer to VFS super block */
 	struct proc_dir_entry *s_proc;		/* proc entry */
@@ -1229,6 +1234,9 @@ struct f2fs_sb_info {
 #endif
 	/* For which write hints are passed down to block layer */
 	int whint_mode;
+
+	/* segment allocation policy */
+	int alloc_mode;
 };
 
 #ifdef CONFIG_F2FS_FAULT_INJECTION
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 0646d5de8cd0..5e5e2936a26a 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2170,6 +2170,11 @@ static unsigned int __get_next_segno(struct f2fs_sb_info *sbi, int type)
 
 	if (SIT_I(sbi)->last_victim[ALLOC_NEXT])
 		return SIT_I(sbi)->last_victim[ALLOC_NEXT];
+
+	/* find segments from 0 to reuse freed segments */
+	if (sbi->alloc_mode == ALLOC_MODE_REUSE)
+		return 0;
+
 	return CURSEG_I(sbi, type)->segno;
 }
 
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 2d832866720c..1345ef167140 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -130,6 +130,7 @@ enum {
 	Opt_jqfmt_vfsv0,
 	Opt_jqfmt_vfsv1,
 	Opt_whint,
+	Opt_alloc,
 	Opt_err,
 };
 
@@ -184,6 +185,7 @@ static match_table_t f2fs_tokens = {
 	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
 	{Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
 	{Opt_whint, "whint_mode=%s"},
+	{Opt_alloc, "alloc_mode=%s"},
 	{Opt_err, NULL},
 };
 
@@ -700,6 +702,23 @@ static int parse_options(struct super_block *sb, char *options)
 			}
 			kfree(name);
 			break;
+		case Opt_alloc:
+			name = match_strdup(&args[0]);
+			if (!name)
+				return -ENOMEM;
+
+			if (strlen(name) == 7 &&
+					!strncmp(name, "default", 7)) {
+				sbi->alloc_mode = ALLOC_MODE_DEFAULT;
+			} else if (strlen(name) == 5 &&
+					!strncmp(name, "reuse", 5)) {
+				sbi->alloc_mode = ALLOC_MODE_REUSE;
+			} else {
+				kfree(name);
+				return -EINVAL;
+			}
+			kfree(name);
+			break;
 		default:
 			f2fs_msg(sb, KERN_ERR,
 				"Unrecognized mount option \"%s\" or missing value",
@@ -1264,6 +1283,10 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
 	else if (sbi->whint_mode == WHINT_MODE_FS)
 		seq_printf(seq, ",whint_mode=%s", "fs-based");
 
+	if (sbi->alloc_mode == ALLOC_MODE_DEFAULT)
+		seq_printf(seq, ",alloc_mode=%s", "default");
+	else if (sbi->alloc_mode == ALLOC_MODE_REUSE)
+		seq_printf(seq, ",alloc_mode=%s", "reuse");
 	return 0;
 }
 
@@ -1273,6 +1296,7 @@ static void default_options(struct f2fs_sb_info *sbi)
 	sbi->active_logs = NR_CURSEG_TYPE;
 	sbi->inline_xattr_size = DEFAULT_INLINE_XATTR_ADDRS;
 	sbi->whint_mode = WHINT_MODE_OFF;
+	sbi->alloc_mode = ALLOC_MODE_DEFAULT;
 
 	set_opt(sbi, BG_GC);
 	set_opt(sbi, INLINE_XATTR);
-- 
2.15.0.531.g2ccb3012c9-goog

Re: [PATCH 1/5 v2] f2fs: add mount option for segment allocation policy

[Chao Yu]

On 2018/2/28 13:09, Jaegeuk Kim wrote:
> Change log from v1:
>  - add doc :)
> 
> This patch adds an mount option, "alloc_mode=%s" having two options, "default"
> and "reuse".
> 
> In "alloc_mode=reuse" case, f2fs starts to allocate segments from 0'th segment
> all the time to reassign segments. It'd be useful for small-sized eMMC parts.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Reviewed-by: Chao Yu <yuchao0@huawei.com>

Thanks,

Re: [f2fs-dev] [PATCH 1/5 v2] f2fs: add mount option for segment allocation policy

[Chao Yu]

On 2018/2/28 13:09, Jaegeuk Kim wrote:
> Change log from v1:
>  - add doc :)
> 
> This patch adds an mount option, "alloc_mode=%s" having two options, "default"
> and "reuse".
> 
> In "alloc_mode=reuse" case, f2fs starts to allocate segments from 0'th segment
> all the time to reassign segments. It'd be useful for small-sized eMMC parts.

We have to restore old alloc_mode if we encounter any failure in ->remount, right?

Thanks,

> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>  Documentation/filesystems/f2fs.txt |  2 ++
>  fs/f2fs/f2fs.h                     |  8 ++++++++
>  fs/f2fs/segment.c                  |  5 +++++
>  fs/f2fs/super.c                    | 24 ++++++++++++++++++++++++
>  4 files changed, 39 insertions(+)
> 
> diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
> index 0caf7da0a532..0409c47584ea 100644
> --- a/Documentation/filesystems/f2fs.txt
> +++ b/Documentation/filesystems/f2fs.txt
> @@ -180,6 +180,8 @@ whint_mode=%s          Control which write hints are passed down to block
>                         down hints. In "user-based" mode, f2fs tries to pass
>                         down hints given by users. And in "fs-based" mode, f2fs
>                         passes down hints with its policy.
> +alloc_mode=%s          Adjust block allocation policy, which supports "reuse"
> +                       and "default".
>  
>  ================================================================================
>  DEBUGFS ENTRIES
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index f68ece08b5a2..d1bfdf691afc 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1043,6 +1043,11 @@ enum {
>  	WHINT_MODE_FS,		/* pass down hints with F2FS policy */
>  };
>  
> +enum {
> +	ALLOC_MODE_DEFAULT,	/* stay default */
> +	ALLOC_MODE_REUSE,	/* reuse segments as much as possible */
> +};
> +
>  struct f2fs_sb_info {
>  	struct super_block *sb;			/* pointer to VFS super block */
>  	struct proc_dir_entry *s_proc;		/* proc entry */
> @@ -1229,6 +1234,9 @@ struct f2fs_sb_info {
>  #endif
>  	/* For which write hints are passed down to block layer */
>  	int whint_mode;
> +
> +	/* segment allocation policy */
> +	int alloc_mode;
>  };
>  
>  #ifdef CONFIG_F2FS_FAULT_INJECTION
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 0646d5de8cd0..5e5e2936a26a 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -2170,6 +2170,11 @@ static unsigned int __get_next_segno(struct f2fs_sb_info *sbi, int type)
>  
>  	if (SIT_I(sbi)->last_victim[ALLOC_NEXT])
>  		return SIT_I(sbi)->last_victim[ALLOC_NEXT];
> +
> +	/* find segments from 0 to reuse freed segments */
> +	if (sbi->alloc_mode == ALLOC_MODE_REUSE)
> +		return 0;
> +
>  	return CURSEG_I(sbi, type)->segno;
>  }
>  
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 2d832866720c..1345ef167140 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -130,6 +130,7 @@ enum {
>  	Opt_jqfmt_vfsv0,
>  	Opt_jqfmt_vfsv1,
>  	Opt_whint,
> +	Opt_alloc,
>  	Opt_err,
>  };
>  
> @@ -184,6 +185,7 @@ static match_table_t f2fs_tokens = {
>  	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
>  	{Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
>  	{Opt_whint, "whint_mode=%s"},
> +	{Opt_alloc, "alloc_mode=%s"},
>  	{Opt_err, NULL},
>  };
>  
> @@ -700,6 +702,23 @@ static int parse_options(struct super_block *sb, char *options)
>  			}
>  			kfree(name);
>  			break;
> +		case Opt_alloc:
> +			name = match_strdup(&args[0]);
> +			if (!name)
> +				return -ENOMEM;
> +
> +			if (strlen(name) == 7 &&
> +					!strncmp(name, "default", 7)) {
> +				sbi->alloc_mode = ALLOC_MODE_DEFAULT;
> +			} else if (strlen(name) == 5 &&
> +					!strncmp(name, "reuse", 5)) {
> +				sbi->alloc_mode = ALLOC_MODE_REUSE;
> +			} else {
> +				kfree(name);
> +				return -EINVAL;
> +			}
> +			kfree(name);
> +			break;
>  		default:
>  			f2fs_msg(sb, KERN_ERR,
>  				"Unrecognized mount option \"%s\" or missing value",
> @@ -1264,6 +1283,10 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
>  	else if (sbi->whint_mode == WHINT_MODE_FS)
>  		seq_printf(seq, ",whint_mode=%s", "fs-based");
>  
> +	if (sbi->alloc_mode == ALLOC_MODE_DEFAULT)
> +		seq_printf(seq, ",alloc_mode=%s", "default");
> +	else if (sbi->alloc_mode == ALLOC_MODE_REUSE)
> +		seq_printf(seq, ",alloc_mode=%s", "reuse");
>  	return 0;
>  }
>  
> @@ -1273,6 +1296,7 @@ static void default_options(struct f2fs_sb_info *sbi)
>  	sbi->active_logs = NR_CURSEG_TYPE;
>  	sbi->inline_xattr_size = DEFAULT_INLINE_XATTR_ADDRS;
>  	sbi->whint_mode = WHINT_MODE_OFF;
> +	sbi->alloc_mode = ALLOC_MODE_DEFAULT;
>  
>  	set_opt(sbi, BG_GC);
>  	set_opt(sbi, INLINE_XATTR);
> 

Re: [f2fs-dev] [PATCH 1/5 v2] f2fs: add mount option for segment allocation policy

[Jaegeuk Kim]

On 02/28, Chao Yu wrote:
> On 2018/2/28 13:09, Jaegeuk Kim wrote:
> > Change log from v1:
> >  - add doc :)
> > 
> > This patch adds an mount option, "alloc_mode=%s" having two options, "default"
> > and "reuse".
> > 
> > In "alloc_mode=reuse" case, f2fs starts to allocate segments from 0'th segment
> > all the time to reassign segments. It'd be useful for small-sized eMMC parts.
> 
> We have to restore old alloc_mode if we encounter any failure in ->remount, right?

Yup, done.

> 
> Thanks,
> 
> > 
> > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> > ---
> >  Documentation/filesystems/f2fs.txt |  2 ++
> >  fs/f2fs/f2fs.h                     |  8 ++++++++
> >  fs/f2fs/segment.c                  |  5 +++++
> >  fs/f2fs/super.c                    | 24 ++++++++++++++++++++++++
> >  4 files changed, 39 insertions(+)
> > 
> > diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
> > index 0caf7da0a532..0409c47584ea 100644
> > --- a/Documentation/filesystems/f2fs.txt
> > +++ b/Documentation/filesystems/f2fs.txt
> > @@ -180,6 +180,8 @@ whint_mode=%s          Control which write hints are passed down to block
> >                         down hints. In "user-based" mode, f2fs tries to pass
> >                         down hints given by users. And in "fs-based" mode, f2fs
> >                         passes down hints with its policy.
> > +alloc_mode=%s          Adjust block allocation policy, which supports "reuse"
> > +                       and "default".
> >  
> >  ================================================================================
> >  DEBUGFS ENTRIES
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index f68ece08b5a2..d1bfdf691afc 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -1043,6 +1043,11 @@ enum {
> >  	WHINT_MODE_FS,		/* pass down hints with F2FS policy */
> >  };
> >  
> > +enum {
> > +	ALLOC_MODE_DEFAULT,	/* stay default */
> > +	ALLOC_MODE_REUSE,	/* reuse segments as much as possible */
> > +};
> > +
> >  struct f2fs_sb_info {
> >  	struct super_block *sb;			/* pointer to VFS super block */
> >  	struct proc_dir_entry *s_proc;		/* proc entry */
> > @@ -1229,6 +1234,9 @@ struct f2fs_sb_info {
> >  #endif
> >  	/* For which write hints are passed down to block layer */
> >  	int whint_mode;
> > +
> > +	/* segment allocation policy */
> > +	int alloc_mode;
> >  };
> >  
> >  #ifdef CONFIG_F2FS_FAULT_INJECTION
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index 0646d5de8cd0..5e5e2936a26a 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -2170,6 +2170,11 @@ static unsigned int __get_next_segno(struct f2fs_sb_info *sbi, int type)
> >  
> >  	if (SIT_I(sbi)->last_victim[ALLOC_NEXT])
> >  		return SIT_I(sbi)->last_victim[ALLOC_NEXT];
> > +
> > +	/* find segments from 0 to reuse freed segments */
> > +	if (sbi->alloc_mode == ALLOC_MODE_REUSE)
> > +		return 0;
> > +
> >  	return CURSEG_I(sbi, type)->segno;
> >  }
> >  
> > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > index 2d832866720c..1345ef167140 100644
> > --- a/fs/f2fs/super.c
> > +++ b/fs/f2fs/super.c
> > @@ -130,6 +130,7 @@ enum {
> >  	Opt_jqfmt_vfsv0,
> >  	Opt_jqfmt_vfsv1,
> >  	Opt_whint,
> > +	Opt_alloc,
> >  	Opt_err,
> >  };
> >  
> > @@ -184,6 +185,7 @@ static match_table_t f2fs_tokens = {
> >  	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
> >  	{Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
> >  	{Opt_whint, "whint_mode=%s"},
> > +	{Opt_alloc, "alloc_mode=%s"},
> >  	{Opt_err, NULL},
> >  };
> >  
> > @@ -700,6 +702,23 @@ static int parse_options(struct super_block *sb, char *options)
> >  			}
> >  			kfree(name);
> >  			break;
> > +		case Opt_alloc:
> > +			name = match_strdup(&args[0]);
> > +			if (!name)
> > +				return -ENOMEM;
> > +
> > +			if (strlen(name) == 7 &&
> > +					!strncmp(name, "default", 7)) {
> > +				sbi->alloc_mode = ALLOC_MODE_DEFAULT;
> > +			} else if (strlen(name) == 5 &&
> > +					!strncmp(name, "reuse", 5)) {
> > +				sbi->alloc_mode = ALLOC_MODE_REUSE;
> > +			} else {
> > +				kfree(name);
> > +				return -EINVAL;
> > +			}
> > +			kfree(name);
> > +			break;
> >  		default:
> >  			f2fs_msg(sb, KERN_ERR,
> >  				"Unrecognized mount option \"%s\" or missing value",
> > @@ -1264,6 +1283,10 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
> >  	else if (sbi->whint_mode == WHINT_MODE_FS)
> >  		seq_printf(seq, ",whint_mode=%s", "fs-based");
> >  
> > +	if (sbi->alloc_mode == ALLOC_MODE_DEFAULT)
> > +		seq_printf(seq, ",alloc_mode=%s", "default");
> > +	else if (sbi->alloc_mode == ALLOC_MODE_REUSE)
> > +		seq_printf(seq, ",alloc_mode=%s", "reuse");
> >  	return 0;
> >  }
> >  
> > @@ -1273,6 +1296,7 @@ static void default_options(struct f2fs_sb_info *sbi)
> >  	sbi->active_logs = NR_CURSEG_TYPE;
> >  	sbi->inline_xattr_size = DEFAULT_INLINE_XATTR_ADDRS;
> >  	sbi->whint_mode = WHINT_MODE_OFF;
> > +	sbi->alloc_mode = ALLOC_MODE_DEFAULT;
> >  
> >  	set_opt(sbi, BG_GC);
> >  	set_opt(sbi, INLINE_XATTR);
> > 

Re: [f2fs-dev] [PATCH 1/5 v2] f2fs: add mount option for segment allocation policy

[Chao Yu]

On 2018/2/28 13:09, Jaegeuk Kim wrote:
> Change log from v1:
>  - add doc :)
> 
> This patch adds an mount option, "alloc_mode=%s" having two options, "default"
> and "reuse".
> 
> In "alloc_mode=reuse" case, f2fs starts to allocate segments from 0'th segment
> all the time to reassign segments. It'd be useful for small-sized eMMC parts.

We have to restore old alloc_mode if we encounter any failure in ->remount, right?

Thanks,

> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>  Documentation/filesystems/f2fs.txt |  2 ++
>  fs/f2fs/f2fs.h                     |  8 ++++++++
>  fs/f2fs/segment.c                  |  5 +++++
>  fs/f2fs/super.c                    | 24 ++++++++++++++++++++++++
>  4 files changed, 39 insertions(+)
> 
> diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
> index 0caf7da0a532..0409c47584ea 100644
> --- a/Documentation/filesystems/f2fs.txt
> +++ b/Documentation/filesystems/f2fs.txt
> @@ -180,6 +180,8 @@ whint_mode=%s          Control which write hints are passed down to block
>                         down hints. In "user-based" mode, f2fs tries to pass
>                         down hints given by users. And in "fs-based" mode, f2fs
>                         passes down hints with its policy.
> +alloc_mode=%s          Adjust block allocation policy, which supports "reuse"
> +                       and "default".
>  
>  ================================================================================
>  DEBUGFS ENTRIES
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index f68ece08b5a2..d1bfdf691afc 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1043,6 +1043,11 @@ enum {
>  	WHINT_MODE_FS,		/* pass down hints with F2FS policy */
>  };
>  
> +enum {
> +	ALLOC_MODE_DEFAULT,	/* stay default */
> +	ALLOC_MODE_REUSE,	/* reuse segments as much as possible */
> +};
> +
>  struct f2fs_sb_info {
>  	struct super_block *sb;			/* pointer to VFS super block */
>  	struct proc_dir_entry *s_proc;		/* proc entry */
> @@ -1229,6 +1234,9 @@ struct f2fs_sb_info {
>  #endif
>  	/* For which write hints are passed down to block layer */
>  	int whint_mode;
> +
> +	/* segment allocation policy */
> +	int alloc_mode;
>  };
>  
>  #ifdef CONFIG_F2FS_FAULT_INJECTION
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 0646d5de8cd0..5e5e2936a26a 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -2170,6 +2170,11 @@ static unsigned int __get_next_segno(struct f2fs_sb_info *sbi, int type)
>  
>  	if (SIT_I(sbi)->last_victim[ALLOC_NEXT])
>  		return SIT_I(sbi)->last_victim[ALLOC_NEXT];
> +
> +	/* find segments from 0 to reuse freed segments */
> +	if (sbi->alloc_mode == ALLOC_MODE_REUSE)
> +		return 0;
> +
>  	return CURSEG_I(sbi, type)->segno;
>  }
>  
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 2d832866720c..1345ef167140 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -130,6 +130,7 @@ enum {
>  	Opt_jqfmt_vfsv0,
>  	Opt_jqfmt_vfsv1,
>  	Opt_whint,
> +	Opt_alloc,
>  	Opt_err,
>  };
>  
> @@ -184,6 +185,7 @@ static match_table_t f2fs_tokens = {
>  	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
>  	{Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
>  	{Opt_whint, "whint_mode=%s"},
> +	{Opt_alloc, "alloc_mode=%s"},
>  	{Opt_err, NULL},
>  };
>  
> @@ -700,6 +702,23 @@ static int parse_options(struct super_block *sb, char *options)
>  			}
>  			kfree(name);
>  			break;
> +		case Opt_alloc:
> +			name = match_strdup(&args[0]);
> +			if (!name)
> +				return -ENOMEM;
> +
> +			if (strlen(name) == 7 &&
> +					!strncmp(name, "default", 7)) {
> +				sbi->alloc_mode = ALLOC_MODE_DEFAULT;
> +			} else if (strlen(name) == 5 &&
> +					!strncmp(name, "reuse", 5)) {
> +				sbi->alloc_mode = ALLOC_MODE_REUSE;
> +			} else {
> +				kfree(name);
> +				return -EINVAL;
> +			}
> +			kfree(name);
> +			break;
>  		default:
>  			f2fs_msg(sb, KERN_ERR,
>  				"Unrecognized mount option \"%s\" or missing value",
> @@ -1264,6 +1283,10 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
>  	else if (sbi->whint_mode == WHINT_MODE_FS)
>  		seq_printf(seq, ",whint_mode=%s", "fs-based");
>  
> +	if (sbi->alloc_mode == ALLOC_MODE_DEFAULT)
> +		seq_printf(seq, ",alloc_mode=%s", "default");
> +	else if (sbi->alloc_mode == ALLOC_MODE_REUSE)
> +		seq_printf(seq, ",alloc_mode=%s", "reuse");
>  	return 0;
>  }
>  
> @@ -1273,6 +1296,7 @@ static void default_options(struct f2fs_sb_info *sbi)
>  	sbi->active_logs = NR_CURSEG_TYPE;
>  	sbi->inline_xattr_size = DEFAULT_INLINE_XATTR_ADDRS;
>  	sbi->whint_mode = WHINT_MODE_OFF;
> +	sbi->alloc_mode = ALLOC_MODE_DEFAULT;
>  
>  	set_opt(sbi, BG_GC);
>  	set_opt(sbi, INLINE_XATTR);
>