* [f2fs-dev] [PATCH v1] mkfs.f2fs: Introduce configurable reserved sections
[not found] <CGME20230317044151epcms2p5872591b638dab3261a9dd563253f1b94@epcms2p5>
@ 2023-03-17 4:41 ` Yonggil Song
2023-03-27 21:26 ` Jaegeuk Kim
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Yonggil Song @ 2023-03-17 4:41 UTC (permalink / raw)
To: jaegeuk, linux-f2fs-devel; +Cc: Seokhwan Kim, Jorn Lee
Overview
========
This option allows zoned block device users to configure GC reserved and
overprovision area manually according to their demands on performance of
sustained write latency and WAF.
Problem
=======
The overprovision segments that mkfs generates are mostly occupied by GC
reserved. This degrades WAF performance.
Experiment
==========
The following experiment evaluated the application of configurable reserved.
The experimental environment is as follows.
System info
- 4.2Ghz, 8 core CPU
- 64GiB Memory
Device info
- a conventional null_blk with 448MiB capacity(meta area) and
- a sequential null_blk with 953 zones of 64MiB
Format
- as-is (find out ovp ratio): mkfs.f2fs <conv null_blk> -c <seq null_blk> -m
Info: Overprovision ratio = 3.700%
Info: Overprovision segments = 1152 (GC reserved = 1088)
- config rsvd: mkfs.f2fs <conv null_blk> -c <seq null_blk> -m 8 -o 2.965
Info: Overprovision ratio = 2.965%
Info: Overprovision segments = 1152 (GC reserved = 256)
Mount
- mount <conv null_blk> <mount point>
Fio script
- fio --rw=randwrite --bs=4k --ba=4k --filesize=58630m --norandommap --overwrite=1 --name=job1 --filename=<mount point>/sustain --time_based --runtime=2h
WAF calculation
- (IOs on conv. null_blk + IOs on seq. null_blk) / random write IOs
Conclusion
==========
In the experiment, it can be shown that reducing the reserved segments
decreases WAF to 10% (from 222 to 23) although it triggers checkpoint more
frequently during gc. With direct IO, the WAF of as-is gets much higher.
In other words, a user can configure more reserved segments for lower GC
latency or allocate less reserved segments for lower WAF on the same number
of OP segments.
Signed-off-by: Yonggil Song <yonggil.song@samsung.com>
---
include/f2fs_fs.h | 22 ++++++++++++++++++++--
lib/libf2fs.c | 22 ++++++++++++++++++++++
man/mkfs.f2fs.8 | 9 +++++++--
mkfs/f2fs_format.c | 29 +++++++++++++++++++++++------
mkfs/f2fs_format_main.c | 5 +++--
5 files changed, 75 insertions(+), 12 deletions(-)
diff --git a/include/f2fs_fs.h b/include/f2fs_fs.h
index 333ae07a5ebd..1d41e9f8397e 100644
--- a/include/f2fs_fs.h
+++ b/include/f2fs_fs.h
@@ -375,6 +375,10 @@ static inline uint64_t bswap_64(uint64_t val)
#define LPF "lost+found"
+/* one for gc buffer, the other for node */
+#define MIN_RSVD_SECS (uint32_t)(NR_CURSEG_TYPE + 2)
+#define CONFIG_RSVD_DEFAULT_OP_RATIO 3.0
+
enum f2fs_config_func {
MKFS,
FSCK,
@@ -460,6 +464,7 @@ typedef struct {
#define ALIGN_UP(addrs, size) ALIGN_DOWN(((addrs) + (size) - 1), (size))
struct f2fs_configuration {
+ uint32_t conf_reserved_sections;
uint32_t reserved_segments;
uint32_t new_reserved_segments;
int sparse_mode;
@@ -1614,6 +1619,20 @@ extern uint32_t f2fs_get_usable_segments(struct f2fs_super_block *sb);
#define ZONE_ALIGN(blks) SIZE_ALIGN(blks, c.blks_per_seg * \
c.segs_per_zone)
+static inline double get_reserved(struct f2fs_super_block *sb, double ovp)
+{
+ double reserved;
+ uint32_t usable_main_segs = f2fs_get_usable_segments(sb);
+ uint32_t segs_per_sec = round_up(usable_main_segs, get_sb(section_count));
+
+ if (c.conf_reserved_sections)
+ reserved = c.conf_reserved_sections * segs_per_sec;
+ else
+ reserved = (100 / ovp + 1 + NR_CURSEG_TYPE) * segs_per_sec;
+
+ return reserved;
+}
+
static inline double get_best_overprovision(struct f2fs_super_block *sb)
{
double reserved, ovp, candidate, end, diff, space;
@@ -1631,8 +1650,7 @@ static inline double get_best_overprovision(struct f2fs_super_block *sb)
}
for (; candidate <= end; candidate += diff) {
- reserved = (100 / candidate + 1 + NR_CURSEG_TYPE) *
- round_up(usable_main_segs, get_sb(section_count));
+ reserved = get_reserved(sb, candidate);
ovp = (usable_main_segs - reserved) * candidate / 100;
if (ovp < 0)
continue;
diff --git a/lib/libf2fs.c b/lib/libf2fs.c
index f63307a42a08..b5644ff6ebdd 100644
--- a/lib/libf2fs.c
+++ b/lib/libf2fs.c
@@ -1069,6 +1069,28 @@ int get_device_info(int i)
dev->nr_rnd_zones);
MSG(0, " %zu blocks per zone\n",
dev->zone_blocks);
+ if (c.conf_reserved_sections) {
+ if (c.conf_reserved_sections < MIN_RSVD_SECS) {
+ MSG(0, " Too small sections are reserved(%u secs)\n",
+ c.conf_reserved_sections);
+ c.conf_reserved_sections =
+ max(c.conf_reserved_sections, MIN_RSVD_SECS);
+ MSG(0, " It is operated as a minimum reserved sections(%u secs)\n",
+ c.conf_reserved_sections);
+ } else {
+ MSG(0, " %u sections are reserved\n",
+ c.conf_reserved_sections);
+ }
+ if (!c.overprovision) {
+ c.overprovision = CONFIG_RSVD_DEFAULT_OP_RATIO;
+ MSG(0, " Overprovision ratio is set to default(%.1lf%%)\n",
+ c.overprovision);
+ }
+ } else {
+ MSG(0,
+ " 0 reserved sections are received.\n"
+ " Reserved sections are calculating\n");
+ }
}
#endif
/* adjust wanted_total_sectors */
diff --git a/man/mkfs.f2fs.8 b/man/mkfs.f2fs.8
index a6249f6ef6ed..800c4c79bf37 100644
--- a/man/mkfs.f2fs.8
+++ b/man/mkfs.f2fs.8
@@ -43,6 +43,7 @@ mkfs.f2fs \- create an F2FS file system
]
[
.B \-m
+.I #-of-reserved-sections
]
[
.B \-o
@@ -152,8 +153,12 @@ Enable extended node bitmap.
.BI \-l " volume-label"
Specify the volume label to the partition mounted as F2FS.
.TP
-.BI \-m
-Specify f2fs filesystem to supports the block zoned feature.
+.BI \-m " #-of-reserved-sections"
+Specify f2fs filesystem to supports the block zoned feature and reserved sections.
+If specified to non-zero, reserved segments count is set to the larger size
+between 8 sections and the input value. If specified to zero, the best number
+will be assigned automatically according to the partition size. If overprovision-ratio-percentage
+is not specifed, it will set to default 3.0%.
Without it, the filesystem doesn't support the feature.
.TP
.BI \-o " overprovision-ratio-percentage"
diff --git a/mkfs/f2fs_format.c b/mkfs/f2fs_format.c
index f4a49acc498c..22e53be5003d 100644
--- a/mkfs/f2fs_format.c
+++ b/mkfs/f2fs_format.c
@@ -483,9 +483,7 @@ static int f2fs_prepare_super_block(void)
if (c.overprovision == 0)
c.overprovision = get_best_overprovision(sb);
- c.reserved_segments =
- (100 / c.overprovision + 1 + NR_CURSEG_TYPE) *
- round_up(f2fs_get_usable_segments(sb), get_sb(section_count));
+ c.reserved_segments = get_reserved(sb, c.overprovision);
if (c.feature & cpu_to_le32(F2FS_FEATURE_RO)) {
c.overprovision = 0;
@@ -765,11 +763,30 @@ static int f2fs_write_check_point_pack(void)
get_cp(rsvd_segment_count)) *
c.overprovision / 100);
- if (get_cp(overprov_segment_count) < get_cp(rsvd_segment_count))
+ if (!(c.conf_reserved_sections) &&
+ get_cp(overprov_segment_count) < get_cp(rsvd_segment_count))
set_cp(overprov_segment_count, get_cp(rsvd_segment_count));
- set_cp(overprov_segment_count, get_cp(overprov_segment_count) +
- 2 * get_sb(segs_per_sec));
+ /*
+ * If conf_reserved_sections has a non zero value, overprov_segment_count
+ * is set to overprov_segment_count + rsvd_segment_count.
+ */
+ if (c.conf_reserved_sections) {
+ /*
+ * Overprovision segments must be bigger than two sections.
+ * In non configurable reserved section case, overprovision
+ * segments are always bigger than two sections.
+ */
+ if (get_cp(overprov_segment_count) < 2 * get_sb(segs_per_sec)) {
+ MSG(0, "\tError: Not enough overprovision segments (%u)\n",
+ get_cp(overprov_segment_count));
+ goto free_cp_payload;
+ }
+ set_cp(overprov_segment_count, get_cp(overprov_segment_count) +
+ get_cp(rsvd_segment_count));
+ } else
+ set_cp(overprov_segment_count, get_cp(overprov_segment_count) +
+ 2 * get_sb(segs_per_sec));
if (f2fs_get_usable_segments(sb) <= get_cp(overprov_segment_count)) {
MSG(0, "\tError: Not enough segments to create F2FS Volume\n");
diff --git a/mkfs/f2fs_format_main.c b/mkfs/f2fs_format_main.c
index f50971c4591c..a4accda91780 100644
--- a/mkfs/f2fs_format_main.c
+++ b/mkfs/f2fs_format_main.c
@@ -61,7 +61,7 @@ static void mkfs_usage()
MSG(0, " -i extended node bitmap, node ratio is 20%% by default\n");
MSG(0, " -l label\n");
MSG(0, " -U uuid\n");
- MSG(0, " -m support zoned block device [default:0]\n");
+ MSG(0, " -m support zoned block device, # of reserved sections [default:0]\n");
MSG(0, " -o overprovision percentage [default:auto]\n");
MSG(0, " -O feature1[,feature2,...] e.g. \"encrypt\"\n");
MSG(0, " -C [encoding[:flag1,...]] Support casefolding with optional flags\n");
@@ -176,7 +176,7 @@ static void add_default_options(void)
static void f2fs_parse_options(int argc, char *argv[])
{
- static const char *option_string = "qa:c:C:d:e:E:g:hil:mo:O:rR:s:S:z:t:T:U:Vfw:";
+ static const char *option_string = "qa:c:C:d:e:E:g:hil:m:o:O:rR:s:S:z:t:T:U:Vfw:";
static const struct option long_opts[] = {
{ .name = "help", .has_arg = 0, .flag = NULL, .val = 'h' },
{ .name = NULL, .has_arg = 0, .flag = NULL, .val = 0 }
@@ -235,6 +235,7 @@ static void f2fs_parse_options(int argc, char *argv[])
break;
case 'm':
c.zoned_mode = 1;
+ c.conf_reserved_sections = atoi(optarg);
break;
case 'o':
c.overprovision = atof(optarg);
--
2.34.1
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [f2fs-dev] [PATCH v1] mkfs.f2fs: Introduce configurable reserved sections
2023-03-17 4:41 ` [f2fs-dev] [PATCH v1] mkfs.f2fs: Introduce configurable reserved sections Yonggil Song
@ 2023-03-27 21:26 ` Jaegeuk Kim
[not found] ` <CGME20230317044151epcms2p5872591b638dab3261a9dd563253f1b94@epcms2p3>
[not found] ` <CGME20230317044151epcms2p5872591b638dab3261a9dd563253f1b94@epcms2p2>
2 siblings, 0 replies; 4+ messages in thread
From: Jaegeuk Kim @ 2023-03-27 21:26 UTC (permalink / raw)
To: Yonggil Song; +Cc: Seokhwan Kim, Jorn Lee, linux-f2fs-devel
On 03/17, Yonggil Song wrote:
> Overview
> ========
>
> This option allows zoned block device users to configure GC reserved and
> overprovision area manually according to their demands on performance of
> sustained write latency and WAF.
>
> Problem
> =======
>
> The overprovision segments that mkfs generates are mostly occupied by GC
> reserved. This degrades WAF performance.
>
> Experiment
> ==========
>
> The following experiment evaluated the application of configurable reserved.
> The experimental environment is as follows.
>
> System info
> - 4.2Ghz, 8 core CPU
> - 64GiB Memory
> Device info
> - a conventional null_blk with 448MiB capacity(meta area) and
> - a sequential null_blk with 953 zones of 64MiB
> Format
> - as-is (find out ovp ratio): mkfs.f2fs <conv null_blk> -c <seq null_blk> -m
> Info: Overprovision ratio = 3.700%
> Info: Overprovision segments = 1152 (GC reserved = 1088)
> - config rsvd: mkfs.f2fs <conv null_blk> -c <seq null_blk> -m 8 -o 2.965
> Info: Overprovision ratio = 2.965%
> Info: Overprovision segments = 1152 (GC reserved = 256)
> Mount
> - mount <conv null_blk> <mount point>
> Fio script
> - fio --rw=randwrite --bs=4k --ba=4k --filesize=58630m --norandommap --overwrite=1 --name=job1 --filename=<mount point>/sustain --time_based --runtime=2h
> WAF calculation
> - (IOs on conv. null_blk + IOs on seq. null_blk) / random write IOs
>
> Conclusion
> ==========
>
> In the experiment, it can be shown that reducing the reserved segments
> decreases WAF to 10% (from 222 to 23) although it triggers checkpoint more
> frequently during gc. With direct IO, the WAF of as-is gets much higher.
> In other words, a user can configure more reserved segments for lower GC
> latency or allocate less reserved segments for lower WAF on the same number
> of OP segments.
>
> Signed-off-by: Yonggil Song <yonggil.song@samsung.com>
> ---
> include/f2fs_fs.h | 22 ++++++++++++++++++++--
> lib/libf2fs.c | 22 ++++++++++++++++++++++
> man/mkfs.f2fs.8 | 9 +++++++--
> mkfs/f2fs_format.c | 29 +++++++++++++++++++++++------
> mkfs/f2fs_format_main.c | 5 +++--
> 5 files changed, 75 insertions(+), 12 deletions(-)
>
> diff --git a/include/f2fs_fs.h b/include/f2fs_fs.h
> index 333ae07a5ebd..1d41e9f8397e 100644
> --- a/include/f2fs_fs.h
> +++ b/include/f2fs_fs.h
> @@ -375,6 +375,10 @@ static inline uint64_t bswap_64(uint64_t val)
>
> #define LPF "lost+found"
>
> +/* one for gc buffer, the other for node */
> +#define MIN_RSVD_SECS (uint32_t)(NR_CURSEG_TYPE + 2)
> +#define CONFIG_RSVD_DEFAULT_OP_RATIO 3.0
> +
> enum f2fs_config_func {
> MKFS,
> FSCK,
> @@ -460,6 +464,7 @@ typedef struct {
> #define ALIGN_UP(addrs, size) ALIGN_DOWN(((addrs) + (size) - 1), (size))
>
> struct f2fs_configuration {
> + uint32_t conf_reserved_sections;
> uint32_t reserved_segments;
> uint32_t new_reserved_segments;
> int sparse_mode;
> @@ -1614,6 +1619,20 @@ extern uint32_t f2fs_get_usable_segments(struct f2fs_super_block *sb);
> #define ZONE_ALIGN(blks) SIZE_ALIGN(blks, c.blks_per_seg * \
> c.segs_per_zone)
>
> +static inline double get_reserved(struct f2fs_super_block *sb, double ovp)
> +{
> + double reserved;
> + uint32_t usable_main_segs = f2fs_get_usable_segments(sb);
> + uint32_t segs_per_sec = round_up(usable_main_segs, get_sb(section_count));
> +
> + if (c.conf_reserved_sections)
> + reserved = c.conf_reserved_sections * segs_per_sec;
> + else
> + reserved = (100 / ovp + 1 + NR_CURSEG_TYPE) * segs_per_sec;
> +
> + return reserved;
> +}
> +
> static inline double get_best_overprovision(struct f2fs_super_block *sb)
> {
> double reserved, ovp, candidate, end, diff, space;
> @@ -1631,8 +1650,7 @@ static inline double get_best_overprovision(struct f2fs_super_block *sb)
> }
>
> for (; candidate <= end; candidate += diff) {
> - reserved = (100 / candidate + 1 + NR_CURSEG_TYPE) *
> - round_up(usable_main_segs, get_sb(section_count));
> + reserved = get_reserved(sb, candidate);
> ovp = (usable_main_segs - reserved) * candidate / 100;
> if (ovp < 0)
> continue;
> diff --git a/lib/libf2fs.c b/lib/libf2fs.c
> index f63307a42a08..b5644ff6ebdd 100644
> --- a/lib/libf2fs.c
> +++ b/lib/libf2fs.c
> @@ -1069,6 +1069,28 @@ int get_device_info(int i)
> dev->nr_rnd_zones);
> MSG(0, " %zu blocks per zone\n",
> dev->zone_blocks);
> + if (c.conf_reserved_sections) {
> + if (c.conf_reserved_sections < MIN_RSVD_SECS) {
> + MSG(0, " Too small sections are reserved(%u secs)\n",
> + c.conf_reserved_sections);
> + c.conf_reserved_sections =
> + max(c.conf_reserved_sections, MIN_RSVD_SECS);
> + MSG(0, " It is operated as a minimum reserved sections(%u secs)\n",
> + c.conf_reserved_sections);
> + } else {
> + MSG(0, " %u sections are reserved\n",
> + c.conf_reserved_sections);
> + }
> + if (!c.overprovision) {
> + c.overprovision = CONFIG_RSVD_DEFAULT_OP_RATIO;
> + MSG(0, " Overprovision ratio is set to default(%.1lf%%)\n",
> + c.overprovision);
> + }
> + } else {
> + MSG(0,
> + " 0 reserved sections are received.\n"
> + " Reserved sections are calculating\n");
> + }
> }
> #endif
> /* adjust wanted_total_sectors */
> diff --git a/man/mkfs.f2fs.8 b/man/mkfs.f2fs.8
> index a6249f6ef6ed..800c4c79bf37 100644
> --- a/man/mkfs.f2fs.8
> +++ b/man/mkfs.f2fs.8
> @@ -43,6 +43,7 @@ mkfs.f2fs \- create an F2FS file system
> ]
> [
> .B \-m
> +.I #-of-reserved-sections
> ]
> [
> .B \-o
> @@ -152,8 +153,12 @@ Enable extended node bitmap.
> .BI \-l " volume-label"
> Specify the volume label to the partition mounted as F2FS.
> .TP
> -.BI \-m
> -Specify f2fs filesystem to supports the block zoned feature.
> +.BI \-m " #-of-reserved-sections"
> +Specify f2fs filesystem to supports the block zoned feature and reserved sections.
> +If specified to non-zero, reserved segments count is set to the larger size
> +between 8 sections and the input value. If specified to zero, the best number
> +will be assigned automatically according to the partition size. If overprovision-ratio-percentage
> +is not specifed, it will set to default 3.0%.
> Without it, the filesystem doesn't support the feature.
> .TP
> .BI \-o " overprovision-ratio-percentage"
> diff --git a/mkfs/f2fs_format.c b/mkfs/f2fs_format.c
> index f4a49acc498c..22e53be5003d 100644
> --- a/mkfs/f2fs_format.c
> +++ b/mkfs/f2fs_format.c
> @@ -483,9 +483,7 @@ static int f2fs_prepare_super_block(void)
> if (c.overprovision == 0)
> c.overprovision = get_best_overprovision(sb);
>
> - c.reserved_segments =
> - (100 / c.overprovision + 1 + NR_CURSEG_TYPE) *
> - round_up(f2fs_get_usable_segments(sb), get_sb(section_count));
> + c.reserved_segments = get_reserved(sb, c.overprovision);
>
> if (c.feature & cpu_to_le32(F2FS_FEATURE_RO)) {
> c.overprovision = 0;
> @@ -765,11 +763,30 @@ static int f2fs_write_check_point_pack(void)
> get_cp(rsvd_segment_count)) *
> c.overprovision / 100);
>
> - if (get_cp(overprov_segment_count) < get_cp(rsvd_segment_count))
> + if (!(c.conf_reserved_sections) &&
> + get_cp(overprov_segment_count) < get_cp(rsvd_segment_count))
> set_cp(overprov_segment_count, get_cp(rsvd_segment_count));
>
> - set_cp(overprov_segment_count, get_cp(overprov_segment_count) +
> - 2 * get_sb(segs_per_sec));
> + /*
> + * If conf_reserved_sections has a non zero value, overprov_segment_count
> + * is set to overprov_segment_count + rsvd_segment_count.
> + */
> + if (c.conf_reserved_sections) {
> + /*
> + * Overprovision segments must be bigger than two sections.
> + * In non configurable reserved section case, overprovision
> + * segments are always bigger than two sections.
> + */
> + if (get_cp(overprov_segment_count) < 2 * get_sb(segs_per_sec)) {
> + MSG(0, "\tError: Not enough overprovision segments (%u)\n",
> + get_cp(overprov_segment_count));
> + goto free_cp_payload;
> + }
> + set_cp(overprov_segment_count, get_cp(overprov_segment_count) +
> + get_cp(rsvd_segment_count));
> + } else
> + set_cp(overprov_segment_count, get_cp(overprov_segment_count) +
> + 2 * get_sb(segs_per_sec));
>
> if (f2fs_get_usable_segments(sb) <= get_cp(overprov_segment_count)) {
> MSG(0, "\tError: Not enough segments to create F2FS Volume\n");
> diff --git a/mkfs/f2fs_format_main.c b/mkfs/f2fs_format_main.c
> index f50971c4591c..a4accda91780 100644
> --- a/mkfs/f2fs_format_main.c
> +++ b/mkfs/f2fs_format_main.c
> @@ -61,7 +61,7 @@ static void mkfs_usage()
> MSG(0, " -i extended node bitmap, node ratio is 20%% by default\n");
> MSG(0, " -l label\n");
> MSG(0, " -U uuid\n");
> - MSG(0, " -m support zoned block device [default:0]\n");
> + MSG(0, " -m support zoned block device, # of reserved sections [default:0]\n");
> MSG(0, " -o overprovision percentage [default:auto]\n");
> MSG(0, " -O feature1[,feature2,...] e.g. \"encrypt\"\n");
> MSG(0, " -C [encoding[:flag1,...]] Support casefolding with optional flags\n");
> @@ -176,7 +176,7 @@ static void add_default_options(void)
>
> static void f2fs_parse_options(int argc, char *argv[])
> {
> - static const char *option_string = "qa:c:C:d:e:E:g:hil:mo:O:rR:s:S:z:t:T:U:Vfw:";
> + static const char *option_string = "qa:c:C:d:e:E:g:hil:m:o:O:rR:s:S:z:t:T:U:Vfw:";
> static const struct option long_opts[] = {
> { .name = "help", .has_arg = 0, .flag = NULL, .val = 'h' },
> { .name = NULL, .has_arg = 0, .flag = NULL, .val = 0 }
> @@ -235,6 +235,7 @@ static void f2fs_parse_options(int argc, char *argv[])
> break;
> case 'm':
> c.zoned_mode = 1;
> + c.conf_reserved_sections = atoi(optarg);
This breaks the existing "-m" option. Can you address to support that?
> break;
> case 'o':
> c.overprovision = atof(optarg);
> --
> 2.34.1
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [f2fs-dev] (2) [PATCH v1] mkfs.f2fs: Introduce configurable reserved sections
[not found] ` <CGME20230317044151epcms2p5872591b638dab3261a9dd563253f1b94@epcms2p3>
@ 2023-03-28 8:06 ` Yonggil Song
0 siblings, 0 replies; 4+ messages in thread
From: Yonggil Song @ 2023-03-28 8:06 UTC (permalink / raw)
To: Jaegeuk Kim; +Cc: Seokhwan Kim, Jorn Lee, linux-f2fs-devel
On 03/17, Yonggil Song wrote:
>> Overview
>> ========
>>
>> This option allows zoned block device users to configure GC reserved and
>> overprovision area manually according to their demands on performance of
>> sustained write latency and WAF.
>>
>> Problem
>> =======
>>
>> The overprovision segments that mkfs generates are mostly occupied by GC
>> reserved. This degrades WAF performance.
>>
>> Experiment
>> ==========
>>
>> The following experiment evaluated the application of configurable reserved.
>> The experimental environment is as follows.
>>
>> System info
>> - 4.2Ghz, 8 core CPU
>> - 64GiB Memory
>> Device info
>> - a conventional null_blk with 448MiB capacity(meta area) and
>> - a sequential null_blk with 953 zones of 64MiB
>> Format
>> - as-is (find out ovp ratio): mkfs.f2fs <conv null_blk> -c <seq null_blk> -m
>> Info: Overprovision ratio = 3.700%
>> Info: Overprovision segments = 1152 (GC reserved = 1088)
>> - config rsvd: mkfs.f2fs <conv null_blk> -c <seq null_blk> -m 8 -o 2.965
>> Info: Overprovision ratio = 2.965%
>> Info: Overprovision segments = 1152 (GC reserved = 256)
>> Mount
>> - mount <conv null_blk> <mount point>
>> Fio script
>> - fio --rw=randwrite --bs=4k --ba=4k --filesize=58630m --norandommap --overwrite=1 --name=job1 --filename=<mount point>/sustain --time_based --runtime=2h
>> WAF calculation
>> - (IOs on conv. null_blk + IOs on seq. null_blk) / random write IOs
>>
>> Conclusion
>> ==========
>>
>> In the experiment, it can be shown that reducing the reserved segments
>> decreases WAF to 10% (from 222 to 23) although it triggers checkpoint more
>> frequently during gc. With direct IO, the WAF of as-is gets much higher.
>> In other words, a user can configure more reserved segments for lower GC
>> latency or allocate less reserved segments for lower WAF on the same number
>> of OP segments.
>>
>> Signed-off-by: Yonggil Song <yonggil.song@samsung.com>
>> ---
>> include/f2fs_fs.h | 22 ++++++++++++++++++++--
>> lib/libf2fs.c | 22 ++++++++++++++++++++++
>> man/mkfs.f2fs.8 | 9 +++++++--
>> mkfs/f2fs_format.c | 29 +++++++++++++++++++++++------
>> mkfs/f2fs_format_main.c | 5 +++--
>> 5 files changed, 75 insertions(+), 12 deletions(-)
>>
>> diff --git a/include/f2fs_fs.h b/include/f2fs_fs.h
>> index 333ae07a5ebd..1d41e9f8397e 100644
>> --- a/include/f2fs_fs.h
>> +++ b/include/f2fs_fs.h
>> @@ -375,6 +375,10 @@ static inline uint64_t bswap_64(uint64_t val)
>>
>> #define LPF "lost+found"
>>
>> +/* one for gc buffer, the other for node */
>> +#define MIN_RSVD_SECS (uint32_t)(NR_CURSEG_TYPE + 2)
>> +#define CONFIG_RSVD_DEFAULT_OP_RATIO 3.0
>> +
>> enum f2fs_config_func {
>> MKFS,
>> FSCK,
>> @@ -460,6 +464,7 @@ typedef struct {
>> #define ALIGN_UP(addrs, size) ALIGN_DOWN(((addrs) + (size) - 1), (size))
>>
>> struct f2fs_configuration {
>> + uint32_t conf_reserved_sections;
>> uint32_t reserved_segments;
>> uint32_t new_reserved_segments;
>> int sparse_mode;
>> @@ -1614,6 +1619,20 @@ extern uint32_t f2fs_get_usable_segments(struct f2fs_super_block *sb);
>> #define ZONE_ALIGN(blks) SIZE_ALIGN(blks, c.blks_per_seg * \
>> c.segs_per_zone)
>>
>> +static inline double get_reserved(struct f2fs_super_block *sb, double ovp)
>> +{
>> + double reserved;
>> + uint32_t usable_main_segs = f2fs_get_usable_segments(sb);
>> + uint32_t segs_per_sec = round_up(usable_main_segs, get_sb(section_count));
>> +
>> + if (c.conf_reserved_sections)
>> + reserved = c.conf_reserved_sections * segs_per_sec;
>> + else
>> + reserved = (100 / ovp + 1 + NR_CURSEG_TYPE) * segs_per_sec;
>> +
>> + return reserved;
>> +}
>> +
>> static inline double get_best_overprovision(struct f2fs_super_block *sb)
>> {
>> double reserved, ovp, candidate, end, diff, space;
>> @@ -1631,8 +1650,7 @@ static inline double get_best_overprovision(struct f2fs_super_block *sb)
>> }
>>
>> for (; candidate <= end; candidate += diff) {
>> - reserved = (100 / candidate + 1 + NR_CURSEG_TYPE) *
>> - round_up(usable_main_segs, get_sb(section_count));
>> + reserved = get_reserved(sb, candidate);
>> ovp = (usable_main_segs - reserved) * candidate / 100;
>> if (ovp < 0)
>> continue;
>> diff --git a/lib/libf2fs.c b/lib/libf2fs.c
>> index f63307a42a08..b5644ff6ebdd 100644
>> --- a/lib/libf2fs.c
>> +++ b/lib/libf2fs.c
>> @@ -1069,6 +1069,28 @@ int get_device_info(int i)
>> dev->nr_rnd_zones);
>> MSG(0, " %zu blocks per zone\n",
>> dev->zone_blocks);
>> + if (c.conf_reserved_sections) {
>> + if (c.conf_reserved_sections < MIN_RSVD_SECS) {
>> + MSG(0, " Too small sections are reserved(%u secs)\n",
>> + c.conf_reserved_sections);
>> + c.conf_reserved_sections =
>> + max(c.conf_reserved_sections, MIN_RSVD_SECS);
>> + MSG(0, " It is operated as a minimum reserved sections(%u secs)\n",
>> + c.conf_reserved_sections);
>> + } else {
>> + MSG(0, " %u sections are reserved\n",
>> + c.conf_reserved_sections);
>> + }
>> + if (!c.overprovision) {
>> + c.overprovision = CONFIG_RSVD_DEFAULT_OP_RATIO;
>> + MSG(0, " Overprovision ratio is set to default(%.1lf%%)\n",
>> + c.overprovision);
>> + }
>> + } else {
>> + MSG(0,
>> + " 0 reserved sections are received.\n"
>> + " Reserved sections are calculating\n");
>> + }
>> }
>> #endif
>> /* adjust wanted_total_sectors */
>> diff --git a/man/mkfs.f2fs.8 b/man/mkfs.f2fs.8
>> index a6249f6ef6ed..800c4c79bf37 100644
>> --- a/man/mkfs.f2fs.8
>> +++ b/man/mkfs.f2fs.8
>> @@ -43,6 +43,7 @@ mkfs.f2fs \- create an F2FS file system
>> ]
>> [
>> .B \-m
>> +.I #-of-reserved-sections
>> ]
>> [
>> .B \-o
>> @@ -152,8 +153,12 @@ Enable extended node bitmap.
>> .BI \-l " volume-label"
>> Specify the volume label to the partition mounted as F2FS.
>> .TP
>> -.BI \-m
>> -Specify f2fs filesystem to supports the block zoned feature.
>> +.BI \-m " #-of-reserved-sections"
>> +Specify f2fs filesystem to supports the block zoned feature and reserved sections.
>> +If specified to non-zero, reserved segments count is set to the larger size
>> +between 8 sections and the input value. If specified to zero, the best number
>> +will be assigned automatically according to the partition size. If overprovision-ratio-percentage
>> +is not specifed, it will set to default 3.0%.
>> Without it, the filesystem doesn't support the feature.
>> .TP
>> .BI \-o " overprovision-ratio-percentage"
>> diff --git a/mkfs/f2fs_format.c b/mkfs/f2fs_format.c
>> index f4a49acc498c..22e53be5003d 100644
>> --- a/mkfs/f2fs_format.c
>> +++ b/mkfs/f2fs_format.c
>> @@ -483,9 +483,7 @@ static int f2fs_prepare_super_block(void)
>> if (c.overprovision == 0)
>> c.overprovision = get_best_overprovision(sb);
>>
>> - c.reserved_segments =
>> - (100 / c.overprovision + 1 + NR_CURSEG_TYPE) *
>> - round_up(f2fs_get_usable_segments(sb), get_sb(section_count));
>> + c.reserved_segments = get_reserved(sb, c.overprovision);
>>
>> if (c.feature & cpu_to_le32(F2FS_FEATURE_RO)) {
>> c.overprovision = 0;
>> @@ -765,11 +763,30 @@ static int f2fs_write_check_point_pack(void)
>> get_cp(rsvd_segment_count)) *
>> c.overprovision / 100);
>>
>> - if (get_cp(overprov_segment_count) < get_cp(rsvd_segment_count))
>> + if (!(c.conf_reserved_sections) &&
>> + get_cp(overprov_segment_count) < get_cp(rsvd_segment_count))
>> set_cp(overprov_segment_count, get_cp(rsvd_segment_count));
>>
>> - set_cp(overprov_segment_count, get_cp(overprov_segment_count) +
>> - 2 * get_sb(segs_per_sec));
>> + /*
>> + * If conf_reserved_sections has a non zero value, overprov_segment_count
>> + * is set to overprov_segment_count + rsvd_segment_count.
>> + */
>> + if (c.conf_reserved_sections) {
>> + /*
>> + * Overprovision segments must be bigger than two sections.
>> + * In non configurable reserved section case, overprovision
>> + * segments are always bigger than two sections.
>> + */
>> + if (get_cp(overprov_segment_count) < 2 * get_sb(segs_per_sec)) {
>> + MSG(0, "\tError: Not enough overprovision segments (%u)\n",
>> + get_cp(overprov_segment_count));
>> + goto free_cp_payload;
>> + }
>> + set_cp(overprov_segment_count, get_cp(overprov_segment_count) +
>> + get_cp(rsvd_segment_count));
>> + } else
>> + set_cp(overprov_segment_count, get_cp(overprov_segment_count) +
>> + 2 * get_sb(segs_per_sec));
>>
>> if (f2fs_get_usable_segments(sb) <= get_cp(overprov_segment_count)) {
>> MSG(0, "\tError: Not enough segments to create F2FS Volume\n");
>> diff --git a/mkfs/f2fs_format_main.c b/mkfs/f2fs_format_main.c
>> index f50971c4591c..a4accda91780 100644
>> --- a/mkfs/f2fs_format_main.c
>> +++ b/mkfs/f2fs_format_main.c
>> @@ -61,7 +61,7 @@ static void mkfs_usage()
>> MSG(0, " -i extended node bitmap, node ratio is 20%% by default\n");
>> MSG(0, " -l label\n");
>> MSG(0, " -U uuid\n");
>> - MSG(0, " -m support zoned block device [default:0]\n");
>> + MSG(0, " -m support zoned block device, # of reserved sections [default:0]\n");
>> MSG(0, " -o overprovision percentage [default:auto]\n");
>> MSG(0, " -O feature1[,feature2,...] e.g. \"encrypt\"\n");
>> MSG(0, " -C [encoding[:flag1,...]] Support casefolding with optional flags\n");
>> @@ -176,7 +176,7 @@ static void add_default_options(void)
>>
>> static void f2fs_parse_options(int argc, char *argv[])
>> {
>> - static const char *option_string = "qa:c:C:d:e:E:g:hil:mo:O:rR:s:S:z:t:T:U:Vfw:";
>> + static const char *option_string = "qa:c:C:d:e:E:g:hil:m:o:O:rR:s:S:z:t:T:U:Vfw:";
>> static const struct option long_opts[] = {
>> { .name = "help", .has_arg = 0, .flag = NULL, .val = 'h' },
>> { .name = NULL, .has_arg = 0, .flag = NULL, .val = 0 }
>> @@ -235,6 +235,7 @@ static void f2fs_parse_options(int argc, char *argv[])
>> break;
>> case 'm':
>> c.zoned_mode = 1;
>> + c.conf_reserved_sections = atoi(optarg);
>
>This breaks the existing "-m" option. Can you address to support that?
>
Ok, we're gonna change it to new letter "-Z".
The option is valid only when "-m" is specified.
Thanks for your review
>> break;
>> case 'o':
>> c.overprovision = atof(optarg);
>> --
>> 2.34.1
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply [flat|nested] 4+ messages in thread
* [f2fs-dev] [PATCH v2] mkfs.f2fs: Introduce configurable reserved sections
[not found] ` <CGME20230317044151epcms2p5872591b638dab3261a9dd563253f1b94@epcms2p2>
@ 2023-04-04 6:21 ` Yonggil Song
0 siblings, 0 replies; 4+ messages in thread
From: Yonggil Song @ 2023-04-04 6:21 UTC (permalink / raw)
To: Jaegeuk Kim, linux-f2fs-devel; +Cc: Seokhwan Kim, Jorn Lee
Overview
========
This option allows zoned block device users to configure GC reserved and
overprovision area manually according to their demands on performance of
sustained write latency and WAF.
Problem
=======
The overprovision segments that mkfs generates are mostly occupied by GC
reserved. This degrades WAF performance.
Experiment
==========
The following experiment evaluated the application of configurable reserved.
The experimental environment is as follows.
System info
- 4.2Ghz, 8 core CPU
- 64GiB Memory
Device info
- a conventional null_blk with 448MiB capacity(meta area) and
- a sequential null_blk with 953 zones of 64MiB
Format
- as-is (find out ovp ratio): mkfs.f2fs <conv null_blk> -c <seq null_blk> -m
Info: Overprovision ratio = 3.700%
Info: Overprovision segments = 1152 (GC reserved = 1088)
- config rsvd: mkfs.f2fs <conv null_blk> -c <seq null_blk> -m -Z 8 -o 2.965
Info: Overprovision ratio = 2.965%
Info: Overprovision segments = 1152 (GC reserved = 256)
Mount
- mount <conv null_blk> <mount point>
Fio script
- fio --rw=randwrite --bs=4k --ba=4k --filesize=58630m --norandommap --overwrite=1 --name=job1 --filename=<mount point>/sustain --time_based --runtime=2h
WAF calculation
- (IOs on conv. null_blk + IOs on seq. null_blk) / random write IOs
Conclusion
==========
In the experiment, it can be shown that reducing the reserved segments
decreases WAF to 10% (from 222 to 23) although it triggers checkpoint more
frequently during gc. With direct IO, the WAF of as-is gets much higher.
In other words, a user can configure more reserved segments for lower GC
latency or allocate less reserved segments for lower WAF on the same number
of OP segments.
Signed-off-by: Yonggil Song <yonggil.song@samsung.com>
---
include/f2fs_fs.h | 22 ++++++++++++++++++++--
lib/libf2fs.c | 18 ++++++++++++++++++
man/mkfs.f2fs.8 | 12 ++++++++++++
mkfs/f2fs_format.c | 30 ++++++++++++++++++++++++------
mkfs/f2fs_format_main.c | 11 ++++++++++-
5 files changed, 84 insertions(+), 9 deletions(-)
diff --git a/include/f2fs_fs.h b/include/f2fs_fs.h
index 333ae07a5ebd..5d74dcc0dc11 100644
--- a/include/f2fs_fs.h
+++ b/include/f2fs_fs.h
@@ -375,6 +375,10 @@ static inline uint64_t bswap_64(uint64_t val)
#define LPF "lost+found"
+/* one for gc buffer, the other for node */
+#define MIN_RSVD_SECS (NR_CURSEG_TYPE + 2U)
+#define CONFIG_RSVD_DEFAULT_OP_RATIO 3.0
+
enum f2fs_config_func {
MKFS,
FSCK,
@@ -460,6 +464,7 @@ typedef struct {
#define ALIGN_UP(addrs, size) ALIGN_DOWN(((addrs) + (size) - 1), (size))
struct f2fs_configuration {
+ uint32_t conf_reserved_sections;
uint32_t reserved_segments;
uint32_t new_reserved_segments;
int sparse_mode;
@@ -1614,6 +1619,20 @@ extern uint32_t f2fs_get_usable_segments(struct f2fs_super_block *sb);
#define ZONE_ALIGN(blks) SIZE_ALIGN(blks, c.blks_per_seg * \
c.segs_per_zone)
+static inline double get_reserved(struct f2fs_super_block *sb, double ovp)
+{
+ double reserved;
+ uint32_t usable_main_segs = f2fs_get_usable_segments(sb);
+ uint32_t segs_per_sec = round_up(usable_main_segs, get_sb(section_count));
+
+ if (c.conf_reserved_sections)
+ reserved = c.conf_reserved_sections * segs_per_sec;
+ else
+ reserved = (100 / ovp + 1 + NR_CURSEG_TYPE) * segs_per_sec;
+
+ return reserved;
+}
+
static inline double get_best_overprovision(struct f2fs_super_block *sb)
{
double reserved, ovp, candidate, end, diff, space;
@@ -1631,8 +1650,7 @@ static inline double get_best_overprovision(struct f2fs_super_block *sb)
}
for (; candidate <= end; candidate += diff) {
- reserved = (100 / candidate + 1 + NR_CURSEG_TYPE) *
- round_up(usable_main_segs, get_sb(section_count));
+ reserved = get_reserved(sb, candidate);
ovp = (usable_main_segs - reserved) * candidate / 100;
if (ovp < 0)
continue;
diff --git a/lib/libf2fs.c b/lib/libf2fs.c
index f63307a42a08..8dcc33bda0b5 100644
--- a/lib/libf2fs.c
+++ b/lib/libf2fs.c
@@ -1069,6 +1069,24 @@ int get_device_info(int i)
dev->nr_rnd_zones);
MSG(0, " %zu blocks per zone\n",
dev->zone_blocks);
+
+ if (c.conf_reserved_sections) {
+ if (c.conf_reserved_sections < MIN_RSVD_SECS) {
+ MSG(0, " Too small sections are reserved(%u secs)\n",
+ c.conf_reserved_sections);
+ c.conf_reserved_sections = MIN_RSVD_SECS;
+ MSG(0, " It is operated as a minimum reserved sections(%u secs)\n",
+ c.conf_reserved_sections);
+ } else {
+ MSG(0, " %u sections are reserved\n",
+ c.conf_reserved_sections);
+ }
+ if (!c.overprovision) {
+ c.overprovision = CONFIG_RSVD_DEFAULT_OP_RATIO;
+ MSG(0, " Overprovision ratio is set to default(%.1lf%%)\n",
+ c.overprovision);
+ }
+ }
}
#endif
/* adjust wanted_total_sectors */
diff --git a/man/mkfs.f2fs.8 b/man/mkfs.f2fs.8
index a6249f6ef6ed..474c40131bae 100644
--- a/man/mkfs.f2fs.8
+++ b/man/mkfs.f2fs.8
@@ -92,6 +92,10 @@ mkfs.f2fs \- create an F2FS file system
[
.B \-V
]
+[
+.B \-Z
+.I #-of-reserved-sections
+]
.I device
.I [sectors]
.SH DESCRIPTION
@@ -265,6 +269,14 @@ Number of sectors. Default is determined by device size.
.BI \-V
Print the version number and exit.
.TP
+.BI \-Z " #-of-reserved-sections"
+Specify the number of GC reserved sections for zoned device. If specified
+to non-zero, reserved segments count is set to the larger size between 8
+sections and the input value. If specified to zero, the best number will be
+assigned automatically according to the partition size.
+If overprovision-ratio-percentage is not specified, it will set to default
+3.0%. Without '-m' option, the filesystem doesn't support the feature.
+.TP
.BI \-h,\ \-\-help
Print usage and exit.
.SH AUTHOR
diff --git a/mkfs/f2fs_format.c b/mkfs/f2fs_format.c
index f4a49acc498c..d3bb62222024 100644
--- a/mkfs/f2fs_format.c
+++ b/mkfs/f2fs_format.c
@@ -483,9 +483,7 @@ static int f2fs_prepare_super_block(void)
if (c.overprovision == 0)
c.overprovision = get_best_overprovision(sb);
- c.reserved_segments =
- (100 / c.overprovision + 1 + NR_CURSEG_TYPE) *
- round_up(f2fs_get_usable_segments(sb), get_sb(section_count));
+ c.reserved_segments = get_reserved(sb, c.overprovision);
if (c.feature & cpu_to_le32(F2FS_FEATURE_RO)) {
c.overprovision = 0;
@@ -765,11 +763,31 @@ static int f2fs_write_check_point_pack(void)
get_cp(rsvd_segment_count)) *
c.overprovision / 100);
- if (get_cp(overprov_segment_count) < get_cp(rsvd_segment_count))
+ if (!(c.conf_reserved_sections) &&
+ get_cp(overprov_segment_count) < get_cp(rsvd_segment_count))
set_cp(overprov_segment_count, get_cp(rsvd_segment_count));
- set_cp(overprov_segment_count, get_cp(overprov_segment_count) +
- 2 * get_sb(segs_per_sec));
+ /*
+ * If conf_reserved_sections has a non zero value, overprov_segment_count
+ * is set to overprov_segment_count + rsvd_segment_count.
+ */
+ if (c.conf_reserved_sections) {
+ /*
+ * Overprovision segments must be bigger than two sections.
+ * In non configurable reserved section case, overprovision
+ * segments are always bigger than two sections.
+ */
+ if (get_cp(overprov_segment_count) < 2 * get_sb(segs_per_sec)) {
+ MSG(0, "\tError: Not enough overprovision segments (%u)\n",
+ get_cp(overprov_segment_count));
+ goto free_cp_payload;
+ }
+ set_cp(overprov_segment_count, get_cp(overprov_segment_count) +
+ get_cp(rsvd_segment_count));
+ } else {
+ set_cp(overprov_segment_count, get_cp(overprov_segment_count) +
+ 2 * get_sb(segs_per_sec));
+ }
if (f2fs_get_usable_segments(sb) <= get_cp(overprov_segment_count)) {
MSG(0, "\tError: Not enough segments to create F2FS Volume\n");
diff --git a/mkfs/f2fs_format_main.c b/mkfs/f2fs_format_main.c
index f50971c4591c..07995b350a70 100644
--- a/mkfs/f2fs_format_main.c
+++ b/mkfs/f2fs_format_main.c
@@ -75,6 +75,7 @@ static void mkfs_usage()
MSG(0, " -w wanted sector size\n");
MSG(0, " -z # of sections per zone [default:1]\n");
MSG(0, " -V print the version number and exit\n");
+ MSG(0, " -Z # of reserved sections [default:auto]\n");
MSG(0, "sectors: number of sectors [default: determined by device size]\n");
exit(1);
}
@@ -176,7 +177,7 @@ static void add_default_options(void)
static void f2fs_parse_options(int argc, char *argv[])
{
- static const char *option_string = "qa:c:C:d:e:E:g:hil:mo:O:rR:s:S:z:t:T:U:Vfw:";
+ static const char *option_string = "qa:c:C:d:e:E:g:hil:mo:O:rR:s:S:z:t:T:U:Vfw:Z:";
static const struct option long_opts[] = {
{ .name = "help", .has_arg = 0, .flag = NULL, .val = 'h' },
{ .name = NULL, .has_arg = 0, .flag = NULL, .val = 0 }
@@ -295,6 +296,9 @@ static void f2fs_parse_options(int argc, char *argv[])
}
c.feature |= cpu_to_le32(F2FS_FEATURE_CASEFOLD);
break;
+ case 'Z':
+ c.conf_reserved_sections = atoi(optarg);
+ break;
default:
MSG(0, "\tError: Unknown option %c\n",option);
mkfs_usage();
@@ -490,6 +494,11 @@ int main(int argc, char *argv[])
goto err_format;
}
+ if (c.conf_reserved_sections && !c.zoned_mode) {
+ MSG(0, "\tError: Reserved area can't be specified on non zoned device\n");
+ goto err_format;
+ }
+
if (f2fs_format_device() < 0)
goto err_format;
--
2.34.1
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
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[not found] <CGME20230317044151epcms2p5872591b638dab3261a9dd563253f1b94@epcms2p5>
2023-03-17 4:41 ` [f2fs-dev] [PATCH v1] mkfs.f2fs: Introduce configurable reserved sections Yonggil Song
2023-03-27 21:26 ` Jaegeuk Kim
[not found] ` <CGME20230317044151epcms2p5872591b638dab3261a9dd563253f1b94@epcms2p3>
2023-03-28 8:06 ` [f2fs-dev] (2) " Yonggil Song
[not found] ` <CGME20230317044151epcms2p5872591b638dab3261a9dd563253f1b94@epcms2p2>
2023-04-04 6:21 ` [f2fs-dev] [PATCH v2] " Yonggil Song
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