* [PATCH v2] f2fs: Reduce zoned block device memory usage
@ 2019-03-06 6:27 Damien Le Moal
2019-03-06 14:32 ` Chao Yu
0 siblings, 1 reply; 11+ messages in thread
From: Damien Le Moal @ 2019-03-06 6:27 UTC (permalink / raw)
To: jaegeuk, yuchao0, linux-f2fs-devel; +Cc: linux-fsdevel, Matias Bjorling
For zoned block devices, an array of zone types for each device is
allocated and initialized in order to determine if a section is stored
on a sequential zone (zone reset needed) or a conventional zone (no
zone reset needed and regular discard applies). Considering this usage,
the zone types stored in memory can be replaced with a bitmap to
indicate an equivalent information, that is, if a zone is sequential or
not. This reduces the memory usage for each zoned device by roughly 8:
on a 14TB disk with zones of 256 MB, the zone type array consumes
13x4KB pages while the bitmap uses only 2x4KB pages.
This patch changes the f2fs_dev_info structure blkz_type field to the
bitmap blkz_seq. Access to this bitmap is done using the helper
function f2fs_blkz_is_seq(), which is a rewrite of the function
get_blkz_type().
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
---
Changes from v1:
* Use kvfree() instead of kfree() to free the zone bitmap
fs/f2fs/f2fs.h | 13 +++++++------
fs/f2fs/segment.c | 23 +++++++----------------
fs/f2fs/super.c | 13 ++++++++-----
3 files changed, 22 insertions(+), 27 deletions(-)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 12fabd6735dd..d7b2de930352 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1067,8 +1067,8 @@ struct f2fs_dev_info {
block_t start_blk;
block_t end_blk;
#ifdef CONFIG_BLK_DEV_ZONED
- unsigned int nr_blkz; /* Total number of zones */
- u8 *blkz_type; /* Array of zones type */
+ unsigned int nr_blkz; /* Total number of zones */
+ unsigned long *blkz_seq; /* Bitmap indicating sequential zones */
#endif
};
@@ -3508,16 +3508,17 @@ F2FS_FEATURE_FUNCS(lost_found, LOST_FOUND);
F2FS_FEATURE_FUNCS(sb_chksum, SB_CHKSUM);
#ifdef CONFIG_BLK_DEV_ZONED
-static inline int get_blkz_type(struct f2fs_sb_info *sbi,
- struct block_device *bdev, block_t blkaddr)
+static inline bool f2fs_blkz_is_seq(struct f2fs_sb_info *sbi,
+ struct block_device *bdev, block_t blkaddr)
{
unsigned int zno = blkaddr >> sbi->log_blocks_per_blkz;
int i;
for (i = 0; i < sbi->s_ndevs; i++)
if (FDEV(i).bdev == bdev)
- return FDEV(i).blkz_type[zno];
- return -EINVAL;
+ return test_bit(zno, FDEV(i).blkz_seq);
+ WARN_ON_ONCE(1);
+ return false;
}
#endif
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 9b79056d705d..65941070776c 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1703,19 +1703,8 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
blkstart -= FDEV(devi).start_blk;
}
- /*
- * We need to know the type of the zone: for conventional zones,
- * use regular discard if the drive supports it. For sequential
- * zones, reset the zone write pointer.
- */
- switch (get_blkz_type(sbi, bdev, blkstart)) {
-
- case BLK_ZONE_TYPE_CONVENTIONAL:
- if (!blk_queue_discard(bdev_get_queue(bdev)))
- return 0;
- return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
- case BLK_ZONE_TYPE_SEQWRITE_REQ:
- case BLK_ZONE_TYPE_SEQWRITE_PREF:
+ /* For sequential zones, reset the zone write pointer */
+ if (f2fs_blkz_is_seq(sbi, bdev, blkstart)) {
sector = SECTOR_FROM_BLOCK(blkstart);
nr_sects = SECTOR_FROM_BLOCK(blklen);
@@ -1730,10 +1719,12 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
trace_f2fs_issue_reset_zone(bdev, blkstart);
return blkdev_reset_zones(bdev, sector,
nr_sects, GFP_NOFS);
- default:
- /* Unknown zone type: broken device ? */
- return -EIO;
}
+
+ /* For conventional zones, use regular discard if supported */
+ if (!blk_queue_discard(bdev_get_queue(bdev)))
+ return 0;
+ return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
}
#endif
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index c46a1d4318d4..91d7429be554 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1017,7 +1017,7 @@ static void destroy_device_list(struct f2fs_sb_info *sbi)
for (i = 0; i < sbi->s_ndevs; i++) {
blkdev_put(FDEV(i).bdev, FMODE_EXCL);
#ifdef CONFIG_BLK_DEV_ZONED
- kvfree(FDEV(i).blkz_type);
+ kvfree(FDEV(i).blkz_seq);
#endif
}
kvfree(sbi->devs);
@@ -2765,9 +2765,11 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
if (nr_sectors & (bdev_zone_sectors(bdev) - 1))
FDEV(devi).nr_blkz++;
- FDEV(devi).blkz_type = f2fs_kmalloc(sbi, FDEV(devi).nr_blkz,
- GFP_KERNEL);
- if (!FDEV(devi).blkz_type)
+ FDEV(devi).blkz_seq = f2fs_kzalloc(sbi,
+ BITS_TO_LONGS(FDEV(devi).nr_blkz)
+ * sizeof(unsigned long),
+ GFP_KERNEL);
+ if (!FDEV(devi).blkz_seq)
return -ENOMEM;
#define F2FS_REPORT_NR_ZONES 4096
@@ -2794,7 +2796,8 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
}
for (i = 0; i < nr_zones; i++) {
- FDEV(devi).blkz_type[n] = zones[i].type;
+ if (zones[i].type != BLK_ZONE_TYPE_CONVENTIONAL)
+ set_bit(n, FDEV(devi).blkz_seq);
sector += zones[i].len;
n++;
}
--
2.20.1
^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [f2fs-dev] [PATCH v2] f2fs: Reduce zoned block device memory usage
2019-03-06 6:27 [PATCH v2] f2fs: Reduce zoned block device memory usage Damien Le Moal
@ 2019-03-06 14:32 ` Chao Yu
0 siblings, 0 replies; 11+ messages in thread
From: Chao Yu @ 2019-03-06 14:32 UTC (permalink / raw)
To: Damien Le Moal, jaegeuk, yuchao0, linux-f2fs-devel
Cc: linux-fsdevel, Matias Bjorling
On 2019-3-6 14:27, Damien Le Moal wrote:
> For zoned block devices, an array of zone types for each device is
> allocated and initialized in order to determine if a section is stored
> on a sequential zone (zone reset needed) or a conventional zone (no
> zone reset needed and regular discard applies). Considering this usage,
> the zone types stored in memory can be replaced with a bitmap to
> indicate an equivalent information, that is, if a zone is sequential or
> not. This reduces the memory usage for each zoned device by roughly 8:
> on a 14TB disk with zones of 256 MB, the zone type array consumes
> 13x4KB pages while the bitmap uses only 2x4KB pages.
>
> This patch changes the f2fs_dev_info structure blkz_type field to the
> bitmap blkz_seq. Access to this bitmap is done using the helper
> function f2fs_blkz_is_seq(), which is a rewrite of the function
> get_blkz_type().
>
> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
> ---
> Changes from v1:
> * Use kvfree() instead of kfree() to free the zone bitmap
>
> fs/f2fs/f2fs.h | 13 +++++++------
> fs/f2fs/segment.c | 23 +++++++----------------
> fs/f2fs/super.c | 13 ++++++++-----
> 3 files changed, 22 insertions(+), 27 deletions(-)
>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 12fabd6735dd..d7b2de930352 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1067,8 +1067,8 @@ struct f2fs_dev_info {
> block_t start_blk;
> block_t end_blk;
> #ifdef CONFIG_BLK_DEV_ZONED
> - unsigned int nr_blkz; /* Total number of zones */
> - u8 *blkz_type; /* Array of zones type */
> + unsigned int nr_blkz; /* Total number of zones */
> + unsigned long *blkz_seq; /* Bitmap indicating sequential zones */
> #endif
> };
>
> @@ -3508,16 +3508,17 @@ F2FS_FEATURE_FUNCS(lost_found, LOST_FOUND);
> F2FS_FEATURE_FUNCS(sb_chksum, SB_CHKSUM);
>
> #ifdef CONFIG_BLK_DEV_ZONED
> -static inline int get_blkz_type(struct f2fs_sb_info *sbi,
> - struct block_device *bdev, block_t blkaddr)
> +static inline bool f2fs_blkz_is_seq(struct f2fs_sb_info *sbi,
> + struct block_device *bdev, block_t blkaddr)
> {
> unsigned int zno = blkaddr >> sbi->log_blocks_per_blkz;
> int i;
>
> for (i = 0; i < sbi->s_ndevs; i++)
> if (FDEV(i).bdev == bdev)
> - return FDEV(i).blkz_type[zno];
> - return -EINVAL;
> + return test_bit(zno, FDEV(i).blkz_seq);
> + WARN_ON_ONCE(1);
> + return false;
How about just handling this case as previous instead of treating device as
conventional zone?
Thanks,
> }
> #endif
>
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 9b79056d705d..65941070776c 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1703,19 +1703,8 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
> blkstart -= FDEV(devi).start_blk;
> }
>
> - /*
> - * We need to know the type of the zone: for conventional zones,
> - * use regular discard if the drive supports it. For sequential
> - * zones, reset the zone write pointer.
> - */
> - switch (get_blkz_type(sbi, bdev, blkstart)) {
> -
> - case BLK_ZONE_TYPE_CONVENTIONAL:
> - if (!blk_queue_discard(bdev_get_queue(bdev)))
> - return 0;
> - return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
> - case BLK_ZONE_TYPE_SEQWRITE_REQ:
> - case BLK_ZONE_TYPE_SEQWRITE_PREF:
> + /* For sequential zones, reset the zone write pointer */
> + if (f2fs_blkz_is_seq(sbi, bdev, blkstart)) {
> sector = SECTOR_FROM_BLOCK(blkstart);
> nr_sects = SECTOR_FROM_BLOCK(blklen);
>
> @@ -1730,10 +1719,12 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
> trace_f2fs_issue_reset_zone(bdev, blkstart);
> return blkdev_reset_zones(bdev, sector,
> nr_sects, GFP_NOFS);
> - default:
> - /* Unknown zone type: broken device ? */
> - return -EIO;
> }
> +
> + /* For conventional zones, use regular discard if supported */
> + if (!blk_queue_discard(bdev_get_queue(bdev)))
> + return 0;
> + return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
> }
> #endif
>
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index c46a1d4318d4..91d7429be554 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -1017,7 +1017,7 @@ static void destroy_device_list(struct f2fs_sb_info *sbi)
> for (i = 0; i < sbi->s_ndevs; i++) {
> blkdev_put(FDEV(i).bdev, FMODE_EXCL);
> #ifdef CONFIG_BLK_DEV_ZONED
> - kvfree(FDEV(i).blkz_type);
> + kvfree(FDEV(i).blkz_seq);
> #endif
> }
> kvfree(sbi->devs);
> @@ -2765,9 +2765,11 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
> if (nr_sectors & (bdev_zone_sectors(bdev) - 1))
> FDEV(devi).nr_blkz++;
>
> - FDEV(devi).blkz_type = f2fs_kmalloc(sbi, FDEV(devi).nr_blkz,
> - GFP_KERNEL);
> - if (!FDEV(devi).blkz_type)
> + FDEV(devi).blkz_seq = f2fs_kzalloc(sbi,
> + BITS_TO_LONGS(FDEV(devi).nr_blkz)
> + * sizeof(unsigned long),
> + GFP_KERNEL);
> + if (!FDEV(devi).blkz_seq)
> return -ENOMEM;
>
> #define F2FS_REPORT_NR_ZONES 4096
> @@ -2794,7 +2796,8 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
> }
>
> for (i = 0; i < nr_zones; i++) {
> - FDEV(devi).blkz_type[n] = zones[i].type;
> + if (zones[i].type != BLK_ZONE_TYPE_CONVENTIONAL)
> + set_bit(n, FDEV(devi).blkz_seq);
> sector += zones[i].len;
> n++;
> }
>
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v2] f2fs: Reduce zoned block device memory usage
@ 2019-03-06 14:32 ` Chao Yu
0 siblings, 0 replies; 11+ messages in thread
From: Chao Yu @ 2019-03-06 14:32 UTC (permalink / raw)
To: Damien Le Moal, jaegeuk, yuchao0, linux-f2fs-devel
Cc: linux-fsdevel, Matias Bjorling
On 2019-3-6 14:27, Damien Le Moal wrote:
> For zoned block devices, an array of zone types for each device is
> allocated and initialized in order to determine if a section is stored
> on a sequential zone (zone reset needed) or a conventional zone (no
> zone reset needed and regular discard applies). Considering this usage,
> the zone types stored in memory can be replaced with a bitmap to
> indicate an equivalent information, that is, if a zone is sequential or
> not. This reduces the memory usage for each zoned device by roughly 8:
> on a 14TB disk with zones of 256 MB, the zone type array consumes
> 13x4KB pages while the bitmap uses only 2x4KB pages.
>
> This patch changes the f2fs_dev_info structure blkz_type field to the
> bitmap blkz_seq. Access to this bitmap is done using the helper
> function f2fs_blkz_is_seq(), which is a rewrite of the function
> get_blkz_type().
>
> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
> ---
> Changes from v1:
> * Use kvfree() instead of kfree() to free the zone bitmap
>
> fs/f2fs/f2fs.h | 13 +++++++------
> fs/f2fs/segment.c | 23 +++++++----------------
> fs/f2fs/super.c | 13 ++++++++-----
> 3 files changed, 22 insertions(+), 27 deletions(-)
>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 12fabd6735dd..d7b2de930352 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1067,8 +1067,8 @@ struct f2fs_dev_info {
> block_t start_blk;
> block_t end_blk;
> #ifdef CONFIG_BLK_DEV_ZONED
> - unsigned int nr_blkz; /* Total number of zones */
> - u8 *blkz_type; /* Array of zones type */
> + unsigned int nr_blkz; /* Total number of zones */
> + unsigned long *blkz_seq; /* Bitmap indicating sequential zones */
> #endif
> };
>
> @@ -3508,16 +3508,17 @@ F2FS_FEATURE_FUNCS(lost_found, LOST_FOUND);
> F2FS_FEATURE_FUNCS(sb_chksum, SB_CHKSUM);
>
> #ifdef CONFIG_BLK_DEV_ZONED
> -static inline int get_blkz_type(struct f2fs_sb_info *sbi,
> - struct block_device *bdev, block_t blkaddr)
> +static inline bool f2fs_blkz_is_seq(struct f2fs_sb_info *sbi,
> + struct block_device *bdev, block_t blkaddr)
> {
> unsigned int zno = blkaddr >> sbi->log_blocks_per_blkz;
> int i;
>
> for (i = 0; i < sbi->s_ndevs; i++)
> if (FDEV(i).bdev == bdev)
> - return FDEV(i).blkz_type[zno];
> - return -EINVAL;
> + return test_bit(zno, FDEV(i).blkz_seq);
> + WARN_ON_ONCE(1);
> + return false;
How about just handling this case as previous instead of treating device as
conventional zone?
Thanks,
> }
> #endif
>
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 9b79056d705d..65941070776c 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1703,19 +1703,8 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
> blkstart -= FDEV(devi).start_blk;
> }
>
> - /*
> - * We need to know the type of the zone: for conventional zones,
> - * use regular discard if the drive supports it. For sequential
> - * zones, reset the zone write pointer.
> - */
> - switch (get_blkz_type(sbi, bdev, blkstart)) {
> -
> - case BLK_ZONE_TYPE_CONVENTIONAL:
> - if (!blk_queue_discard(bdev_get_queue(bdev)))
> - return 0;
> - return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
> - case BLK_ZONE_TYPE_SEQWRITE_REQ:
> - case BLK_ZONE_TYPE_SEQWRITE_PREF:
> + /* For sequential zones, reset the zone write pointer */
> + if (f2fs_blkz_is_seq(sbi, bdev, blkstart)) {
> sector = SECTOR_FROM_BLOCK(blkstart);
> nr_sects = SECTOR_FROM_BLOCK(blklen);
>
> @@ -1730,10 +1719,12 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
> trace_f2fs_issue_reset_zone(bdev, blkstart);
> return blkdev_reset_zones(bdev, sector,
> nr_sects, GFP_NOFS);
> - default:
> - /* Unknown zone type: broken device ? */
> - return -EIO;
> }
> +
> + /* For conventional zones, use regular discard if supported */
> + if (!blk_queue_discard(bdev_get_queue(bdev)))
> + return 0;
> + return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
> }
> #endif
>
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index c46a1d4318d4..91d7429be554 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -1017,7 +1017,7 @@ static void destroy_device_list(struct f2fs_sb_info *sbi)
> for (i = 0; i < sbi->s_ndevs; i++) {
> blkdev_put(FDEV(i).bdev, FMODE_EXCL);
> #ifdef CONFIG_BLK_DEV_ZONED
> - kvfree(FDEV(i).blkz_type);
> + kvfree(FDEV(i).blkz_seq);
> #endif
> }
> kvfree(sbi->devs);
> @@ -2765,9 +2765,11 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
> if (nr_sectors & (bdev_zone_sectors(bdev) - 1))
> FDEV(devi).nr_blkz++;
>
> - FDEV(devi).blkz_type = f2fs_kmalloc(sbi, FDEV(devi).nr_blkz,
> - GFP_KERNEL);
> - if (!FDEV(devi).blkz_type)
> + FDEV(devi).blkz_seq = f2fs_kzalloc(sbi,
> + BITS_TO_LONGS(FDEV(devi).nr_blkz)
> + * sizeof(unsigned long),
> + GFP_KERNEL);
> + if (!FDEV(devi).blkz_seq)
> return -ENOMEM;
>
> #define F2FS_REPORT_NR_ZONES 4096
> @@ -2794,7 +2796,8 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
> }
>
> for (i = 0; i < nr_zones; i++) {
> - FDEV(devi).blkz_type[n] = zones[i].type;
> + if (zones[i].type != BLK_ZONE_TYPE_CONVENTIONAL)
> + set_bit(n, FDEV(devi).blkz_seq);
> sector += zones[i].len;
> n++;
> }
>
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [f2fs-dev] [PATCH v2] f2fs: Reduce zoned block device memory usage
2019-03-06 14:32 ` Chao Yu
@ 2019-03-06 18:15 ` Damien Le Moal
-1 siblings, 0 replies; 11+ messages in thread
From: Damien Le Moal @ 2019-03-06 18:15 UTC (permalink / raw)
To: Chao Yu, jaegeuk, yuchao0, linux-f2fs-devel
Cc: linux-fsdevel, Matias Bjorling
On 2019/03/06 23:32, Chao Yu wrote:
> On 2019-3-6 14:27, Damien Le Moal wrote:
>> For zoned block devices, an array of zone types for each device is
>> allocated and initialized in order to determine if a section is stored
>> on a sequential zone (zone reset needed) or a conventional zone (no
>> zone reset needed and regular discard applies). Considering this usage,
>> the zone types stored in memory can be replaced with a bitmap to
>> indicate an equivalent information, that is, if a zone is sequential or
>> not. This reduces the memory usage for each zoned device by roughly 8:
>> on a 14TB disk with zones of 256 MB, the zone type array consumes
>> 13x4KB pages while the bitmap uses only 2x4KB pages.
>>
>> This patch changes the f2fs_dev_info structure blkz_type field to the
>> bitmap blkz_seq. Access to this bitmap is done using the helper
>> function f2fs_blkz_is_seq(), which is a rewrite of the function
>> get_blkz_type().
>>
>> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
>> ---
>> Changes from v1:
>> * Use kvfree() instead of kfree() to free the zone bitmap
>>
>> fs/f2fs/f2fs.h | 13 +++++++------
>> fs/f2fs/segment.c | 23 +++++++----------------
>> fs/f2fs/super.c | 13 ++++++++-----
>> 3 files changed, 22 insertions(+), 27 deletions(-)
>>
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index 12fabd6735dd..d7b2de930352 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -1067,8 +1067,8 @@ struct f2fs_dev_info {
>> block_t start_blk;
>> block_t end_blk;
>> #ifdef CONFIG_BLK_DEV_ZONED
>> - unsigned int nr_blkz; /* Total number of zones */
>> - u8 *blkz_type; /* Array of zones type */
>> + unsigned int nr_blkz; /* Total number of zones */
>> + unsigned long *blkz_seq; /* Bitmap indicating sequential zones */
>> #endif
>> };
>>
>> @@ -3508,16 +3508,17 @@ F2FS_FEATURE_FUNCS(lost_found, LOST_FOUND);
>> F2FS_FEATURE_FUNCS(sb_chksum, SB_CHKSUM);
>>
>> #ifdef CONFIG_BLK_DEV_ZONED
>> -static inline int get_blkz_type(struct f2fs_sb_info *sbi,
>> - struct block_device *bdev, block_t blkaddr)
>> +static inline bool f2fs_blkz_is_seq(struct f2fs_sb_info *sbi,
>> + struct block_device *bdev, block_t blkaddr)
>> {
>> unsigned int zno = blkaddr >> sbi->log_blocks_per_blkz;
>> int i;
>>
>> for (i = 0; i < sbi->s_ndevs; i++)
>> if (FDEV(i).bdev == bdev)
>> - return FDEV(i).blkz_type[zno];
>> - return -EINVAL;
>> + return test_bit(zno, FDEV(i).blkz_seq);
>> + WARN_ON_ONCE(1);
>> + return false;
>
> How about just handling this case as previous instead of treating device as
> conventional zone?
Before this patch, if the device is not found, an error was returned, which was
propagated up by __f2fs_issue_discard_zone() as an -EIO. Do you mean to do the
same here too ?
Now that I look at this again, another possible change that I think actually may
make more sense is to pass the devi (device index) variable set by
__f2fs_issue_discard_zone() to this function. No need for the device search loop
doing so and invalid block numbers leading to invalid device indexes can/should
be handled in __f2fs_issue_discard_zone().
What do you think ?
>
> Thanks,
>
>> }
>> #endif
>>
>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>> index 9b79056d705d..65941070776c 100644
>> --- a/fs/f2fs/segment.c
>> +++ b/fs/f2fs/segment.c
>> @@ -1703,19 +1703,8 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
>> blkstart -= FDEV(devi).start_blk;
>> }
>>
>> - /*
>> - * We need to know the type of the zone: for conventional zones,
>> - * use regular discard if the drive supports it. For sequential
>> - * zones, reset the zone write pointer.
>> - */
>> - switch (get_blkz_type(sbi, bdev, blkstart)) {
>> -
>> - case BLK_ZONE_TYPE_CONVENTIONAL:
>> - if (!blk_queue_discard(bdev_get_queue(bdev)))
>> - return 0;
>> - return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
>> - case BLK_ZONE_TYPE_SEQWRITE_REQ:
>> - case BLK_ZONE_TYPE_SEQWRITE_PREF:
>> + /* For sequential zones, reset the zone write pointer */
>> + if (f2fs_blkz_is_seq(sbi, bdev, blkstart)) {
>> sector = SECTOR_FROM_BLOCK(blkstart);
>> nr_sects = SECTOR_FROM_BLOCK(blklen);
>>
>> @@ -1730,10 +1719,12 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
>> trace_f2fs_issue_reset_zone(bdev, blkstart);
>> return blkdev_reset_zones(bdev, sector,
>> nr_sects, GFP_NOFS);
>> - default:
>> - /* Unknown zone type: broken device ? */
>> - return -EIO;
>> }
>> +
>> + /* For conventional zones, use regular discard if supported */
>> + if (!blk_queue_discard(bdev_get_queue(bdev)))
>> + return 0;
>> + return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
>> }
>> #endif
>>
>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>> index c46a1d4318d4..91d7429be554 100644
>> --- a/fs/f2fs/super.c
>> +++ b/fs/f2fs/super.c
>> @@ -1017,7 +1017,7 @@ static void destroy_device_list(struct f2fs_sb_info *sbi)
>> for (i = 0; i < sbi->s_ndevs; i++) {
>> blkdev_put(FDEV(i).bdev, FMODE_EXCL);
>> #ifdef CONFIG_BLK_DEV_ZONED
>> - kvfree(FDEV(i).blkz_type);
>> + kvfree(FDEV(i).blkz_seq);
>> #endif
>> }
>> kvfree(sbi->devs);
>> @@ -2765,9 +2765,11 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
>> if (nr_sectors & (bdev_zone_sectors(bdev) - 1))
>> FDEV(devi).nr_blkz++;
>>
>> - FDEV(devi).blkz_type = f2fs_kmalloc(sbi, FDEV(devi).nr_blkz,
>> - GFP_KERNEL);
>> - if (!FDEV(devi).blkz_type)
>> + FDEV(devi).blkz_seq = f2fs_kzalloc(sbi,
>> + BITS_TO_LONGS(FDEV(devi).nr_blkz)
>> + * sizeof(unsigned long),
>> + GFP_KERNEL);
>> + if (!FDEV(devi).blkz_seq)
>> return -ENOMEM;
>>
>> #define F2FS_REPORT_NR_ZONES 4096
>> @@ -2794,7 +2796,8 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
>> }
>>
>> for (i = 0; i < nr_zones; i++) {
>> - FDEV(devi).blkz_type[n] = zones[i].type;
>> + if (zones[i].type != BLK_ZONE_TYPE_CONVENTIONAL)
>> + set_bit(n, FDEV(devi).blkz_seq);
>> sector += zones[i].len;
>> n++;
>> }
>>
>
--
Damien Le Moal
Western Digital Research
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v2] f2fs: Reduce zoned block device memory usage
@ 2019-03-06 18:15 ` Damien Le Moal
0 siblings, 0 replies; 11+ messages in thread
From: Damien Le Moal @ 2019-03-06 18:15 UTC (permalink / raw)
To: Chao Yu, jaegeuk, yuchao0, linux-f2fs-devel
Cc: linux-fsdevel, Matias Bjorling
On 2019/03/06 23:32, Chao Yu wrote:
> On 2019-3-6 14:27, Damien Le Moal wrote:
>> For zoned block devices, an array of zone types for each device is
>> allocated and initialized in order to determine if a section is stored
>> on a sequential zone (zone reset needed) or a conventional zone (no
>> zone reset needed and regular discard applies). Considering this usage,
>> the zone types stored in memory can be replaced with a bitmap to
>> indicate an equivalent information, that is, if a zone is sequential or
>> not. This reduces the memory usage for each zoned device by roughly 8:
>> on a 14TB disk with zones of 256 MB, the zone type array consumes
>> 13x4KB pages while the bitmap uses only 2x4KB pages.
>>
>> This patch changes the f2fs_dev_info structure blkz_type field to the
>> bitmap blkz_seq. Access to this bitmap is done using the helper
>> function f2fs_blkz_is_seq(), which is a rewrite of the function
>> get_blkz_type().
>>
>> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
>> ---
>> Changes from v1:
>> * Use kvfree() instead of kfree() to free the zone bitmap
>>
>> fs/f2fs/f2fs.h | 13 +++++++------
>> fs/f2fs/segment.c | 23 +++++++----------------
>> fs/f2fs/super.c | 13 ++++++++-----
>> 3 files changed, 22 insertions(+), 27 deletions(-)
>>
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index 12fabd6735dd..d7b2de930352 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -1067,8 +1067,8 @@ struct f2fs_dev_info {
>> block_t start_blk;
>> block_t end_blk;
>> #ifdef CONFIG_BLK_DEV_ZONED
>> - unsigned int nr_blkz; /* Total number of zones */
>> - u8 *blkz_type; /* Array of zones type */
>> + unsigned int nr_blkz; /* Total number of zones */
>> + unsigned long *blkz_seq; /* Bitmap indicating sequential zones */
>> #endif
>> };
>>
>> @@ -3508,16 +3508,17 @@ F2FS_FEATURE_FUNCS(lost_found, LOST_FOUND);
>> F2FS_FEATURE_FUNCS(sb_chksum, SB_CHKSUM);
>>
>> #ifdef CONFIG_BLK_DEV_ZONED
>> -static inline int get_blkz_type(struct f2fs_sb_info *sbi,
>> - struct block_device *bdev, block_t blkaddr)
>> +static inline bool f2fs_blkz_is_seq(struct f2fs_sb_info *sbi,
>> + struct block_device *bdev, block_t blkaddr)
>> {
>> unsigned int zno = blkaddr >> sbi->log_blocks_per_blkz;
>> int i;
>>
>> for (i = 0; i < sbi->s_ndevs; i++)
>> if (FDEV(i).bdev == bdev)
>> - return FDEV(i).blkz_type[zno];
>> - return -EINVAL;
>> + return test_bit(zno, FDEV(i).blkz_seq);
>> + WARN_ON_ONCE(1);
>> + return false;
>
> How about just handling this case as previous instead of treating device as
> conventional zone?
Before this patch, if the device is not found, an error was returned, which was
propagated up by __f2fs_issue_discard_zone() as an -EIO. Do you mean to do the
same here too ?
Now that I look at this again, another possible change that I think actually may
make more sense is to pass the devi (device index) variable set by
__f2fs_issue_discard_zone() to this function. No need for the device search loop
doing so and invalid block numbers leading to invalid device indexes can/should
be handled in __f2fs_issue_discard_zone().
What do you think ?
>
> Thanks,
>
>> }
>> #endif
>>
>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>> index 9b79056d705d..65941070776c 100644
>> --- a/fs/f2fs/segment.c
>> +++ b/fs/f2fs/segment.c
>> @@ -1703,19 +1703,8 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
>> blkstart -= FDEV(devi).start_blk;
>> }
>>
>> - /*
>> - * We need to know the type of the zone: for conventional zones,
>> - * use regular discard if the drive supports it. For sequential
>> - * zones, reset the zone write pointer.
>> - */
>> - switch (get_blkz_type(sbi, bdev, blkstart)) {
>> -
>> - case BLK_ZONE_TYPE_CONVENTIONAL:
>> - if (!blk_queue_discard(bdev_get_queue(bdev)))
>> - return 0;
>> - return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
>> - case BLK_ZONE_TYPE_SEQWRITE_REQ:
>> - case BLK_ZONE_TYPE_SEQWRITE_PREF:
>> + /* For sequential zones, reset the zone write pointer */
>> + if (f2fs_blkz_is_seq(sbi, bdev, blkstart)) {
>> sector = SECTOR_FROM_BLOCK(blkstart);
>> nr_sects = SECTOR_FROM_BLOCK(blklen);
>>
>> @@ -1730,10 +1719,12 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
>> trace_f2fs_issue_reset_zone(bdev, blkstart);
>> return blkdev_reset_zones(bdev, sector,
>> nr_sects, GFP_NOFS);
>> - default:
>> - /* Unknown zone type: broken device ? */
>> - return -EIO;
>> }
>> +
>> + /* For conventional zones, use regular discard if supported */
>> + if (!blk_queue_discard(bdev_get_queue(bdev)))
>> + return 0;
>> + return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
>> }
>> #endif
>>
>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>> index c46a1d4318d4..91d7429be554 100644
>> --- a/fs/f2fs/super.c
>> +++ b/fs/f2fs/super.c
>> @@ -1017,7 +1017,7 @@ static void destroy_device_list(struct f2fs_sb_info *sbi)
>> for (i = 0; i < sbi->s_ndevs; i++) {
>> blkdev_put(FDEV(i).bdev, FMODE_EXCL);
>> #ifdef CONFIG_BLK_DEV_ZONED
>> - kvfree(FDEV(i).blkz_type);
>> + kvfree(FDEV(i).blkz_seq);
>> #endif
>> }
>> kvfree(sbi->devs);
>> @@ -2765,9 +2765,11 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
>> if (nr_sectors & (bdev_zone_sectors(bdev) - 1))
>> FDEV(devi).nr_blkz++;
>>
>> - FDEV(devi).blkz_type = f2fs_kmalloc(sbi, FDEV(devi).nr_blkz,
>> - GFP_KERNEL);
>> - if (!FDEV(devi).blkz_type)
>> + FDEV(devi).blkz_seq = f2fs_kzalloc(sbi,
>> + BITS_TO_LONGS(FDEV(devi).nr_blkz)
>> + * sizeof(unsigned long),
>> + GFP_KERNEL);
>> + if (!FDEV(devi).blkz_seq)
>> return -ENOMEM;
>>
>> #define F2FS_REPORT_NR_ZONES 4096
>> @@ -2794,7 +2796,8 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
>> }
>>
>> for (i = 0; i < nr_zones; i++) {
>> - FDEV(devi).blkz_type[n] = zones[i].type;
>> + if (zones[i].type != BLK_ZONE_TYPE_CONVENTIONAL)
>> + set_bit(n, FDEV(devi).blkz_seq);
>> sector += zones[i].len;
>> n++;
>> }
>>
>
--
Damien Le Moal
Western Digital Research
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [f2fs-dev] [PATCH v2] f2fs: Reduce zoned block device memory usage
2019-03-06 18:15 ` Damien Le Moal
@ 2019-03-07 1:19 ` Chao Yu
-1 siblings, 0 replies; 11+ messages in thread
From: Chao Yu @ 2019-03-07 1:19 UTC (permalink / raw)
To: Damien Le Moal, Chao Yu, jaegeuk, linux-f2fs-devel
Cc: linux-fsdevel, Matias Bjorling
On 2019/3/7 2:15, Damien Le Moal wrote:
> On 2019/03/06 23:32, Chao Yu wrote:
>> On 2019-3-6 14:27, Damien Le Moal wrote:
>>> For zoned block devices, an array of zone types for each device is
>>> allocated and initialized in order to determine if a section is stored
>>> on a sequential zone (zone reset needed) or a conventional zone (no
>>> zone reset needed and regular discard applies). Considering this usage,
>>> the zone types stored in memory can be replaced with a bitmap to
>>> indicate an equivalent information, that is, if a zone is sequential or
>>> not. This reduces the memory usage for each zoned device by roughly 8:
>>> on a 14TB disk with zones of 256 MB, the zone type array consumes
>>> 13x4KB pages while the bitmap uses only 2x4KB pages.
>>>
>>> This patch changes the f2fs_dev_info structure blkz_type field to the
>>> bitmap blkz_seq. Access to this bitmap is done using the helper
>>> function f2fs_blkz_is_seq(), which is a rewrite of the function
>>> get_blkz_type().
>>>
>>> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
>>> ---
>>> Changes from v1:
>>> * Use kvfree() instead of kfree() to free the zone bitmap
>>>
>>> fs/f2fs/f2fs.h | 13 +++++++------
>>> fs/f2fs/segment.c | 23 +++++++----------------
>>> fs/f2fs/super.c | 13 ++++++++-----
>>> 3 files changed, 22 insertions(+), 27 deletions(-)
>>>
>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>> index 12fabd6735dd..d7b2de930352 100644
>>> --- a/fs/f2fs/f2fs.h
>>> +++ b/fs/f2fs/f2fs.h
>>> @@ -1067,8 +1067,8 @@ struct f2fs_dev_info {
>>> block_t start_blk;
>>> block_t end_blk;
>>> #ifdef CONFIG_BLK_DEV_ZONED
>>> - unsigned int nr_blkz; /* Total number of zones */
>>> - u8 *blkz_type; /* Array of zones type */
>>> + unsigned int nr_blkz; /* Total number of zones */
>>> + unsigned long *blkz_seq; /* Bitmap indicating sequential zones */
>>> #endif
>>> };
>>>
>>> @@ -3508,16 +3508,17 @@ F2FS_FEATURE_FUNCS(lost_found, LOST_FOUND);
>>> F2FS_FEATURE_FUNCS(sb_chksum, SB_CHKSUM);
>>>
>>> #ifdef CONFIG_BLK_DEV_ZONED
>>> -static inline int get_blkz_type(struct f2fs_sb_info *sbi,
>>> - struct block_device *bdev, block_t blkaddr)
>>> +static inline bool f2fs_blkz_is_seq(struct f2fs_sb_info *sbi,
>>> + struct block_device *bdev, block_t blkaddr)
>>> {
>>> unsigned int zno = blkaddr >> sbi->log_blocks_per_blkz;
>>> int i;
>>>
>>> for (i = 0; i < sbi->s_ndevs; i++)
>>> if (FDEV(i).bdev == bdev)
>>> - return FDEV(i).blkz_type[zno];
>>> - return -EINVAL;
>>> + return test_bit(zno, FDEV(i).blkz_seq);
>>> + WARN_ON_ONCE(1);
>>> + return false;
>>
>> How about just handling this case as previous instead of treating device as
>> conventional zone?
>
> Before this patch, if the device is not found, an error was returned, which was
> propagated up by __f2fs_issue_discard_zone() as an -EIO. Do you mean to do the
> same here too ?
Yes.
>
> Now that I look at this again, another possible change that I think actually may
> make more sense is to pass the devi (device index) variable set by
> __f2fs_issue_discard_zone() to this function. No need for the device search loop
> doing so and invalid block numbers leading to invalid device indexes can/should
> be handled in __f2fs_issue_discard_zone().
>
> What do you think ?
That will be better, please go ahead. :)
Thanks,
>
>>
>> Thanks,
>>
>>> }
>>> #endif
>>>
>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>> index 9b79056d705d..65941070776c 100644
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -1703,19 +1703,8 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
>>> blkstart -= FDEV(devi).start_blk;
>>> }
>>>
>>> - /*
>>> - * We need to know the type of the zone: for conventional zones,
>>> - * use regular discard if the drive supports it. For sequential
>>> - * zones, reset the zone write pointer.
>>> - */
>>> - switch (get_blkz_type(sbi, bdev, blkstart)) {
>>> -
>>> - case BLK_ZONE_TYPE_CONVENTIONAL:
>>> - if (!blk_queue_discard(bdev_get_queue(bdev)))
>>> - return 0;
>>> - return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
>>> - case BLK_ZONE_TYPE_SEQWRITE_REQ:
>>> - case BLK_ZONE_TYPE_SEQWRITE_PREF:
>>> + /* For sequential zones, reset the zone write pointer */
>>> + if (f2fs_blkz_is_seq(sbi, bdev, blkstart)) {
>>> sector = SECTOR_FROM_BLOCK(blkstart);
>>> nr_sects = SECTOR_FROM_BLOCK(blklen);
>>>
>>> @@ -1730,10 +1719,12 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
>>> trace_f2fs_issue_reset_zone(bdev, blkstart);
>>> return blkdev_reset_zones(bdev, sector,
>>> nr_sects, GFP_NOFS);
>>> - default:
>>> - /* Unknown zone type: broken device ? */
>>> - return -EIO;
>>> }
>>> +
>>> + /* For conventional zones, use regular discard if supported */
>>> + if (!blk_queue_discard(bdev_get_queue(bdev)))
>>> + return 0;
>>> + return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
>>> }
>>> #endif
>>>
>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>> index c46a1d4318d4..91d7429be554 100644
>>> --- a/fs/f2fs/super.c
>>> +++ b/fs/f2fs/super.c
>>> @@ -1017,7 +1017,7 @@ static void destroy_device_list(struct f2fs_sb_info *sbi)
>>> for (i = 0; i < sbi->s_ndevs; i++) {
>>> blkdev_put(FDEV(i).bdev, FMODE_EXCL);
>>> #ifdef CONFIG_BLK_DEV_ZONED
>>> - kvfree(FDEV(i).blkz_type);
>>> + kvfree(FDEV(i).blkz_seq);
>>> #endif
>>> }
>>> kvfree(sbi->devs);
>>> @@ -2765,9 +2765,11 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
>>> if (nr_sectors & (bdev_zone_sectors(bdev) - 1))
>>> FDEV(devi).nr_blkz++;
>>>
>>> - FDEV(devi).blkz_type = f2fs_kmalloc(sbi, FDEV(devi).nr_blkz,
>>> - GFP_KERNEL);
>>> - if (!FDEV(devi).blkz_type)
>>> + FDEV(devi).blkz_seq = f2fs_kzalloc(sbi,
>>> + BITS_TO_LONGS(FDEV(devi).nr_blkz)
>>> + * sizeof(unsigned long),
>>> + GFP_KERNEL);
>>> + if (!FDEV(devi).blkz_seq)
>>> return -ENOMEM;
>>>
>>> #define F2FS_REPORT_NR_ZONES 4096
>>> @@ -2794,7 +2796,8 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
>>> }
>>>
>>> for (i = 0; i < nr_zones; i++) {
>>> - FDEV(devi).blkz_type[n] = zones[i].type;
>>> + if (zones[i].type != BLK_ZONE_TYPE_CONVENTIONAL)
>>> + set_bit(n, FDEV(devi).blkz_seq);
>>> sector += zones[i].len;
>>> n++;
>>> }
>>>
>>
>
>
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v2] f2fs: Reduce zoned block device memory usage
@ 2019-03-07 1:19 ` Chao Yu
0 siblings, 0 replies; 11+ messages in thread
From: Chao Yu @ 2019-03-07 1:19 UTC (permalink / raw)
To: Damien Le Moal, Chao Yu, jaegeuk, linux-f2fs-devel
Cc: linux-fsdevel, Matias Bjorling
On 2019/3/7 2:15, Damien Le Moal wrote:
> On 2019/03/06 23:32, Chao Yu wrote:
>> On 2019-3-6 14:27, Damien Le Moal wrote:
>>> For zoned block devices, an array of zone types for each device is
>>> allocated and initialized in order to determine if a section is stored
>>> on a sequential zone (zone reset needed) or a conventional zone (no
>>> zone reset needed and regular discard applies). Considering this usage,
>>> the zone types stored in memory can be replaced with a bitmap to
>>> indicate an equivalent information, that is, if a zone is sequential or
>>> not. This reduces the memory usage for each zoned device by roughly 8:
>>> on a 14TB disk with zones of 256 MB, the zone type array consumes
>>> 13x4KB pages while the bitmap uses only 2x4KB pages.
>>>
>>> This patch changes the f2fs_dev_info structure blkz_type field to the
>>> bitmap blkz_seq. Access to this bitmap is done using the helper
>>> function f2fs_blkz_is_seq(), which is a rewrite of the function
>>> get_blkz_type().
>>>
>>> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
>>> ---
>>> Changes from v1:
>>> * Use kvfree() instead of kfree() to free the zone bitmap
>>>
>>> fs/f2fs/f2fs.h | 13 +++++++------
>>> fs/f2fs/segment.c | 23 +++++++----------------
>>> fs/f2fs/super.c | 13 ++++++++-----
>>> 3 files changed, 22 insertions(+), 27 deletions(-)
>>>
>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>> index 12fabd6735dd..d7b2de930352 100644
>>> --- a/fs/f2fs/f2fs.h
>>> +++ b/fs/f2fs/f2fs.h
>>> @@ -1067,8 +1067,8 @@ struct f2fs_dev_info {
>>> block_t start_blk;
>>> block_t end_blk;
>>> #ifdef CONFIG_BLK_DEV_ZONED
>>> - unsigned int nr_blkz; /* Total number of zones */
>>> - u8 *blkz_type; /* Array of zones type */
>>> + unsigned int nr_blkz; /* Total number of zones */
>>> + unsigned long *blkz_seq; /* Bitmap indicating sequential zones */
>>> #endif
>>> };
>>>
>>> @@ -3508,16 +3508,17 @@ F2FS_FEATURE_FUNCS(lost_found, LOST_FOUND);
>>> F2FS_FEATURE_FUNCS(sb_chksum, SB_CHKSUM);
>>>
>>> #ifdef CONFIG_BLK_DEV_ZONED
>>> -static inline int get_blkz_type(struct f2fs_sb_info *sbi,
>>> - struct block_device *bdev, block_t blkaddr)
>>> +static inline bool f2fs_blkz_is_seq(struct f2fs_sb_info *sbi,
>>> + struct block_device *bdev, block_t blkaddr)
>>> {
>>> unsigned int zno = blkaddr >> sbi->log_blocks_per_blkz;
>>> int i;
>>>
>>> for (i = 0; i < sbi->s_ndevs; i++)
>>> if (FDEV(i).bdev == bdev)
>>> - return FDEV(i).blkz_type[zno];
>>> - return -EINVAL;
>>> + return test_bit(zno, FDEV(i).blkz_seq);
>>> + WARN_ON_ONCE(1);
>>> + return false;
>>
>> How about just handling this case as previous instead of treating device as
>> conventional zone?
>
> Before this patch, if the device is not found, an error was returned, which was
> propagated up by __f2fs_issue_discard_zone() as an -EIO. Do you mean to do the
> same here too ?
Yes.
>
> Now that I look at this again, another possible change that I think actually may
> make more sense is to pass the devi (device index) variable set by
> __f2fs_issue_discard_zone() to this function. No need for the device search loop
> doing so and invalid block numbers leading to invalid device indexes can/should
> be handled in __f2fs_issue_discard_zone().
>
> What do you think ?
That will be better, please go ahead. :)
Thanks,
>
>>
>> Thanks,
>>
>>> }
>>> #endif
>>>
>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>> index 9b79056d705d..65941070776c 100644
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -1703,19 +1703,8 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
>>> blkstart -= FDEV(devi).start_blk;
>>> }
>>>
>>> - /*
>>> - * We need to know the type of the zone: for conventional zones,
>>> - * use regular discard if the drive supports it. For sequential
>>> - * zones, reset the zone write pointer.
>>> - */
>>> - switch (get_blkz_type(sbi, bdev, blkstart)) {
>>> -
>>> - case BLK_ZONE_TYPE_CONVENTIONAL:
>>> - if (!blk_queue_discard(bdev_get_queue(bdev)))
>>> - return 0;
>>> - return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
>>> - case BLK_ZONE_TYPE_SEQWRITE_REQ:
>>> - case BLK_ZONE_TYPE_SEQWRITE_PREF:
>>> + /* For sequential zones, reset the zone write pointer */
>>> + if (f2fs_blkz_is_seq(sbi, bdev, blkstart)) {
>>> sector = SECTOR_FROM_BLOCK(blkstart);
>>> nr_sects = SECTOR_FROM_BLOCK(blklen);
>>>
>>> @@ -1730,10 +1719,12 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
>>> trace_f2fs_issue_reset_zone(bdev, blkstart);
>>> return blkdev_reset_zones(bdev, sector,
>>> nr_sects, GFP_NOFS);
>>> - default:
>>> - /* Unknown zone type: broken device ? */
>>> - return -EIO;
>>> }
>>> +
>>> + /* For conventional zones, use regular discard if supported */
>>> + if (!blk_queue_discard(bdev_get_queue(bdev)))
>>> + return 0;
>>> + return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
>>> }
>>> #endif
>>>
>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>> index c46a1d4318d4..91d7429be554 100644
>>> --- a/fs/f2fs/super.c
>>> +++ b/fs/f2fs/super.c
>>> @@ -1017,7 +1017,7 @@ static void destroy_device_list(struct f2fs_sb_info *sbi)
>>> for (i = 0; i < sbi->s_ndevs; i++) {
>>> blkdev_put(FDEV(i).bdev, FMODE_EXCL);
>>> #ifdef CONFIG_BLK_DEV_ZONED
>>> - kvfree(FDEV(i).blkz_type);
>>> + kvfree(FDEV(i).blkz_seq);
>>> #endif
>>> }
>>> kvfree(sbi->devs);
>>> @@ -2765,9 +2765,11 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
>>> if (nr_sectors & (bdev_zone_sectors(bdev) - 1))
>>> FDEV(devi).nr_blkz++;
>>>
>>> - FDEV(devi).blkz_type = f2fs_kmalloc(sbi, FDEV(devi).nr_blkz,
>>> - GFP_KERNEL);
>>> - if (!FDEV(devi).blkz_type)
>>> + FDEV(devi).blkz_seq = f2fs_kzalloc(sbi,
>>> + BITS_TO_LONGS(FDEV(devi).nr_blkz)
>>> + * sizeof(unsigned long),
>>> + GFP_KERNEL);
>>> + if (!FDEV(devi).blkz_seq)
>>> return -ENOMEM;
>>>
>>> #define F2FS_REPORT_NR_ZONES 4096
>>> @@ -2794,7 +2796,8 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
>>> }
>>>
>>> for (i = 0; i < nr_zones; i++) {
>>> - FDEV(devi).blkz_type[n] = zones[i].type;
>>> + if (zones[i].type != BLK_ZONE_TYPE_CONVENTIONAL)
>>> + set_bit(n, FDEV(devi).blkz_seq);
>>> sector += zones[i].len;
>>> n++;
>>> }
>>>
>>
>
>
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [f2fs-dev] [PATCH v2] f2fs: Reduce zoned block device memory usage
2019-03-07 1:19 ` Chao Yu
@ 2019-03-07 22:44 ` Damien Le Moal
-1 siblings, 0 replies; 11+ messages in thread
From: Damien Le Moal @ 2019-03-07 22:44 UTC (permalink / raw)
To: Chao Yu, Chao Yu, jaegeuk, linux-f2fs-devel
Cc: linux-fsdevel, Matias Bjorling
On 2019/03/07 10:19, Chao Yu wrote:
> On 2019/3/7 2:15, Damien Le Moal wrote:
>> On 2019/03/06 23:32, Chao Yu wrote:
>>> On 2019-3-6 14:27, Damien Le Moal wrote:
>>>> For zoned block devices, an array of zone types for each device is
>>>> allocated and initialized in order to determine if a section is stored
>>>> on a sequential zone (zone reset needed) or a conventional zone (no
>>>> zone reset needed and regular discard applies). Considering this usage,
>>>> the zone types stored in memory can be replaced with a bitmap to
>>>> indicate an equivalent information, that is, if a zone is sequential or
>>>> not. This reduces the memory usage for each zoned device by roughly 8:
>>>> on a 14TB disk with zones of 256 MB, the zone type array consumes
>>>> 13x4KB pages while the bitmap uses only 2x4KB pages.
>>>>
>>>> This patch changes the f2fs_dev_info structure blkz_type field to the
>>>> bitmap blkz_seq. Access to this bitmap is done using the helper
>>>> function f2fs_blkz_is_seq(), which is a rewrite of the function
>>>> get_blkz_type().
>>>>
>>>> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
>>>> ---
>>>> Changes from v1:
>>>> * Use kvfree() instead of kfree() to free the zone bitmap
>>>>
>>>> fs/f2fs/f2fs.h | 13 +++++++------
>>>> fs/f2fs/segment.c | 23 +++++++----------------
>>>> fs/f2fs/super.c | 13 ++++++++-----
>>>> 3 files changed, 22 insertions(+), 27 deletions(-)
>>>>
>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>>> index 12fabd6735dd..d7b2de930352 100644
>>>> --- a/fs/f2fs/f2fs.h
>>>> +++ b/fs/f2fs/f2fs.h
>>>> @@ -1067,8 +1067,8 @@ struct f2fs_dev_info {
>>>> block_t start_blk;
>>>> block_t end_blk;
>>>> #ifdef CONFIG_BLK_DEV_ZONED
>>>> - unsigned int nr_blkz; /* Total number of zones */
>>>> - u8 *blkz_type; /* Array of zones type */
>>>> + unsigned int nr_blkz; /* Total number of zones */
>>>> + unsigned long *blkz_seq; /* Bitmap indicating sequential zones */
>>>> #endif
>>>> };
>>>>
>>>> @@ -3508,16 +3508,17 @@ F2FS_FEATURE_FUNCS(lost_found, LOST_FOUND);
>>>> F2FS_FEATURE_FUNCS(sb_chksum, SB_CHKSUM);
>>>>
>>>> #ifdef CONFIG_BLK_DEV_ZONED
>>>> -static inline int get_blkz_type(struct f2fs_sb_info *sbi,
>>>> - struct block_device *bdev, block_t blkaddr)
>>>> +static inline bool f2fs_blkz_is_seq(struct f2fs_sb_info *sbi,
>>>> + struct block_device *bdev, block_t blkaddr)
>>>> {
>>>> unsigned int zno = blkaddr >> sbi->log_blocks_per_blkz;
>>>> int i;
>>>>
>>>> for (i = 0; i < sbi->s_ndevs; i++)
>>>> if (FDEV(i).bdev == bdev)
>>>> - return FDEV(i).blkz_type[zno];
>>>> - return -EINVAL;
>>>> + return test_bit(zno, FDEV(i).blkz_seq);
>>>> + WARN_ON_ONCE(1);
>>>> + return false;
>>>
>>> How about just handling this case as previous instead of treating device as
>>> conventional zone?
>>
>> Before this patch, if the device is not found, an error was returned, which was
>> propagated up by __f2fs_issue_discard_zone() as an -EIO. Do you mean to do the
>> same here too ?
>
> Yes.
Regarding this, I noticed that non of the callers of f2fs_target_device_index()
actually check if the correct device was found, that is, if the block number is
correct. I am suspecting that block number checks are already done by the time
f2fs_target_device_index() is called, which would mean that the correct device
can always be found and so no special checks are required for f2fs_blkz_is_seq()
or __f2fs_issue_discard_zone(). Can you confirm this ?
>> Now that I look at this again, another possible change that I think actually may
>> make more sense is to pass the devi (device index) variable set by
>> __f2fs_issue_discard_zone() to this function. No need for the device search loop
>> doing so and invalid block numbers leading to invalid device indexes can/should
>> be handled in __f2fs_issue_discard_zone().
>>
>> What do you think ?
>
> That will be better, please go ahead. :)
I made the change but while testing I got fsync() failures due to write commands
being issued to full sequential zones. The test case is the following simple script:
#!/bin/bash
for (( i = 1; i <= 2000; ++i )); do
dd if=/dev/zero of=/mnt/foo.$i bs=65536 count=1600 conv=fsync
done
that I run on top of a dm-linear device aggregating 10 conventional zones + 256
sequential zones of a real SMR disk.
The problem systematically happens by rerunning the above script which causes
the files to be overwritten. The problem also happens when the disk space used
reaches 75% or above.
The problem is probably not related to this patch, but I need to further
investigate. So putting this patch on hold for now.
>
> Thanks,
>
>>
>>>
>>> Thanks,
>>>
>>>> }
>>>> #endif
>>>>
>>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>>> index 9b79056d705d..65941070776c 100644
>>>> --- a/fs/f2fs/segment.c
>>>> +++ b/fs/f2fs/segment.c
>>>> @@ -1703,19 +1703,8 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
>>>> blkstart -= FDEV(devi).start_blk;
>>>> }
>>>>
>>>> - /*
>>>> - * We need to know the type of the zone: for conventional zones,
>>>> - * use regular discard if the drive supports it. For sequential
>>>> - * zones, reset the zone write pointer.
>>>> - */
>>>> - switch (get_blkz_type(sbi, bdev, blkstart)) {
>>>> -
>>>> - case BLK_ZONE_TYPE_CONVENTIONAL:
>>>> - if (!blk_queue_discard(bdev_get_queue(bdev)))
>>>> - return 0;
>>>> - return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
>>>> - case BLK_ZONE_TYPE_SEQWRITE_REQ:
>>>> - case BLK_ZONE_TYPE_SEQWRITE_PREF:
>>>> + /* For sequential zones, reset the zone write pointer */
>>>> + if (f2fs_blkz_is_seq(sbi, bdev, blkstart)) {
>>>> sector = SECTOR_FROM_BLOCK(blkstart);
>>>> nr_sects = SECTOR_FROM_BLOCK(blklen);
>>>>
>>>> @@ -1730,10 +1719,12 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
>>>> trace_f2fs_issue_reset_zone(bdev, blkstart);
>>>> return blkdev_reset_zones(bdev, sector,
>>>> nr_sects, GFP_NOFS);
>>>> - default:
>>>> - /* Unknown zone type: broken device ? */
>>>> - return -EIO;
>>>> }
>>>> +
>>>> + /* For conventional zones, use regular discard if supported */
>>>> + if (!blk_queue_discard(bdev_get_queue(bdev)))
>>>> + return 0;
>>>> + return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
>>>> }
>>>> #endif
>>>>
>>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>>> index c46a1d4318d4..91d7429be554 100644
>>>> --- a/fs/f2fs/super.c
>>>> +++ b/fs/f2fs/super.c
>>>> @@ -1017,7 +1017,7 @@ static void destroy_device_list(struct f2fs_sb_info *sbi)
>>>> for (i = 0; i < sbi->s_ndevs; i++) {
>>>> blkdev_put(FDEV(i).bdev, FMODE_EXCL);
>>>> #ifdef CONFIG_BLK_DEV_ZONED
>>>> - kvfree(FDEV(i).blkz_type);
>>>> + kvfree(FDEV(i).blkz_seq);
>>>> #endif
>>>> }
>>>> kvfree(sbi->devs);
>>>> @@ -2765,9 +2765,11 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
>>>> if (nr_sectors & (bdev_zone_sectors(bdev) - 1))
>>>> FDEV(devi).nr_blkz++;
>>>>
>>>> - FDEV(devi).blkz_type = f2fs_kmalloc(sbi, FDEV(devi).nr_blkz,
>>>> - GFP_KERNEL);
>>>> - if (!FDEV(devi).blkz_type)
>>>> + FDEV(devi).blkz_seq = f2fs_kzalloc(sbi,
>>>> + BITS_TO_LONGS(FDEV(devi).nr_blkz)
>>>> + * sizeof(unsigned long),
>>>> + GFP_KERNEL);
>>>> + if (!FDEV(devi).blkz_seq)
>>>> return -ENOMEM;
>>>>
>>>> #define F2FS_REPORT_NR_ZONES 4096
>>>> @@ -2794,7 +2796,8 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
>>>> }
>>>>
>>>> for (i = 0; i < nr_zones; i++) {
>>>> - FDEV(devi).blkz_type[n] = zones[i].type;
>>>> + if (zones[i].type != BLK_ZONE_TYPE_CONVENTIONAL)
>>>> + set_bit(n, FDEV(devi).blkz_seq);
>>>> sector += zones[i].len;
>>>> n++;
>>>> }
>>>>
>>>
>>
>>
>
>
--
Damien Le Moal
Western Digital Research
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v2] f2fs: Reduce zoned block device memory usage
@ 2019-03-07 22:44 ` Damien Le Moal
0 siblings, 0 replies; 11+ messages in thread
From: Damien Le Moal @ 2019-03-07 22:44 UTC (permalink / raw)
To: Chao Yu, Chao Yu, jaegeuk, linux-f2fs-devel
Cc: linux-fsdevel, Matias Bjorling
On 2019/03/07 10:19, Chao Yu wrote:
> On 2019/3/7 2:15, Damien Le Moal wrote:
>> On 2019/03/06 23:32, Chao Yu wrote:
>>> On 2019-3-6 14:27, Damien Le Moal wrote:
>>>> For zoned block devices, an array of zone types for each device is
>>>> allocated and initialized in order to determine if a section is stored
>>>> on a sequential zone (zone reset needed) or a conventional zone (no
>>>> zone reset needed and regular discard applies). Considering this usage,
>>>> the zone types stored in memory can be replaced with a bitmap to
>>>> indicate an equivalent information, that is, if a zone is sequential or
>>>> not. This reduces the memory usage for each zoned device by roughly 8:
>>>> on a 14TB disk with zones of 256 MB, the zone type array consumes
>>>> 13x4KB pages while the bitmap uses only 2x4KB pages.
>>>>
>>>> This patch changes the f2fs_dev_info structure blkz_type field to the
>>>> bitmap blkz_seq. Access to this bitmap is done using the helper
>>>> function f2fs_blkz_is_seq(), which is a rewrite of the function
>>>> get_blkz_type().
>>>>
>>>> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
>>>> ---
>>>> Changes from v1:
>>>> * Use kvfree() instead of kfree() to free the zone bitmap
>>>>
>>>> fs/f2fs/f2fs.h | 13 +++++++------
>>>> fs/f2fs/segment.c | 23 +++++++----------------
>>>> fs/f2fs/super.c | 13 ++++++++-----
>>>> 3 files changed, 22 insertions(+), 27 deletions(-)
>>>>
>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>>> index 12fabd6735dd..d7b2de930352 100644
>>>> --- a/fs/f2fs/f2fs.h
>>>> +++ b/fs/f2fs/f2fs.h
>>>> @@ -1067,8 +1067,8 @@ struct f2fs_dev_info {
>>>> block_t start_blk;
>>>> block_t end_blk;
>>>> #ifdef CONFIG_BLK_DEV_ZONED
>>>> - unsigned int nr_blkz; /* Total number of zones */
>>>> - u8 *blkz_type; /* Array of zones type */
>>>> + unsigned int nr_blkz; /* Total number of zones */
>>>> + unsigned long *blkz_seq; /* Bitmap indicating sequential zones */
>>>> #endif
>>>> };
>>>>
>>>> @@ -3508,16 +3508,17 @@ F2FS_FEATURE_FUNCS(lost_found, LOST_FOUND);
>>>> F2FS_FEATURE_FUNCS(sb_chksum, SB_CHKSUM);
>>>>
>>>> #ifdef CONFIG_BLK_DEV_ZONED
>>>> -static inline int get_blkz_type(struct f2fs_sb_info *sbi,
>>>> - struct block_device *bdev, block_t blkaddr)
>>>> +static inline bool f2fs_blkz_is_seq(struct f2fs_sb_info *sbi,
>>>> + struct block_device *bdev, block_t blkaddr)
>>>> {
>>>> unsigned int zno = blkaddr >> sbi->log_blocks_per_blkz;
>>>> int i;
>>>>
>>>> for (i = 0; i < sbi->s_ndevs; i++)
>>>> if (FDEV(i).bdev == bdev)
>>>> - return FDEV(i).blkz_type[zno];
>>>> - return -EINVAL;
>>>> + return test_bit(zno, FDEV(i).blkz_seq);
>>>> + WARN_ON_ONCE(1);
>>>> + return false;
>>>
>>> How about just handling this case as previous instead of treating device as
>>> conventional zone?
>>
>> Before this patch, if the device is not found, an error was returned, which was
>> propagated up by __f2fs_issue_discard_zone() as an -EIO. Do you mean to do the
>> same here too ?
>
> Yes.
Regarding this, I noticed that non of the callers of f2fs_target_device_index()
actually check if the correct device was found, that is, if the block number is
correct. I am suspecting that block number checks are already done by the time
f2fs_target_device_index() is called, which would mean that the correct device
can always be found and so no special checks are required for f2fs_blkz_is_seq()
or __f2fs_issue_discard_zone(). Can you confirm this ?
>> Now that I look at this again, another possible change that I think actually may
>> make more sense is to pass the devi (device index) variable set by
>> __f2fs_issue_discard_zone() to this function. No need for the device search loop
>> doing so and invalid block numbers leading to invalid device indexes can/should
>> be handled in __f2fs_issue_discard_zone().
>>
>> What do you think ?
>
> That will be better, please go ahead. :)
I made the change but while testing I got fsync() failures due to write commands
being issued to full sequential zones. The test case is the following simple script:
#!/bin/bash
for (( i = 1; i <= 2000; ++i )); do
dd if=/dev/zero of=/mnt/foo.$i bs=65536 count=1600 conv=fsync
done
that I run on top of a dm-linear device aggregating 10 conventional zones + 256
sequential zones of a real SMR disk.
The problem systematically happens by rerunning the above script which causes
the files to be overwritten. The problem also happens when the disk space used
reaches 75% or above.
The problem is probably not related to this patch, but I need to further
investigate. So putting this patch on hold for now.
>
> Thanks,
>
>>
>>>
>>> Thanks,
>>>
>>>> }
>>>> #endif
>>>>
>>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>>> index 9b79056d705d..65941070776c 100644
>>>> --- a/fs/f2fs/segment.c
>>>> +++ b/fs/f2fs/segment.c
>>>> @@ -1703,19 +1703,8 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
>>>> blkstart -= FDEV(devi).start_blk;
>>>> }
>>>>
>>>> - /*
>>>> - * We need to know the type of the zone: for conventional zones,
>>>> - * use regular discard if the drive supports it. For sequential
>>>> - * zones, reset the zone write pointer.
>>>> - */
>>>> - switch (get_blkz_type(sbi, bdev, blkstart)) {
>>>> -
>>>> - case BLK_ZONE_TYPE_CONVENTIONAL:
>>>> - if (!blk_queue_discard(bdev_get_queue(bdev)))
>>>> - return 0;
>>>> - return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
>>>> - case BLK_ZONE_TYPE_SEQWRITE_REQ:
>>>> - case BLK_ZONE_TYPE_SEQWRITE_PREF:
>>>> + /* For sequential zones, reset the zone write pointer */
>>>> + if (f2fs_blkz_is_seq(sbi, bdev, blkstart)) {
>>>> sector = SECTOR_FROM_BLOCK(blkstart);
>>>> nr_sects = SECTOR_FROM_BLOCK(blklen);
>>>>
>>>> @@ -1730,10 +1719,12 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
>>>> trace_f2fs_issue_reset_zone(bdev, blkstart);
>>>> return blkdev_reset_zones(bdev, sector,
>>>> nr_sects, GFP_NOFS);
>>>> - default:
>>>> - /* Unknown zone type: broken device ? */
>>>> - return -EIO;
>>>> }
>>>> +
>>>> + /* For conventional zones, use regular discard if supported */
>>>> + if (!blk_queue_discard(bdev_get_queue(bdev)))
>>>> + return 0;
>>>> + return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
>>>> }
>>>> #endif
>>>>
>>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>>> index c46a1d4318d4..91d7429be554 100644
>>>> --- a/fs/f2fs/super.c
>>>> +++ b/fs/f2fs/super.c
>>>> @@ -1017,7 +1017,7 @@ static void destroy_device_list(struct f2fs_sb_info *sbi)
>>>> for (i = 0; i < sbi->s_ndevs; i++) {
>>>> blkdev_put(FDEV(i).bdev, FMODE_EXCL);
>>>> #ifdef CONFIG_BLK_DEV_ZONED
>>>> - kvfree(FDEV(i).blkz_type);
>>>> + kvfree(FDEV(i).blkz_seq);
>>>> #endif
>>>> }
>>>> kvfree(sbi->devs);
>>>> @@ -2765,9 +2765,11 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
>>>> if (nr_sectors & (bdev_zone_sectors(bdev) - 1))
>>>> FDEV(devi).nr_blkz++;
>>>>
>>>> - FDEV(devi).blkz_type = f2fs_kmalloc(sbi, FDEV(devi).nr_blkz,
>>>> - GFP_KERNEL);
>>>> - if (!FDEV(devi).blkz_type)
>>>> + FDEV(devi).blkz_seq = f2fs_kzalloc(sbi,
>>>> + BITS_TO_LONGS(FDEV(devi).nr_blkz)
>>>> + * sizeof(unsigned long),
>>>> + GFP_KERNEL);
>>>> + if (!FDEV(devi).blkz_seq)
>>>> return -ENOMEM;
>>>>
>>>> #define F2FS_REPORT_NR_ZONES 4096
>>>> @@ -2794,7 +2796,8 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
>>>> }
>>>>
>>>> for (i = 0; i < nr_zones; i++) {
>>>> - FDEV(devi).blkz_type[n] = zones[i].type;
>>>> + if (zones[i].type != BLK_ZONE_TYPE_CONVENTIONAL)
>>>> + set_bit(n, FDEV(devi).blkz_seq);
>>>> sector += zones[i].len;
>>>> n++;
>>>> }
>>>>
>>>
>>
>>
>
>
--
Damien Le Moal
Western Digital Research
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [f2fs-dev] [PATCH v2] f2fs: Reduce zoned block device memory usage
2019-03-07 22:44 ` Damien Le Moal
@ 2019-03-08 3:49 ` Chao Yu
-1 siblings, 0 replies; 11+ messages in thread
From: Chao Yu @ 2019-03-08 3:49 UTC (permalink / raw)
To: Damien Le Moal, Chao Yu, jaegeuk, linux-f2fs-devel
Cc: linux-fsdevel, Matias Bjorling
On 2019/3/8 6:44, Damien Le Moal wrote:
> On 2019/03/07 10:19, Chao Yu wrote:
>> On 2019/3/7 2:15, Damien Le Moal wrote:
>>> On 2019/03/06 23:32, Chao Yu wrote:
>>>> On 2019-3-6 14:27, Damien Le Moal wrote:
>>>>> For zoned block devices, an array of zone types for each device is
>>>>> allocated and initialized in order to determine if a section is stored
>>>>> on a sequential zone (zone reset needed) or a conventional zone (no
>>>>> zone reset needed and regular discard applies). Considering this usage,
>>>>> the zone types stored in memory can be replaced with a bitmap to
>>>>> indicate an equivalent information, that is, if a zone is sequential or
>>>>> not. This reduces the memory usage for each zoned device by roughly 8:
>>>>> on a 14TB disk with zones of 256 MB, the zone type array consumes
>>>>> 13x4KB pages while the bitmap uses only 2x4KB pages.
>>>>>
>>>>> This patch changes the f2fs_dev_info structure blkz_type field to the
>>>>> bitmap blkz_seq. Access to this bitmap is done using the helper
>>>>> function f2fs_blkz_is_seq(), which is a rewrite of the function
>>>>> get_blkz_type().
>>>>>
>>>>> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
>>>>> ---
>>>>> Changes from v1:
>>>>> * Use kvfree() instead of kfree() to free the zone bitmap
>>>>>
>>>>> fs/f2fs/f2fs.h | 13 +++++++------
>>>>> fs/f2fs/segment.c | 23 +++++++----------------
>>>>> fs/f2fs/super.c | 13 ++++++++-----
>>>>> 3 files changed, 22 insertions(+), 27 deletions(-)
>>>>>
>>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>>>> index 12fabd6735dd..d7b2de930352 100644
>>>>> --- a/fs/f2fs/f2fs.h
>>>>> +++ b/fs/f2fs/f2fs.h
>>>>> @@ -1067,8 +1067,8 @@ struct f2fs_dev_info {
>>>>> block_t start_blk;
>>>>> block_t end_blk;
>>>>> #ifdef CONFIG_BLK_DEV_ZONED
>>>>> - unsigned int nr_blkz; /* Total number of zones */
>>>>> - u8 *blkz_type; /* Array of zones type */
>>>>> + unsigned int nr_blkz; /* Total number of zones */
>>>>> + unsigned long *blkz_seq; /* Bitmap indicating sequential zones */
>>>>> #endif
>>>>> };
>>>>>
>>>>> @@ -3508,16 +3508,17 @@ F2FS_FEATURE_FUNCS(lost_found, LOST_FOUND);
>>>>> F2FS_FEATURE_FUNCS(sb_chksum, SB_CHKSUM);
>>>>>
>>>>> #ifdef CONFIG_BLK_DEV_ZONED
>>>>> -static inline int get_blkz_type(struct f2fs_sb_info *sbi,
>>>>> - struct block_device *bdev, block_t blkaddr)
>>>>> +static inline bool f2fs_blkz_is_seq(struct f2fs_sb_info *sbi,
>>>>> + struct block_device *bdev, block_t blkaddr)
>>>>> {
>>>>> unsigned int zno = blkaddr >> sbi->log_blocks_per_blkz;
>>>>> int i;
>>>>>
>>>>> for (i = 0; i < sbi->s_ndevs; i++)
>>>>> if (FDEV(i).bdev == bdev)
>>>>> - return FDEV(i).blkz_type[zno];
>>>>> - return -EINVAL;
>>>>> + return test_bit(zno, FDEV(i).blkz_seq);
>>>>> + WARN_ON_ONCE(1);
>>>>> + return false;
>>>>
>>>> How about just handling this case as previous instead of treating device as
>>>> conventional zone?
>>>
>>> Before this patch, if the device is not found, an error was returned, which was
>>> propagated up by __f2fs_issue_discard_zone() as an -EIO. Do you mean to do the
>>> same here too ?
>>
>> Yes.
>
> Regarding this, I noticed that non of the callers of f2fs_target_device_index()
> actually check if the correct device was found, that is, if the block number is
> correct. I am suspecting that block number checks are already done by the time
Usually, f2fs_target_device_index()'s caller should handle the error that
we didn't found correct device index, but actually, I checked its callers,
it would be hard to handle such error, since some paths should guarantee
success at that point.
I suspect we will fail to find device index in f2fs_target_device_index()
only when encountering bit-flip or memory overflow? that would be very
rare, so I prefer to add a f2fs_bug_on in f2fs_target_device_index() to
detect any further bug, how do you think?
> f2fs_target_device_index() is called, which would mean that the correct device
> can always be found and so no special checks are required for f2fs_blkz_is_seq()
> or __f2fs_issue_discard_zone(). Can you confirm this ?
Yes, I'm okay with it.
>
>>> Now that I look at this again, another possible change that I think actually may
>>> make more sense is to pass the devi (device index) variable set by
>>> __f2fs_issue_discard_zone() to this function. No need for the device search loop
>>> doing so and invalid block numbers leading to invalid device indexes can/should
>>> be handled in __f2fs_issue_discard_zone().
>>>
>>> What do you think ?
>>
>> That will be better, please go ahead. :)
>
> I made the change but while testing I got fsync() failures due to write commands
> being issued to full sequential zones. The test case is the following simple script:
>
> #!/bin/bash
>
> for (( i = 1; i <= 2000; ++i )); do
> dd if=/dev/zero of=/mnt/foo.$i bs=65536 count=1600 conv=fsync
> done
>
> that I run on top of a dm-linear device aggregating 10 conventional zones + 256
> sequential zones of a real SMR disk.
>
> The problem systematically happens by rerunning the above script which causes
> the files to be overwritten. The problem also happens when the disk space used
> reaches 75% or above.
>
> The problem is probably not related to this patch, but I need to further
> investigate. So putting this patch on hold for now.
Oh, that is strange, maybe we can add some tracepoints (e.g. fsync,
writepages, writepage...) to find clue of such failure.
Thanks,
>
>>
>> Thanks,
>>
>>>
>>>>
>>>> Thanks,
>>>>
>>>>> }
>>>>> #endif
>>>>>
>>>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>>>> index 9b79056d705d..65941070776c 100644
>>>>> --- a/fs/f2fs/segment.c
>>>>> +++ b/fs/f2fs/segment.c
>>>>> @@ -1703,19 +1703,8 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
>>>>> blkstart -= FDEV(devi).start_blk;
>>>>> }
>>>>>
>>>>> - /*
>>>>> - * We need to know the type of the zone: for conventional zones,
>>>>> - * use regular discard if the drive supports it. For sequential
>>>>> - * zones, reset the zone write pointer.
>>>>> - */
>>>>> - switch (get_blkz_type(sbi, bdev, blkstart)) {
>>>>> -
>>>>> - case BLK_ZONE_TYPE_CONVENTIONAL:
>>>>> - if (!blk_queue_discard(bdev_get_queue(bdev)))
>>>>> - return 0;
>>>>> - return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
>>>>> - case BLK_ZONE_TYPE_SEQWRITE_REQ:
>>>>> - case BLK_ZONE_TYPE_SEQWRITE_PREF:
>>>>> + /* For sequential zones, reset the zone write pointer */
>>>>> + if (f2fs_blkz_is_seq(sbi, bdev, blkstart)) {
>>>>> sector = SECTOR_FROM_BLOCK(blkstart);
>>>>> nr_sects = SECTOR_FROM_BLOCK(blklen);
>>>>>
>>>>> @@ -1730,10 +1719,12 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
>>>>> trace_f2fs_issue_reset_zone(bdev, blkstart);
>>>>> return blkdev_reset_zones(bdev, sector,
>>>>> nr_sects, GFP_NOFS);
>>>>> - default:
>>>>> - /* Unknown zone type: broken device ? */
>>>>> - return -EIO;
>>>>> }
>>>>> +
>>>>> + /* For conventional zones, use regular discard if supported */
>>>>> + if (!blk_queue_discard(bdev_get_queue(bdev)))
>>>>> + return 0;
>>>>> + return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
>>>>> }
>>>>> #endif
>>>>>
>>>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>>>> index c46a1d4318d4..91d7429be554 100644
>>>>> --- a/fs/f2fs/super.c
>>>>> +++ b/fs/f2fs/super.c
>>>>> @@ -1017,7 +1017,7 @@ static void destroy_device_list(struct f2fs_sb_info *sbi)
>>>>> for (i = 0; i < sbi->s_ndevs; i++) {
>>>>> blkdev_put(FDEV(i).bdev, FMODE_EXCL);
>>>>> #ifdef CONFIG_BLK_DEV_ZONED
>>>>> - kvfree(FDEV(i).blkz_type);
>>>>> + kvfree(FDEV(i).blkz_seq);
>>>>> #endif
>>>>> }
>>>>> kvfree(sbi->devs);
>>>>> @@ -2765,9 +2765,11 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
>>>>> if (nr_sectors & (bdev_zone_sectors(bdev) - 1))
>>>>> FDEV(devi).nr_blkz++;
>>>>>
>>>>> - FDEV(devi).blkz_type = f2fs_kmalloc(sbi, FDEV(devi).nr_blkz,
>>>>> - GFP_KERNEL);
>>>>> - if (!FDEV(devi).blkz_type)
>>>>> + FDEV(devi).blkz_seq = f2fs_kzalloc(sbi,
>>>>> + BITS_TO_LONGS(FDEV(devi).nr_blkz)
>>>>> + * sizeof(unsigned long),
>>>>> + GFP_KERNEL);
>>>>> + if (!FDEV(devi).blkz_seq)
>>>>> return -ENOMEM;
>>>>>
>>>>> #define F2FS_REPORT_NR_ZONES 4096
>>>>> @@ -2794,7 +2796,8 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
>>>>> }
>>>>>
>>>>> for (i = 0; i < nr_zones; i++) {
>>>>> - FDEV(devi).blkz_type[n] = zones[i].type;
>>>>> + if (zones[i].type != BLK_ZONE_TYPE_CONVENTIONAL)
>>>>> + set_bit(n, FDEV(devi).blkz_seq);
>>>>> sector += zones[i].len;
>>>>> n++;
>>>>> }
>>>>>
>>>>
>>>
>>>
>>
>>
>
>
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v2] f2fs: Reduce zoned block device memory usage
@ 2019-03-08 3:49 ` Chao Yu
0 siblings, 0 replies; 11+ messages in thread
From: Chao Yu @ 2019-03-08 3:49 UTC (permalink / raw)
To: Damien Le Moal, Chao Yu, jaegeuk, linux-f2fs-devel
Cc: linux-fsdevel, Matias Bjorling
On 2019/3/8 6:44, Damien Le Moal wrote:
> On 2019/03/07 10:19, Chao Yu wrote:
>> On 2019/3/7 2:15, Damien Le Moal wrote:
>>> On 2019/03/06 23:32, Chao Yu wrote:
>>>> On 2019-3-6 14:27, Damien Le Moal wrote:
>>>>> For zoned block devices, an array of zone types for each device is
>>>>> allocated and initialized in order to determine if a section is stored
>>>>> on a sequential zone (zone reset needed) or a conventional zone (no
>>>>> zone reset needed and regular discard applies). Considering this usage,
>>>>> the zone types stored in memory can be replaced with a bitmap to
>>>>> indicate an equivalent information, that is, if a zone is sequential or
>>>>> not. This reduces the memory usage for each zoned device by roughly 8:
>>>>> on a 14TB disk with zones of 256 MB, the zone type array consumes
>>>>> 13x4KB pages while the bitmap uses only 2x4KB pages.
>>>>>
>>>>> This patch changes the f2fs_dev_info structure blkz_type field to the
>>>>> bitmap blkz_seq. Access to this bitmap is done using the helper
>>>>> function f2fs_blkz_is_seq(), which is a rewrite of the function
>>>>> get_blkz_type().
>>>>>
>>>>> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
>>>>> ---
>>>>> Changes from v1:
>>>>> * Use kvfree() instead of kfree() to free the zone bitmap
>>>>>
>>>>> fs/f2fs/f2fs.h | 13 +++++++------
>>>>> fs/f2fs/segment.c | 23 +++++++----------------
>>>>> fs/f2fs/super.c | 13 ++++++++-----
>>>>> 3 files changed, 22 insertions(+), 27 deletions(-)
>>>>>
>>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>>>> index 12fabd6735dd..d7b2de930352 100644
>>>>> --- a/fs/f2fs/f2fs.h
>>>>> +++ b/fs/f2fs/f2fs.h
>>>>> @@ -1067,8 +1067,8 @@ struct f2fs_dev_info {
>>>>> block_t start_blk;
>>>>> block_t end_blk;
>>>>> #ifdef CONFIG_BLK_DEV_ZONED
>>>>> - unsigned int nr_blkz; /* Total number of zones */
>>>>> - u8 *blkz_type; /* Array of zones type */
>>>>> + unsigned int nr_blkz; /* Total number of zones */
>>>>> + unsigned long *blkz_seq; /* Bitmap indicating sequential zones */
>>>>> #endif
>>>>> };
>>>>>
>>>>> @@ -3508,16 +3508,17 @@ F2FS_FEATURE_FUNCS(lost_found, LOST_FOUND);
>>>>> F2FS_FEATURE_FUNCS(sb_chksum, SB_CHKSUM);
>>>>>
>>>>> #ifdef CONFIG_BLK_DEV_ZONED
>>>>> -static inline int get_blkz_type(struct f2fs_sb_info *sbi,
>>>>> - struct block_device *bdev, block_t blkaddr)
>>>>> +static inline bool f2fs_blkz_is_seq(struct f2fs_sb_info *sbi,
>>>>> + struct block_device *bdev, block_t blkaddr)
>>>>> {
>>>>> unsigned int zno = blkaddr >> sbi->log_blocks_per_blkz;
>>>>> int i;
>>>>>
>>>>> for (i = 0; i < sbi->s_ndevs; i++)
>>>>> if (FDEV(i).bdev == bdev)
>>>>> - return FDEV(i).blkz_type[zno];
>>>>> - return -EINVAL;
>>>>> + return test_bit(zno, FDEV(i).blkz_seq);
>>>>> + WARN_ON_ONCE(1);
>>>>> + return false;
>>>>
>>>> How about just handling this case as previous instead of treating device as
>>>> conventional zone?
>>>
>>> Before this patch, if the device is not found, an error was returned, which was
>>> propagated up by __f2fs_issue_discard_zone() as an -EIO. Do you mean to do the
>>> same here too ?
>>
>> Yes.
>
> Regarding this, I noticed that non of the callers of f2fs_target_device_index()
> actually check if the correct device was found, that is, if the block number is
> correct. I am suspecting that block number checks are already done by the time
Usually, f2fs_target_device_index()'s caller should handle the error that
we didn't found correct device index, but actually, I checked its callers,
it would be hard to handle such error, since some paths should guarantee
success at that point.
I suspect we will fail to find device index in f2fs_target_device_index()
only when encountering bit-flip or memory overflow? that would be very
rare, so I prefer to add a f2fs_bug_on in f2fs_target_device_index() to
detect any further bug, how do you think?
> f2fs_target_device_index() is called, which would mean that the correct device
> can always be found and so no special checks are required for f2fs_blkz_is_seq()
> or __f2fs_issue_discard_zone(). Can you confirm this ?
Yes, I'm okay with it.
>
>>> Now that I look at this again, another possible change that I think actually may
>>> make more sense is to pass the devi (device index) variable set by
>>> __f2fs_issue_discard_zone() to this function. No need for the device search loop
>>> doing so and invalid block numbers leading to invalid device indexes can/should
>>> be handled in __f2fs_issue_discard_zone().
>>>
>>> What do you think ?
>>
>> That will be better, please go ahead. :)
>
> I made the change but while testing I got fsync() failures due to write commands
> being issued to full sequential zones. The test case is the following simple script:
>
> #!/bin/bash
>
> for (( i = 1; i <= 2000; ++i )); do
> dd if=/dev/zero of=/mnt/foo.$i bs=65536 count=1600 conv=fsync
> done
>
> that I run on top of a dm-linear device aggregating 10 conventional zones + 256
> sequential zones of a real SMR disk.
>
> The problem systematically happens by rerunning the above script which causes
> the files to be overwritten. The problem also happens when the disk space used
> reaches 75% or above.
>
> The problem is probably not related to this patch, but I need to further
> investigate. So putting this patch on hold for now.
Oh, that is strange, maybe we can add some tracepoints (e.g. fsync,
writepages, writepage...) to find clue of such failure.
Thanks,
>
>>
>> Thanks,
>>
>>>
>>>>
>>>> Thanks,
>>>>
>>>>> }
>>>>> #endif
>>>>>
>>>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>>>> index 9b79056d705d..65941070776c 100644
>>>>> --- a/fs/f2fs/segment.c
>>>>> +++ b/fs/f2fs/segment.c
>>>>> @@ -1703,19 +1703,8 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
>>>>> blkstart -= FDEV(devi).start_blk;
>>>>> }
>>>>>
>>>>> - /*
>>>>> - * We need to know the type of the zone: for conventional zones,
>>>>> - * use regular discard if the drive supports it. For sequential
>>>>> - * zones, reset the zone write pointer.
>>>>> - */
>>>>> - switch (get_blkz_type(sbi, bdev, blkstart)) {
>>>>> -
>>>>> - case BLK_ZONE_TYPE_CONVENTIONAL:
>>>>> - if (!blk_queue_discard(bdev_get_queue(bdev)))
>>>>> - return 0;
>>>>> - return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
>>>>> - case BLK_ZONE_TYPE_SEQWRITE_REQ:
>>>>> - case BLK_ZONE_TYPE_SEQWRITE_PREF:
>>>>> + /* For sequential zones, reset the zone write pointer */
>>>>> + if (f2fs_blkz_is_seq(sbi, bdev, blkstart)) {
>>>>> sector = SECTOR_FROM_BLOCK(blkstart);
>>>>> nr_sects = SECTOR_FROM_BLOCK(blklen);
>>>>>
>>>>> @@ -1730,10 +1719,12 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
>>>>> trace_f2fs_issue_reset_zone(bdev, blkstart);
>>>>> return blkdev_reset_zones(bdev, sector,
>>>>> nr_sects, GFP_NOFS);
>>>>> - default:
>>>>> - /* Unknown zone type: broken device ? */
>>>>> - return -EIO;
>>>>> }
>>>>> +
>>>>> + /* For conventional zones, use regular discard if supported */
>>>>> + if (!blk_queue_discard(bdev_get_queue(bdev)))
>>>>> + return 0;
>>>>> + return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
>>>>> }
>>>>> #endif
>>>>>
>>>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>>>> index c46a1d4318d4..91d7429be554 100644
>>>>> --- a/fs/f2fs/super.c
>>>>> +++ b/fs/f2fs/super.c
>>>>> @@ -1017,7 +1017,7 @@ static void destroy_device_list(struct f2fs_sb_info *sbi)
>>>>> for (i = 0; i < sbi->s_ndevs; i++) {
>>>>> blkdev_put(FDEV(i).bdev, FMODE_EXCL);
>>>>> #ifdef CONFIG_BLK_DEV_ZONED
>>>>> - kvfree(FDEV(i).blkz_type);
>>>>> + kvfree(FDEV(i).blkz_seq);
>>>>> #endif
>>>>> }
>>>>> kvfree(sbi->devs);
>>>>> @@ -2765,9 +2765,11 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
>>>>> if (nr_sectors & (bdev_zone_sectors(bdev) - 1))
>>>>> FDEV(devi).nr_blkz++;
>>>>>
>>>>> - FDEV(devi).blkz_type = f2fs_kmalloc(sbi, FDEV(devi).nr_blkz,
>>>>> - GFP_KERNEL);
>>>>> - if (!FDEV(devi).blkz_type)
>>>>> + FDEV(devi).blkz_seq = f2fs_kzalloc(sbi,
>>>>> + BITS_TO_LONGS(FDEV(devi).nr_blkz)
>>>>> + * sizeof(unsigned long),
>>>>> + GFP_KERNEL);
>>>>> + if (!FDEV(devi).blkz_seq)
>>>>> return -ENOMEM;
>>>>>
>>>>> #define F2FS_REPORT_NR_ZONES 4096
>>>>> @@ -2794,7 +2796,8 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
>>>>> }
>>>>>
>>>>> for (i = 0; i < nr_zones; i++) {
>>>>> - FDEV(devi).blkz_type[n] = zones[i].type;
>>>>> + if (zones[i].type != BLK_ZONE_TYPE_CONVENTIONAL)
>>>>> + set_bit(n, FDEV(devi).blkz_seq);
>>>>> sector += zones[i].len;
>>>>> n++;
>>>>> }
>>>>>
>>>>
>>>
>>>
>>
>>
>
>
^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2019-03-08 3:49 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-03-06 6:27 [PATCH v2] f2fs: Reduce zoned block device memory usage Damien Le Moal
2019-03-06 14:32 ` [f2fs-dev] " Chao Yu
2019-03-06 14:32 ` Chao Yu
2019-03-06 18:15 ` [f2fs-dev] " Damien Le Moal
2019-03-06 18:15 ` Damien Le Moal
2019-03-07 1:19 ` [f2fs-dev] " Chao Yu
2019-03-07 1:19 ` Chao Yu
2019-03-07 22:44 ` [f2fs-dev] " Damien Le Moal
2019-03-07 22:44 ` Damien Le Moal
2019-03-08 3:49 ` [f2fs-dev] " Chao Yu
2019-03-08 3:49 ` Chao Yu
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