diff mbox

[5/5,v2] f2fs: introduce a batched trim

Message ID 20150202232803.GB34575@jaegeuk-mac02.mot.com (mailing list archive)
State New, archived
Headers show

Commit Message

Jaegeuk Kim Feb. 2, 2015, 11:29 p.m. UTC
Change long from v1:
 o add description
 o change the # of batched segments suggested by Chao
 o make consistent for # of batched segments

This patch introduces a batched trimming feature, which submits split discard
commands.

This patch introduces a batched trimming feature, which submits split discard
commands.

This is to avoid long latency due to huge trim commands.
If fstrim was triggered ranging from 0 to the end of device, we should lock
all the checkpoint-related mutexes, resulting in very long latency.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/f2fs.h    |  2 ++
 fs/f2fs/segment.c | 16 +++++++++++-----
 2 files changed, 13 insertions(+), 5 deletions(-)

Comments

??? Feb. 3, 2015, 2:48 a.m. UTC | #1
Hi Jaegeuk,

IMHO, it looks better user could decide the size of trim considering latency of trim.
Otherwise, additional checkpoints user doesn't want will occur.

Regards,
Changman

On Mon, Feb 02, 2015 at 03:29:25PM -0800, Jaegeuk Kim wrote:
> Change long from v1:
>  o add description
>  o change the # of batched segments suggested by Chao
>  o make consistent for # of batched segments
> 
> This patch introduces a batched trimming feature, which submits split discard
> commands.
> 
> This patch introduces a batched trimming feature, which submits split discard
> commands.
> 
> This is to avoid long latency due to huge trim commands.
> If fstrim was triggered ranging from 0 to the end of device, we should lock
> all the checkpoint-related mutexes, resulting in very long latency.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>  fs/f2fs/f2fs.h    |  2 ++
>  fs/f2fs/segment.c | 16 +++++++++++-----
>  2 files changed, 13 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 8231a59..ec5e66f 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -105,6 +105,8 @@ enum {
>  	CP_DISCARD,
>  };
>  
> +#define BATCHED_TRIM_SEGMENTS(sbi)	(((sbi)->segs_per_sec) << 5)
> +
>  struct cp_control {
>  	int reason;
>  	__u64 trim_start;
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 5ea57ec..b85bb97 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1066,14 +1066,20 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
>  	end_segno = (end >= MAX_BLKADDR(sbi)) ? MAIN_SEGS(sbi) - 1 :
>  						GET_SEGNO(sbi, end);
>  	cpc.reason = CP_DISCARD;
> -	cpc.trim_start = start_segno;
> -	cpc.trim_end = end_segno;
>  	cpc.trim_minlen = range->minlen >> sbi->log_blocksize;
>  
>  	/* do checkpoint to issue discard commands safely */
> -	mutex_lock(&sbi->gc_mutex);
> -	write_checkpoint(sbi, &cpc);
> -	mutex_unlock(&sbi->gc_mutex);
> +	for (; start_segno <= end_segno;
> +				start_segno += BATCHED_TRIM_SEGMENTS(sbi)) {
> +		cpc.trim_start = start_segno;
> +		cpc.trim_end = min_t(unsigned int,
> +				start_segno + BATCHED_TRIM_SEGMENTS (sbi) - 1,
> +				end_segno);
> +
> +		mutex_lock(&sbi->gc_mutex);
> +		write_checkpoint(sbi, &cpc);
> +		mutex_unlock(&sbi->gc_mutex);
> +	}
>  out:
>  	range->len = cpc.trimmed << sbi->log_blocksize;
>  	return 0;
> -- 
> 2.1.1
> 
> 
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diff mbox

Patch

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 8231a59..ec5e66f 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -105,6 +105,8 @@  enum {
 	CP_DISCARD,
 };
 
+#define BATCHED_TRIM_SEGMENTS(sbi)	(((sbi)->segs_per_sec) << 5)
+
 struct cp_control {
 	int reason;
 	__u64 trim_start;
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 5ea57ec..b85bb97 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1066,14 +1066,20 @@  int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
 	end_segno = (end >= MAX_BLKADDR(sbi)) ? MAIN_SEGS(sbi) - 1 :
 						GET_SEGNO(sbi, end);
 	cpc.reason = CP_DISCARD;
-	cpc.trim_start = start_segno;
-	cpc.trim_end = end_segno;
 	cpc.trim_minlen = range->minlen >> sbi->log_blocksize;
 
 	/* do checkpoint to issue discard commands safely */
-	mutex_lock(&sbi->gc_mutex);
-	write_checkpoint(sbi, &cpc);
-	mutex_unlock(&sbi->gc_mutex);
+	for (; start_segno <= end_segno;
+				start_segno += BATCHED_TRIM_SEGMENTS(sbi)) {
+		cpc.trim_start = start_segno;
+		cpc.trim_end = min_t(unsigned int,
+				start_segno + BATCHED_TRIM_SEGMENTS (sbi) - 1,
+				end_segno);
+
+		mutex_lock(&sbi->gc_mutex);
+		write_checkpoint(sbi, &cpc);
+		mutex_unlock(&sbi->gc_mutex);
+	}
 out:
 	range->len = cpc.trimmed << sbi->log_blocksize;
 	return 0;