Re: [f2fs-dev] [PATCH 1/2] f2fs: run discard jobs when put_super

From: Chao Yu
Date: Wed Jan 23 2019 - 07:15:19 EST


On 2019/1/23 8:02, Jaegeuk Kim wrote:
> When we umount f2fs, we need to avoid long delay due to discard commands, which
> is actually taking tens of seconds, if storage is very slow on UNMAP. So, this
> patch introduces timeout-based work on it.
>
> By default, let me give 5 seconds for discard.
>
> Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
> ---
> Documentation/ABI/testing/sysfs-fs-f2fs | 7 +++++++
> fs/f2fs/f2fs.h | 5 ++++-
> fs/f2fs/segment.c | 11 ++++++++++-
> fs/f2fs/super.c | 17 ++++++++---------
> fs/f2fs/sysfs.c | 3 +++
> 5 files changed, 32 insertions(+), 11 deletions(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
> index a7ce33199457..91822ce25831 100644
> --- a/Documentation/ABI/testing/sysfs-fs-f2fs
> +++ b/Documentation/ABI/testing/sysfs-fs-f2fs
> @@ -86,6 +86,13 @@ Description:
> The unit size is one block, now only support configuring in range
> of [1, 512].
>
> +What: /sys/fs/f2fs/<disk>/umount_discard_timeout
> +Date: January 2019
> +Contact: "Jaegeuk Kim" <jaegeuk@xxxxxxxxxx>
> +Description:
> + Set timeout to issue discard commands during umount.
> + Default: 5 secs
> +
> What: /sys/fs/f2fs/<disk>/max_victim_search
> Date: January 2014
> Contact: "Jaegeuk Kim" <jaegeuk.kim@xxxxxxxxxxx>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 0f564883e078..6b6ec5600089 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -191,6 +191,7 @@ enum {
> #define DEF_CP_INTERVAL 60 /* 60 secs */
> #define DEF_IDLE_INTERVAL 5 /* 5 secs */
> #define DEF_DISABLE_INTERVAL 5 /* 5 secs */
> +#define DEF_UMOUNT_DISCARD_TIMEOUT 5 /* 5 secs */
>
> struct cp_control {
> int reason;
> @@ -310,6 +311,7 @@ struct discard_policy {
> bool sync; /* submit discard with REQ_SYNC flag */
> bool ordered; /* issue discard by lba order */
> unsigned int granularity; /* discard granularity */
> + int timeout; /* discard timeout for put_super */
> };
>
> struct discard_cmd_control {
> @@ -1110,6 +1112,7 @@ enum {
> DISCARD_TIME,
> GC_TIME,
> DISABLE_TIME,
> + UMOUNT_DISCARD_TIMEOUT,
> MAX_TIME,

After the patch, MAX_TIME will be 6, so if we set @timeout to 6 via sysfs,
the configuration will not be enabled due to below condition, right?

+ if (dpolicy->timeout != MAX_TIME)
+ f2fs_update_time(sbi, dpolicy->timeout);

> };
>
> @@ -3006,7 +3009,7 @@ void f2fs_invalidate_blocks(struct f2fs_sb_info *sbi, block_t addr);
> bool f2fs_is_checkpointed_data(struct f2fs_sb_info *sbi, block_t blkaddr);
> void f2fs_drop_discard_cmd(struct f2fs_sb_info *sbi);
> void f2fs_stop_discard_thread(struct f2fs_sb_info *sbi);
> -bool f2fs_wait_discard_bios(struct f2fs_sb_info *sbi);
> +bool f2fs_issue_discard_timeout(struct f2fs_sb_info *sbi);
> void f2fs_clear_prefree_segments(struct f2fs_sb_info *sbi,
> struct cp_control *cpc);
> void f2fs_dirty_to_prefree(struct f2fs_sb_info *sbi);
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 9b79056d705d..97e0faf09ebf 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1037,6 +1037,7 @@ static void __init_discard_policy(struct f2fs_sb_info *sbi,
>
> dpolicy->max_requests = DEF_MAX_DISCARD_REQUEST;
> dpolicy->io_aware_gran = MAX_PLIST_NUM;
> + dpolicy->timeout = MAX_TIME;
>
> if (discard_type == DPOLICY_BG) {
> dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME;
> @@ -1424,7 +1425,14 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> int i, issued = 0;
> bool io_interrupted = false;
>
> + if (dpolicy->timeout != MAX_TIME)
> + f2fs_update_time(sbi, dpolicy->timeout);
> +
> for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
> + if (dpolicy->timeout != MAX_TIME &&
> + f2fs_time_over(sbi, dpolicy->timeout))
> + break;
> +
> if (i + 1 < dpolicy->granularity)
> break;
>
> @@ -1611,7 +1619,7 @@ void f2fs_stop_discard_thread(struct f2fs_sb_info *sbi)
> }
>
> /* This comes from f2fs_put_super */
> -bool f2fs_wait_discard_bios(struct f2fs_sb_info *sbi)
> +bool f2fs_issue_discard_timeout(struct f2fs_sb_info *sbi)
> {
> struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
> struct discard_policy dpolicy;
> @@ -1619,6 +1627,7 @@ bool f2fs_wait_discard_bios(struct f2fs_sb_info *sbi)
>
> __init_discard_policy(sbi, &dpolicy, DPOLICY_UMOUNT,
> dcc->discard_granularity);
> + dpolicy.timeout = UMOUNT_DISCARD_TIMEOUT;
> __issue_discard_cmd(sbi, &dpolicy);
> dropped = __drop_discard_cmd(sbi);
>
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index ea514acede36..7998ff5418f2 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -1029,6 +1029,9 @@ static void f2fs_put_super(struct super_block *sb)
> int i;
> bool dropped;
>
> + /* be sure to wait for any on-going discard commands */
> + dropped = f2fs_issue_discard_timeout(sbi);
> +
> f2fs_quota_off_umount(sb);
>
> /* prevent remaining shrinker jobs */
> @@ -1044,17 +1047,12 @@ static void f2fs_put_super(struct super_block *sb)
> struct cp_control cpc = {
> .reason = CP_UMOUNT,
> };
> - f2fs_write_checkpoint(sbi, &cpc);
> - }
>
> - /* be sure to wait for any on-going discard commands */
> - dropped = f2fs_wait_discard_bios(sbi);
> + if ((f2fs_hw_support_discard(sbi) ||
> + f2fs_hw_should_discard(sbi)) &&
> + !sbi->discard_blks && !dropped)
> + cpc.reason |= CP_TRIMMED;
>
> - if ((f2fs_hw_support_discard(sbi) || f2fs_hw_should_discard(sbi)) &&
> - !sbi->discard_blks && !dropped) {
> - struct cp_control cpc = {
> - .reason = CP_UMOUNT | CP_TRIMMED,
> - };
> f2fs_write_checkpoint(sbi, &cpc);

Still, there will be problematic as I commented in last patch, could you
check that?

Thanks,

> }
>
> @@ -2706,6 +2704,7 @@ static void init_sb_info(struct f2fs_sb_info *sbi)
> sbi->interval_time[DISCARD_TIME] = DEF_IDLE_INTERVAL;
> sbi->interval_time[GC_TIME] = DEF_IDLE_INTERVAL;
> sbi->interval_time[DISABLE_TIME] = DEF_DISABLE_INTERVAL;
> + sbi->interval_time[UMOUNT_DISCARD_TIMEOUT] = DEF_UMOUNT_DISCARD_TIMEOUT;
> clear_sbi_flag(sbi, SBI_NEED_FSCK);
>
> for (i = 0; i < NR_COUNT_TYPE; i++)
> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> index 5b83e1d66cb3..18c627e8fc90 100644
> --- a/fs/f2fs/sysfs.c
> +++ b/fs/f2fs/sysfs.c
> @@ -426,6 +426,8 @@ F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, idle_interval, interval_time[REQ_TIME]);
> F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, discard_idle_interval,
> interval_time[DISCARD_TIME]);
> F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, gc_idle_interval, interval_time[GC_TIME]);
> +F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info,
> + umount_discard_timeout, interval_time[UMOUNT_DISCARD_TIMEOUT]);
> F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, iostat_enable, iostat_enable);
> F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, readdir_ra, readdir_ra);
> F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, gc_pin_file_thresh, gc_pin_file_threshold);
> @@ -483,6 +485,7 @@ static struct attribute *f2fs_attrs[] = {
> ATTR_LIST(idle_interval),
> ATTR_LIST(discard_idle_interval),
> ATTR_LIST(gc_idle_interval),
> + ATTR_LIST(umount_discard_timeout),
> ATTR_LIST(iostat_enable),
> ATTR_LIST(readdir_ra),
> ATTR_LIST(gc_pin_file_thresh),
>