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

From: Chao Yu
Date: Thu Jan 24 2019 - 20:26:07 EST


On 2019/1/25 8:56, Jaegeuk Kim wrote:
> On 01/23, Chao Yu wrote:
>> 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?
>
> Yup.
>
>>
>> + 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?

Ping,

If this checkpoint generate discard entry, tagged CP_TRIMMED flag should be
wrong, so the right order should be?

write_checkpoint(CP_UMOUNT)

dropped = f2fs_wait_discard_bios()

if (... && no_drop && no_remain_discard)
f2fs_write_checkpoint(sbi, CP_UMOUNT | CP_TRIMMED);

Am I missing something?

Thanks,

>>
>> 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),
>>>
>
> .
>