* Re: [f2fs-dev] [PATCH v3] f2fs: fix long latency due to discard during umount
[not found] <1585550730-1858-1-git-send-email-stummala@codeaurora.org>
@ 2020-03-31 18:46 ` Jaegeuk Kim
2020-04-01 9:22 ` Sahitya Tummala
0 siblings, 1 reply; 7+ messages in thread
From: Jaegeuk Kim @ 2020-03-31 18:46 UTC (permalink / raw)
To: Sahitya Tummala; +Cc: linux-kernel, linux-f2fs-devel
On 03/30, Sahitya Tummala wrote:
> F2FS already has a default timeout of 5 secs for discards that
> can be issued during umount, but it can take more than the 5 sec
> timeout if the underlying UFS device queue is already full and there
> are no more available free tags to be used. In that case, submit_bio()
> will wait for the already queued discard requests to complete to get
> a free tag, which can potentially take way more than 5 sec.
>
> Fix this by submitting the discard requests with REQ_NOWAIT
> flags during umount. This will return -EAGAIN for UFS queue/tag full
> scenario without waiting in the context of submit_bio(). The FS can
> then handle these requests by retrying again within the stipulated
> discard timeout period to avoid long latencies.
Sorry, Sahitya, but, do we really need to do like this? How about just
controlling # of outstanding discarding bios in __issue_discard_cmd()?
>
> Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
> ---
> v3:
> -Handle the regression reported by Chao with v2.
> -simplify the logic to split the dc with multiple bios incase any bio returns
> EAGAIN and retry those new dc within 5 sec timeout.
>
> fs/f2fs/segment.c | 65 +++++++++++++++++++++++++++++++++++++++++++------------
> 1 file changed, 51 insertions(+), 14 deletions(-)
>
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index fb3e531..55d18c7 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1029,13 +1029,16 @@ static void f2fs_submit_discard_endio(struct bio *bio)
> struct discard_cmd *dc = (struct discard_cmd *)bio->bi_private;
> unsigned long flags;
>
> - dc->error = blk_status_to_errno(bio->bi_status);
> -
> spin_lock_irqsave(&dc->lock, flags);
> + if (!dc->error)
> + dc->error = blk_status_to_errno(bio->bi_status);
> +
> dc->bio_ref--;
> - if (!dc->bio_ref && dc->state == D_SUBMIT) {
> - dc->state = D_DONE;
> - complete_all(&dc->wait);
> + if (!dc->bio_ref) {
> + if (dc->error || dc->state == D_SUBMIT) {
> + dc->state = D_DONE;
> + complete_all(&dc->wait);
> + }
> }
> spin_unlock_irqrestore(&dc->lock, flags);
> bio_put(bio);
> @@ -1124,10 +1127,13 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
> struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ?
> &(dcc->fstrim_list) : &(dcc->wait_list);
> - int flag = dpolicy->sync ? REQ_SYNC : 0;
> + int flag;
> block_t lstart, start, len, total_len;
> int err = 0;
>
> + flag = dpolicy->sync ? REQ_SYNC : 0;
> + flag |= dpolicy->type == DPOLICY_UMOUNT ? REQ_NOWAIT : 0;
> +
> if (dc->state != D_PREP)
> return 0;
>
> @@ -1192,10 +1198,6 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> dc->bio_ref++;
> spin_unlock_irqrestore(&dc->lock, flags);
>
> - atomic_inc(&dcc->queued_discard);
> - dc->queued++;
> - list_move_tail(&dc->list, wait_list);
> -
> /* sanity check on discard range */
> __check_sit_bitmap(sbi, lstart, lstart + len);
>
> @@ -1203,6 +1205,29 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> bio->bi_end_io = f2fs_submit_discard_endio;
> bio->bi_opf |= flag;
> submit_bio(bio);
> + if (flag & REQ_NOWAIT) {
> + if (dc->error == -EAGAIN) {
> + spin_lock_irqsave(&dc->lock, flags);
> + dc->len -= len;
> + if (!dc->len) {
> + dc->len = total_len;
> + dc->state = D_PREP;
> + reinit_completion(&dc->wait);
> + } else {
> + dcc->undiscard_blks -= total_len;
> + if (dc->state == D_PARTIAL)
> + dc->state = D_SUBMIT;
> + }
> + err = dc->error;
> + dc->error = 0;
> + spin_unlock_irqrestore(&dc->lock, flags);
> + break;
> + }
> + }
> +
> + atomic_inc(&dcc->queued_discard);
> + dc->queued++;
> + list_move_tail(&dc->list, wait_list);
>
> atomic_inc(&dcc->issued_discard);
>
> @@ -1214,8 +1239,9 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> len = total_len;
> }
>
> - if (!err && len)
> - __update_discard_tree_range(sbi, bdev, lstart, start, len);
> + if ((!err || err == -EAGAIN) && total_len && dc->start != start)
> + __update_discard_tree_range(sbi, bdev, lstart, start,
> + total_len);
> return err;
> }
>
> @@ -1470,12 +1496,15 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> struct list_head *pend_list;
> struct discard_cmd *dc, *tmp;
> struct blk_plug plug;
> - int i, issued = 0;
> + int i, err, issued = 0;
> bool io_interrupted = false;
> + bool retry;
>
> if (dpolicy->timeout != 0)
> f2fs_update_time(sbi, dpolicy->timeout);
>
> +retry:
> + retry = false;
> for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
> if (dpolicy->timeout != 0 &&
> f2fs_time_over(sbi, dpolicy->timeout))
> @@ -1509,7 +1538,12 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> break;
> }
>
> - __submit_discard_cmd(sbi, dpolicy, dc, &issued);
> + err = __submit_discard_cmd(sbi, dpolicy, dc, &issued);
> + if (err == -EAGAIN) {
> + congestion_wait(BLK_RW_ASYNC,
> + DEFAULT_IO_TIMEOUT);
> + retry = true;
> + }
>
> if (issued >= dpolicy->max_requests)
> break;
> @@ -1522,6 +1556,9 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> break;
> }
>
> + if (retry)
> + goto retry;
> +
> if (!issued && io_interrupted)
> issued = -1;
>
> --
> Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] [PATCH v3] f2fs: fix long latency due to discard during umount
2020-03-31 18:46 ` [f2fs-dev] [PATCH v3] f2fs: fix long latency due to discard during umount Jaegeuk Kim
@ 2020-04-01 9:22 ` Sahitya Tummala
2020-04-02 9:32 ` Chao Yu
2020-04-03 17:19 ` Jaegeuk Kim
0 siblings, 2 replies; 7+ messages in thread
From: Sahitya Tummala @ 2020-04-01 9:22 UTC (permalink / raw)
To: Jaegeuk Kim; +Cc: linux-kernel, linux-f2fs-devel
Hi Jaegeuk,
On Tue, Mar 31, 2020 at 11:46:55AM -0700, Jaegeuk Kim wrote:
> On 03/30, Sahitya Tummala wrote:
> > F2FS already has a default timeout of 5 secs for discards that
> > can be issued during umount, but it can take more than the 5 sec
> > timeout if the underlying UFS device queue is already full and there
> > are no more available free tags to be used. In that case, submit_bio()
> > will wait for the already queued discard requests to complete to get
> > a free tag, which can potentially take way more than 5 sec.
> >
> > Fix this by submitting the discard requests with REQ_NOWAIT
> > flags during umount. This will return -EAGAIN for UFS queue/tag full
> > scenario without waiting in the context of submit_bio(). The FS can
> > then handle these requests by retrying again within the stipulated
> > discard timeout period to avoid long latencies.
>
> Sorry, Sahitya, but, do we really need to do like this? How about just
> controlling # of outstanding discarding bios in __issue_discard_cmd()?
Do you mean something like this?
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 1a62b27..860dd43 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1099,7 +1099,7 @@ static void __init_discard_policy(struct f2fs_sb_info *sbi,
} else if (discard_type == DPOLICY_FSTRIM) {
dpolicy->io_aware = false;
} else if (discard_type == DPOLICY_UMOUNT) {
- dpolicy->max_requests = UINT_MAX;
+ dpolicy->max_requests = 30;
dpolicy->io_aware = false;
/* we need to issue all to keep CP_TRIMMED_FLAG */
dpolicy->granularity = 1;
@@ -1470,12 +1470,14 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
struct list_head *pend_list;
struct discard_cmd *dc, *tmp;
struct blk_plug plug;
- int i, issued = 0;
+ int i, issued;
bool io_interrupted = false;
if (dpolicy->timeout != 0)
f2fs_update_time(sbi, dpolicy->timeout);
+retry:
+ issued = 0;
for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
if (dpolicy->timeout != 0 &&
f2fs_time_over(sbi, dpolicy->timeout))
@@ -1522,6 +1524,11 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
break;
}
+ if (dpolicy->type == DPOLICY_UMOUNT && issued) {
+ __wait_all_discard_cmd(sbi, dpolicy);
+ goto retry;
+ }
+
if (!issued && io_interrupted)
issued = -1;
Thanks,
>
> >
> > Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
> > ---
> > v3:
> > -Handle the regression reported by Chao with v2.
> > -simplify the logic to split the dc with multiple bios incase any bio returns
> > EAGAIN and retry those new dc within 5 sec timeout.
> >
> > fs/f2fs/segment.c | 65 +++++++++++++++++++++++++++++++++++++++++++------------
> > 1 file changed, 51 insertions(+), 14 deletions(-)
> >
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index fb3e531..55d18c7 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -1029,13 +1029,16 @@ static void f2fs_submit_discard_endio(struct bio *bio)
> > struct discard_cmd *dc = (struct discard_cmd *)bio->bi_private;
> > unsigned long flags;
> >
> > - dc->error = blk_status_to_errno(bio->bi_status);
> > -
> > spin_lock_irqsave(&dc->lock, flags);
> > + if (!dc->error)
> > + dc->error = blk_status_to_errno(bio->bi_status);
> > +
> > dc->bio_ref--;
> > - if (!dc->bio_ref && dc->state == D_SUBMIT) {
> > - dc->state = D_DONE;
> > - complete_all(&dc->wait);
> > + if (!dc->bio_ref) {
> > + if (dc->error || dc->state == D_SUBMIT) {
> > + dc->state = D_DONE;
> > + complete_all(&dc->wait);
> > + }
> > }
> > spin_unlock_irqrestore(&dc->lock, flags);
> > bio_put(bio);
> > @@ -1124,10 +1127,13 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
> > struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ?
> > &(dcc->fstrim_list) : &(dcc->wait_list);
> > - int flag = dpolicy->sync ? REQ_SYNC : 0;
> > + int flag;
> > block_t lstart, start, len, total_len;
> > int err = 0;
> >
> > + flag = dpolicy->sync ? REQ_SYNC : 0;
> > + flag |= dpolicy->type == DPOLICY_UMOUNT ? REQ_NOWAIT : 0;
> > +
> > if (dc->state != D_PREP)
> > return 0;
> >
> > @@ -1192,10 +1198,6 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > dc->bio_ref++;
> > spin_unlock_irqrestore(&dc->lock, flags);
> >
> > - atomic_inc(&dcc->queued_discard);
> > - dc->queued++;
> > - list_move_tail(&dc->list, wait_list);
> > -
> > /* sanity check on discard range */
> > __check_sit_bitmap(sbi, lstart, lstart + len);
> >
> > @@ -1203,6 +1205,29 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > bio->bi_end_io = f2fs_submit_discard_endio;
> > bio->bi_opf |= flag;
> > submit_bio(bio);
> > + if (flag & REQ_NOWAIT) {
> > + if (dc->error == -EAGAIN) {
> > + spin_lock_irqsave(&dc->lock, flags);
> > + dc->len -= len;
> > + if (!dc->len) {
> > + dc->len = total_len;
> > + dc->state = D_PREP;
> > + reinit_completion(&dc->wait);
> > + } else {
> > + dcc->undiscard_blks -= total_len;
> > + if (dc->state == D_PARTIAL)
> > + dc->state = D_SUBMIT;
> > + }
> > + err = dc->error;
> > + dc->error = 0;
> > + spin_unlock_irqrestore(&dc->lock, flags);
> > + break;
> > + }
> > + }
> > +
> > + atomic_inc(&dcc->queued_discard);
> > + dc->queued++;
> > + list_move_tail(&dc->list, wait_list);
> >
> > atomic_inc(&dcc->issued_discard);
> >
> > @@ -1214,8 +1239,9 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > len = total_len;
> > }
> >
> > - if (!err && len)
> > - __update_discard_tree_range(sbi, bdev, lstart, start, len);
> > + if ((!err || err == -EAGAIN) && total_len && dc->start != start)
> > + __update_discard_tree_range(sbi, bdev, lstart, start,
> > + total_len);
> > return err;
> > }
> >
> > @@ -1470,12 +1496,15 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > struct list_head *pend_list;
> > struct discard_cmd *dc, *tmp;
> > struct blk_plug plug;
> > - int i, issued = 0;
> > + int i, err, issued = 0;
> > bool io_interrupted = false;
> > + bool retry;
> >
> > if (dpolicy->timeout != 0)
> > f2fs_update_time(sbi, dpolicy->timeout);
> >
> > +retry:
> > + retry = false;
> > for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
> > if (dpolicy->timeout != 0 &&
> > f2fs_time_over(sbi, dpolicy->timeout))
> > @@ -1509,7 +1538,12 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > break;
> > }
> >
> > - __submit_discard_cmd(sbi, dpolicy, dc, &issued);
> > + err = __submit_discard_cmd(sbi, dpolicy, dc, &issued);
> > + if (err == -EAGAIN) {
> > + congestion_wait(BLK_RW_ASYNC,
> > + DEFAULT_IO_TIMEOUT);
> > + retry = true;
> > + }
> >
> > if (issued >= dpolicy->max_requests)
> > break;
> > @@ -1522,6 +1556,9 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > break;
> > }
> >
> > + if (retry)
> > + goto retry;
> > +
> > if (!issued && io_interrupted)
> > issued = -1;
> >
> > --
> > Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
> > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
--
--
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] [PATCH v3] f2fs: fix long latency due to discard during umount
2020-04-01 9:22 ` Sahitya Tummala
@ 2020-04-02 9:32 ` Chao Yu
2020-04-03 17:19 ` Jaegeuk Kim
1 sibling, 0 replies; 7+ messages in thread
From: Chao Yu @ 2020-04-02 9:32 UTC (permalink / raw)
To: Sahitya Tummala, Jaegeuk Kim; +Cc: linux-kernel, linux-f2fs-devel
On 2020/4/1 17:22, Sahitya Tummala wrote:
> Hi Jaegeuk,
>
> On Tue, Mar 31, 2020 at 11:46:55AM -0700, Jaegeuk Kim wrote:
>> On 03/30, Sahitya Tummala wrote:
>>> F2FS already has a default timeout of 5 secs for discards that
>>> can be issued during umount, but it can take more than the 5 sec
>>> timeout if the underlying UFS device queue is already full and there
>>> are no more available free tags to be used. In that case, submit_bio()
>>> will wait for the already queued discard requests to complete to get
>>> a free tag, which can potentially take way more than 5 sec.
>>>
>>> Fix this by submitting the discard requests with REQ_NOWAIT
>>> flags during umount. This will return -EAGAIN for UFS queue/tag full
>>> scenario without waiting in the context of submit_bio(). The FS can
>>> then handle these requests by retrying again within the stipulated
>>> discard timeout period to avoid long latencies.
>>
>> Sorry, Sahitya, but, do we really need to do like this? How about just
>> controlling # of outstanding discarding bios in __issue_discard_cmd()?
>
> Do you mean something like this?
>
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 1a62b27..860dd43 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1099,7 +1099,7 @@ static void __init_discard_policy(struct f2fs_sb_info *sbi,
> } else if (discard_type == DPOLICY_FSTRIM) {
> dpolicy->io_aware = false;
> } else if (discard_type == DPOLICY_UMOUNT) {
> - dpolicy->max_requests = UINT_MAX;
> + dpolicy->max_requests = 30;
8 or 16?
It looks more simple than previous implementation.
Thanks,
> dpolicy->io_aware = false;
> /* we need to issue all to keep CP_TRIMMED_FLAG */
> dpolicy->granularity = 1;
> @@ -1470,12 +1470,14 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> struct list_head *pend_list;
> struct discard_cmd *dc, *tmp;
> struct blk_plug plug;
> - int i, issued = 0;
> + int i, issued;
> bool io_interrupted = false;
>
> if (dpolicy->timeout != 0)
> f2fs_update_time(sbi, dpolicy->timeout);
>
> +retry:
> + issued = 0;
> for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
> if (dpolicy->timeout != 0 &&
> f2fs_time_over(sbi, dpolicy->timeout))
> @@ -1522,6 +1524,11 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> break;
> }
>
> + if (dpolicy->type == DPOLICY_UMOUNT && issued) {
> + __wait_all_discard_cmd(sbi, dpolicy);
> + goto retry;
> + }
> +
> if (!issued && io_interrupted)
> issued = -1;
>
> Thanks,
>
>>
>>>
>>> Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
>>> ---
>>> v3:
>>> -Handle the regression reported by Chao with v2.
>>> -simplify the logic to split the dc with multiple bios incase any bio returns
>>> EAGAIN and retry those new dc within 5 sec timeout.
>>>
>>> fs/f2fs/segment.c | 65 +++++++++++++++++++++++++++++++++++++++++++------------
>>> 1 file changed, 51 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>> index fb3e531..55d18c7 100644
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -1029,13 +1029,16 @@ static void f2fs_submit_discard_endio(struct bio *bio)
>>> struct discard_cmd *dc = (struct discard_cmd *)bio->bi_private;
>>> unsigned long flags;
>>>
>>> - dc->error = blk_status_to_errno(bio->bi_status);
>>> -
>>> spin_lock_irqsave(&dc->lock, flags);
>>> + if (!dc->error)
>>> + dc->error = blk_status_to_errno(bio->bi_status);
>>> +
>>> dc->bio_ref--;
>>> - if (!dc->bio_ref && dc->state == D_SUBMIT) {
>>> - dc->state = D_DONE;
>>> - complete_all(&dc->wait);
>>> + if (!dc->bio_ref) {
>>> + if (dc->error || dc->state == D_SUBMIT) {
>>> + dc->state = D_DONE;
>>> + complete_all(&dc->wait);
>>> + }
>>> }
>>> spin_unlock_irqrestore(&dc->lock, flags);
>>> bio_put(bio);
>>> @@ -1124,10 +1127,13 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
>>> struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
>>> struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ?
>>> &(dcc->fstrim_list) : &(dcc->wait_list);
>>> - int flag = dpolicy->sync ? REQ_SYNC : 0;
>>> + int flag;
>>> block_t lstart, start, len, total_len;
>>> int err = 0;
>>>
>>> + flag = dpolicy->sync ? REQ_SYNC : 0;
>>> + flag |= dpolicy->type == DPOLICY_UMOUNT ? REQ_NOWAIT : 0;
>>> +
>>> if (dc->state != D_PREP)
>>> return 0;
>>>
>>> @@ -1192,10 +1198,6 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
>>> dc->bio_ref++;
>>> spin_unlock_irqrestore(&dc->lock, flags);
>>>
>>> - atomic_inc(&dcc->queued_discard);
>>> - dc->queued++;
>>> - list_move_tail(&dc->list, wait_list);
>>> -
>>> /* sanity check on discard range */
>>> __check_sit_bitmap(sbi, lstart, lstart + len);
>>>
>>> @@ -1203,6 +1205,29 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
>>> bio->bi_end_io = f2fs_submit_discard_endio;
>>> bio->bi_opf |= flag;
>>> submit_bio(bio);
>>> + if (flag & REQ_NOWAIT) {
>>> + if (dc->error == -EAGAIN) {
>>> + spin_lock_irqsave(&dc->lock, flags);
>>> + dc->len -= len;
>>> + if (!dc->len) {
>>> + dc->len = total_len;
>>> + dc->state = D_PREP;
>>> + reinit_completion(&dc->wait);
>>> + } else {
>>> + dcc->undiscard_blks -= total_len;
>>> + if (dc->state == D_PARTIAL)
>>> + dc->state = D_SUBMIT;
>>> + }
>>> + err = dc->error;
>>> + dc->error = 0;
>>> + spin_unlock_irqrestore(&dc->lock, flags);
>>> + break;
>>> + }
>>> + }
>>> +
>>> + atomic_inc(&dcc->queued_discard);
>>> + dc->queued++;
>>> + list_move_tail(&dc->list, wait_list);
>>>
>>> atomic_inc(&dcc->issued_discard);
>>>
>>> @@ -1214,8 +1239,9 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
>>> len = total_len;
>>> }
>>>
>>> - if (!err && len)
>>> - __update_discard_tree_range(sbi, bdev, lstart, start, len);
>>> + if ((!err || err == -EAGAIN) && total_len && dc->start != start)
>>> + __update_discard_tree_range(sbi, bdev, lstart, start,
>>> + total_len);
>>> return err;
>>> }
>>>
>>> @@ -1470,12 +1496,15 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
>>> struct list_head *pend_list;
>>> struct discard_cmd *dc, *tmp;
>>> struct blk_plug plug;
>>> - int i, issued = 0;
>>> + int i, err, issued = 0;
>>> bool io_interrupted = false;
>>> + bool retry;
>>>
>>> if (dpolicy->timeout != 0)
>>> f2fs_update_time(sbi, dpolicy->timeout);
>>>
>>> +retry:
>>> + retry = false;
>>> for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
>>> if (dpolicy->timeout != 0 &&
>>> f2fs_time_over(sbi, dpolicy->timeout))
>>> @@ -1509,7 +1538,12 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
>>> break;
>>> }
>>>
>>> - __submit_discard_cmd(sbi, dpolicy, dc, &issued);
>>> + err = __submit_discard_cmd(sbi, dpolicy, dc, &issued);
>>> + if (err == -EAGAIN) {
>>> + congestion_wait(BLK_RW_ASYNC,
>>> + DEFAULT_IO_TIMEOUT);
>>> + retry = true;
>>> + }
>>>
>>> if (issued >= dpolicy->max_requests)
>>> break;
>>> @@ -1522,6 +1556,9 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
>>> break;
>>> }
>>>
>>> + if (retry)
>>> + goto retry;
>>> +
>>> if (!issued && io_interrupted)
>>> issued = -1;
>>>
>>> --
>>> Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
>>> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
>
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] [PATCH v3] f2fs: fix long latency due to discard during umount
2020-04-01 9:22 ` Sahitya Tummala
2020-04-02 9:32 ` Chao Yu
@ 2020-04-03 17:19 ` Jaegeuk Kim
[not found] ` <20200408090024.GC20234@codeaurora.org>
1 sibling, 1 reply; 7+ messages in thread
From: Jaegeuk Kim @ 2020-04-03 17:19 UTC (permalink / raw)
To: Sahitya Tummala; +Cc: linux-kernel, linux-f2fs-devel
On 04/01, Sahitya Tummala wrote:
> Hi Jaegeuk,
>
> On Tue, Mar 31, 2020 at 11:46:55AM -0700, Jaegeuk Kim wrote:
> > On 03/30, Sahitya Tummala wrote:
> > > F2FS already has a default timeout of 5 secs for discards that
> > > can be issued during umount, but it can take more than the 5 sec
> > > timeout if the underlying UFS device queue is already full and there
> > > are no more available free tags to be used. In that case, submit_bio()
> > > will wait for the already queued discard requests to complete to get
> > > a free tag, which can potentially take way more than 5 sec.
> > >
> > > Fix this by submitting the discard requests with REQ_NOWAIT
> > > flags during umount. This will return -EAGAIN for UFS queue/tag full
> > > scenario without waiting in the context of submit_bio(). The FS can
> > > then handle these requests by retrying again within the stipulated
> > > discard timeout period to avoid long latencies.
> >
> > Sorry, Sahitya, but, do we really need to do like this? How about just
> > controlling # of outstanding discarding bios in __issue_discard_cmd()?
>
> Do you mean something like this?
>
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 1a62b27..860dd43 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1099,7 +1099,7 @@ static void __init_discard_policy(struct f2fs_sb_info *sbi,
> } else if (discard_type == DPOLICY_FSTRIM) {
> dpolicy->io_aware = false;
> } else if (discard_type == DPOLICY_UMOUNT) {
> - dpolicy->max_requests = UINT_MAX;
> + dpolicy->max_requests = 30;
Can we use max queue depth of the block device?
> dpolicy->io_aware = false;
> /* we need to issue all to keep CP_TRIMMED_FLAG */
> dpolicy->granularity = 1;
> @@ -1470,12 +1470,14 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> struct list_head *pend_list;
> struct discard_cmd *dc, *tmp;
> struct blk_plug plug;
> - int i, issued = 0;
> + int i, issued;
> bool io_interrupted = false;
>
> if (dpolicy->timeout != 0)
> f2fs_update_time(sbi, dpolicy->timeout);
>
> +retry:
> + issued = 0;
> for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
> if (dpolicy->timeout != 0 &&
> f2fs_time_over(sbi, dpolicy->timeout))
> @@ -1522,6 +1524,11 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> break;
> }
>
> + if (dpolicy->type == DPOLICY_UMOUNT && issued) {
> + __wait_all_discard_cmd(sbi, dpolicy);
> + goto retry;
> + }
> +
> if (!issued && io_interrupted)
> issued = -1;
>
> Thanks,
>
> >
> > >
> > > Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
> > > ---
> > > v3:
> > > -Handle the regression reported by Chao with v2.
> > > -simplify the logic to split the dc with multiple bios incase any bio returns
> > > EAGAIN and retry those new dc within 5 sec timeout.
> > >
> > > fs/f2fs/segment.c | 65 +++++++++++++++++++++++++++++++++++++++++++------------
> > > 1 file changed, 51 insertions(+), 14 deletions(-)
> > >
> > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > index fb3e531..55d18c7 100644
> > > --- a/fs/f2fs/segment.c
> > > +++ b/fs/f2fs/segment.c
> > > @@ -1029,13 +1029,16 @@ static void f2fs_submit_discard_endio(struct bio *bio)
> > > struct discard_cmd *dc = (struct discard_cmd *)bio->bi_private;
> > > unsigned long flags;
> > >
> > > - dc->error = blk_status_to_errno(bio->bi_status);
> > > -
> > > spin_lock_irqsave(&dc->lock, flags);
> > > + if (!dc->error)
> > > + dc->error = blk_status_to_errno(bio->bi_status);
> > > +
> > > dc->bio_ref--;
> > > - if (!dc->bio_ref && dc->state == D_SUBMIT) {
> > > - dc->state = D_DONE;
> > > - complete_all(&dc->wait);
> > > + if (!dc->bio_ref) {
> > > + if (dc->error || dc->state == D_SUBMIT) {
> > > + dc->state = D_DONE;
> > > + complete_all(&dc->wait);
> > > + }
> > > }
> > > spin_unlock_irqrestore(&dc->lock, flags);
> > > bio_put(bio);
> > > @@ -1124,10 +1127,13 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > > struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
> > > struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ?
> > > &(dcc->fstrim_list) : &(dcc->wait_list);
> > > - int flag = dpolicy->sync ? REQ_SYNC : 0;
> > > + int flag;
> > > block_t lstart, start, len, total_len;
> > > int err = 0;
> > >
> > > + flag = dpolicy->sync ? REQ_SYNC : 0;
> > > + flag |= dpolicy->type == DPOLICY_UMOUNT ? REQ_NOWAIT : 0;
> > > +
> > > if (dc->state != D_PREP)
> > > return 0;
> > >
> > > @@ -1192,10 +1198,6 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > > dc->bio_ref++;
> > > spin_unlock_irqrestore(&dc->lock, flags);
> > >
> > > - atomic_inc(&dcc->queued_discard);
> > > - dc->queued++;
> > > - list_move_tail(&dc->list, wait_list);
> > > -
> > > /* sanity check on discard range */
> > > __check_sit_bitmap(sbi, lstart, lstart + len);
> > >
> > > @@ -1203,6 +1205,29 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > > bio->bi_end_io = f2fs_submit_discard_endio;
> > > bio->bi_opf |= flag;
> > > submit_bio(bio);
> > > + if (flag & REQ_NOWAIT) {
> > > + if (dc->error == -EAGAIN) {
> > > + spin_lock_irqsave(&dc->lock, flags);
> > > + dc->len -= len;
> > > + if (!dc->len) {
> > > + dc->len = total_len;
> > > + dc->state = D_PREP;
> > > + reinit_completion(&dc->wait);
> > > + } else {
> > > + dcc->undiscard_blks -= total_len;
> > > + if (dc->state == D_PARTIAL)
> > > + dc->state = D_SUBMIT;
> > > + }
> > > + err = dc->error;
> > > + dc->error = 0;
> > > + spin_unlock_irqrestore(&dc->lock, flags);
> > > + break;
> > > + }
> > > + }
> > > +
> > > + atomic_inc(&dcc->queued_discard);
> > > + dc->queued++;
> > > + list_move_tail(&dc->list, wait_list);
> > >
> > > atomic_inc(&dcc->issued_discard);
> > >
> > > @@ -1214,8 +1239,9 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > > len = total_len;
> > > }
> > >
> > > - if (!err && len)
> > > - __update_discard_tree_range(sbi, bdev, lstart, start, len);
> > > + if ((!err || err == -EAGAIN) && total_len && dc->start != start)
> > > + __update_discard_tree_range(sbi, bdev, lstart, start,
> > > + total_len);
> > > return err;
> > > }
> > >
> > > @@ -1470,12 +1496,15 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > > struct list_head *pend_list;
> > > struct discard_cmd *dc, *tmp;
> > > struct blk_plug plug;
> > > - int i, issued = 0;
> > > + int i, err, issued = 0;
> > > bool io_interrupted = false;
> > > + bool retry;
> > >
> > > if (dpolicy->timeout != 0)
> > > f2fs_update_time(sbi, dpolicy->timeout);
> > >
> > > +retry:
> > > + retry = false;
> > > for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
> > > if (dpolicy->timeout != 0 &&
> > > f2fs_time_over(sbi, dpolicy->timeout))
> > > @@ -1509,7 +1538,12 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > > break;
> > > }
> > >
> > > - __submit_discard_cmd(sbi, dpolicy, dc, &issued);
> > > + err = __submit_discard_cmd(sbi, dpolicy, dc, &issued);
> > > + if (err == -EAGAIN) {
> > > + congestion_wait(BLK_RW_ASYNC,
> > > + DEFAULT_IO_TIMEOUT);
> > > + retry = true;
> > > + }
> > >
> > > if (issued >= dpolicy->max_requests)
> > > break;
> > > @@ -1522,6 +1556,9 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > > break;
> > > }
> > >
> > > + if (retry)
> > > + goto retry;
> > > +
> > > if (!issued && io_interrupted)
> > > issued = -1;
> > >
> > > --
> > > Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
> > > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
>
> --
> --
> Sent by a consultant of the Qualcomm Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] [PATCH v3] f2fs: fix long latency due to discard during umount
[not found] ` <20200408090024.GC20234@codeaurora.org>
@ 2020-04-09 2:29 ` Jaegeuk Kim
[not found] ` <20200409114756.GD20234@codeaurora.org>
0 siblings, 1 reply; 7+ messages in thread
From: Jaegeuk Kim @ 2020-04-09 2:29 UTC (permalink / raw)
To: Sahitya Tummala; +Cc: linux-kernel, linux-f2fs-devel
On 04/08, Sahitya Tummala wrote:
> Hi Jaegeuk,
>
> On Fri, Apr 03, 2020 at 10:19:43AM -0700, Jaegeuk Kim wrote:
> > On 04/01, Sahitya Tummala wrote:
> > > Hi Jaegeuk,
> > >
> > > On Tue, Mar 31, 2020 at 11:46:55AM -0700, Jaegeuk Kim wrote:
> > > > On 03/30, Sahitya Tummala wrote:
> > > > > F2FS already has a default timeout of 5 secs for discards that
> > > > > can be issued during umount, but it can take more than the 5 sec
> > > > > timeout if the underlying UFS device queue is already full and there
> > > > > are no more available free tags to be used. In that case, submit_bio()
> > > > > will wait for the already queued discard requests to complete to get
> > > > > a free tag, which can potentially take way more than 5 sec.
> > > > >
> > > > > Fix this by submitting the discard requests with REQ_NOWAIT
> > > > > flags during umount. This will return -EAGAIN for UFS queue/tag full
> > > > > scenario without waiting in the context of submit_bio(). The FS can
> > > > > then handle these requests by retrying again within the stipulated
> > > > > discard timeout period to avoid long latencies.
> > > >
> > > > Sorry, Sahitya, but, do we really need to do like this? How about just
> > > > controlling # of outstanding discarding bios in __issue_discard_cmd()?
> > >
> > > Do you mean something like this?
> > >
> > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > index 1a62b27..860dd43 100644
> > > --- a/fs/f2fs/segment.c
> > > +++ b/fs/f2fs/segment.c
> > > @@ -1099,7 +1099,7 @@ static void __init_discard_policy(struct f2fs_sb_info *sbi,
> > > } else if (discard_type == DPOLICY_FSTRIM) {
> > > dpolicy->io_aware = false;
> > > } else if (discard_type == DPOLICY_UMOUNT) {
> > > - dpolicy->max_requests = UINT_MAX;
> > > + dpolicy->max_requests = 30;
> >
> > Can we use max queue depth of the block device?
>
> I think it should be limited to 8 or 16 as Chao suggested, so that we can have
> better control on the given timeout value? Thoughts?
Where is 8 or 16 coming from? What about SSD? Sorry, it's unclear to me.
>
> Thanks,
>
> >
> > > dpolicy->io_aware = false;
> > > /* we need to issue all to keep CP_TRIMMED_FLAG */
> > > dpolicy->granularity = 1;
> > > @@ -1470,12 +1470,14 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > > struct list_head *pend_list;
> > > struct discard_cmd *dc, *tmp;
> > > struct blk_plug plug;
> > > - int i, issued = 0;
> > > + int i, issued;
> > > bool io_interrupted = false;
> > >
> > > if (dpolicy->timeout != 0)
> > > f2fs_update_time(sbi, dpolicy->timeout);
> > >
> > > +retry:
> > > + issued = 0;
> > > for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
> > > if (dpolicy->timeout != 0 &&
> > > f2fs_time_over(sbi, dpolicy->timeout))
> > > @@ -1522,6 +1524,11 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > > break;
> > > }
> > >
> > > + if (dpolicy->type == DPOLICY_UMOUNT && issued) {
> > > + __wait_all_discard_cmd(sbi, dpolicy);
> > > + goto retry;
> > > + }
> > > +
> > > if (!issued && io_interrupted)
> > > issued = -1;
> > >
> > > Thanks,
> > >
> > > >
> > > > >
> > > > > Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
> > > > > ---
> > > > > v3:
> > > > > -Handle the regression reported by Chao with v2.
> > > > > -simplify the logic to split the dc with multiple bios incase any bio returns
> > > > > EAGAIN and retry those new dc within 5 sec timeout.
> > > > >
> > > > > fs/f2fs/segment.c | 65 +++++++++++++++++++++++++++++++++++++++++++------------
> > > > > 1 file changed, 51 insertions(+), 14 deletions(-)
> > > > >
> > > > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > > > index fb3e531..55d18c7 100644
> > > > > --- a/fs/f2fs/segment.c
> > > > > +++ b/fs/f2fs/segment.c
> > > > > @@ -1029,13 +1029,16 @@ static void f2fs_submit_discard_endio(struct bio *bio)
> > > > > struct discard_cmd *dc = (struct discard_cmd *)bio->bi_private;
> > > > > unsigned long flags;
> > > > >
> > > > > - dc->error = blk_status_to_errno(bio->bi_status);
> > > > > -
> > > > > spin_lock_irqsave(&dc->lock, flags);
> > > > > + if (!dc->error)
> > > > > + dc->error = blk_status_to_errno(bio->bi_status);
> > > > > +
> > > > > dc->bio_ref--;
> > > > > - if (!dc->bio_ref && dc->state == D_SUBMIT) {
> > > > > - dc->state = D_DONE;
> > > > > - complete_all(&dc->wait);
> > > > > + if (!dc->bio_ref) {
> > > > > + if (dc->error || dc->state == D_SUBMIT) {
> > > > > + dc->state = D_DONE;
> > > > > + complete_all(&dc->wait);
> > > > > + }
> > > > > }
> > > > > spin_unlock_irqrestore(&dc->lock, flags);
> > > > > bio_put(bio);
> > > > > @@ -1124,10 +1127,13 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
> > > > > struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ?
> > > > > &(dcc->fstrim_list) : &(dcc->wait_list);
> > > > > - int flag = dpolicy->sync ? REQ_SYNC : 0;
> > > > > + int flag;
> > > > > block_t lstart, start, len, total_len;
> > > > > int err = 0;
> > > > >
> > > > > + flag = dpolicy->sync ? REQ_SYNC : 0;
> > > > > + flag |= dpolicy->type == DPOLICY_UMOUNT ? REQ_NOWAIT : 0;
> > > > > +
> > > > > if (dc->state != D_PREP)
> > > > > return 0;
> > > > >
> > > > > @@ -1192,10 +1198,6 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > dc->bio_ref++;
> > > > > spin_unlock_irqrestore(&dc->lock, flags);
> > > > >
> > > > > - atomic_inc(&dcc->queued_discard);
> > > > > - dc->queued++;
> > > > > - list_move_tail(&dc->list, wait_list);
> > > > > -
> > > > > /* sanity check on discard range */
> > > > > __check_sit_bitmap(sbi, lstart, lstart + len);
> > > > >
> > > > > @@ -1203,6 +1205,29 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > bio->bi_end_io = f2fs_submit_discard_endio;
> > > > > bio->bi_opf |= flag;
> > > > > submit_bio(bio);
> > > > > + if (flag & REQ_NOWAIT) {
> > > > > + if (dc->error == -EAGAIN) {
> > > > > + spin_lock_irqsave(&dc->lock, flags);
> > > > > + dc->len -= len;
> > > > > + if (!dc->len) {
> > > > > + dc->len = total_len;
> > > > > + dc->state = D_PREP;
> > > > > + reinit_completion(&dc->wait);
> > > > > + } else {
> > > > > + dcc->undiscard_blks -= total_len;
> > > > > + if (dc->state == D_PARTIAL)
> > > > > + dc->state = D_SUBMIT;
> > > > > + }
> > > > > + err = dc->error;
> > > > > + dc->error = 0;
> > > > > + spin_unlock_irqrestore(&dc->lock, flags);
> > > > > + break;
> > > > > + }
> > > > > + }
> > > > > +
> > > > > + atomic_inc(&dcc->queued_discard);
> > > > > + dc->queued++;
> > > > > + list_move_tail(&dc->list, wait_list);
> > > > >
> > > > > atomic_inc(&dcc->issued_discard);
> > > > >
> > > > > @@ -1214,8 +1239,9 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > len = total_len;
> > > > > }
> > > > >
> > > > > - if (!err && len)
> > > > > - __update_discard_tree_range(sbi, bdev, lstart, start, len);
> > > > > + if ((!err || err == -EAGAIN) && total_len && dc->start != start)
> > > > > + __update_discard_tree_range(sbi, bdev, lstart, start,
> > > > > + total_len);
> > > > > return err;
> > > > > }
> > > > >
> > > > > @@ -1470,12 +1496,15 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > struct list_head *pend_list;
> > > > > struct discard_cmd *dc, *tmp;
> > > > > struct blk_plug plug;
> > > > > - int i, issued = 0;
> > > > > + int i, err, issued = 0;
> > > > > bool io_interrupted = false;
> > > > > + bool retry;
> > > > >
> > > > > if (dpolicy->timeout != 0)
> > > > > f2fs_update_time(sbi, dpolicy->timeout);
> > > > >
> > > > > +retry:
> > > > > + retry = false;
> > > > > for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
> > > > > if (dpolicy->timeout != 0 &&
> > > > > f2fs_time_over(sbi, dpolicy->timeout))
> > > > > @@ -1509,7 +1538,12 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > break;
> > > > > }
> > > > >
> > > > > - __submit_discard_cmd(sbi, dpolicy, dc, &issued);
> > > > > + err = __submit_discard_cmd(sbi, dpolicy, dc, &issued);
> > > > > + if (err == -EAGAIN) {
> > > > > + congestion_wait(BLK_RW_ASYNC,
> > > > > + DEFAULT_IO_TIMEOUT);
> > > > > + retry = true;
> > > > > + }
> > > > >
> > > > > if (issued >= dpolicy->max_requests)
> > > > > break;
> > > > > @@ -1522,6 +1556,9 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > break;
> > > > > }
> > > > >
> > > > > + if (retry)
> > > > > + goto retry;
> > > > > +
> > > > > if (!issued && io_interrupted)
> > > > > issued = -1;
> > > > >
> > > > > --
> > > > > Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
> > > > > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
> > >
> > > --
> > > --
> > > Sent by a consultant of the Qualcomm Innovation Center, Inc.
> > > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
>
> --
> --
> Sent by a consultant of the Qualcomm Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
_______________________________________________
Linux-f2fs-devel mailing list
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] [PATCH v3] f2fs: fix long latency due to discard during umount
[not found] ` <20200409114756.GD20234@codeaurora.org>
@ 2020-04-13 16:52 ` Jaegeuk Kim
2020-04-14 17:45 ` Jaegeuk Kim
0 siblings, 1 reply; 7+ messages in thread
From: Jaegeuk Kim @ 2020-04-13 16:52 UTC (permalink / raw)
To: Sahitya Tummala; +Cc: linux-kernel, linux-f2fs-devel
On 04/09, Sahitya Tummala wrote:
> On Wed, Apr 08, 2020 at 07:29:28PM -0700, Jaegeuk Kim wrote:
> > On 04/08, Sahitya Tummala wrote:
> > > Hi Jaegeuk,
> > >
> > > On Fri, Apr 03, 2020 at 10:19:43AM -0700, Jaegeuk Kim wrote:
> > > > On 04/01, Sahitya Tummala wrote:
> > > > > Hi Jaegeuk,
> > > > >
> > > > > On Tue, Mar 31, 2020 at 11:46:55AM -0700, Jaegeuk Kim wrote:
> > > > > > On 03/30, Sahitya Tummala wrote:
> > > > > > > F2FS already has a default timeout of 5 secs for discards that
> > > > > > > can be issued during umount, but it can take more than the 5 sec
> > > > > > > timeout if the underlying UFS device queue is already full and there
> > > > > > > are no more available free tags to be used. In that case, submit_bio()
> > > > > > > will wait for the already queued discard requests to complete to get
> > > > > > > a free tag, which can potentially take way more than 5 sec.
> > > > > > >
> > > > > > > Fix this by submitting the discard requests with REQ_NOWAIT
> > > > > > > flags during umount. This will return -EAGAIN for UFS queue/tag full
> > > > > > > scenario without waiting in the context of submit_bio(). The FS can
> > > > > > > then handle these requests by retrying again within the stipulated
> > > > > > > discard timeout period to avoid long latencies.
> > > > > >
> > > > > > Sorry, Sahitya, but, do we really need to do like this? How about just
> > > > > > controlling # of outstanding discarding bios in __issue_discard_cmd()?
> > > > >
> > > > > Do you mean something like this?
> > > > >
> > > > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > > > index 1a62b27..860dd43 100644
> > > > > --- a/fs/f2fs/segment.c
> > > > > +++ b/fs/f2fs/segment.c
> > > > > @@ -1099,7 +1099,7 @@ static void __init_discard_policy(struct f2fs_sb_info *sbi,
> > > > > } else if (discard_type == DPOLICY_FSTRIM) {
> > > > > dpolicy->io_aware = false;
> > > > > } else if (discard_type == DPOLICY_UMOUNT) {
> > > > > - dpolicy->max_requests = UINT_MAX;
> > > > > + dpolicy->max_requests = 30;
> > > >
> > > > Can we use max queue depth of the block device?
> > >
> > > I think it should be limited to 8 or 16 as Chao suggested, so that we can have
> > > better control on the given timeout value? Thoughts?
> >
> > Where is 8 or 16 coming from? What about SSD? Sorry, it's unclear to me.
>
> With this patch we now wait for a batch of discard requests in __issue_discard_cmd()
> with a upper timeout of 5 sec. So, I thought that having a smaller batch of
> discard requests would help us to avoid queuing more requests and end up waiting
> for more time in __wait_all_discard_cmd(). Today we have DEF_MAX_DISCARD_REQUEST
> as 8 for default max discard requests. If it too less, may be for umount
> we can use 16 instead. But the idea is to avoid more wait time.
Ok, then, it seems we can just remove this line to use dpolicy->max_requests,
and retry issuing all the discard commands like below. Later, I thnk it'd be
fine to tune the max_requests based on bd_queue->queue_depth.
>
> If you would like to propose to use max queue depth, we can get it from bdev as
> sbi->sb->s_bdev->bd_queue->queue_depth. Is it okay to use it in our FS? or you
> think it should be hardcoded to 32 (as most UFS/eMMC devices will have this as
> its queue depth)? Please let me know.
>
> Thanks,
>
> >
> > >
> > > Thanks,
> > >
> > > >
> > > > > dpolicy->io_aware = false;
> > > > > /* we need to issue all to keep CP_TRIMMED_FLAG */
> > > > > dpolicy->granularity = 1;
> > > > > @@ -1470,12 +1470,14 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > struct list_head *pend_list;
> > > > > struct discard_cmd *dc, *tmp;
> > > > > struct blk_plug plug;
> > > > > - int i, issued = 0;
> > > > > + int i, issued;
> > > > > bool io_interrupted = false;
> > > > >
> > > > > if (dpolicy->timeout != 0)
> > > > > f2fs_update_time(sbi, dpolicy->timeout);
> > > > >
> > > > > +retry:
> > > > > + issued = 0;
> > > > > for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
> > > > > if (dpolicy->timeout != 0 &&
> > > > > f2fs_time_over(sbi, dpolicy->timeout))
> > > > > @@ -1522,6 +1524,11 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > break;
> > > > > }
> > > > >
> > > > > + if (dpolicy->type == DPOLICY_UMOUNT && issued) {
> > > > > + __wait_all_discard_cmd(sbi, dpolicy);
> > > > > + goto retry;
> > > > > + }
> > > > > +
> > > > > if (!issued && io_interrupted)
> > > > > issued = -1;
> > > > >
> > > > > Thanks,
> > > > >
> > > > > >
> > > > > > >
> > > > > > > Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
> > > > > > > ---
> > > > > > > v3:
> > > > > > > -Handle the regression reported by Chao with v2.
> > > > > > > -simplify the logic to split the dc with multiple bios incase any bio returns
> > > > > > > EAGAIN and retry those new dc within 5 sec timeout.
> > > > > > >
> > > > > > > fs/f2fs/segment.c | 65 +++++++++++++++++++++++++++++++++++++++++++------------
> > > > > > > 1 file changed, 51 insertions(+), 14 deletions(-)
> > > > > > >
> > > > > > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > > > > > index fb3e531..55d18c7 100644
> > > > > > > --- a/fs/f2fs/segment.c
> > > > > > > +++ b/fs/f2fs/segment.c
> > > > > > > @@ -1029,13 +1029,16 @@ static void f2fs_submit_discard_endio(struct bio *bio)
> > > > > > > struct discard_cmd *dc = (struct discard_cmd *)bio->bi_private;
> > > > > > > unsigned long flags;
> > > > > > >
> > > > > > > - dc->error = blk_status_to_errno(bio->bi_status);
> > > > > > > -
> > > > > > > spin_lock_irqsave(&dc->lock, flags);
> > > > > > > + if (!dc->error)
> > > > > > > + dc->error = blk_status_to_errno(bio->bi_status);
> > > > > > > +
> > > > > > > dc->bio_ref--;
> > > > > > > - if (!dc->bio_ref && dc->state == D_SUBMIT) {
> > > > > > > - dc->state = D_DONE;
> > > > > > > - complete_all(&dc->wait);
> > > > > > > + if (!dc->bio_ref) {
> > > > > > > + if (dc->error || dc->state == D_SUBMIT) {
> > > > > > > + dc->state = D_DONE;
> > > > > > > + complete_all(&dc->wait);
> > > > > > > + }
> > > > > > > }
> > > > > > > spin_unlock_irqrestore(&dc->lock, flags);
> > > > > > > bio_put(bio);
> > > > > > > @@ -1124,10 +1127,13 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > > > struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
> > > > > > > struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ?
> > > > > > > &(dcc->fstrim_list) : &(dcc->wait_list);
> > > > > > > - int flag = dpolicy->sync ? REQ_SYNC : 0;
> > > > > > > + int flag;
> > > > > > > block_t lstart, start, len, total_len;
> > > > > > > int err = 0;
> > > > > > >
> > > > > > > + flag = dpolicy->sync ? REQ_SYNC : 0;
> > > > > > > + flag |= dpolicy->type == DPOLICY_UMOUNT ? REQ_NOWAIT : 0;
> > > > > > > +
> > > > > > > if (dc->state != D_PREP)
> > > > > > > return 0;
> > > > > > >
> > > > > > > @@ -1192,10 +1198,6 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > > > dc->bio_ref++;
> > > > > > > spin_unlock_irqrestore(&dc->lock, flags);
> > > > > > >
> > > > > > > - atomic_inc(&dcc->queued_discard);
> > > > > > > - dc->queued++;
> > > > > > > - list_move_tail(&dc->list, wait_list);
> > > > > > > -
> > > > > > > /* sanity check on discard range */
> > > > > > > __check_sit_bitmap(sbi, lstart, lstart + len);
> > > > > > >
> > > > > > > @@ -1203,6 +1205,29 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > > > bio->bi_end_io = f2fs_submit_discard_endio;
> > > > > > > bio->bi_opf |= flag;
> > > > > > > submit_bio(bio);
> > > > > > > + if (flag & REQ_NOWAIT) {
> > > > > > > + if (dc->error == -EAGAIN) {
> > > > > > > + spin_lock_irqsave(&dc->lock, flags);
> > > > > > > + dc->len -= len;
> > > > > > > + if (!dc->len) {
> > > > > > > + dc->len = total_len;
> > > > > > > + dc->state = D_PREP;
> > > > > > > + reinit_completion(&dc->wait);
> > > > > > > + } else {
> > > > > > > + dcc->undiscard_blks -= total_len;
> > > > > > > + if (dc->state == D_PARTIAL)
> > > > > > > + dc->state = D_SUBMIT;
> > > > > > > + }
> > > > > > > + err = dc->error;
> > > > > > > + dc->error = 0;
> > > > > > > + spin_unlock_irqrestore(&dc->lock, flags);
> > > > > > > + break;
> > > > > > > + }
> > > > > > > + }
> > > > > > > +
> > > > > > > + atomic_inc(&dcc->queued_discard);
> > > > > > > + dc->queued++;
> > > > > > > + list_move_tail(&dc->list, wait_list);
> > > > > > >
> > > > > > > atomic_inc(&dcc->issued_discard);
> > > > > > >
> > > > > > > @@ -1214,8 +1239,9 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > > > len = total_len;
> > > > > > > }
> > > > > > >
> > > > > > > - if (!err && len)
> > > > > > > - __update_discard_tree_range(sbi, bdev, lstart, start, len);
> > > > > > > + if ((!err || err == -EAGAIN) && total_len && dc->start != start)
> > > > > > > + __update_discard_tree_range(sbi, bdev, lstart, start,
> > > > > > > + total_len);
> > > > > > > return err;
> > > > > > > }
> > > > > > >
> > > > > > > @@ -1470,12 +1496,15 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > > > struct list_head *pend_list;
> > > > > > > struct discard_cmd *dc, *tmp;
> > > > > > > struct blk_plug plug;
> > > > > > > - int i, issued = 0;
> > > > > > > + int i, err, issued = 0;
> > > > > > > bool io_interrupted = false;
> > > > > > > + bool retry;
> > > > > > >
> > > > > > > if (dpolicy->timeout != 0)
> > > > > > > f2fs_update_time(sbi, dpolicy->timeout);
> > > > > > >
> > > > > > > +retry:
> > > > > > > + retry = false;
> > > > > > > for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
> > > > > > > if (dpolicy->timeout != 0 &&
> > > > > > > f2fs_time_over(sbi, dpolicy->timeout))
> > > > > > > @@ -1509,7 +1538,12 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > > > break;
> > > > > > > }
> > > > > > >
> > > > > > > - __submit_discard_cmd(sbi, dpolicy, dc, &issued);
> > > > > > > + err = __submit_discard_cmd(sbi, dpolicy, dc, &issued);
> > > > > > > + if (err == -EAGAIN) {
> > > > > > > + congestion_wait(BLK_RW_ASYNC,
> > > > > > > + DEFAULT_IO_TIMEOUT);
> > > > > > > + retry = true;
> > > > > > > + }
> > > > > > >
> > > > > > > if (issued >= dpolicy->max_requests)
> > > > > > > break;
> > > > > > > @@ -1522,6 +1556,9 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > > > break;
> > > > > > > }
> > > > > > >
> > > > > > > + if (retry)
> > > > > > > + goto retry;
> > > > > > > +
> > > > > > > if (!issued && io_interrupted)
> > > > > > > issued = -1;
> > > > > > >
> > > > > > > --
> > > > > > > Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
> > > > > > > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
> > > > >
> > > > > --
> > > > > --
> > > > > Sent by a consultant of the Qualcomm Innovation Center, Inc.
> > > > > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
> > >
> > > --
> > > --
> > > Sent by a consultant of the Qualcomm Innovation Center, Inc.
> > > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
>
> --
> --
> Sent by a consultant of the Qualcomm Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] [PATCH v3] f2fs: fix long latency due to discard during umount
2020-04-13 16:52 ` Jaegeuk Kim
@ 2020-04-14 17:45 ` Jaegeuk Kim
0 siblings, 0 replies; 7+ messages in thread
From: Jaegeuk Kim @ 2020-04-14 17:45 UTC (permalink / raw)
To: Sahitya Tummala; +Cc: linux-kernel, linux-f2fs-devel
Hi Sahitya,
Could you please post the revised patch?
Thanks,
On 04/13, Jaegeuk Kim wrote:
> On 04/09, Sahitya Tummala wrote:
> > On Wed, Apr 08, 2020 at 07:29:28PM -0700, Jaegeuk Kim wrote:
> > > On 04/08, Sahitya Tummala wrote:
> > > > Hi Jaegeuk,
> > > >
> > > > On Fri, Apr 03, 2020 at 10:19:43AM -0700, Jaegeuk Kim wrote:
> > > > > On 04/01, Sahitya Tummala wrote:
> > > > > > Hi Jaegeuk,
> > > > > >
> > > > > > On Tue, Mar 31, 2020 at 11:46:55AM -0700, Jaegeuk Kim wrote:
> > > > > > > On 03/30, Sahitya Tummala wrote:
> > > > > > > > F2FS already has a default timeout of 5 secs for discards that
> > > > > > > > can be issued during umount, but it can take more than the 5 sec
> > > > > > > > timeout if the underlying UFS device queue is already full and there
> > > > > > > > are no more available free tags to be used. In that case, submit_bio()
> > > > > > > > will wait for the already queued discard requests to complete to get
> > > > > > > > a free tag, which can potentially take way more than 5 sec.
> > > > > > > >
> > > > > > > > Fix this by submitting the discard requests with REQ_NOWAIT
> > > > > > > > flags during umount. This will return -EAGAIN for UFS queue/tag full
> > > > > > > > scenario without waiting in the context of submit_bio(). The FS can
> > > > > > > > then handle these requests by retrying again within the stipulated
> > > > > > > > discard timeout period to avoid long latencies.
> > > > > > >
> > > > > > > Sorry, Sahitya, but, do we really need to do like this? How about just
> > > > > > > controlling # of outstanding discarding bios in __issue_discard_cmd()?
> > > > > >
> > > > > > Do you mean something like this?
> > > > > >
> > > > > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > > > > index 1a62b27..860dd43 100644
> > > > > > --- a/fs/f2fs/segment.c
> > > > > > +++ b/fs/f2fs/segment.c
> > > > > > @@ -1099,7 +1099,7 @@ static void __init_discard_policy(struct f2fs_sb_info *sbi,
> > > > > > } else if (discard_type == DPOLICY_FSTRIM) {
> > > > > > dpolicy->io_aware = false;
> > > > > > } else if (discard_type == DPOLICY_UMOUNT) {
> > > > > > - dpolicy->max_requests = UINT_MAX;
> > > > > > + dpolicy->max_requests = 30;
> > > > >
> > > > > Can we use max queue depth of the block device?
> > > >
> > > > I think it should be limited to 8 or 16 as Chao suggested, so that we can have
> > > > better control on the given timeout value? Thoughts?
> > >
> > > Where is 8 or 16 coming from? What about SSD? Sorry, it's unclear to me.
> >
> > With this patch we now wait for a batch of discard requests in __issue_discard_cmd()
> > with a upper timeout of 5 sec. So, I thought that having a smaller batch of
> > discard requests would help us to avoid queuing more requests and end up waiting
> > for more time in __wait_all_discard_cmd(). Today we have DEF_MAX_DISCARD_REQUEST
> > as 8 for default max discard requests. If it too less, may be for umount
> > we can use 16 instead. But the idea is to avoid more wait time.
>
> Ok, then, it seems we can just remove this line to use dpolicy->max_requests,
> and retry issuing all the discard commands like below. Later, I thnk it'd be
> fine to tune the max_requests based on bd_queue->queue_depth.
>
> >
> > If you would like to propose to use max queue depth, we can get it from bdev as
> > sbi->sb->s_bdev->bd_queue->queue_depth. Is it okay to use it in our FS? or you
> > think it should be hardcoded to 32 (as most UFS/eMMC devices will have this as
> > its queue depth)? Please let me know.
> >
> > Thanks,
> >
> > >
> > > >
> > > > Thanks,
> > > >
> > > > >
> > > > > > dpolicy->io_aware = false;
> > > > > > /* we need to issue all to keep CP_TRIMMED_FLAG */
> > > > > > dpolicy->granularity = 1;
> > > > > > @@ -1470,12 +1470,14 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > > struct list_head *pend_list;
> > > > > > struct discard_cmd *dc, *tmp;
> > > > > > struct blk_plug plug;
> > > > > > - int i, issued = 0;
> > > > > > + int i, issued;
> > > > > > bool io_interrupted = false;
> > > > > >
> > > > > > if (dpolicy->timeout != 0)
> > > > > > f2fs_update_time(sbi, dpolicy->timeout);
> > > > > >
> > > > > > +retry:
> > > > > > + issued = 0;
> > > > > > for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
> > > > > > if (dpolicy->timeout != 0 &&
> > > > > > f2fs_time_over(sbi, dpolicy->timeout))
> > > > > > @@ -1522,6 +1524,11 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > > break;
> > > > > > }
> > > > > >
> > > > > > + if (dpolicy->type == DPOLICY_UMOUNT && issued) {
> > > > > > + __wait_all_discard_cmd(sbi, dpolicy);
> > > > > > + goto retry;
> > > > > > + }
> > > > > > +
> > > > > > if (!issued && io_interrupted)
> > > > > > issued = -1;
> > > > > >
> > > > > > Thanks,
> > > > > >
> > > > > > >
> > > > > > > >
> > > > > > > > Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
> > > > > > > > ---
> > > > > > > > v3:
> > > > > > > > -Handle the regression reported by Chao with v2.
> > > > > > > > -simplify the logic to split the dc with multiple bios incase any bio returns
> > > > > > > > EAGAIN and retry those new dc within 5 sec timeout.
> > > > > > > >
> > > > > > > > fs/f2fs/segment.c | 65 +++++++++++++++++++++++++++++++++++++++++++------------
> > > > > > > > 1 file changed, 51 insertions(+), 14 deletions(-)
> > > > > > > >
> > > > > > > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > > > > > > index fb3e531..55d18c7 100644
> > > > > > > > --- a/fs/f2fs/segment.c
> > > > > > > > +++ b/fs/f2fs/segment.c
> > > > > > > > @@ -1029,13 +1029,16 @@ static void f2fs_submit_discard_endio(struct bio *bio)
> > > > > > > > struct discard_cmd *dc = (struct discard_cmd *)bio->bi_private;
> > > > > > > > unsigned long flags;
> > > > > > > >
> > > > > > > > - dc->error = blk_status_to_errno(bio->bi_status);
> > > > > > > > -
> > > > > > > > spin_lock_irqsave(&dc->lock, flags);
> > > > > > > > + if (!dc->error)
> > > > > > > > + dc->error = blk_status_to_errno(bio->bi_status);
> > > > > > > > +
> > > > > > > > dc->bio_ref--;
> > > > > > > > - if (!dc->bio_ref && dc->state == D_SUBMIT) {
> > > > > > > > - dc->state = D_DONE;
> > > > > > > > - complete_all(&dc->wait);
> > > > > > > > + if (!dc->bio_ref) {
> > > > > > > > + if (dc->error || dc->state == D_SUBMIT) {
> > > > > > > > + dc->state = D_DONE;
> > > > > > > > + complete_all(&dc->wait);
> > > > > > > > + }
> > > > > > > > }
> > > > > > > > spin_unlock_irqrestore(&dc->lock, flags);
> > > > > > > > bio_put(bio);
> > > > > > > > @@ -1124,10 +1127,13 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > > > > struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
> > > > > > > > struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ?
> > > > > > > > &(dcc->fstrim_list) : &(dcc->wait_list);
> > > > > > > > - int flag = dpolicy->sync ? REQ_SYNC : 0;
> > > > > > > > + int flag;
> > > > > > > > block_t lstart, start, len, total_len;
> > > > > > > > int err = 0;
> > > > > > > >
> > > > > > > > + flag = dpolicy->sync ? REQ_SYNC : 0;
> > > > > > > > + flag |= dpolicy->type == DPOLICY_UMOUNT ? REQ_NOWAIT : 0;
> > > > > > > > +
> > > > > > > > if (dc->state != D_PREP)
> > > > > > > > return 0;
> > > > > > > >
> > > > > > > > @@ -1192,10 +1198,6 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > > > > dc->bio_ref++;
> > > > > > > > spin_unlock_irqrestore(&dc->lock, flags);
> > > > > > > >
> > > > > > > > - atomic_inc(&dcc->queued_discard);
> > > > > > > > - dc->queued++;
> > > > > > > > - list_move_tail(&dc->list, wait_list);
> > > > > > > > -
> > > > > > > > /* sanity check on discard range */
> > > > > > > > __check_sit_bitmap(sbi, lstart, lstart + len);
> > > > > > > >
> > > > > > > > @@ -1203,6 +1205,29 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > > > > bio->bi_end_io = f2fs_submit_discard_endio;
> > > > > > > > bio->bi_opf |= flag;
> > > > > > > > submit_bio(bio);
> > > > > > > > + if (flag & REQ_NOWAIT) {
> > > > > > > > + if (dc->error == -EAGAIN) {
> > > > > > > > + spin_lock_irqsave(&dc->lock, flags);
> > > > > > > > + dc->len -= len;
> > > > > > > > + if (!dc->len) {
> > > > > > > > + dc->len = total_len;
> > > > > > > > + dc->state = D_PREP;
> > > > > > > > + reinit_completion(&dc->wait);
> > > > > > > > + } else {
> > > > > > > > + dcc->undiscard_blks -= total_len;
> > > > > > > > + if (dc->state == D_PARTIAL)
> > > > > > > > + dc->state = D_SUBMIT;
> > > > > > > > + }
> > > > > > > > + err = dc->error;
> > > > > > > > + dc->error = 0;
> > > > > > > > + spin_unlock_irqrestore(&dc->lock, flags);
> > > > > > > > + break;
> > > > > > > > + }
> > > > > > > > + }
> > > > > > > > +
> > > > > > > > + atomic_inc(&dcc->queued_discard);
> > > > > > > > + dc->queued++;
> > > > > > > > + list_move_tail(&dc->list, wait_list);
> > > > > > > >
> > > > > > > > atomic_inc(&dcc->issued_discard);
> > > > > > > >
> > > > > > > > @@ -1214,8 +1239,9 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > > > > len = total_len;
> > > > > > > > }
> > > > > > > >
> > > > > > > > - if (!err && len)
> > > > > > > > - __update_discard_tree_range(sbi, bdev, lstart, start, len);
> > > > > > > > + if ((!err || err == -EAGAIN) && total_len && dc->start != start)
> > > > > > > > + __update_discard_tree_range(sbi, bdev, lstart, start,
> > > > > > > > + total_len);
> > > > > > > > return err;
> > > > > > > > }
> > > > > > > >
> > > > > > > > @@ -1470,12 +1496,15 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > > > > struct list_head *pend_list;
> > > > > > > > struct discard_cmd *dc, *tmp;
> > > > > > > > struct blk_plug plug;
> > > > > > > > - int i, issued = 0;
> > > > > > > > + int i, err, issued = 0;
> > > > > > > > bool io_interrupted = false;
> > > > > > > > + bool retry;
> > > > > > > >
> > > > > > > > if (dpolicy->timeout != 0)
> > > > > > > > f2fs_update_time(sbi, dpolicy->timeout);
> > > > > > > >
> > > > > > > > +retry:
> > > > > > > > + retry = false;
> > > > > > > > for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
> > > > > > > > if (dpolicy->timeout != 0 &&
> > > > > > > > f2fs_time_over(sbi, dpolicy->timeout))
> > > > > > > > @@ -1509,7 +1538,12 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > > > > break;
> > > > > > > > }
> > > > > > > >
> > > > > > > > - __submit_discard_cmd(sbi, dpolicy, dc, &issued);
> > > > > > > > + err = __submit_discard_cmd(sbi, dpolicy, dc, &issued);
> > > > > > > > + if (err == -EAGAIN) {
> > > > > > > > + congestion_wait(BLK_RW_ASYNC,
> > > > > > > > + DEFAULT_IO_TIMEOUT);
> > > > > > > > + retry = true;
> > > > > > > > + }
> > > > > > > >
> > > > > > > > if (issued >= dpolicy->max_requests)
> > > > > > > > break;
> > > > > > > > @@ -1522,6 +1556,9 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > > > > > > > break;
> > > > > > > > }
> > > > > > > >
> > > > > > > > + if (retry)
> > > > > > > > + goto retry;
> > > > > > > > +
> > > > > > > > if (!issued && io_interrupted)
> > > > > > > > issued = -1;
> > > > > > > >
> > > > > > > > --
> > > > > > > > Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
> > > > > > > > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
> > > > > >
> > > > > > --
> > > > > > --
> > > > > > Sent by a consultant of the Qualcomm Innovation Center, Inc.
> > > > > > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
> > > >
> > > > --
> > > > --
> > > > Sent by a consultant of the Qualcomm Innovation Center, Inc.
> > > > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
> >
> > --
> > --
> > Sent by a consultant of the Qualcomm Innovation Center, Inc.
> > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
>
>
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2020-04-14 17:46 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
[not found] <1585550730-1858-1-git-send-email-stummala@codeaurora.org>
2020-03-31 18:46 ` [f2fs-dev] [PATCH v3] f2fs: fix long latency due to discard during umount Jaegeuk Kim
2020-04-01 9:22 ` Sahitya Tummala
2020-04-02 9:32 ` Chao Yu
2020-04-03 17:19 ` Jaegeuk Kim
[not found] ` <20200408090024.GC20234@codeaurora.org>
2020-04-09 2:29 ` Jaegeuk Kim
[not found] ` <20200409114756.GD20234@codeaurora.org>
2020-04-13 16:52 ` Jaegeuk Kim
2020-04-14 17:45 ` Jaegeuk Kim
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