2022-11-18 04:06:29

by 李扬韬

Subject: [PATCH] f2fs: init discard policy after thread wakeup

Under the current logic, after the discard thread wakes up, it will not
run according to the expected policy, but will use the expected policy
before sleep. Move the strategy selection to after the thread wakes up,
so that the running state of the thread meets expectations.

Signed-off-by: Yangtao Li <[email protected]>
---
fs/f2fs/segment.c | 20 +++++++++-----------
1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 8b0b76550578..609e90aa80c2 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1685,6 +1685,11 @@ static int issue_discard_thread(void *data)
set_freezable();

do {
+ wait_event_interruptible_timeout(*q,
+ kthread_should_stop() || freezing(current) ||
+ dcc->discard_wake,
+ msecs_to_jiffies(wait_ms));
+
if (sbi->gc_mode == GC_URGENT_HIGH ||
!f2fs_available_free_memory(sbi, DISCARD_CACHE))
__init_discard_policy(sbi, &dpolicy, DPOLICY_FORCE, 1);
@@ -1692,14 +1697,6 @@ static int issue_discard_thread(void *data)
__init_discard_policy(sbi, &dpolicy, DPOLICY_BG,
dcc->discard_granularity);

- if (!atomic_read(&dcc->discard_cmd_cnt))
- wait_ms = dpolicy.max_interval;
-
- wait_event_interruptible_timeout(*q,
- kthread_should_stop() || freezing(current) ||
- dcc->discard_wake,
- msecs_to_jiffies(wait_ms));
-
if (dcc->discard_wake)
dcc->discard_wake = 0;

@@ -1713,12 +1710,11 @@ static int issue_discard_thread(void *data)
continue;
if (kthread_should_stop())
return 0;
- if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
+ if (is_sbi_flag_set(sbi, SBI_NEED_FSCK) ||
+ !atomic_read(&dcc->discard_cmd_cnt)) {
wait_ms = dpolicy.max_interval;
continue;
}
- if (!atomic_read(&dcc->discard_cmd_cnt))
- continue;

sb_start_intwrite(sbi->sb);

@@ -1733,6 +1729,8 @@ static int issue_discard_thread(void *data)
} else {
wait_ms = dpolicy.max_interval;
}
+ if (!atomic_read(&dcc->discard_cmd_cnt))
+ wait_ms = dpolicy.max_interval;

sb_end_intwrite(sbi->sb);

--
2.25.1

2022-11-23 15:44:00

by Chao Yu

Subject: Re: [PATCH] f2fs: init discard policy after thread wakeup

On 2022/11/18 11:46, Yangtao Li wrote:
> Under the current logic, after the discard thread wakes up, it will not
> run according to the expected policy, but will use the expected policy
> before sleep. Move the strategy selection to after the thread wakes up,
> so that the running state of the thread meets expectations.
>
> Signed-off-by: Yangtao Li <[email protected]>
> ---
> fs/f2fs/segment.c | 20 +++++++++-----------
> 1 file changed, 9 insertions(+), 11 deletions(-)
>
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 8b0b76550578..609e90aa80c2 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1685,6 +1685,11 @@ static int issue_discard_thread(void *data)
> set_freezable();
>
> do {

if (!atomic_read(&dcc->discard_cmd_cnt))
wait_ms = dpolicy.max_interval;

Thanks,

> + wait_event_interruptible_timeout(*q,
> + kthread_should_stop() || freezing(current) ||
> + dcc->discard_wake,
> + msecs_to_jiffies(wait_ms));
> +
> if (sbi->gc_mode == GC_URGENT_HIGH ||
> !f2fs_available_free_memory(sbi, DISCARD_CACHE))
> __init_discard_policy(sbi, &dpolicy, DPOLICY_FORCE, 1);
> @@ -1692,14 +1697,6 @@ static int issue_discard_thread(void *data)
> __init_discard_policy(sbi, &dpolicy, DPOLICY_BG,
> dcc->discard_granularity);
>
> - if (!atomic_read(&dcc->discard_cmd_cnt))
> - wait_ms = dpolicy.max_interval;
> -
> - wait_event_interruptible_timeout(*q,
> - kthread_should_stop() || freezing(current) ||
> - dcc->discard_wake,
> - msecs_to_jiffies(wait_ms));
> -
> if (dcc->discard_wake)
> dcc->discard_wake = 0;
>
> @@ -1713,12 +1710,11 @@ static int issue_discard_thread(void *data)
> continue;
> if (kthread_should_stop())
> return 0;
> - if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
> + if (is_sbi_flag_set(sbi, SBI_NEED_FSCK) ||
> + !atomic_read(&dcc->discard_cmd_cnt)) {
> wait_ms = dpolicy.max_interval;
> continue;
> }
> - if (!atomic_read(&dcc->discard_cmd_cnt))
> - continue;
>
> sb_start_intwrite(sbi->sb);
>
> @@ -1733,6 +1729,8 @@ static int issue_discard_thread(void *data)
> } else {
> wait_ms = dpolicy.max_interval;
> }
> + if (!atomic_read(&dcc->discard_cmd_cnt))
> + wait_ms = dpolicy.max_interval;
>
> sb_end_intwrite(sbi->sb);
>

2022-11-23 16:33:00

by 李扬韬

Subject: Re: [PATCH] f2fs: init discard policy after thread wakeup

HI Chao,
>> set_freezable();
>>
>> do {
>
> if (!atomic_read(&dcc->discard_cmd_cnt))
> wait_ms = dpolicy.max_interval;

dpolicy has not been initialized for the first time, and the value in the stack is unstable.

Thx,
Yangtao

2022-11-24 14:23:42

by Chao Yu

Subject: Re: [PATCH] f2fs: init discard policy after thread wakeup

On 2022/11/18 11:46, Yangtao Li wrote:
> Under the current logic, after the discard thread wakes up, it will not
> run according to the expected policy, but will use the expected policy
> before sleep. Move the strategy selection to after the thread wakes up,
> so that the running state of the thread meets expectations.
>
> Signed-off-by: Yangtao Li <[email protected]>

Reviewed-by: Chao Yu <[email protected]>

Thanks,