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

From: Chao Yu
Date: Wed Nov 23 2022 - 10:36:49 EST


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 <frank.li@xxxxxxxx>
---
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);