Fix the unnecessary periodic wakeups of discard thread that happens under
below two conditions -
1. When f2fs is heavily utilized over 80%, the current discard policy
sets the max sleep timeout of discard thread as 50ms
(DEF_MIN_DISCARD_ISSUE_TIME). But this is set even when there are
no pending discard commands to be issued.
2. In the issue_discard_thread() path when there are no pending discard
commands, it fails to reset the wait_ms to max timeout value.
Signed-off-by: Sahitya Tummala <stumm...@codeaurora.org>
---
v2:
- Fix the second scenario mentioned above in commit text
fs/f2fs/segment.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index d7076796..59efec5 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1112,6 +1112,8 @@ static void __init_discard_policy(struct f2fs_sb_info
*sbi,
struct discard_policy *dpolicy,
int discard_type, unsigned int granularity)
{
+ struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+
/* common policy */
dpolicy->type = discard_type;
dpolicy->sync = true;
@@ -1131,7 +1133,9 @@ static void __init_discard_policy(struct f2fs_sb_info
*sbi,
dpolicy->ordered = true;
if (utilization(sbi) > DEF_DISCARD_URGENT_UTIL) {
dpolicy->granularity = 1;
- dpolicy->max_interval = DEF_MIN_DISCARD_ISSUE_TIME;
+ if (atomic_read(&dcc->discard_cmd_cnt))
+ dpolicy->max_interval =
+ DEF_MIN_DISCARD_ISSUE_TIME;
}
} else if (discard_type == DPOLICY_FORCE) {
dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME;
@@ -1747,8 +1751,15 @@ static int issue_discard_thread(void *data)
set_freezable();
do {
- __init_discard_policy(sbi, &dpolicy, DPOLICY_BG,
- dcc->discard_granularity);
+ if (sbi->gc_mode == GC_URGENT_HIGH ||
+ !f2fs_available_free_memory(sbi, DISCARD_CACHE))
+ __init_discard_policy(sbi, &dpolicy, DPOLICY_FORCE, 1);
+ else
+ __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) ||
@@ -1775,10 +1786,6 @@ static int issue_discard_thread(void *data)
if (!atomic_read(&dcc->discard_cmd_cnt))
continue;
- if (sbi->gc_mode == GC_URGENT_HIGH ||
- !f2fs_available_free_memory(sbi, DISCARD_CACHE))
- __init_discard_policy(sbi, &dpolicy, DPOLICY_FORCE, 1);
-
sb_start_intwrite(sbi->sb);
issued = __issue_discard_cmd(sbi, &dpolicy);
--
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.
