linux-kernel - [PATCH] f2fs: do decrease_sleep_time() if any of the victims have been selected

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Date:   Fri,  9 Dec 2022 19:28:13 +0800
From:   Yuwei Guan <ssawgyw@...il.com>
To:     jaegeuk@...nel.org, chao@...nel.org
Cc:     linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org, Yuwei.Guan@...krlife.com
Subject: [PATCH] f2fs: do decrease_sleep_time() if any of the victims have been selected

In non-foreground gc mode, if no victim is selected, the gc process
will wait for no_gc_sleep_time before waking up again. In this
subsequent time, even though a victim will be selected, the gc process
still waits for no_gc_sleep_time before waking up. The configuration
of wait_ms is not reasonable.

After any of the victims have been selected, we need to do
decrease_sleep_time() to reduce wait_ms.

If it is GC_URGENT_HIGH or GC_URGENT_MID gc mode,
wait_ms will keep urgent_sleep_time after executing decrease_sleep_time().

In decrease_sleep_time() wait_time will be reduced to max_sleep_time
from no_gc_sleep_time, if *wait is no_gc_sleep_time. And then it goes
down in the next step.

Signed-off-by: Yuwei Guan <Yuwei.Guan@...krlife.com>
---
 fs/f2fs/gc.c | 2 ++
 fs/f2fs/gc.h | 7 ++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index f0c6506d8975..c023ffeb9268 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -141,6 +141,8 @@ static int gc_thread_func(void *data)
 			/* don't bother wait_ms by foreground gc */
 			if (!foreground)
 				wait_ms = gc_th->no_gc_sleep_time;
+		} else {
+			decrease_sleep_time(gc_th, &wait_ms);
 		}

 		if (foreground)
diff --git a/fs/f2fs/gc.h b/fs/f2fs/gc.h
index 19b956c2d697..6402584dcd72 100644
--- a/fs/f2fs/gc.h
+++ b/fs/f2fs/gc.h
@@ -150,8 +150,13 @@ static inline void decrease_sleep_time(struct f2fs_gc_kthread *gc_th,
 {
 	unsigned int min_time = gc_th->min_sleep_time;

-	if (*wait == gc_th->no_gc_sleep_time)
+	if (*wait == gc_th->urgent_sleep_time)
+		return;
+
+	if (*wait == gc_th->no_gc_sleep_time) {
 		*wait = gc_th->max_sleep_time;
+		return;
+	}

 	if ((long long)*wait - (long long)min_time < (long long)min_time)
 		*wait = min_time;
-- 
2.34.1