linux-kernel - [PATCH] PM / Wakeup / freezer: Check pm_wakeup_pending() before freeze

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Message-Id: <1742278664-398536-1-git-send-email-liuyuan1@oppo.com>
Date: Tue, 18 Mar 2025 14:17:44 +0800
From: liuyuan1 <liuyuan1@...o.com>
To: rafael@...nel.org,
	len.brown@...el.com,
	pavel@...nel.org
Cc: linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	chenzhengding@...o.com,
	liuyuan1 <liuyuan1@...o.com>
Subject: [PATCH] PM / Wakeup / freezer: Check pm_wakeup_pending() before freeze_task()

Check pm_wakeup_pending() before freeze_task() can reduce
overhead by not freeze tasks in aborted case. freeze_task()
will cause high cpu loading especially when system has a large
number of tasks need to be freeze.

Signed-off-by: liuyuan1 <liuyuan1@...o.com>
---
 kernel/power/process.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/kernel/power/process.c b/kernel/power/process.c
index 66ac067..84704b3 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -49,6 +49,12 @@ static int try_to_freeze_tasks(bool user_only)
 
 	while (true) {
 		todo = 0;
+		if (pm_wakeup_pending()) {
+			wakeup = true;
+			todo++;
+			break;
+		}
+
 		read_lock(&tasklist_lock);
 		for_each_process_thread(g, p) {
 			if (p == current || !freeze_task(p))
@@ -66,11 +72,6 @@ static int try_to_freeze_tasks(bool user_only)
 		if (!todo || time_after(jiffies, end_time))
 			break;
 
-		if (pm_wakeup_pending()) {
-			wakeup = true;
-			break;
-		}
-
 		/*
 		 * We need to retry, but first give the freezing tasks some
 		 * time to enter the refrigerator.  Start with an initial
-- 
2.7.4