+ delayacct-fix-incomplete-disable-operation-when-switch-enable-to-disable.patch added to -mm tree

+ delayacct-fix-incomplete-disable-operation-when-switch-enable-to-disable.patch added to -mm tree

[akpm]

The patch titled
     Subject: delayacct: fix incomplete disable operation when switch enable to disable
has been added to the -mm tree.  Its filename is
     delayacct-fix-incomplete-disable-operation-when-switch-enable-to-disable.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/delayacct-fix-incomplete-disable-operation-when-switch-enable-to-disable.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/delayacct-fix-incomplete-disable-operation-when-switch-enable-to-disable.patch

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The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Yang Yang <yang.yang29@zte.com.cn>
Subject: delayacct: fix incomplete disable operation when switch enable to disable

When a task is created after delayacct is enabled, kernel will do all the
delay accountings for that task.  The problems is if user disables
delayacct by set /proc/sys/kernel/task_delayacct to zero, only blkio delay
accounting is disabled.

Now disable all the kinds of delay accountings when
/proc/sys/kernel/task_delayacct sets to zero.

Link: https://lkml.kernel.org/r/20211123140342.32962-1-ran.xiaokai@zte.com.cn
Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Reported-by: Zeal Robot <zealci@zte.com.cn>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/delayacct.h |   18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

--- a/include/linux/delayacct.h~delayacct-fix-incomplete-disable-operation-when-switch-enable-to-disable
+++ a/include/linux/delayacct.h
@@ -131,36 +131,54 @@ static inline __u64 delayacct_blkio_tick
 
 static inline void delayacct_freepages_start(void)
 {
+	if (!static_branch_unlikely(&delayacct_key))
+		return;
+
 	if (current->delays)
 		__delayacct_freepages_start();
 }
 
 static inline void delayacct_freepages_end(void)
 {
+	if (!static_branch_unlikely(&delayacct_key))
+		return;
+
 	if (current->delays)
 		__delayacct_freepages_end();
 }
 
 static inline void delayacct_thrashing_start(void)
 {
+	if (!static_branch_unlikely(&delayacct_key))
+		return;
+
 	if (current->delays)
 		__delayacct_thrashing_start();
 }
 
 static inline void delayacct_thrashing_end(void)
 {
+	if (!static_branch_unlikely(&delayacct_key))
+		return;
+
 	if (current->delays)
 		__delayacct_thrashing_end();
 }
 
 static inline void delayacct_swapin_start(void)
 {
+	if (!static_branch_unlikely(&delayacct_key))
+		return;
+
 	if (current->delays)
 		__delayacct_swapin_start();
 }
 
 static inline void delayacct_swapin_end(void)
 {
+	if (!static_branch_unlikely(&delayacct_key))
+		return;
+
 	if (current->delays)
 		__delayacct_swapin_end();
 }
_

Patches currently in -mm which might be from yang.yang29@zte.com.cn are

delayacct-support-swapin-delay-accounting-for-swapping-without-blkio.patch
delayacct-fix-incomplete-disable-operation-when-switch-enable-to-disable.patch