* [PATCH] locking/rwsem: use OWNER_NONSPINNABLE directly instead of OWNER_SPINNABLE
@ 2025-06-10 13:01 alexjlzheng
2025-06-13 5:52 ` Waiman Long
2025-07-19 17:40 ` [tip: locking/core] locking/rwsem: Use " tip-bot2 for Jinliang Zheng
0 siblings, 2 replies; 4+ messages in thread
From: alexjlzheng @ 2025-06-10 13:01 UTC (permalink / raw)
To: peterz, will, boqun.feng, longman; +Cc: linux-kernel, Jinliang Zheng
From: Jinliang Zheng <alexjlzheng@tencent.com>
After commit 7d43f1ce9dd0 ("locking/rwsem: Enable time-based spinning on
reader-owned rwsem"), OWNER_SPINNABLE contains all possible values except
OWNER_NONSPINNABLE, namely OWNER_NULL | OWNER_WRITER | OWNER_READER.
Therefore, it is better to use OWNER_NONSPINNABLE directly to determine
whether to exit optimistic spin.
And, remove useless OWNER_SPINNABLE to simplify the code.
Signed-off-by: Jinliang Zheng <alexjlzheng@tencent.com>
---
kernel/locking/rwsem.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index 2ddb827e3bea..8572dba95af4 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -727,8 +727,6 @@ static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem)
return ret;
}
-#define OWNER_SPINNABLE (OWNER_NULL | OWNER_WRITER | OWNER_READER)
-
static inline enum owner_state
rwsem_owner_state(struct task_struct *owner, unsigned long flags)
{
@@ -835,7 +833,7 @@ static bool rwsem_optimistic_spin(struct rw_semaphore *sem)
enum owner_state owner_state;
owner_state = rwsem_spin_on_owner(sem);
- if (!(owner_state & OWNER_SPINNABLE))
+ if (owner_state == OWNER_NONSPINNABLE)
break;
/*
--
2.49.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] locking/rwsem: use OWNER_NONSPINNABLE directly instead of OWNER_SPINNABLE
2025-06-10 13:01 [PATCH] locking/rwsem: use OWNER_NONSPINNABLE directly instead of OWNER_SPINNABLE alexjlzheng
@ 2025-06-13 5:52 ` Waiman Long
2025-06-17 17:13 ` Boqun Feng
2025-07-19 17:40 ` [tip: locking/core] locking/rwsem: Use " tip-bot2 for Jinliang Zheng
1 sibling, 1 reply; 4+ messages in thread
From: Waiman Long @ 2025-06-13 5:52 UTC (permalink / raw)
To: alexjlzheng, peterz, will, boqun.feng; +Cc: linux-kernel, Jinliang Zheng
On 6/10/25 9:01 AM, alexjlzheng@gmail.com wrote:
> From: Jinliang Zheng <alexjlzheng@tencent.com>
>
> After commit 7d43f1ce9dd0 ("locking/rwsem: Enable time-based spinning on
> reader-owned rwsem"), OWNER_SPINNABLE contains all possible values except
> OWNER_NONSPINNABLE, namely OWNER_NULL | OWNER_WRITER | OWNER_READER.
>
> Therefore, it is better to use OWNER_NONSPINNABLE directly to determine
> whether to exit optimistic spin.
>
> And, remove useless OWNER_SPINNABLE to simplify the code.
>
> Signed-off-by: Jinliang Zheng <alexjlzheng@tencent.com>
> ---
> kernel/locking/rwsem.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
> index 2ddb827e3bea..8572dba95af4 100644
> --- a/kernel/locking/rwsem.c
> +++ b/kernel/locking/rwsem.c
> @@ -727,8 +727,6 @@ static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem)
> return ret;
> }
>
> -#define OWNER_SPINNABLE (OWNER_NULL | OWNER_WRITER | OWNER_READER)
> -
> static inline enum owner_state
> rwsem_owner_state(struct task_struct *owner, unsigned long flags)
> {
> @@ -835,7 +833,7 @@ static bool rwsem_optimistic_spin(struct rw_semaphore *sem)
> enum owner_state owner_state;
>
> owner_state = rwsem_spin_on_owner(sem);
> - if (!(owner_state & OWNER_SPINNABLE))
> + if (owner_state == OWNER_NONSPINNABLE)
> break;
>
> /*
Right, OWNER_SPINNABLE is no longer needed after commit 7d43f1ce9dd0.
Acked-by: Waiman Long <longman@redhat.com>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] locking/rwsem: use OWNER_NONSPINNABLE directly instead of OWNER_SPINNABLE
2025-06-13 5:52 ` Waiman Long
@ 2025-06-17 17:13 ` Boqun Feng
0 siblings, 0 replies; 4+ messages in thread
From: Boqun Feng @ 2025-06-17 17:13 UTC (permalink / raw)
To: Waiman Long; +Cc: alexjlzheng, peterz, will, linux-kernel, Jinliang Zheng
On Fri, Jun 13, 2025 at 01:52:43AM -0400, Waiman Long wrote:
>
> On 6/10/25 9:01 AM, alexjlzheng@gmail.com wrote:
> > From: Jinliang Zheng <alexjlzheng@tencent.com>
> >
> > After commit 7d43f1ce9dd0 ("locking/rwsem: Enable time-based spinning on
> > reader-owned rwsem"), OWNER_SPINNABLE contains all possible values except
> > OWNER_NONSPINNABLE, namely OWNER_NULL | OWNER_WRITER | OWNER_READER.
> >
> > Therefore, it is better to use OWNER_NONSPINNABLE directly to determine
> > whether to exit optimistic spin.
> >
> > And, remove useless OWNER_SPINNABLE to simplify the code.
> >
> > Signed-off-by: Jinliang Zheng <alexjlzheng@tencent.com>
> > ---
> > kernel/locking/rwsem.c | 4 +---
> > 1 file changed, 1 insertion(+), 3 deletions(-)
> >
> > diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
> > index 2ddb827e3bea..8572dba95af4 100644
> > --- a/kernel/locking/rwsem.c
> > +++ b/kernel/locking/rwsem.c
> > @@ -727,8 +727,6 @@ static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem)
> > return ret;
> > }
> > -#define OWNER_SPINNABLE (OWNER_NULL | OWNER_WRITER | OWNER_READER)
> > -
> > static inline enum owner_state
> > rwsem_owner_state(struct task_struct *owner, unsigned long flags)
> > {
> > @@ -835,7 +833,7 @@ static bool rwsem_optimistic_spin(struct rw_semaphore *sem)
> > enum owner_state owner_state;
> > owner_state = rwsem_spin_on_owner(sem);
> > - if (!(owner_state & OWNER_SPINNABLE))
> > + if (owner_state == OWNER_NONSPINNABLE)
> > break;
> > /*
>
> Right, OWNER_SPINNABLE is no longer needed after commit 7d43f1ce9dd0.
>
> Acked-by: Waiman Long <longman@redhat.com>
>
Queued for more tests and reviews, thank you both!
Regards,
Boqun
^ permalink raw reply [flat|nested] 4+ messages in thread
* [tip: locking/core] locking/rwsem: Use OWNER_NONSPINNABLE directly instead of OWNER_SPINNABLE
2025-06-10 13:01 [PATCH] locking/rwsem: use OWNER_NONSPINNABLE directly instead of OWNER_SPINNABLE alexjlzheng
2025-06-13 5:52 ` Waiman Long
@ 2025-07-19 17:40 ` tip-bot2 for Jinliang Zheng
1 sibling, 0 replies; 4+ messages in thread
From: tip-bot2 for Jinliang Zheng @ 2025-07-19 17:40 UTC (permalink / raw)
To: linux-tip-commits
Cc: Jinliang Zheng, Waiman Long, Boqun Feng, x86, linux-kernel
The following commit has been merged into the locking/core branch of tip:
Commit-ID: f84a15b90d96f3da99f67fea2e116850d99fb7c4
Gitweb: https://git.kernel.org/tip/f84a15b90d96f3da99f67fea2e116850d99fb7c4
Author: Jinliang Zheng <alexjlzheng@tencent.com>
AuthorDate: Tue, 10 Jun 2025 21:01:58 +08:00
Committer: Boqun Feng <boqun.feng@gmail.com>
CommitterDate: Fri, 11 Jul 2025 15:11:54 -07:00
locking/rwsem: Use OWNER_NONSPINNABLE directly instead of OWNER_SPINNABLE
After commit 7d43f1ce9dd0 ("locking/rwsem: Enable time-based spinning on
reader-owned rwsem"), OWNER_SPINNABLE contains all possible values except
OWNER_NONSPINNABLE, namely OWNER_NULL | OWNER_WRITER | OWNER_READER.
Therefore, it is better to use OWNER_NONSPINNABLE directly to determine
whether to exit optimistic spin.
And, remove useless OWNER_SPINNABLE to simplify the code.
Signed-off-by: Jinliang Zheng <alexjlzheng@tencent.com>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20250610130158.4876-1-alexjlzheng@tencent.com
---
kernel/locking/rwsem.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index 2ddb827..8572dba 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -727,8 +727,6 @@ static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem)
return ret;
}
-#define OWNER_SPINNABLE (OWNER_NULL | OWNER_WRITER | OWNER_READER)
-
static inline enum owner_state
rwsem_owner_state(struct task_struct *owner, unsigned long flags)
{
@@ -835,7 +833,7 @@ static bool rwsem_optimistic_spin(struct rw_semaphore *sem)
enum owner_state owner_state;
owner_state = rwsem_spin_on_owner(sem);
- if (!(owner_state & OWNER_SPINNABLE))
+ if (owner_state == OWNER_NONSPINNABLE)
break;
/*
^ permalink raw reply related [flat|nested] 4+ messages in thread
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2025-06-10 13:01 [PATCH] locking/rwsem: use OWNER_NONSPINNABLE directly instead of OWNER_SPINNABLE alexjlzheng
2025-06-13 5:52 ` Waiman Long
2025-06-17 17:13 ` Boqun Feng
2025-07-19 17:40 ` [tip: locking/core] locking/rwsem: Use " tip-bot2 for Jinliang Zheng
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