Re: [PATCH rcu 03/12] srcu: Renaming in preparation for additional reader flavor
On 10/14/2024 10:22 PM, Paul E. McKenney wrote:
> On Mon, Oct 14, 2024 at 02:40:35PM +0530, Neeraj Upadhyay wrote:
>> On 10/9/2024 11:37 PM, Paul E. McKenney wrote:
>>> Currently, there are only two flavors of readers, normal and NMI-safe.
>>> A number of fields, functions, and types reflect this restriction.
>>> This renaming-only commit prepares for the addition of light-weight
>>> (as in memory-barrier-free) readers. OK, OK, there is also a drive-by
>>> white-space fixeup!
>>>
>>> Signed-off-by: Paul E. McKenney
>>> Cc: Alexei Starovoitov
>>> Cc: Andrii Nakryiko
>>> Cc: Peter Zijlstra
>>> Cc: Kent Overstreet
>>> Cc:
>>> ---
>>> include/linux/srcu.h | 21 ++---
>>> include/linux/srcutree.h | 2 +-
>>> kernel/rcu/srcutree.c| 22 +++---
>>> 3 files changed, 22 insertions(+), 23 deletions(-)
>>>
>>> diff --git a/include/linux/srcu.h b/include/linux/srcu.h
>>> index 835bbb2d1f88a..06728ef6f32a4 100644
>>> --- a/include/linux/srcu.h
>>> +++ b/include/linux/srcu.h
>>> @@ -181,10 +181,9 @@ static inline int srcu_read_lock_held(const struct
>>> srcu_struct *ssp)
>>> #define SRCU_NMI_SAFE 0x2
>>>
>>> #if defined(CONFIG_PROVE_RCU) && defined(CONFIG_TREE_SRCU)
>>> -void srcu_check_nmi_safety(struct srcu_struct *ssp, bool nmi_safe);
>>> +void srcu_check_read_flavor(struct srcu_struct *ssp, int read_flavor);
>>> #else
>>> -static inline void srcu_check_nmi_safety(struct srcu_struct *ssp,
>>> -bool nmi_safe) { }
>>> +static inline void srcu_check_read_flavor(struct srcu_struct *ssp, int
>>> read_flavor) { }
>>> #endif
>>>
>>>
>>> @@ -245,7 +244,7 @@ static inline int srcu_read_lock(struct srcu_struct
>>> *ssp) __acquires(ssp)
>>> {
>>> int retval;
>>>
>>> - srcu_check_nmi_safety(ssp, false);
>>> + srcu_check_read_flavor(ssp, false);
>>
>> As srcu_check_read_flavor() takes an "int" now, passing a macro for the type
>> of reader would
>> be better here?
>
> Agreed, and a later commit does introduce macros.
>
>>> retval = __srcu_read_lock(ssp);
>>> srcu_lock_acquire(&ssp->dep_map);
>>> return retval;
>>> @@ -262,7 +261,7 @@ static inline int srcu_read_lock_nmisafe(struct
>>> srcu_struct *ssp) __acquires(ssp
>>> {
>>> int retval;
>>>
>>> - srcu_check_nmi_safety(ssp, true);
>>> + srcu_check_read_flavor(ssp, true);
>>> retval = __srcu_read_lock_nmisafe(ssp);
>>> rcu_try_lock_acquire(&ssp->dep_map);
>>> return retval;
>>> @@ -274,7 +273,7 @@ srcu_read_lock_notrace(struct srcu_struct *ssp)
>>> __acquires(ssp)
>>> {
>>> int retval;
>>>
>>> - srcu_check_nmi_safety(ssp, false);
>>> + srcu_check_read_flavor(ssp, false);
>>> retval = __srcu_read_lock(ssp);
>>> return retval;
>>> }
>>> @@ -303,7 +302,7 @@ srcu_read_lock_notrace(struct srcu_struct *ssp)
>>> __acquires(ssp)
>>> static inline int srcu_down_read(struct srcu_struct *ssp) __acquires(ssp)
>>> {
>>> WARN_ON_ONCE(in_nmi());
>>> - srcu_check_nmi_safety(ssp, false);
>>> + srcu_check_read_flavor(ssp, false);
>>> return __srcu_read_lock(ssp);
>>> }
>>>
>>> @@ -318,7 +317,7 @@ static inline void srcu_read_unlock(struct srcu_struct
>>> *ssp, int idx)
>>> __releases(ssp)
>>> {
>>> WARN_ON_ONCE(idx & ~0x1);
>>> - srcu_check_nmi_safety(ssp, false);
>>> + srcu_check_read_flavor(ssp, false);
>>> srcu_lock_release(&ssp->dep_map);
>>> __srcu_read_unlock(ssp, idx);
>>> }
>>> @@ -334,7 +333,7 @@ static inline void srcu_read_unlock_nmisafe(struct
>>> srcu_struct *ssp, int idx)
>>> __releases(ssp)
>>> {
>>> WARN_ON_ONCE(idx & ~0x1);
>>> - srcu_check_nmi_safety(ssp, true);
>>> + srcu_check_read_flavor(ssp, true);
>>> rcu_lock_release(&ssp->dep_map);
>>> __srcu_read_unlock_nmisafe(ssp, idx);
>>> }
>>> @@ -343,7 +342,7 @@ static inline void srcu_read_unlock_nmisafe(struct
>>> srcu_struct *ssp, int idx)
>>> static inline notrace void
>>> srcu_read_unlock_notrace(struct srcu_struct *ssp, int idx) __releases(ssp)
>>> {
>>> - srcu_check_nmi_safety(ssp, false);
>>> + srcu_check_read_flavor(ssp, false);
>>> __srcu_read_unlock(ssp, idx);
>>> }
>>>
>>> @@ -360,7 +359,7 @@ static inline void srcu_up_read(struct srcu_struct
>>> *ssp, int idx)
>>> {
>>> WARN_ON_ONCE(idx & ~0x1);
>>> WARN_ON_ONCE(in_nmi());
>>> - srcu_check_nmi_safety(ssp, false);
>>> + srcu_check_read_flavor(ssp, false);
>>> __srcu_read_unlock(ssp, idx);
>>> }
>>>
>>> diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h
>>> index ed57598394de3..ab7d8d215b84b 100644
>>> --- a/include/linux/srcutree.h
>>> +++ b/include/linux/srcutree.h
>>> @@ -25,7 +25,7 @@ struct srcu_data {
>>> /* Read-side state. */
>>> atomic_long_t srcu_lock_count[2]; /* Locks per CPU. */
>>> atomic_long_t srcu_unlock_count[2]; /* Unlocks per CPU. */
>>> - int srcu_nmi_safety;/* NMI-safe srcu_struct
>>> structure? */
>>> + int src
Re: [PATCH rcu 03/12] srcu: Renaming in preparation for additional reader flavor
On Mon, Oct 14, 2024 at 02:40:35PM +0530, Neeraj Upadhyay wrote:
> On 10/9/2024 11:37 PM, Paul E. McKenney wrote:
> > Currently, there are only two flavors of readers, normal and NMI-safe.
> > A number of fields, functions, and types reflect this restriction.
> > This renaming-only commit prepares for the addition of light-weight
> > (as in memory-barrier-free) readers. OK, OK, there is also a drive-by
> > white-space fixeup!
> >
> > Signed-off-by: Paul E. McKenney
> > Cc: Alexei Starovoitov
> > Cc: Andrii Nakryiko
> > Cc: Peter Zijlstra
> > Cc: Kent Overstreet
> > Cc:
> > ---
> > include/linux/srcu.h | 21 ++---
> > include/linux/srcutree.h | 2 +-
> > kernel/rcu/srcutree.c| 22 +++---
> > 3 files changed, 22 insertions(+), 23 deletions(-)
> >
> > diff --git a/include/linux/srcu.h b/include/linux/srcu.h
> > index 835bbb2d1f88a..06728ef6f32a4 100644
> > --- a/include/linux/srcu.h
> > +++ b/include/linux/srcu.h
> > @@ -181,10 +181,9 @@ static inline int srcu_read_lock_held(const struct
> > srcu_struct *ssp)
> > #define SRCU_NMI_SAFE 0x2
> >
> > #if defined(CONFIG_PROVE_RCU) && defined(CONFIG_TREE_SRCU)
> > -void srcu_check_nmi_safety(struct srcu_struct *ssp, bool nmi_safe);
> > +void srcu_check_read_flavor(struct srcu_struct *ssp, int read_flavor);
> > #else
> > -static inline void srcu_check_nmi_safety(struct srcu_struct *ssp,
> > -bool nmi_safe) { }
> > +static inline void srcu_check_read_flavor(struct srcu_struct *ssp, int
> > read_flavor) { }
> > #endif
> >
> >
> > @@ -245,7 +244,7 @@ static inline int srcu_read_lock(struct srcu_struct
> > *ssp) __acquires(ssp)
> > {
> > int retval;
> >
> > - srcu_check_nmi_safety(ssp, false);
> > + srcu_check_read_flavor(ssp, false);
>
> As srcu_check_read_flavor() takes an "int" now, passing a macro for the type
> of reader would
> be better here?
Agreed, and a later commit does introduce macros.
> > retval = __srcu_read_lock(ssp);
> > srcu_lock_acquire(&ssp->dep_map);
> > return retval;
> > @@ -262,7 +261,7 @@ static inline int srcu_read_lock_nmisafe(struct
> > srcu_struct *ssp) __acquires(ssp
> > {
> > int retval;
> >
> > - srcu_check_nmi_safety(ssp, true);
> > + srcu_check_read_flavor(ssp, true);
> > retval = __srcu_read_lock_nmisafe(ssp);
> > rcu_try_lock_acquire(&ssp->dep_map);
> > return retval;
> > @@ -274,7 +273,7 @@ srcu_read_lock_notrace(struct srcu_struct *ssp)
> > __acquires(ssp)
> > {
> > int retval;
> >
> > - srcu_check_nmi_safety(ssp, false);
> > + srcu_check_read_flavor(ssp, false);
> > retval = __srcu_read_lock(ssp);
> > return retval;
> > }
> > @@ -303,7 +302,7 @@ srcu_read_lock_notrace(struct srcu_struct *ssp)
> > __acquires(ssp)
> > static inline int srcu_down_read(struct srcu_struct *ssp) __acquires(ssp)
> > {
> > WARN_ON_ONCE(in_nmi());
> > - srcu_check_nmi_safety(ssp, false);
> > + srcu_check_read_flavor(ssp, false);
> > return __srcu_read_lock(ssp);
> > }
> >
> > @@ -318,7 +317,7 @@ static inline void srcu_read_unlock(struct srcu_struct
> > *ssp, int idx)
> > __releases(ssp)
> > {
> > WARN_ON_ONCE(idx & ~0x1);
> > - srcu_check_nmi_safety(ssp, false);
> > + srcu_check_read_flavor(ssp, false);
> > srcu_lock_release(&ssp->dep_map);
> > __srcu_read_unlock(ssp, idx);
> > }
> > @@ -334,7 +333,7 @@ static inline void srcu_read_unlock_nmisafe(struct
> > srcu_struct *ssp, int idx)
> > __releases(ssp)
> > {
> > WARN_ON_ONCE(idx & ~0x1);
> > - srcu_check_nmi_safety(ssp, true);
> > + srcu_check_read_flavor(ssp, true);
> > rcu_lock_release(&ssp->dep_map);
> > __srcu_read_unlock_nmisafe(ssp, idx);
> > }
> > @@ -343,7 +342,7 @@ static inline void srcu_read_unlock_nmisafe(struct
> > srcu_struct *ssp, int idx)
> > static inline notrace void
> > srcu_read_unlock_notrace(struct srcu_struct *ssp, int idx) __releases(ssp)
> > {
> > - srcu_check_nmi_safety(ssp, false);
> > + srcu_check_read_flavor(ssp, false);
> > __srcu_read_unlock(ssp, idx);
> > }
> >
> > @@ -360,7 +359,7 @@ static inline void srcu_up_read(struct srcu_struct
> > *ssp, int idx)
> > {
> > WARN_ON_ONCE(idx & ~0x1);
> > WARN_ON_ONCE(in_nmi());
> > - srcu_check_nmi_safety(ssp, false);
> > + srcu_check_read_flavor(ssp, false);
> > __srcu_read_unlock(ssp, idx);
> > }
> >
> > diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h
> > index ed57598394de3..ab7d8d215b84b 100644
> > --- a/include/linux/srcutree.h
> > +++ b/include/linux/srcutree.h
> > @@ -25,7 +25,7 @@ struct srcu_data {
> > /* Read-side state. */
> > atomic_long_t srcu_lock_count[2]; /* Locks per CPU. */
> > atomic_long_t srcu_unlock_count[2]; /* Unlocks per CPU. */
> > - int srcu_nmi_safety;/* NMI-safe srcu_struct
> > structure? */
> > + int srcu_reader_flavor; /* Reader flavor for
> > sr
Re: [PATCH rcu 03/12] srcu: Renaming in preparation for additional reader flavor
On 10/9/2024 11:37 PM, Paul E. McKenney wrote:
> Currently, there are only two flavors of readers, normal and NMI-safe.
> A number of fields, functions, and types reflect this restriction.
> This renaming-only commit prepares for the addition of light-weight
> (as in memory-barrier-free) readers. OK, OK, there is also a drive-by
> white-space fixeup!
>
> Signed-off-by: Paul E. McKenney
> Cc: Alexei Starovoitov
> Cc: Andrii Nakryiko
> Cc: Peter Zijlstra
> Cc: Kent Overstreet
> Cc:
> ---
> include/linux/srcu.h | 21 ++---
> include/linux/srcutree.h | 2 +-
> kernel/rcu/srcutree.c| 22 +++---
> 3 files changed, 22 insertions(+), 23 deletions(-)
>
> diff --git a/include/linux/srcu.h b/include/linux/srcu.h
> index 835bbb2d1f88a..06728ef6f32a4 100644
> --- a/include/linux/srcu.h
> +++ b/include/linux/srcu.h
> @@ -181,10 +181,9 @@ static inline int srcu_read_lock_held(const struct
> srcu_struct *ssp)
> #define SRCU_NMI_SAFE0x2
>
> #if defined(CONFIG_PROVE_RCU) && defined(CONFIG_TREE_SRCU)
> -void srcu_check_nmi_safety(struct srcu_struct *ssp, bool nmi_safe);
> +void srcu_check_read_flavor(struct srcu_struct *ssp, int read_flavor);
> #else
> -static inline void srcu_check_nmi_safety(struct srcu_struct *ssp,
> - bool nmi_safe) { }
> +static inline void srcu_check_read_flavor(struct srcu_struct *ssp, int
> read_flavor) { }
> #endif
>
>
> @@ -245,7 +244,7 @@ static inline int srcu_read_lock(struct srcu_struct *ssp)
> __acquires(ssp)
> {
> int retval;
>
> - srcu_check_nmi_safety(ssp, false);
> + srcu_check_read_flavor(ssp, false);
As srcu_check_read_flavor() takes an "int" now, passing a macro for the type of
reader would
be better here?
> retval = __srcu_read_lock(ssp);
> srcu_lock_acquire(&ssp->dep_map);
> return retval;
> @@ -262,7 +261,7 @@ static inline int srcu_read_lock_nmisafe(struct
> srcu_struct *ssp) __acquires(ssp
> {
> int retval;
>
> - srcu_check_nmi_safety(ssp, true);
> + srcu_check_read_flavor(ssp, true);
> retval = __srcu_read_lock_nmisafe(ssp);
> rcu_try_lock_acquire(&ssp->dep_map);
> return retval;
> @@ -274,7 +273,7 @@ srcu_read_lock_notrace(struct srcu_struct *ssp)
> __acquires(ssp)
> {
> int retval;
>
> - srcu_check_nmi_safety(ssp, false);
> + srcu_check_read_flavor(ssp, false);
> retval = __srcu_read_lock(ssp);
> return retval;
> }
> @@ -303,7 +302,7 @@ srcu_read_lock_notrace(struct srcu_struct *ssp)
> __acquires(ssp)
> static inline int srcu_down_read(struct srcu_struct *ssp) __acquires(ssp)
> {
> WARN_ON_ONCE(in_nmi());
> - srcu_check_nmi_safety(ssp, false);
> + srcu_check_read_flavor(ssp, false);
> return __srcu_read_lock(ssp);
> }
>
> @@ -318,7 +317,7 @@ static inline void srcu_read_unlock(struct srcu_struct
> *ssp, int idx)
> __releases(ssp)
> {
> WARN_ON_ONCE(idx & ~0x1);
> - srcu_check_nmi_safety(ssp, false);
> + srcu_check_read_flavor(ssp, false);
> srcu_lock_release(&ssp->dep_map);
> __srcu_read_unlock(ssp, idx);
> }
> @@ -334,7 +333,7 @@ static inline void srcu_read_unlock_nmisafe(struct
> srcu_struct *ssp, int idx)
> __releases(ssp)
> {
> WARN_ON_ONCE(idx & ~0x1);
> - srcu_check_nmi_safety(ssp, true);
> + srcu_check_read_flavor(ssp, true);
> rcu_lock_release(&ssp->dep_map);
> __srcu_read_unlock_nmisafe(ssp, idx);
> }
> @@ -343,7 +342,7 @@ static inline void srcu_read_unlock_nmisafe(struct
> srcu_struct *ssp, int idx)
> static inline notrace void
> srcu_read_unlock_notrace(struct srcu_struct *ssp, int idx) __releases(ssp)
> {
> - srcu_check_nmi_safety(ssp, false);
> + srcu_check_read_flavor(ssp, false);
> __srcu_read_unlock(ssp, idx);
> }
>
> @@ -360,7 +359,7 @@ static inline void srcu_up_read(struct srcu_struct *ssp,
> int idx)
> {
> WARN_ON_ONCE(idx & ~0x1);
> WARN_ON_ONCE(in_nmi());
> - srcu_check_nmi_safety(ssp, false);
> + srcu_check_read_flavor(ssp, false);
> __srcu_read_unlock(ssp, idx);
> }
>
> diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h
> index ed57598394de3..ab7d8d215b84b 100644
> --- a/include/linux/srcutree.h
> +++ b/include/linux/srcutree.h
> @@ -25,7 +25,7 @@ struct srcu_data {
> /* Read-side state. */
> atomic_long_t srcu_lock_count[2]; /* Locks per CPU. */
> atomic_long_t srcu_unlock_count[2]; /* Unlocks per CPU. */
> - int srcu_nmi_safety;/* NMI-safe srcu_struct
> structure? */
> + int srcu_reader_flavor; /* Reader flavor for
> srcu_struct structure? */
This is a mask for the reader flavor, so
s/srcu_reader_flavor/srcu_reader_flavor_mask ?
- Neeraj
>
> /* Update-side state. */
> spinlock_t __private lock cacheline_internodealigned_in_smp;
> diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/s
