Re: [PATCH v2] Documentation/locking/locktypes: minor copy editor fixes

Paul E. McKenney
2020-03-26T02:40:45Z

On Wed, Mar 25, 2020 at 09:58:14AM -0700, Randy Dunlap wrote:
> From: Randy Dunlap <rdunlap@infradead.org>
>
> Minor editorial fixes:
> - add some hyphens in multi-word adjectives
> - add some periods for consistency
> - add "'" for possessive CPU's
> - capitalize IRQ when it's an acronym and not part of a function name
>
> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> Cc: Paul McKenney <paulmck@kernel.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Sebastian Siewior <bigeasy@linutronix.de>
> Cc: Joel Fernandes <joel@joelfernandes.org>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>

Some nits below, but with or without those suggested changes:

Reviewed-by: Paul E. McKenney <paulmck@kernel.org>

> ---
> Documentation/locking/locktypes.rst | 16 ++++++++--------
> 1 file changed, 8 insertions(+), 8 deletions(-)
>
> --- linux-next-20200325.orig/Documentation/locking/locktypes.rst
> +++ linux-next-20200325/Documentation/locking/locktypes.rst
> @@ -84,7 +84,7 @@ rtmutex
>
> RT-mutexes are mutexes with support for priority inheritance (PI).
>
> -PI has limitations on non PREEMPT_RT enabled kernels due to preemption and
> +PI has limitations on non-PREEMPT_RT-enabled kernels due to preemption and

Or just drop the " enabled".

> interrupt disabled sections.
>
> PI clearly cannot preempt preemption-disabled or interrupt-disabled
> @@ -150,7 +150,7 @@ kernel configuration including PREEMPT_R
>
> raw_spinlock_t is a strict spinning lock implementation in all kernels,
> including PREEMPT_RT kernels. Use raw_spinlock_t only in real critical
> -core code, low level interrupt handling and places where disabling
> +core code, low-level interrupt handling and places where disabling
> preemption or interrupts is required, for example, to safely access
> hardware state. raw_spinlock_t can sometimes also be used when the
> critical section is tiny, thus avoiding RT-mutex overhead.
> @@ -160,20 +160,20 @@ spinlock_t
>
> The semantics of spinlock_t change with the state of PREEMPT_RT.
>
> -On a non PREEMPT_RT enabled kernel spinlock_t is mapped to raw_spinlock_t
> +On a non-PREEMPT_RT-enabled kernel spinlock_t is mapped to raw_spinlock_t

Ditto.

> and has exactly the same semantics.
>
> spinlock_t and PREEMPT_RT
> -------------------------
>
> -On a PREEMPT_RT enabled kernel spinlock_t is mapped to a separate
> +On a PREEMPT_RT-enabled kernel spinlock_t is mapped to a separate

And here as well.

> implementation based on rt_mutex which changes the semantics:
>
> - - Preemption is not disabled
> + - Preemption is not disabled.
>
> - The hard interrupt related suffixes for spin_lock / spin_unlock
> - operations (_irq, _irqsave / _irqrestore) do not affect the CPUs
> - interrupt disabled state
> + operations (_irq, _irqsave / _irqrestore) do not affect the CPU's
> + interrupt disabled state.
>
> - The soft interrupt related suffix (_bh()) still disables softirq
> handlers.
> @@ -279,7 +279,7 @@ fully preemptible context. Instead, use
> spin_lock_irqsave() and their unlock counterparts. In cases where the
> interrupt disabling and locking must remain separate, PREEMPT_RT offers a
> local_lock mechanism. Acquiring the local_lock pins the task to a CPU,
> -allowing things like per-CPU irq-disabled locks to be acquired. However,
> +allowing things like per-CPU IRQ-disabled locks to be acquired. However,

Quite a bit of text in the kernel uses "irq", lower case. Another
option is to spell out "interrupt".

> this approach should be used only where absolutely necessary.
>
>
>