Message-ID: <20200326024037.GJ19865@paulmck-ThinkPad-P72>
Date:   Wed, 25 Mar 2020 19:40:37 -0700
From:   "Paul E. McKenney" <paulmck@...nel.org>
To:     Randy Dunlap <rdunlap@...radead.org>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        LKML <linux-kernel@...r.kernel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Sebastian Siewior <bigeasy@...utronix.de>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Joel Fernandes <joel@...lfernandes.org>,
        Oleg Nesterov <oleg@...hat.com>,
        Davidlohr Bueso <dave@...olabs.net>,
        Jonathan Corbet <corbet@....net>,
        Logan Gunthorpe <logang@...tatee.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Kurt Schwemmer <kurt.schwemmer@...rosemi.com>,
        linux-pci@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Felipe Balbi <balbi@...nel.org>, linux-usb@...r.kernel.org,
        Kalle Valo <kvalo@...eaurora.org>,
        "David S. Miller" <davem@...emloft.net>,
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        Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        platform-driver-x86@...r.kernel.org,
        Zhang Rui <rui.zhang@...el.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        linux-pm@...r.kernel.org, Len Brown <lenb@...nel.org>,
        linux-acpi@...r.kernel.org, kbuild test robot <lkp@...el.com>,
        Nick Hu <nickhu@...estech.com>,
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        Guo Ren <guoren@...nel.org>, linux-csky@...r.kernel.org,
        Brian Cain <bcain@...eaurora.org>,
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        Fenghua Yu <fenghua.yu@...el.com>, linux-ia64@...r.kernel.org,
        Michal Simek <monstr@...str.eu>,
        Michael Ellerman <mpe@...erman.id.au>,
        Arnd Bergmann <arnd@...db.de>,
        Geoff Levand <geoff@...radead.org>,
        linuxppc-dev@...ts.ozlabs.org, Davidlohr Bueso <dbueso@...e.de>
Subject: Re: [PATCH v2] Documentation/locking/locktypes: minor copy editor
 fixes

On Wed, Mar 25, 2020 at 09:58:14AM -0700, Randy Dunlap wrote:
> From: Randy Dunlap <rdunlap@...radead.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@...radead.org>
> Cc: Paul McKenney <paulmck@...nel.org>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Cc: Sebastian Siewior <bigeasy@...utronix.de>
> Cc: Joel Fernandes <joel@...lfernandes.org>
> Cc: Ingo Molnar <mingo@...nel.org>
> Cc: Peter Zijlstra <peterz@...radead.org>

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

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

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