From: Alexey Dobriyan <adobriyan@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: mingo@redhat.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/5] sched: make struct task_struct::state 32-bit
Date: Mon, 8 Feb 2021 17:33:58 +0300 [thread overview]
Message-ID: <20210208143358.GB10066@localhost.localdomain> (raw)
In-Reply-To: <YCEU3SSoYneIh5t1@hirez.programming.kicks-ass.net>
On Mon, Feb 08, 2021 at 11:39:25AM +0100, Peter Zijlstra wrote:
> On Sat, Feb 06, 2021 at 06:18:32PM +0300, Alexey Dobriyan wrote:
> > 32-bit accesses are shorter than 64-bit accesses on x86_64.
> > Nothing uses 64-bitness of struct task_struct::state.
> >
> > Propagate 32-bitness to other variables and functions.
>
> You're saving a handful of bytes, why?
Eeh? To save handful of bytes.
> > --- a/include/linux/sched.h
> > +++ b/include/linux/sched.h
> > @@ -655,7 +655,7 @@ struct task_struct {
> > struct thread_info thread_info;
> > #endif
> > /* -1 unrunnable, 0 runnable, >0 stopped: */
> > - volatile long state;
> > + volatile int state;
>
> A much larger, but probably more useful cleanup would be to get rid of
> that volatile.
volatile is separate patch. It is independent of ->state type.
I didn't think about this specific volatile at all.
prev parent reply other threads:[~2021-02-08 14:48 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-06 15:18 [PATCH 1/5] sched: make struct task_struct::state 32-bit Alexey Dobriyan
2021-02-06 15:20 ` [PATCH 2/5] sched: make nr_running() return 32-bit Alexey Dobriyan
2021-02-06 15:22 ` [PATCH 3/5] sched: make nr_iowait() return 32-bit value Alexey Dobriyan
2021-02-06 15:24 ` [PATCH 4/5] sched: make nr_iowait_cpu() return 32-bit Alexey Dobriyan
2021-02-06 15:30 ` [PATCH 5/5] sched: make multiple runqueue task counters 32-bit Alexey Dobriyan
2021-02-08 10:34 ` [PATCH 1/5] sched: make struct task_struct::state 32-bit Peter Zijlstra
2021-02-08 14:30 ` Alexey Dobriyan
2021-02-08 14:52 ` Alexey Dobriyan
2021-02-08 15:25 ` Peter Zijlstra
2021-02-08 16:45 ` Alexey Dobriyan
2021-02-08 10:39 ` Peter Zijlstra
2021-02-08 14:33 ` Alexey Dobriyan [this message]
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