lkml.org 
[lkml]   [2021]   [Feb]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/5] sched: make struct task_struct::state 32-bit
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.

\
 
 \ /
  Last update: 2021-02-08 15:49    [W:0.127 / U:1.532 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site