On Wed, Nov 15, 2017 at 09:27:43AM +0100, Ingo Molnar wrote: > * Matthew Wilcox <[email protected]> wrote: > > commit 799ba82de01e7543f6b2042e1a739f3a20255f23 > > Author: luca abeni <[email protected]> > > Date: Thu Sep 7 12:09:31 2017 +0200 > > > > sched/deadline: Use C bitfields for the state flags > > > > Ask the compiler to use a single bit for storing true / false values, > > instead of wasting the size of a whole int value. > > Tested with gcc 5.4.0 on x86_64, and the compiler produces the expected > > Assembly (similar to the Assembly code generated when explicitly > > accessing > > the bits with bitmasks, "&" and "|"). > > > > produces four warnings from sparse for every file which includes sched.h: > > > > ./include/linux/sched.h:476:62: error: dubious one-bit signed bitfield > > ./include/linux/sched.h:477:62: error: dubious one-bit signed bitfield > > ./include/linux/sched.h:478:62: error: dubious one-bit signed bitfield > > ./include/linux/sched.h:479:62: error: dubious one-bit signed bitfield > > > > This seems like the trivial fix (untested): > > > > > > diff --git a/include/linux/sched.h b/include/linux/sched.h > > index a5dc7c98b0a2..21991d668d35 100644 > > --- a/include/linux/sched.h > > +++ b/include/linux/sched.h > > @@ -473,10 +473,10 @@ struct sched_dl_entity { > > * conditions between the inactive timer handler and the wakeup > > * code. > > */ > > - int dl_throttled : 1; > > - int dl_boosted : 1; > > - int dl_yielded : 1; > > - int dl_non_contending : 1; > > + unsigned int dl_throttled : 1; > > + unsigned int dl_boosted : 1; > > + unsigned int dl_yielded : 1; > > + unsigned int dl_non_contending : 1; > > > > /* > > * Bandwidth enforcement timer. Each -deadline task has its > > Mind sending a proper patch with a SOB once it's tested?
I'd be more than happy to do that. I have no idea what this code is, what it's used for, or how to test it, so I'll have to rely on somebody else to test it.
