Re: [RFC PATCH 08/11] sched: Remove SD_WAKE_AFFINE flag and replace it with SD_BALANCE_WAKE

From	Peter Zijlstra <peterz@infradead.org>
Newsgroups	linux.kernel
Subject	Re: [RFC PATCH 08/11] sched: Remove SD_WAKE_AFFINE flag and replace it with SD_BALANCE_WAKE
Date	2016-06-23 16:00 +0200
Message-ID	<rNdkK-2nl-15@gated-at.bofh.it> (permalink)
References	<rKC5X-6GJ-3@gated-at.bofh.it> <rKC5Y-6GJ-39@gated-at.bofh.it> <rNcyl-1Zv-1@gated-at.bofh.it>
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On Thu, Jun 23, 2016 at 02:04:33PM +0100, Matt Fleming wrote:
> On Thu, 16 Jun, at 09:49:32AM, Yuyang Du wrote:
> > --- a/include/linux/sched.h
> > +++ b/include/linux/sched.h
> > @@ -1014,7 +1014,6 @@ extern void wake_up_q(struct wake_q_head *head);
> >  #define SD_BALANCE_EXEC		0x0004	/* Balance on exec */
> >  #define SD_BALANCE_FORK		0x0008	/* Balance on fork, clone */
> >  #define SD_BALANCE_WAKE		0x0010  /* Balance on wakeup */
> > -#define SD_WAKE_AFFINE		0x0020	/* Wake task to waking CPU */
> >  #define SD_SHARE_CPUCAPACITY	0x0080	/* Domain members share cpu power */
> >  #define SD_SHARE_POWERDOMAIN	0x0100	/* Domain members share power domain */
> >  #define SD_SHARE_PKG_RESOURCES	0x0200	/* Domain members share cpu pkg resources */
> 
> I'm curious - doesn't this break userspace ABI? These flags are
> exported via procfs, so I would have assumed removing or changing the
> value of any of these constants would be forbidden.

Generally I ignore this little issue. Also, I suppose we should move
that whole sched_domain cruft into /debug/sched/ or so.

Thread

[RFC PATCH 00/11] Refactor select_task_rq_fair() Yuyang Du <yuyang.du@intel.com> - 2016-06-16 11:50 +0200
  [RFC PATCH 02/11] sched: Restructure destroy_sched_domain() Yuyang Du <yuyang.du@intel.com> - 2016-06-16 11:50 +0200
  [RFC PATCH 01/11] sched: Remove unused @cpu argument from destroy_sched_domain*() Yuyang Du <yuyang.du@intel.com> - 2016-06-16 11:50 +0200
  [RFC PATCH 06/11] sched: Optimize SCHED_SMT Yuyang Du <yuyang.du@intel.com> - 2016-06-16 11:50 +0200
  [RFC PATCH 09/11] sched: Add per CPU variable sd_socket_id to specify the CPU's socket Yuyang Du <yuyang.du@intel.com> - 2016-06-16 11:50 +0200
  [RFC PATCH 07/11] sched: Clean up SD_BALANCE_WAKE flags in sched domain build-up Yuyang Du <yuyang.du@intel.com> - 2016-06-16 11:50 +0200
  [RFC PATCH 10/11] sched: Add sched_llc_complete static key to specify whether the LLC covers all CPUs Yuyang Du <yuyang.du@intel.com> - 2016-06-16 11:50 +0200
  [RFC PATCH 03/11] sched: Introduce struct sched_domain_shared Yuyang Du <yuyang.du@intel.com> - 2016-06-16 11:50 +0200
  [RFC PATCH 08/11] sched: Remove SD_WAKE_AFFINE flag and replace it with SD_BALANCE_WAKE Yuyang Du <yuyang.du@intel.com> - 2016-06-16 11:50 +0200
    Re: [RFC PATCH 08/11] sched: Remove SD_WAKE_AFFINE flag and replace  it with SD_BALANCE_WAKE Matt Fleming <matt@codeblueprint.co.uk> - 2016-06-23 15:10 +0200
      Re: [RFC PATCH 08/11] sched: Remove SD_WAKE_AFFINE flag and replace  it with SD_BALANCE_WAKE Peter Zijlstra <peterz@infradead.org> - 2016-06-23 16:00 +0200
      Re: [RFC PATCH 08/11] sched: Remove SD_WAKE_AFFINE flag and replace  it with SD_BALANCE_WAKE Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-06-23 16:10 +0200
  [RFC PATCH 05/11] sched: Rewrite select_idle_siblings() Yuyang Du <yuyang.du@intel.com> - 2016-06-16 11:50 +0200

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