From: Frederic Weisbecker <fweisbec@gmail.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 0/3] nohz: Convert tick dependency mask to atomic_t
Date: Fri, 25 Mar 2016 14:17:34 +0100 [thread overview]
Message-ID: <20160325131732.GA16488@lerouge> (raw)
In-Reply-To: <20160325084847.GA15235@gmail.com>
On Fri, Mar 25, 2016 at 09:48:47AM +0100, Ingo Molnar wrote:
>
> * Frederic Weisbecker <fweisbec@gmail.com> wrote:
>
> > As per Linus suggestion, lets convert the tick dependency mask to
> > atomic_t. Introduce atomic_fetch_or() and confine fetch_or() back to
> > scheduler guts.
> >
> > git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
> > timers/nohz
> >
> > HEAD: 7b7e5da5733f58668181077ec394a718e08c392c
> >
> > Thanks,
> > Frederic
> > ---
> >
> > Frederic Weisbecker (3):
> > atomic: Introduce atomic_fetch_or
> > nohz: Convert tick dependency mask to atomic_t
> > Revert "atomic: Export fetch_or()"
> >
> >
> > include/linux/atomic.h | 34 +++++++++++++--------------
> > include/linux/sched.h | 4 ++--
> > kernel/sched/core.c | 18 ++++++++++++++
> > kernel/time/tick-sched.c | 61 ++++++++++++++++++++++++------------------------
> > kernel/time/tick-sched.h | 2 +-
> > 5 files changed, 68 insertions(+), 51 deletions(-)
>
> Could you please also convert the sched/core.c usage, so that we can get rid of
> the private fetch_or() definition? Please also double check that it does not
> result in worse code generation.
That involve converting thread_info::flags to atomic_t and given how much the type varies
across architectures:
$ grep 'flags;' $(ls arch/*/include/asm/thread_info.h)
arch/alpha/include/asm/thread_info.h: unsigned int flags; /* low level flags */
arch/arc/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/arm64/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/arm/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/avr32/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/blackfin/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/c6x/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/cris/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/frv/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/h8300/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/hexagon/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/ia64/include/asm/thread_info.h: __u32 flags; /* thread_info flags (see TIF_*) */
arch/m32r/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/m68k/include/asm/thread_info.h: unsigned long flags;
arch/metag/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/microblaze/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/mips/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/mn10300/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/nios2/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/openrisc/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/parisc/include/asm/thread_info.h: unsigned long flags; /* thread_info flags (see TIF_*) */
arch/powerpc/include/asm/thread_info.h: unsigned long local_flags; /* private flags for thread */
arch/s390/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/score/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/sh/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/tile/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/um/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/unicore32/include/asm/thread_info.h: unsigned long flags; /* low level flags */
arch/x86/include/asm/thread_info.h: __u32 flags; /* low level flags */
arch/xtensa/include/asm/thread_info.h: unsigned long flags; /* low level flags */
also given how much it is accessed (and that happens a lot in ASM as well). This conversion deserves quite a
whole project on its own.
It might be possible to do it incrementally though.
next prev parent reply other threads:[~2016-03-25 13:17 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-24 14:37 [PATCH 0/3] nohz: Convert tick dependency mask to atomic_t Frederic Weisbecker
2016-03-24 14:37 ` [PATCH 1/3] atomic: Introduce atomic_fetch_or Frederic Weisbecker
2016-03-29 10:36 ` [tip:core/urgent] locking/atomic: Introduce atomic_fetch_or() tip-bot for Frederic Weisbecker
2016-03-24 14:38 ` [PATCH 2/3] nohz: Convert tick dependency mask to atomic_t Frederic Weisbecker
2016-03-25 8:52 ` Ingo Molnar
2016-03-25 14:56 ` Frederic Weisbecker
2016-03-29 10:37 ` [tip:core/urgent] timers/nohz: " tip-bot for Frederic Weisbecker
2016-03-24 14:38 ` [PATCH 3/3] Revert "atomic: Export fetch_or()" Frederic Weisbecker
2016-03-29 10:37 ` [tip:core/urgent] locking/atomic, sched: Unexport fetch_or() tip-bot for Frederic Weisbecker
2016-03-25 8:48 ` [PATCH 0/3] nohz: Convert tick dependency mask to atomic_t Ingo Molnar
2016-03-25 13:17 ` Frederic Weisbecker [this message]
2016-03-29 9:44 ` Ingo Molnar
2016-03-29 12:23 ` Linus Torvalds
2016-03-29 12:59 ` Ingo Molnar
2016-03-29 13:05 ` Ingo Molnar
2016-03-29 13:08 ` Frederic Weisbecker
2016-03-31 6:54 ` Ingo Molnar
2016-03-31 9:20 ` Peter Zijlstra
2016-03-31 13:18 ` Ingo Molnar
2016-03-29 13:14 ` Ingo Molnar
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