Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Thu, 1 Aug 2019 13:27:03 +0200 | Subject | Re: [PATCH 5/5] spi: Reduce kthread priority |
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Hi Peter,
On Thu, Aug 1, 2019 at 1:18 PM Peter Zijlstra <peterz@infradead.org> wrote: > The SPI thingies request FIFO-99 by default, reduce this to FIFO-50. > > FIFO-99 is the very highest priority available to SCHED_FIFO and > it not a suitable default; it would indicate the SPI work is the > most important work on the machine. > > Cc: Benson Leung <bleung@chromium.org> > Cc: Enric Balletbo i Serra <enric.balletbo@collabora.com> > Cc: Guenter Roeck <groeck@chromium.org> > Cc: Mark Brown <broonie@kernel.org> > Cc: linux-spi@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> > --- > drivers/platform/chrome/cros_ec_spi.c | 2 +- > drivers/spi/spi.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > --- a/drivers/platform/chrome/cros_ec_spi.c > +++ b/drivers/platform/chrome/cros_ec_spi.c > @@ -706,7 +706,7 @@ static int cros_ec_spi_devm_high_pri_all > struct cros_ec_spi *ec_spi) > { > struct sched_param sched_priority = { > - .sched_priority = MAX_RT_PRIO - 1, > + .sched_priority = MAX_RT_PRIO / 2,
include/linux/sched/prio.h says:
* Priority of a process goes from 0..MAX_PRIO-1, valid RT * priority is 0..MAX_RT_PRIO-1, and SCHED_NORMAL/SCHED_BATCH * tasks are in the range MAX_RT_PRIO..MAX_PRIO-1. Priority * values are inverted: lower p->prio value means higher priority.
So the new 50 is actually a higher priority than the old 99?
Given I'm far from an RT expert, I must be missing something? Thanks!
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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