[PATCH 0/5] context_tracking: Flatter archs not using exception_enter/exit() v2

From: Frederic Weisbecker <frederic@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Frederic Weisbecker <frederic@kernel.org>,
	"Paul E . McKenney" <paulmck@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Phil Auld <pauld@redhat.com>,
	Marcelo Tosatti <mtosatti@redhat.com>
Subject: [PATCH 0/5] context_tracking: Flatter archs not using exception_enter/exit() v2
Date: Tue, 27 Oct 2020 16:08:22 +0100	[thread overview]
Message-ID: <20201027150827.148821-1-frederic@kernel.org> (raw)

In order to be able to turn on/off nohz_full at runtime, we'll need
the archs to give up saving the context tracking state on the task stack
because this forces context tracking to run system wide, even on CPUs
that don't have nohz_full enabled.

Now being able to do so require sane entry code meeting some
requirements that at least x86 just achieved recently (I haven't checked
other archs yet).

Changes since v2:

- Rebase against v5.10-rc1
- Use SCHED_WARN_ON() instead of WARN_ON_ONCE() for the context tracking
  sanity check on schedule().

git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
	core/isolation-v2

HEAD: 79f60f3dd0e0aea8b17c825371d8697444ae5faf

Thanks,
	Frederic
---

Frederic Weisbecker (5):
      context_tracking: Introduce HAVE_CONTEXT_TRACKING_OFFSTACK
      context_tracking:  Don't implement exception_enter/exit() on CONFIG_HAVE_CONTEXT_TRACKING_OFFSTACK
      sched: Detect call to schedule from critical entry code
      context_tracking: Only define schedule_user() on !HAVE_CONTEXT_TRACKING_OFFSTACK archs
      x86: Support HAVE_CONTEXT_TRACKING_OFFSTACK

 arch/Kconfig                     | 17 +++++++++++++++++
 arch/x86/Kconfig                 |  1 +
 include/linux/context_tracking.h |  6 ++++--
 kernel/sched/core.c              |  3 ++-
 4 files changed, 24 insertions(+), 3 deletions(-)