In commit:
3fed382b46 ("sched/numa: Implement NUMA node level wake_affine()")
Rik changed wake_affine to consider NUMA information when balancing
between LLC domains.
There are a number of problems here which this patch tries to address:
- LLC < NODE; in this case we'd use the wrong information to balance
- !NUMA_BALANCING: in this case, the new code doesn't do any
balancing at all
- re-computes the NUMA data for every wakeup, this can mean iterating
up to 64 CPUs for every wakeup.
- default affine wakeups inside a cache
We address these by saving the load/capacity values for each
sched_domain during regular load-balance and using these values in
wake_affine_llc(). The obvious down-side to using cached values is
that they can be too old and poorly reflect reality.
But this way we can use LLC wide information and thus not rely on
assuming LLC matches NODE. We also don't rely on NUMA_BALANCING nor do
we have to aggegate two nodes (or even cache domains) worth of CPUs
for each wakeup.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Fixes: 3fed382b46 ("sched/numa: Implement NUMA node level wake_affine()")
[ Minor readability improvements. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
It's used only by a single (rarely used) inline function (task_node(p)),
which we can move to <linux/sched/topology.h>.
( Add <linux/nodemask.h>, because we rely on that. )
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The <linux/sched/topology.h> file is a self-contained header and users of
it either don't need <linux/sched.h> - or have already included it.
This reduces the size of the header dependency graph.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The vast majority of sched.h users does not require the topology types and
interfaces, so split them out into <linux/sched/topology.h>.
This reduces the size of linux/sched.h by ~6%.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We are going to split <linux/sched/idle.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/idle.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We are going to split <linux/sched/topology.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/topology.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
