The patch titled
Subject: mm: disable NUMA_BALANCING_DEFAULT_ENABLED and TRANSPARENT_HUGEPAGE on PREEMPT_RT
has been added to the -mm tree. Its filename is
mm-disable-numa_balancing_default_enabled-and-transparent_hugepage-on-preempt_rt.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-disable-numa_balancing_default_enabled-and-transparent_hugepage-on-preempt_rt.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-disable-numa_balancing_default_enabled-and-transparent_hugepage-on-preempt_rt.patch
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------------------------------------------------------
From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Subject: mm: disable NUMA_BALANCING_DEFAULT_ENABLED and TRANSPARENT_HUGEPAGE on PREEMPT_RT
TRANSPARENT_HUGEPAGE:
There are potential non-deterministic delays to an RT thread if a critical
memory region is not THP-aligned and a non-RT buffer is located in the same
hugepage-aligned region. It's also possible for an unrelated thread to migrate
pages belonging to an RT task incurring unexpected page faults due to memory
defragmentation even if khugepaged is disabled.
Regular HUGEPAGEs are not affected by this can be used.
NUMA_BALANCING:
There is a non-deterministic delay to mark PTEs PROT_NONE to gather NUMA fault
samples, increased page faults of regions even if mlocked and non-deterministic
delays when migrating pages.
[Mel Gorman worded 99% of the commit description].
Link: https://lore.kernel.org/all/20200304091159.GN3818@xxxxxxxxxxxxxxxxxxx/
Link: https://lore.kernel.org/all/20211026165100.ahz5bkx44lrrw5pt@xxxxxxxxxxxxx/
Link: https://lkml.kernel.org/r/20211028143327.hfbxjze7palrpfgp@xxxxxxxxxxxxx
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Acked-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
init/Kconfig | 2 +-
mm/Kconfig | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
--- a/init/Kconfig~mm-disable-numa_balancing_default_enabled-and-transparent_hugepage-on-preempt_rt
+++ a/init/Kconfig
@@ -901,7 +901,7 @@ config NUMA_BALANCING
bool "Memory placement aware NUMA scheduler"
depends on ARCH_SUPPORTS_NUMA_BALANCING
depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
- depends on SMP && NUMA && MIGRATION
+ depends on SMP && NUMA && MIGRATION && !PREEMPT_RT
help
This option adds support for automatic NUMA aware memory/task placement.
The mechanism is quite primitive and is based on migrating memory when
--- a/mm/Kconfig~mm-disable-numa_balancing_default_enabled-and-transparent_hugepage-on-preempt_rt
+++ a/mm/Kconfig
@@ -371,7 +371,7 @@ config NOMMU_INITIAL_TRIM_EXCESS
config TRANSPARENT_HUGEPAGE
bool "Transparent Hugepage Support"
- depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE
+ depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE && !PREEMPT_RT
select COMPACTION
select XARRAY_MULTI
help
_
Patches currently in -mm which might be from bigeasy@xxxxxxxxxxxxx are
mm-disable-numa_balancing_default_enabled-and-transparent_hugepage-on-preempt_rt.patch
mm-page_alloc-use-migrate_disable-in-drain_local_pages_wq.patch
mm-disable-zsmalloc-on-preempt_rt.patch
documentation-kcov-include-typesh-in-the-example.patch
documentation-kcov-define-ip-in-the-example.patch
kcov-allocate-per-cpu-memory-on-the-relevant-node.patch
kcov-avoid-enabledisable-interrupts-if-in_task.patch
kcov-replace-local_irq_save-with-a-local_lock_t.patch
