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| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2021-11-05 13:35:27 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-11-06 13:30:33 -0700 |
| commit | 554b0f3ca6f4948fdbab5f199858d902061318d0 (patch) | |
| tree | 2d64713fbc901708c7937970a768174446a4cb74 /init/Kconfig | |
| parent | 04b4b006139b58ffbd90df3befecc13711b1faf8 (diff) | |
| download | lwn-554b0f3ca6f4948fdbab5f199858d902061318d0.tar.gz lwn-554b0f3ca6f4948fdbab5f199858d902061318d0.zip | |
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@techsingularity.net/
Link: https://lore.kernel.org/all/20211026165100.ahz5bkx44lrrw5pt@linutronix.de/
Link: https://lkml.kernel.org/r/20211028143327.hfbxjze7palrpfgp@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'init/Kconfig')
| -rw-r--r-- | init/Kconfig | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/init/Kconfig b/init/Kconfig index 11f8a845f259..21b1f4870c80 100644 --- a/init/Kconfig +++ b/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 |