Re: Minor page faults from memory compaction causing in-band transitions
Florian Bezdeka <[email protected]>
| Newsgroups | dev.linux.lists.xenomai |
|---|---|
| Message-ID | <[email protected]> |
On Mon, 2026-04-13 at 20:31 +0200, Philippe Gerum wrote: > Brandon Ho <[email protected]> writes: > > > Thank you for the responses! I recently came across the > > `compact_unevictable_allowed` sysctl option and it seems like it could be a > > good fit for our use case. Setting it to 0 would prevent the kernel from > > compacting/migrating locked pages, which should eliminate the minor faults > > we're seeing during compaction. > > > > Could we possibly set `compact_unevictable_allowed=0` by default when > > CONFIG_EVL is enabled? > > Definitely, yes. Thanks for chasing this issue down. This patch is going > to be merged upstream asap, you may want to apply it for a preview. Targeting linux-evl or linux-dovetail? This is of interest for Xenomai 3 as well, so merging on Dovetail-level would be nice. The same applies for the documentation update. Once we have it for x4 we should consider that for x4 as well. > > diff --git a/mm/Kconfig b/mm/Kconfig > index 7bf469354faf3..759af896a5c7b 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -648,7 +648,7 @@ config COMPACTION > config COMPACT_UNEVICTABLE_DEFAULT > int > depends on COMPACTION > - default 0 if PREEMPT_RT > + default 0 if PREEMPT_RT || DOVETAIL > default 1 > > # > > > > > https://www.infradead.org/~mchehab/kernel_docs/admin-guide/sysctl/vm.html#compact-unevictable-allowed > > -- > Philippe.