Messages in this thread Patch in this message | | | Date | Mon, 19 Feb 2024 10:30:18 +0100 | Subject | Re: [PATCH v3] sched/numa, mm: do not promote folios to nodes not set N_MEMORY | From | David Hildenbrand <> |
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On 16.02.24 12:40, Byungchul Park wrote: > Changes from v2: > 1. Rewrite the comment in code and the commit message becasue it > turns out that this patch is not the real fix for the oops > descriped. The real fix goes in another patch below: > > https://lore.kernel.org/lkml/20240216111502.79759-1-byungchul@sk.com/ > > Changes from v1: > 1. Trim the verbose oops in the commit message. (feedbacked by > Phil Auld) > 2. Rewrite a comment in code. (feedbacked by Phil Auld) > > --->8--- > From 150af2f78e19217a1d03e47e3ee5279684590fb4 Mon Sep 17 00:00:00 2001 > From: Byungchul Park <byungchul@sk.com> > Date: Fri, 16 Feb 2024 20:18:10 +0900 > Subject: [PATCH v3] sched/numa, mm: do not promote folios to nodes not set N_MEMORY > > A numa node might not have its local memory but CPUs. Promoting a folio > to the node's local memory is nonsense. So avoid nodes not set N_MEMORY > from getting promoted.
So there is no bug/panic that can be triggered and this is not a "fix" but an optimization?
> > Signed-off-by: Byungchul Park <byungchul@sk.com> > --- > kernel/sched/fair.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index d7a3c63a2171..7ed9ef3c0134 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -1828,6 +1828,13 @@ bool should_numa_migrate_memory(struct task_struct *p, struct folio *folio, > int dst_nid = cpu_to_node(dst_cpu); > int last_cpupid, this_cpupid; > > + /* > + * A node of dst_nid might not have its local memory. Promoting > + * a folio to the node is meaningless. > + */ > + if (!node_state(dst_nid, N_MEMORY)) > + return false; > + > /* > * The pages in slow memory node should be migrated according > * to hot/cold instead of private/shared.
Acked-by: David Hildenbrand <david@redhat.com>
-- Cheers,
David / dhildenb
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