diff options
| author | Pratyush Yadav (Google) <pratyush@kernel.org> | 2026-03-09 12:34:06 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-04-05 13:53:24 -0700 |
| commit | 91e74fa8b1bc1e44612cb677a710edce2061b6a7 (patch) | |
| tree | 8810271485919304a32f640fe9fe354c5f758c2f | |
| parent | 396042fb2b834a8fbcea9c850dbbd4ae7c7b75a9 (diff) | |
kho: make sure preservations do not span multiple NUMA nodes
The KHO restoration machinery is not capable of dealing with preservations
that span multiple NUMA nodes. kho_preserve_folio() guarantees the
preservation will only span one NUMA node since folios can't span multiple
nodes.
This leaves kho_preserve_pages(). While semantically kho_preserve_pages()
only deals with 0-order pages, so all preservations should be single page
only, in practice it combines preservations to higher orders for
efficiency. This can result in a preservation spanning multiple nodes.
Break up the preservations into a smaller order if that happens.
Link: https://lkml.kernel.org/r/20260309123410.382308-1-pratyush@kernel.org
Signed-off-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Suggested-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Samiullah Khawaja <skhawaja@google.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | kernel/liveupdate/kexec_handover.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c index 747a35107c84..3586490f7487 100644 --- a/kernel/liveupdate/kexec_handover.c +++ b/kernel/liveupdate/kexec_handover.c @@ -870,9 +870,17 @@ int kho_preserve_pages(struct page *page, unsigned long nr_pages) } while (pfn < end_pfn) { - const unsigned int order = + unsigned int order = min(count_trailing_zeros(pfn), ilog2(end_pfn - pfn)); + /* + * Make sure all the pages in a single preservation are in the + * same NUMA node. The restore machinery can not cope with a + * preservation spanning multiple NUMA nodes. + */ + while (pfn_to_nid(pfn) != pfn_to_nid(pfn + (1UL << order) - 1)) + order--; + err = kho_radix_add_page(tree, pfn, order); if (err) { failed_pfn = pfn; |