Re: [PATCH v5 28/36] mm: add NODE_PRIVATE_CAP_HOTUNPLUG for opted-in private nodes
Gregory Price <[email protected]>
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| Message-ID | <amDNMmbdE_ZhUgl1@gourry-fedora-PF4VCD3F> |
On Mon, Jul 20, 2026 at 03:34:22PM -0400, Gregory Price wrote: > Add CAP_HOTUNPLUG, which allows memory_hotplug to migrate a private > node's folios for the purpose of hotunplugging memory. > > Without this, hotunplug fails if any folio on the node is allocated. > > Add node_allows_hotunplug() - which returns true for any normal node > and private nodes with CAP_HOTUNPLUG. > > Signed-off-by: Gregory Price <[email protected]> after this question: https://lore.kernel.org/linux-mm/al-pkvmgIxGu3LzM@gourry-fedora-PF4VCD3F/T/#m5b8166212a276fece2380f2dd03d6864375a576b and some off-list feedback about limiting initial cap bits to active use cases, I realized that this CAP bit can be entirely eliminated. hotplug notifier callbacks already allow a driver to prevent memory block state transitions - so that control already exists. v6 will remove both the filtering here and the cap bit. ~Gregory