On Thu, Mar 07, 2024 at 07:07:07PM +0000, Catalin Marinas wrote: > On Wed, 06 Mar 2024 17:45:04 -0800, Christoph Lameter (Ampere) wrote: > > Currently defconfig selects NR_CPUS=256, but some vendors (e.g. Ampere > > Computing) are planning to ship systems with 512 CPUs. So that all CPUs on > > these systems can be used with defconfig, we'd like to bump NR_CPUS to 512. > > Therefore this patch increases the default NR_CPUS from 256 to 512. > > > > As increasing NR_CPUS will increase the size of cpumasks, there's a fear that > > this might have a significant impact on stack usage due to code which places > > cpumasks on the stack. To mitigate that concern, we can select > > CPUMASK_OFFSTACK. As that doesn't seem to be a problem today with > > NR_CPUS=256, we only select this when NR_CPUS > 256. > > > > [...] > > Applied to arm64 (for-next/misc), thanks! > > I dropped the config entry and comment, replaced it with a select as per > Mark's suggestion. > > [1/1] ARM64: Dynamically allocate cpumasks and increase supported CPUs to 512 > https://git.kernel.org/arm64/c/0499a78369ad I re-instated this patch in arm64 for-next/core as: https://git.kernel.org/arm64/c/3fbd56f0e7c1 -- Catalin
