Messages in this thread | | | From | Srikar Dronamraju <> | Subject | [PATCH 0/3] Offline memoryless cpuless node 0 | Date | Wed, 11 Mar 2020 16:32:34 +0530 |
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Linux kernel configured with CONFIG_NUMA on a system with multiple possible nodes, marks node 0 as online at boot. However in practice, there are systems which have node 0 as memoryless and cpuless.
This can cause 1. numa_balancing to be enabled on systems with only one online node. 2. Existence of dummy (cpuless and memoryless) node which can confuse users/scripts looking at output of lscpu / numactl.
This patchset wants to correct this anomaly.
This should only affect systems that have CONFIG_MEMORYLESS_NODES. Currently there are only 2 architectures ia64 and powerpc that have this config.
v5.6-rc4 available: 2 nodes (0,2) node 0 cpus: node 0 size: 0 MB node 0 free: 0 MB node 2 cpus: 0 1 2 3 4 5 6 7 node 2 size: 32625 MB node 2 free: 31490 MB node distances: node 0 2 0: 10 20 2: 20 10
proc and sys files ------------------ /sys/devices/system/node/online: 0,2 /proc/sys/kernel/numa_balancing: 1 /sys/devices/system/node/has_cpu: 2 /sys/devices/system/node/has_memory: 2 /sys/devices/system/node/has_normal_memory: 2 /sys/devices/system/node/possible: 0-31
v5.6-rc4 + patches ------------------ available: 1 nodes (2) node 2 cpus: 0 1 2 3 4 5 6 7 node 2 size: 32625 MB node 2 free: 31487 MB node distances: node 2 2: 10
proc and sys files ------------------ /sys/devices/system/node/online: 2 /proc/sys/kernel/numa_balancing: 0 /sys/devices/system/node/has_cpu: 2 /sys/devices/system/node/has_memory: 2 /sys/devices/system/node/has_normal_memory: 2 /sys/devices/system/node/possible: 0-31
Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org Cc: Michal Hocko <mhocko@suse.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Christopher Lameter <cl@linux.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org>
Srikar Dronamraju (3): powerpc/numa: Set numa_node for all possible cpus powerpc/numa: Prefer node id queried from vphn mm/page_alloc: Keep memoryless cpuless node 0 offline
arch/powerpc/mm/numa.c | 32 ++++++++++++++++++++++---------- mm/page_alloc.c | 4 +++- 2 files changed, 25 insertions(+), 11 deletions(-)
-- 1.8.3.1
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