Skip set_mempolicy for phantom NUMA nodes#296
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Pull request overview
This PR prevents numa_run_on_node() (and the resulting set_mempolicy calls) from being invoked for “phantom” NUMA nodes that aren’t present in the process’ allowed memory-node mask, avoiding EINVAL errors on platforms that expose NUMA nodes without memory backing.
Changes:
- Guard
numa_run_on_node(exeIndex)behind anuma_get_mems_allowed()/numa_bitmask_isbitset()check in the CPU executor path.
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CollectTopology() probes each NUMA node by allocating a small buffer, which calls numa_set_preferred(i) for all numa_num_configured_nodes(). If some nodes have no memory backing, set_mempolicy(MPOL_PREFERRED) returns EINVAL for them. Guard the call with numa_get_mems_allowed() so only nodes with real memory get a preferred policy set. Co-authored-by: Claude <claude@anthropic.com>
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| // Skip memory-less NUMA nodes to avoid set_mempolicy EINVAL | ||
| if (deviceIdx < 0 || numa_bitmask_isbitset(numa_get_mems_allowed(), deviceIdx)) { | ||
| numa_set_preferred(deviceIdx); | ||
| } |
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Motivation
Fix set_mempolicy EINVAL for memory-less NUMA nodes during topology init
Technical Details
CollectTopology() probes each NUMA node by allocating a small buffer, which calls
numa_set_preferred(i)for allnuma_num_configured_nodes(). If some nodes have no memory backing,set_mempolicy(MPOL_PREFERRED)returns EINVAL for them.Guard the call with
numa_get_mems_allowed()so only nodes with real memory get a preferred policy set.Test Plan
Test Result
Submission Checklist