Make host USM resident before kernel use#585
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Host USM allocations (HostBuffer) and the host pattern buffer used by `fill!` were never made resident on the device, unlike DeviceBuffer and SharedBuffer allocations (which already call `make_resident`). A GPU kernel that reads a non-resident host buffer can take a NotPresent pagefault under GC/allocation churn, even though host USM is nominally device-accessible. Make host USM resident at allocation time and for `fill!`'s pattern buffer, removing the asymmetry with device/shared USM. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #585 +/- ##
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- Coverage 80.92% 80.90% -0.02%
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Files 48 48
Lines 3234 3237 +3
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+ Hits 2617 2619 +2
- Misses 617 618 +1 ☔ View full report in Codecov by Harness. 🚀 New features to boost your workflow:
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Summary
Host USM allocations (
HostBuffer) and the host pattern buffer used byfill!were never made resident on the device, unlikeDeviceBufferandSharedBufferallocations (which already callmake_resident). A GPU kernel that reads a non-resident host buffer can take a NotPresent pagefault under GC/allocation churn, even though host USM is nominally device-accessible.This makes host USM resident at allocation time (
src/pool.jl) and forfill!'s pattern buffer (src/array.jl), removing the asymmetry with device/shared USM.Notes
Extracted as a standalone, stack-independent fix from the Aurora LTS work; the residency omission is a real asymmetry on
mainregardless of runtime.🤖 Generated with Claude Code