golang/go

runtime: make Windows VirtualAlloc failure more informative

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#70558 opened on Nov 25, 2024

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NeedsInvestigationOS-Windowscompiler/runtimehelp wanted

Description

When a Windows build fails due to OOM, the error log looks like this: https://logs.chromium.org/logs/golang/buildbucket/cr-buildbucket/8730352753718672849/+/u/step/19/log/2 It contains a thread dump of the go test command at the moment after VirtualAlloc failed, but I suspect the real culprits here are the test child processes, among which is x/tools/go/ssa, which is known to have a big appetite for memory. Unfortunately that information is somewhat obscure in the log.

The task of this issue is to consider whether there are ways that the Windows OOM crash could be made more informative, for example by including the committed size of the current process. Alternatively, whether there are changes we could make to go test or the builders that would point the finger of blame more clearly.

@prattmic

Contributor guide

Tech stack
go
Domain
backenddeveloper experience
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Go runtimeWindows memory managementgo test subprocesses
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Examine the Go runtime's Windows VirtualAlloc call (likely in runtime/mem windows.go) and the os package's process creation. Investigate how go test spawns child processes and whether diagnostic info like committed size can be added at the point of failure. Consider changes to the builder scripts to capture per process memory usage. Review existing comments and the referenced logs for clues.