host: switch snapshot mapping to PAGE_READONLY (PR #1373) - #7
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Signed-off-by: danbugs <danilochiarlone@gmail.com>
Signed-off-by: danbugs <danilochiarlone@gmail.com>
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Summary
snapshot-to-diskbranch (which usedPAGE_WRITECOPY/FILE_MAP_COPYfrom PR #1391) todisk_snapshot_copy(PR #1373'sPAGE_READONLY/FILE_MAP_READapproach)from_snapshot_file_withto the updatedMultiUseSandbox::from_snapshotAPI which now requiresHostFunctionsand an optionalSandboxConfigurationThis eliminates the Windows commit-charge problem where each VM reserved ~2.5 GB of virtual commit for the CoW mapping. With
PAGE_READONLY, CoW is handled at the hypervisor level (SLAT/EPT) rather than the host OS level, so Windows does not reserve commit charge per VM.Before: ~2535 MB commit per VM, max 5-6 VMs on 16 GB machine
After: 6 MB private per VM, 10 VMs verified at 59 MB total