Memory Leak if pointer compression is enabled

[xinwei tang]

I found that when compiling V8 with Pointer Compression enabled but Sandbox disabled, the ExternalPointerTable only increases without decreasing, causing a memory leak. After a detailed investigation, I discovered that the garbage collection-related calls for the ExternalPointerTable are shielded by Sandbox-related macros. After enabling Sandbox, the leak is resolved, but the garbage collection of the ExternalPointerTable introduces approximately 100MB of peak memory usage and around 50MB of normal memory usage, which completely offsets the memory reduction brought by Pointer Compression. Is there a way to reduce the garbage collection overhead of the ExternalPointerTable or resolve the memory leak issue without enabling Sandbox?

[Michael Lippautz]

Can you file a bug on crbug.com for Blink>JavaScript>GarbageCollection with a repro and hints to the missing hooks?

This is probably a historic artifact of only using EPT in sandbox configurations. In order to avoid maintenance cost we have since made quite a few sandbox concepts also the default on non-sandbox builds. We should fix this.

-Michael

On Thu, Aug 28, 2025 at 5:42 PM xinwei tang <txw19...@gmail.com> wrote:

I found that when compiling V8 with Pointer Compression enabled but Sandbox disabled, the ExternalPointerTable only increases without decreasing, causing a memory leak. After a detailed investigation, I discovered that the garbage collection-related calls for the ExternalPointerTable are shielded by Sandbox-related macros. After enabling Sandbox, the leak is resolved, but the garbage collection of the ExternalPointerTable introduces approximately 100MB of peak memory usage and around 50MB of normal memory usage, which completely offsets the memory reduction brought by Pointer Compression. Is there a way to reduce the garbage collection overhead of the ExternalPointerTable or resolve the memory leak issue without enabling Sandbox?

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[xinwei tang]

i have reported a bug at https://issues.chromium.org/issues/441679229

Michael Lippautz <mlip...@chromium.org> 于2025年8月29日周五 16:26写道：

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