[release/10.0] [mono] Allocate helper page with mono_valloc so it doesn't confuse instruments #120293
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mono_valloc uses mmap behind the scene.
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jkotas
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Oct 1, 2025
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Backport of #120060 to release/10.0
/cc @BrzVlad
Customer Impact
Profiling with instruments doesn't work on maui maccatalyst/ios primarily when interpreter is enabled.
Regression
This is not really a regression on maui, but the problematic code is usually executed when interpreter is enabled. Given that on Xamarin the interpreter was less likely to be enabled, this could be a regression for some users.
Testing
Tested locally on ios and maccatalyst with complex enough applications that trigger this.
Risk
This fix just changes the way we allocate the page that we use to trigger memory barrier. I believe the risk of this change is low, but we are relying on undocumented side effects in order to trigger the process wide memory barrier (even before this change), so there is a chance for unforeseen side effects.