Kernel/Memory: Various fixes for anonymous mmaps

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Kernel/Memory: Various fixes for anonymous mmaps #24639

Open brody-qq opened 5 days ago

brody-qq commented 5 days ago

This PR fixes the following problems related to anonymous mmaps:

After a fork, writes to an anonymous mmap cause redundant page faults (#24637)
Writes to a shared anonymous mmap are not visible to other processes that share the mmap (#24638)
VMObject::try_clone() overcommits pages to m_shared_committed_cow_pages

This PR also adds more test cases for anonymous mmaps.

BuggieBot commented 5 days ago

Hello!

One or more of the commit messages in this PR do not match the SerenityOS code submission policy, please check the lint_commits CI job for more details on which commits were flagged and why. Please do not close this PR and open another, instead modify your commit message(s) with git commit --amend and force push those changes to update this PR.

nico commented 4 days ago

@spholz You know this code a bit, right? Want to look at this? :)