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This commit removes Wasmtime's dependency on the `region` crate. The motivation for this came about when I was updating dependencies and saw that `region` had a new major version at 3.0.0 as opposed to our currently used 2.3 track. In reviewing the use cases of `region` within Wasmtime I found two trends in particular which motivated this commit: * Some unix-specific areas of `wasmtime_runtime` use `rustix::mm::mprotect` instead of `region::protect` already. This means that the usage of `region::protect` for changing virtual memory protections was already inconsistent. * Many uses of `region::protect` were already in unix-specific regions which could make use of `rustix`. Overall I opted to remove the dependency on the `region` crate to avoid chasing its versions over time. Unix-specific changes of protections were easily changed to `rustix::mm::mprotect`. There were two locations where a windows/unix split is now required and I subjectively ruled "that seems ok". Finally removing `region` also meant that the "what is the current page size" query needed to be inlined into `wasmtime_runtime`, which I have also subjectively ruled "that seems fine". Finally one final refactoring here was that the `unix.rs` and `linux.rs` split for the pooling allocator was merged. These two files already only differed in one function so I slapped a `cfg_if!` in there to help reduce the duplication.pull/4413/head
Alex Crichton
2 years ago
committed by
GitHub
GitHub
14 changed files with 134 additions and 121 deletions
@ -1,56 +0,0 @@ |
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use anyhow::{Context, Result}; |
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fn decommit(addr: *mut u8, len: usize, protect: bool) -> Result<()> { |
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if len == 0 { |
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return Ok(()); |
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} |
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unsafe { |
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if protect { |
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region::protect(addr, len, region::Protection::NONE) |
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.context("failed to protect memory pages")?; |
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} |
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// On Linux, this is enough to cause the kernel to initialize the pages to 0 on next access
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rustix::mm::madvise(addr as _, len, rustix::mm::Advice::LinuxDontNeed) |
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.context("madvise failed to decommit: {}")?; |
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} |
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Ok(()) |
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} |
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pub fn commit_memory_pages(addr: *mut u8, len: usize) -> Result<()> { |
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if len == 0 { |
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return Ok(()); |
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} |
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// Just change the protection level to READ|WRITE
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unsafe { |
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region::protect(addr, len, region::Protection::READ_WRITE) |
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.context("failed to make linear memory pages read/write") |
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} |
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} |
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pub fn decommit_memory_pages(addr: *mut u8, len: usize) -> Result<()> { |
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decommit(addr, len, true) |
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} |
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pub fn commit_table_pages(_addr: *mut u8, _len: usize) -> Result<()> { |
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// A no-op as table pages remain READ|WRITE
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Ok(()) |
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} |
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pub fn decommit_table_pages(addr: *mut u8, len: usize) -> Result<()> { |
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decommit(addr, len, false) |
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} |
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#[cfg(feature = "async")] |
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pub fn commit_stack_pages(_addr: *mut u8, _len: usize) -> Result<()> { |
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// A no-op as stack pages remain READ|WRITE
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Ok(()) |
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} |
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#[cfg(feature = "async")] |
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pub fn decommit_stack_pages(addr: *mut u8, len: usize) -> Result<()> { |
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decommit(addr, len, false) |
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} |
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