f8f51afac1
This commit splits out a `FiberStack` from `Fiber`, allowing the instance allocator trait to return `FiberStack` rather than raw stack pointers. This keeps the stack creation mostly in `wasmtime_fiber`, but now the on-demand instance allocator can make use of it. The instance allocators no longer have to return a "not supported" error to indicate that the store should allocate its own fiber stack. This includes a bunch of cleanup in the instance allocator to scope stacks to the new "async" feature in the runtime. Closes #2708.
61 lines
1.6 KiB
Rust
61 lines
1.6 KiB
Rust
use anyhow::{bail, 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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if libc::madvise(addr as _, len, libc::MADV_DONTNEED) != 0 {
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bail!(
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"madvise failed to decommit: {}",
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std::io::Error::last_os_error()
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);
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}
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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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