JakeHillion/scx-upstream
1
0
Fork 0
mirror of https://github.com/sched-ext/scx.git synced 2024-11-24 20:00:22 +00:00
Code Issues Packages Projects Releases Wiki Activity

scx_rustland: support aligned allocations in RustLandAllocator

Browse Source 
Even if the current implementation of the user-space scheduler doesn't
require to allocate aligned memory, add a simple support to aligned
allocations in RustLandAllocator, in order to make it more generic and
potentially usable by other schedulers / components.

Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
This commit is contained in:
Andrea Righi 2024-01-15 13:37:30 +01:00
parent c593e3605e
commit 63209b865d
1 changed files with 16 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
scheds/rust/scx_rustland/src/bpf/alloc.rs
View File

@ -48,6 +48,14 @@ static MEMORY: RustLandMemory = RustLandMemory {
pub struct RustLandAllocator;
impl RustLandAllocator {
unsafe fn block_to_addr(&self, block: usize) -> *mut u8 {
MEMORY.arena.get().cast::<u8>().add(block * BLOCK_SIZE)
}
unsafe fn is_aligned(&self, block: usize, align_size: usize) -> bool {
self.block_to_addr(block) as usize & (align_size - 1) == 0
}
pub fn lock_memory(&self) {
unsafe {
// Call setrlimit to set the locked-in-memory limit to unlimited.
@ -73,9 +81,6 @@ impl RustLandAllocator {
unsafe impl GlobalAlloc for RustLandAllocator {
unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
let align = layout.align();
if align > BLOCK_SIZE {
panic!("unsupported alignment: {}", align);
}
let size = layout.size();
// Find the first sequence of free blocks that can accommodate the requested size.
@ -83,15 +88,18 @@ unsafe impl GlobalAlloc for RustLandAllocator {
let mut contiguous_blocks = 0;
let mut start_block = None;
for (index, &is_allocated) in map_guard.iter().enumerate() {
if is_allocated {
// Reset consecutive blocks count if an allocated block is encountered.
for (block, &is_allocated) in map_guard.iter().enumerate() {
// Reset consecutive blocks count if an allocated block is encountered or if the
// first block is not aligned to the requested alignment.
if is_allocated
|| (contiguous_blocks == 0 && !self.is_aligned(block, align))
{
contiguous_blocks = 0;
} else {
contiguous_blocks += 1;
if contiguous_blocks * BLOCK_SIZE >= size {
// Found a sequence of free blocks that can accommodate the size.
start_block = Some(index + 1 - contiguous_blocks);
start_block = Some(block + 1 - contiguous_blocks);
break;
}
}
@ -104,7 +112,7 @@ unsafe impl GlobalAlloc for RustLandAllocator {
map_guard[i] = true;
}
// Return a pointer to the aligned allocated block.
MEMORY.arena.get().cast::<u8>().add(start * BLOCK_SIZE)
self.block_to_addr(start)
}
None => {
// No contiguous block sequence found, just panic.