const Thread = struct_: void = {}Avoid false sharing.
mutex: std.atomic.Mutex = .unlockedProtects the state in this struct (per-thread state).
Threads lock this before accessing their own state in order to support freelist reclamation.
next_addrs: [size_class_count]usize = @splat(0)For each size class, tracks the next address to be returned from alloc when the freelist is empty.
frees: [size_class_count]usize = @splat(0)For each size class, points to the freed pointer.
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98const Thread = struct {
/// Avoid false sharing.
_: void align(std.atomic.cache_line) = {},
/// Protects the state in this struct (per-thread state).
///
/// Threads lock this before accessing their own state in order
/// to support freelist reclamation.
mutex: std.atomic.Mutex = .unlocked,
/// For each size class, tracks the next address to be returned from
/// `alloc` when the freelist is empty.
next_addrs: [size_class_count]usize = @splat(0),
/// For each size class, points to the freed pointer.
frees: [size_class_count]usize = @splat(0),
fn lock() *Thread {
var index = thread_index;
{
const t = &global.threads[index];
if (t.mutex.tryLock()) {
@branchHint(.likely);
return t;
}
}
const cpu_count = getCpuCount();
assert(cpu_count != 0);
while (true) {
index = (index + 1) % cpu_count;
const t = &global.threads[index];
if (t.mutex.tryLock()) {
thread_index = index;
return t;
}
}
}
fn unlock(t: *Thread) void {
t.mutex.unlock();
}
}