Crate scx_arena 

SCX Arena library setup utilities

Crate for setting up the BPF arena library for sched-ext schedulers.

Modules

arenalib 🔒

bpf_skel 🔒

Structs

ArenaLib

Live BPF arena library state. Returned by setup() and must be kept alive for as long as the scheduler instance uses the arena: dropping it stops and joins the library’s background threads.

Daemon 🔒

One background thread and the eventfd that stops it. Dropping writes the eventfd and joins the thread.

Constants

BPF_STDERR 🔒

BPF_STDOUT 🔒

BPF_STREAMS 🔒

CACHELINE_SIZE

MEMBARRIER_CMD_GLOBAL 🔒

STREAM_POLL_INTERVAL 🔒

URCU_DOORBELL 🔒

URCU_MIN_INTERVAL 🔒

Functions

prog_fd_clone 🔒

Duplicate @prog’s fd, None for programs that were not loaded and thus have no fd, prog.as_fd() on those would construct a BorrowedFd from an invalid fd. Errors only when a loaded program’s fd cannot be duplicated.

stop_eventfd 🔒

Create the eventfd a Daemon is stopped through.

stream_extract_lines 🔒

Split the complete lines out of @carry, keeping a trailing partial for the next read. Stream elements are concatenated without separators and reads split lines arbitrarily, so prefixes may only be matched on complete lines. @new_data says whether this poll read anything: a partial with no continuation after a full poll interval is flushed as a line of its own.

stream_is_fatal 🔒

The kernel prefixes the errors it reports on a program’s BPF stderr stream with “ERROR: “.

stream_read 🔒

stream_watcher_spawn 🔒

Forward the BPF stdout/stderr streams of every program in the object to the scheduler’s stdout and stderr respectively, and abort when the kernel reports an error on a stderr stream. Nothing reads these streams otherwise, so messages would be silently dropped. Lines prefixed “IGN: “ are dropped instead of forwarded, for prints with side effects that nobody needs to see, the arena association print in scx_arena_subprog_init() for example. Called from ArenaLib::setup(), the watcher is owned by the returned ArenaLib.

urcu_daemon 🔒

urcu_run_prog 🔒

Userspace half of the scx_urcu machinery, see the BPF side in lib/sdt_alloc.bpf.c. ArenaLib::setup() spawns the daemon when the object carries the scx_urcu doorbell. The returned ArenaLib owns it and stops and joins it on drop, so nothing else is visible to the scheduler: its whole runtime surface is calling the scx_*_free_rcu() variants from its free path hooks.

urcu_spawn 🔒

Spawn the urcu reclaim daemon if @obj carries the scx_urcu doorbell and driver programs. Called from ArenaLib::setup(), the daemon is owned by the returned ArenaLib.