kernel/rcu/tree_nocb.h

File Facts

System

Linux kernel

Corpus path

kernel/rcu/tree_nocb.h

Extension

.h

Size

51551 bytes

Lines

1703

Domain

Core OS

Bucket

Scheduler, Processes, Timers, Sync, And Syscalls

Inferred role

Core OS: exported/initcall integration point

Status

integration implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

• Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.
• Exports symbols or registers init work; inspect boot/module ordering and who consumes the exported contract.
• Uses kernel synchronization; read lock ordering, sleepability, and interrupt context assumptions before translating.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• No C-style include directives detected by the generator.

Detected Declarations

• function rcu_current_is_nocb_kthread
• function wake_up
• function parse_rcu_nocb_poll
• function rcu_nocb_bypass_lock
• function rcu_nocb_bypass_trylock
• function rcu_nocb_bypass_unlock
• function rcu_nocb_lock
• function rcu_nocb_unlock
• function rcu_nocb_unlock_irqrestore
• function rcu_lockdep_assert_cblist_protected
• function rcu_nocb_gp_cleanup
• function rcu_init_one_nocb
• function nocb_defer_wakeup_cancel
• function __wake_nocb_gp
• function wake_nocb_gp
• function rcu_set_jiffies_lazy_flush
• function rcu_get_jiffies_lazy_flush
• function wake_nocb_gp_defer
• function rcu_nocb_do_flush_bypass
• function rcu_nocb_flush_bypass
• function rcu_nocb_try_flush_bypass
• function nocb_bypass_needs_flush
• function rcu_barrier
• function __call_rcu_nocb_wake
• function call_rcu_nocb
• function nocb_gp_toggle_rdp
• function nocb_gp_sleep
• function nocb_gp_wait
• function rcu_nocb_gp_kthread
• function nocb_cb_wait_cond
• function nocb_cb_wait
• function kthread_park
• function rcu_seq_done
• function nocb_cb_wait
• function rcu_nocb_need_deferred_wakeup
• function do_nocb_deferred_wakeup_common
• function do_nocb_deferred_wakeup_timer
• function rcu_nocb_kthread
• function rcu_nocb_flush_deferred_wakeup
• function rcu_nocb_queue_toggle_rdp
• function rcu_nocb_rdp_deoffload_wait_cond
• function rcu_nocb_rdp_deoffload
• function rcu_nocb_rdp_offload_wait_cond
• function rcu_nocb_rdp_offload
• function rcu_nocb_cpu_toggle_offload
• function rcu_nocb_cpu_deoffload
• function rcu_nocb_cpu_offload
• function lazy_rcu_shrink_count

Annotated Snippet

if (cpulist_parse(++str, rcu_nocb_mask)) {
			pr_warn("rcu_nocbs= bad CPU range, all CPUs set\n");
			cpumask_setall(rcu_nocb_mask);
		}
	}
	rcu_state.nocb_is_setup = true;
	return 1;
}
__setup("rcu_nocbs", rcu_nocb_setup);

static int __init parse_rcu_nocb_poll(char *arg)
{
	rcu_nocb_poll = true;
	return 1;
}
__setup("rcu_nocb_poll", parse_rcu_nocb_poll);

/*
 * Don't bother bypassing ->cblist if the call_rcu() rate is low.
 * After all, the main point of bypassing is to avoid lock contention
 * on ->nocb_lock, which only can happen at high call_rcu() rates.
 */
static int nocb_nobypass_lim_per_jiffy = 16 * 1000 / HZ;
module_param(nocb_nobypass_lim_per_jiffy, int, 0);

/*
 * Acquire the specified rcu_data structure's ->nocb_bypass_lock.  If the
 * lock isn't immediately available, perform minimal sanity check.
 */
static void rcu_nocb_bypass_lock(struct rcu_data *rdp)
	__acquires(&rdp->nocb_bypass_lock)
{
	lockdep_assert_irqs_disabled();
	if (raw_spin_trylock(&rdp->nocb_bypass_lock))
		return;
	/*
	 * Contention expected only when local enqueue collide with
	 * remote flush from kthreads.
	 */
	WARN_ON_ONCE(smp_processor_id() != rdp->cpu);
	raw_spin_lock(&rdp->nocb_bypass_lock);
}

/*
 * Conditionally acquire the specified rcu_data structure's
 * ->nocb_bypass_lock.
 */
static bool rcu_nocb_bypass_trylock(struct rcu_data *rdp)
{
	lockdep_assert_irqs_disabled();
	return raw_spin_trylock(&rdp->nocb_bypass_lock);
}

/*
 * Release the specified rcu_data structure's ->nocb_bypass_lock.
 */
static void rcu_nocb_bypass_unlock(struct rcu_data *rdp)
	__releases(&rdp->nocb_bypass_lock)
{
	lockdep_assert_irqs_disabled();
	raw_spin_unlock(&rdp->nocb_bypass_lock);
}

/*
 * Acquire the specified rcu_data structure's ->nocb_lock, but only
 * if it corresponds to a no-CBs CPU.
 */
static void rcu_nocb_lock(struct rcu_data *rdp)
{
	lockdep_assert_irqs_disabled();
	if (!rcu_rdp_is_offloaded(rdp))
		return;
	raw_spin_lock(&rdp->nocb_lock);
}

/*
 * Release the specified rcu_data structure's ->nocb_lock, but only
 * if it corresponds to a no-CBs CPU.
 */
static void rcu_nocb_unlock(struct rcu_data *rdp)
{
	if (rcu_rdp_is_offloaded(rdp)) {
		lockdep_assert_irqs_disabled();
		raw_spin_unlock(&rdp->nocb_lock);
	}
}

/*
 * Release the specified rcu_data structure's ->nocb_lock and restore
 * interrupts, but only if it corresponds to a no-CBs CPU.

Annotation

• Detected declarations: `function rcu_current_is_nocb_kthread`, `function wake_up`, `function parse_rcu_nocb_poll`, `function rcu_nocb_bypass_lock`, `function rcu_nocb_bypass_trylock`, `function rcu_nocb_bypass_unlock`, `function rcu_nocb_lock`, `function rcu_nocb_unlock`, `function rcu_nocb_unlock_irqrestore`, `function rcu_lockdep_assert_cblist_protected`.
• Atlas domain: Core OS / Scheduler, Processes, Timers, Sync, And Syscalls.
• Implementation status: integration implementation candidate.
• Synchronization appears in or near this file; preserve lock ordering, sleepability, and interrupt-context constraints.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.