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author	Kamil Kieliszczyk <kamil@kieliszczyk.net>	2023-07-28 11:26:35 +0200
committer	GitHub <noreply@github.com>	2023-07-28 12:26:35 +0300
commit	ea23a946ec377ec64ed4e7877d41a94f2613f1d6 (patch)
tree	6778a05e4322678efd718ed924034c311659bf10 /packaging/installer/methods
parent	8274d44f1f7c61672ef1a3dc90708f54063c3ff0 (diff)

Update documentation (#15606)

Co-authored-by: Ilya Mashchenko <ilya@netdata.cloud>

Diffstat (limited to 'packaging/installer/methods')

-rw-r--r--

packaging/installer/methods/kickstart.md

1 files changed, 1 insertions, 1 deletions

/* * Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * * Copyright IBM Corporation, 2008 * * Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com> * * For detailed explanation of Read-Copy Update mechanism see - * Documentation/RCU */ #include <linux/completion.h> #include <linux/interrupt.h> #include <linux/notifier.h> #include <linux/rcupdate.h> #include <linux/kernel.h> #include <linux/export.h> #include <linux/mutex.h> #include <linux/sched.h> #include <linux/types.h> #include <linux/init.h> #include <linux/time.h> #include <linux/cpu.h> #include <linux/prefetch.h> #ifdef CONFIG_RCU_TRACE #include <trace/events/rcu.h> #endif /* #else #ifdef CONFIG_RCU_TRACE */ #include "rcu.h" /* Forward declarations for rcutiny_plugin.h. */ struct rcu_ctrlblk; static void invoke_rcu_callbacks(void); static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp); static void rcu_process_callbacks(struct softirq_action *unused); static void __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu), struct rcu_ctrlblk *rcp); #include "rcutiny_plugin.h" static long long rcu_dynticks_nesting = DYNTICK_TASK_EXIT_IDLE; /* Common code for rcu_idle_enter() and rcu_irq_exit(), see kernel/rcutree.c. */ static void rcu_idle_enter_common(long long oldval) { if (rcu_dynticks_nesting) { RCU_TRACE(trace_rcu_dyntick("--=", oldval, rcu_dynticks_nesting)); return; } RCU_TRACE(trace_rcu_dyntick("Start", oldval, rcu_dynticks_nesting)); if (!is_idle_task(current)) { struct task_struct *idle = idle_task(smp_processor_id()); RCU_TRACE(trace_rcu_dyntick("Error on entry: not idle task", oldval, rcu_dynticks_nesting)); ftrace_dump(DUMP_ALL); WARN_ONCE(1, "Current pid: %d comm: %s / Idle pid: %d comm: %s", current->pid, current->comm, idle->pid, idle->comm); /* must be idle task! */ } rcu_sched_qs(0); /* implies rcu_bh_qsctr_inc(0) */ } /* * Enter idle, which is an extended quiescent state if we have fully * entered that mode (i.e., if the new value of dynticks_nesting is zero). */ void rcu_idle_enter(void) { unsigned long flags; long long oldval; local_irq_save(flags); oldval = rcu_dynticks_nesting; WARN_ON_ONCE((rcu_dynticks_nesting & DYNTICK_TASK_NEST_MASK) == 0); if ((rcu_dynticks_nesting & DYNTICK_TASK_NEST_MASK) == DYNTICK_TASK_NEST_VALUE) rcu_dynticks_nesting = 0; else rcu_dynticks_nesting -= DYNTICK_TASK_NEST_VALUE; rcu_idle_enter_common(oldval); local_irq_restore(flags); } EXPORT_SYMBOL_GPL(rcu_idle_enter); /* * Exit an interrupt handler towards idle. */ void rcu_irq_exit(void) { unsigned long flags; long long oldval; local_irq_save(flags); oldval = rcu_dynticks_nesting; rcu_dynticks_nesting--; WARN_ON_ONCE(rcu_dynticks_nesting < 0); rcu_idle_enter_common(oldval); local_irq_restore(flags); } /* Common code for rcu_idle_exit() and rcu_irq_enter(), see kernel/rcutree.c. */ static void rcu_idle_exit_common(long long oldval) { if (oldval) { RCU_TRACE(trace_rcu_dyntick("++=", oldval, rcu_dynticks_nesting)); return; } RCU_TRACE(trace_rcu_dyntick("End", oldval, rcu_dynticks_nesting)); if (!is_idle_task(current)) { struct task_struct *idle = idle_task(smp_processor_id()); RCU_TRACE(trace_rcu_dyntick("Error on exit: not idle task", oldval, rcu_dynticks_nesting)); ftrace_dump(DUMP_ALL); WARN_ONCE(1, "Current pid: %d comm: %s / Idle pid: %d comm: %s", current->pid, current->comm, idle->pid, idle->comm); /* must be idle task! */ } } /* * Exit idle, so that we are no longer in an extended quiescent state. */ void rcu_idle_exit(void) { unsigned long flags; long long oldval; local_irq_save(flags); oldval = rcu_dynticks_nesting; WARN_ON_ONCE(rcu_dynticks_nesting < 0); if (rcu_dynticks_nesting & DYNTICK_TASK_NEST_MASK) rcu_dynticks_nesting += DYNTICK_TASK_NEST_VALUE; else rcu_dynticks_nesting = DYNTICK_TASK_EXIT_IDLE; rcu_idle_exit_common(oldval); local_irq_restore(flags); } EXPORT_SYMBOL_GPL(rcu_idle_exit); /* * Enter an interrupt handler, moving away from idle. */ void rcu_irq_enter(void) { unsigned long flags; long long oldval; local_irq_save(flags); oldval = rcu_dynticks_nesting; rcu_dynticks_nesting++; WARN_ON_ONCE(rcu_dynticks_nesting == 0); rcu_idle_exit_common(oldval); local_irq_restore(flags); } #ifdef CONFIG_PROVE_RCU /* * Test whether RCU thinks that the current CPU is idle. */ int rcu_is_cpu_idle(void) { return !rcu_dynticks_nesting; } EXPORT_SYMBOL(rcu_is_cpu_idle); #endif /* #ifdef CONFIG_PROVE_RCU */ /* * Test whether the current CPU was interrupted from idle. Nested * interrupts don't count, we must be running at the first interrupt * level. */ int rcu_is_cpu_rrupt_from_idle(void) { return rcu_dynticks_nesting <= 0; } /* * Helper function for rcu_sched_qs() and rcu_bh_qs(). * Also irqs are disabled to avoid confusion due to interrupt handlers * invoking call_rcu(). */ static int rcu_qsctr_help(struct rcu_ctrlblk *rcp) { if (rcp->rcucblist != NULL && rcp->donetail != rcp->curtail) { rcp->donetail = rcp->curtail; return 1; } return 0; } /* * Record an rcu quiescent state. And an rcu_bh quiescent state while we * are at it, given that any rcu quiescent state is also an rcu_bh * quiescent state. Use "+" instead of "||" to defeat short circuiting. */ void rcu_sched_qs(int cpu) { unsigned long flags; local_irq_save(flags); if (rcu_qsctr_help(&rcu_sched_ctrlblk) + rcu_qsctr_help(&rcu_bh_ctrlblk)) invoke_rcu_callbacks(); local_irq_restore(flags); } /* * Record an rcu_bh quiescent state. */ void rcu_bh_qs(int cpu) { unsigned long flags; local_irq_save(flags); if (rcu_qsctr_help(&rcu_bh_ctrlblk)) invoke_rcu_callbacks(); local_irq_restore(flags); } /* * Check to see if the scheduling-clock interrupt came from an extended * quiescent state, and, if so, tell RCU about it. This function must * be called from hardirq context. It is normally called from the * scheduling-clock interrupt. */ void rcu_check_callbacks(int cpu, int user) { if (user || rcu_is_cpu_rrupt_from_idle()) rcu_sched_qs(cpu); else if (!in_softirq()) rcu_bh_qs(cpu); rcu_preempt_check_callbacks(); } /* * Invoke the RCU callbacks on the specified rcu_ctrlkblk structure * whose grace period has elapsed. */ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp) { char *rn = NULL; struct rcu_head *next, *list; unsigned long flags; RCU_TRACE(int cb_count = 0); /* If no RCU callbacks ready to invoke, just return. */ if (&rcp->rcucblist == rcp->donetail) { RCU_TRACE(trace_rcu_batch_start(rcp->name, 0, 0, -1)); RCU_TRACE(trace_rcu_batch_end(rcp->name, 0, ACCESS_ONCE(rcp->rcucblist), need_resched(), is_idle_task(current), rcu_is_callbacks_kthread())); return; } /* Move the ready-to-invoke callbacks to a local list. */ local_irq_save(flags); RCU_TRACE(trace_rcu_batch_start(rcp->name, 0, rcp->qlen, -1)); list = rcp->rcucblist; rcp->rcucblist = *rcp->donetail; *rcp->donetail = NULL; if (rcp->curtail == rcp->donetail) rcp->curtail = &rcp->rcucblist; rcu_preempt_remove_callbacks(rcp); rcp->donetail = &rcp->rcucblist; local_irq_restore(flags); /* Invoke the callbacks on the local list. */ RCU_TRACE(rn = rcp->name); while (list) { next = list->next; prefetch(next); debug_rcu_head_unqueue(list); local_bh_disable(); __rcu_reclaim(rn, list); local_bh_enable(); list = next; RCU_TRACE(cb_count++); } RCU_TRACE(rcu_trace_sub_qlen(rcp, cb_count)); RCU_TRACE(trace_rcu_batch_end(rcp->name, cb_count, 0, need_resched(), is_idle_task(current), rcu_is_callbacks_kthread())); } static void rcu_process_callbacks(struct softirq_action *unused) { __rcu_process_callbacks(&rcu_sched_ctrlblk); __rcu_process_callbacks(&rcu_bh_ctrlblk); rcu_preempt_process_callbacks(); } /* * Wait for a grace period to elapse. But it is illegal to invoke * synchronize_sched() from within an RCU read-side critical section. * Therefore, any legal call to synchronize_sched() is a quiescent * state, and so on a UP system, synchronize_sched() need do nothing. * Ditto for synchronize_rcu_bh(). (But Lai Jiangshan points out the * benefits of doing might_sleep() to reduce latency.) * * Cool, huh? (Due to Josh Triplett.) * * But we want to make this a static inline later. The cond_resched() * currently makes this problematic. */ void synchronize_sched(void) { rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map) && !lock_is_held(&rcu_lock_map) && !lock_is_held(&rcu_sched_lock_map), "Illegal synchronize_sched() in RCU read-side critical section"); cond_resched(); } EXPORT_SYMBOL_GPL(synchronize_sched); /* * Helper function for call_rcu() and call_rcu_bh(). */ static void __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu), struct rcu_ctrlblk *rcp) { unsigned long flags; debug_rcu_head_queue(head); head->


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