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-rw-r--r--debian/patches/libdde_rcu.patch816
1 files changed, 816 insertions, 0 deletions
diff --git a/debian/patches/libdde_rcu.patch b/debian/patches/libdde_rcu.patch
new file mode 100644
index 00000000..25f8a395
--- /dev/null
+++ b/debian/patches/libdde_rcu.patch
@@ -0,0 +1,816 @@
+--- /dev/null 2011-08-03 18:03:30.000000000 +0000
++++ b/libdde_linux26/contrib/kernel/rcuclassic.c 2012-04-15 23:40:54.000000000 +0000
+@@ -0,0 +1,788 @@
++/*
++ * Read-Copy Update mechanism for mutual exclusion
++ *
++ * 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, 2001
++ *
++ * Authors: Dipankar Sarma <dipankar@in.ibm.com>
++ * Manfred Spraul <manfred@colorfullife.com>
++ *
++ * Based on the original work by Paul McKenney <paulmck@us.ibm.com>
++ * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
++ * Papers:
++ * http://www.rdrop.com/users/paulmck/paper/rclockpdcsproof.pdf
++ * http://lse.sourceforge.net/locking/rclock_OLS.2001.05.01c.sc.pdf (OLS2001)
++ *
++ * For detailed explanation of Read-Copy Update mechanism see -
++ * Documentation/RCU
++ *
++ */
++#include <linux/types.h>
++#include <linux/kernel.h>
++#include <linux/init.h>
++#include <linux/spinlock.h>
++#include <linux/smp.h>
++#include <linux/rcupdate.h>
++#include <linux/interrupt.h>
++#include <linux/sched.h>
++#include <asm/atomic.h>
++#include <linux/bitops.h>
++#include <linux/module.h>
++#include <linux/completion.h>
++#include <linux/moduleparam.h>
++#include <linux/percpu.h>
++#include <linux/notifier.h>
++#include <linux/cpu.h>
++#include <linux/mutex.h>
++#include <linux/time.h>
++
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++static struct lock_class_key rcu_lock_key;
++struct lockdep_map rcu_lock_map =
++ STATIC_LOCKDEP_MAP_INIT("rcu_read_lock", &rcu_lock_key);
++EXPORT_SYMBOL_GPL(rcu_lock_map);
++#endif
++
++
++/* Definition for rcupdate control block. */
++static struct rcu_ctrlblk rcu_ctrlblk = {
++ .cur = -300,
++ .completed = -300,
++ .pending = -300,
++ .lock = __SPIN_LOCK_UNLOCKED(&rcu_ctrlblk.lock),
++ .cpumask = CPU_BITS_NONE,
++};
++static struct rcu_ctrlblk rcu_bh_ctrlblk = {
++ .cur = -300,
++ .completed = -300,
++ .pending = -300,
++ .lock = __SPIN_LOCK_UNLOCKED(&rcu_bh_ctrlblk.lock),
++ .cpumask = CPU_BITS_NONE,
++};
++
++DEFINE_PER_CPU(struct rcu_data, rcu_data) = { 0L };
++DEFINE_PER_CPU(struct rcu_data, rcu_bh_data) = { 0L };
++
++static int blimit = 10;
++static int qhimark = 10000;
++static int qlowmark = 100;
++
++#ifdef CONFIG_SMP
++static void force_quiescent_state(struct rcu_data *rdp,
++ struct rcu_ctrlblk *rcp)
++{
++ int cpu;
++ unsigned long flags;
++
++ set_need_resched();
++ spin_lock_irqsave(&rcp->lock, flags);
++ if (unlikely(!rcp->signaled)) {
++ rcp->signaled = 1;
++ /*
++ * Don't send IPI to itself. With irqs disabled,
++ * rdp->cpu is the current cpu.
++ *
++ * cpu_online_mask is updated by the _cpu_down()
++ * using __stop_machine(). Since we're in irqs disabled
++ * section, __stop_machine() is not exectuting, hence
++ * the cpu_online_mask is stable.
++ *
++ * However, a cpu might have been offlined _just_ before
++ * we disabled irqs while entering here.
++ * And rcu subsystem might not yet have handled the CPU_DEAD
++ * notification, leading to the offlined cpu's bit
++ * being set in the rcp->cpumask.
++ *
++ * Hence cpumask = (rcp->cpumask & cpu_online_mask) to prevent
++ * sending smp_reschedule() to an offlined CPU.
++ */
++ for_each_cpu_and(cpu,
++ to_cpumask(rcp->cpumask), cpu_online_mask) {
++ if (cpu != rdp->cpu)
++ smp_send_reschedule(cpu);
++ }
++ }
++ spin_unlock_irqrestore(&rcp->lock, flags);
++}
++#else
++static inline void force_quiescent_state(struct rcu_data *rdp,
++ struct rcu_ctrlblk *rcp)
++{
++ set_need_resched();
++}
++#endif
++
++static void __call_rcu(struct rcu_head *head, struct rcu_ctrlblk *rcp,
++ struct rcu_data *rdp)
++{
++ long batch;
++
++ head->next = NULL;
++ smp_mb(); /* Read of rcu->cur must happen after any change by caller. */
++
++ /*
++ * Determine the batch number of this callback.
++ *
++ * Using ACCESS_ONCE to avoid the following error when gcc eliminates
++ * local variable "batch" and emits codes like this:
++ * 1) rdp->batch = rcp->cur + 1 # gets old value
++ * ......
++ * 2)rcu_batch_after(rcp->cur + 1, rdp->batch) # gets new value
++ * then [*nxttail[0], *nxttail[1]) may contain callbacks
++ * that batch# = rdp->batch, see the comment of struct rcu_data.
++ */
++ batch = ACCESS_ONCE(rcp->cur) + 1;
++
++ if (rdp->nxtlist && rcu_batch_after(batch, rdp->batch)) {
++ /* process callbacks */
++ rdp->nxttail[0] = rdp->nxttail[1];
++ rdp->nxttail[1] = rdp->nxttail[2];
++ if (rcu_batch_after(batch - 1, rdp->batch))
++ rdp->nxttail[0] = rdp->nxttail[2];
++ }
++
++ rdp->batch = batch;
++ *rdp->nxttail[2] = head;
++ rdp->nxttail[2] = &head->next;
++
++ if (unlikely(++rdp->qlen > qhimark)) {
++ rdp->blimit = INT_MAX;
++ force_quiescent_state(rdp, &rcu_ctrlblk);
++ }
++}
++
++#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
++
++static void record_gp_stall_check_time(struct rcu_ctrlblk *rcp)
++{
++ rcp->gp_start = jiffies;
++ rcp->jiffies_stall = jiffies + RCU_SECONDS_TILL_STALL_CHECK;
++}
++
++static void print_other_cpu_stall(struct rcu_ctrlblk *rcp)
++{
++ int cpu;
++ long delta;
++ unsigned long flags;
++
++ /* Only let one CPU complain about others per time interval. */
++
++ spin_lock_irqsave(&rcp->lock, flags);
++ delta = jiffies - rcp->jiffies_stall;
++ if (delta < 2 || rcp->cur != rcp->completed) {
++ spin_unlock_irqrestore(&rcp->lock, flags);
++ return;
++ }
++ rcp->jiffies_stall = jiffies + RCU_SECONDS_TILL_STALL_RECHECK;
++ spin_unlock_irqrestore(&rcp->lock, flags);
++
++ /* OK, time to rat on our buddy... */
++
++ printk(KERN_ERR "INFO: RCU detected CPU stalls:");
++ for_each_possible_cpu(cpu) {
++ if (cpumask_test_cpu(cpu, to_cpumask(rcp->cpumask)))
++ printk(" %d", cpu);
++ }
++ printk(" (detected by %d, t=%ld jiffies)\n",
++ smp_processor_id(), (long)(jiffies - rcp->gp_start));
++}
++
++static void print_cpu_stall(struct rcu_ctrlblk *rcp)
++{
++ unsigned long flags;
++
++ printk(KERN_ERR "INFO: RCU detected CPU %d stall (t=%lu/%lu jiffies)\n",
++ smp_processor_id(), jiffies,
++ jiffies - rcp->gp_start);
++ dump_stack();
++ spin_lock_irqsave(&rcp->lock, flags);
++ if ((long)(jiffies - rcp->jiffies_stall) >= 0)
++ rcp->jiffies_stall =
++ jiffies + RCU_SECONDS_TILL_STALL_RECHECK;
++ spin_unlock_irqrestore(&rcp->lock, flags);
++ set_need_resched(); /* kick ourselves to get things going. */
++}
++
++static void check_cpu_stall(struct rcu_ctrlblk *rcp)
++{
++ long delta;
++
++ delta = jiffies - rcp->jiffies_stall;
++ if (cpumask_test_cpu(smp_processor_id(), to_cpumask(rcp->cpumask)) &&
++ delta >= 0) {
++
++ /* We haven't checked in, so go dump stack. */
++ print_cpu_stall(rcp);
++
++ } else if (rcp->cur != rcp->completed && delta >= 2) {
++
++ /* They had two seconds to dump stack, so complain. */
++ print_other_cpu_stall(rcp);
++ }
++}
++
++#else /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
++
++static void record_gp_stall_check_time(struct rcu_ctrlblk *rcp)
++{
++}
++
++static inline void check_cpu_stall(struct rcu_ctrlblk *rcp)
++{
++}
++
++#endif /* #else #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
++
++/**
++ * call_rcu - Queue an RCU callback for invocation after a grace period.
++ * @head: structure to be used for queueing the RCU updates.
++ * @func: actual update function to be invoked after the grace period
++ *
++ * The update function will be invoked some time after a full grace
++ * period elapses, in other words after all currently executing RCU
++ * read-side critical sections have completed. RCU read-side critical
++ * sections are delimited by rcu_read_lock() and rcu_read_unlock(),
++ * and may be nested.
++ */
++void call_rcu(struct rcu_head *head,
++ void (*func)(struct rcu_head *rcu))
++{
++ unsigned long flags;
++
++ head->func = func;
++ local_irq_save(flags);
++ __call_rcu(head, &rcu_ctrlblk, &__get_cpu_var(rcu_data));
++ local_irq_restore(flags);
++}
++EXPORT_SYMBOL_GPL(call_rcu);
++
++/**
++ * call_rcu_bh - Queue an RCU for invocation after a quicker grace period.
++ * @head: structure to be used for queueing the RCU updates.
++ * @func: actual update function to be invoked after the grace period
++ *
++ * The update function will be invoked some time after a full grace
++ * period elapses, in other words after all currently executing RCU
++ * read-side critical sections have completed. call_rcu_bh() assumes
++ * that the read-side critical sections end on completion of a softirq
++ * handler. This means that read-side critical sections in process
++ * context must not be interrupted by softirqs. This interface is to be
++ * used when most of the read-side critical sections are in softirq context.
++ * RCU read-side critical sections are delimited by rcu_read_lock() and
++ * rcu_read_unlock(), * if in interrupt context or rcu_read_lock_bh()
++ * and rcu_read_unlock_bh(), if in process context. These may be nested.
++ */
++void call_rcu_bh(struct rcu_head *head,
++ void (*func)(struct rcu_head *rcu))
++{
++ unsigned long flags;
++
++ head->func = func;
++ local_irq_save(flags);
++ __call_rcu(head, &rcu_bh_ctrlblk, &__get_cpu_var(rcu_bh_data));
++ local_irq_restore(flags);
++}
++EXPORT_SYMBOL_GPL(call_rcu_bh);
++
++/*
++ * Return the number of RCU batches processed thus far. Useful
++ * for debug and statistics.
++ */
++long rcu_batches_completed(void)
++{
++ return rcu_ctrlblk.completed;
++}
++EXPORT_SYMBOL_GPL(rcu_batches_completed);
++
++/*
++ * Return the number of RCU batches processed thus far. Useful
++ * for debug and statistics.
++ */
++long rcu_batches_completed_bh(void)
++{
++ return rcu_bh_ctrlblk.completed;
++}
++EXPORT_SYMBOL_GPL(rcu_batches_completed_bh);
++
++/* Raises the softirq for processing rcu_callbacks. */
++static inline void raise_rcu_softirq(void)
++{
++ raise_softirq(RCU_SOFTIRQ);
++}
++
++/*
++ * Invoke the completed RCU callbacks. They are expected to be in
++ * a per-cpu list.
++ */
++static void rcu_do_batch(struct rcu_data *rdp)
++{
++ unsigned long flags;
++ struct rcu_head *next, *list;
++ int count = 0;
++
++ list = rdp->donelist;
++ while (list) {
++ next = list->next;
++ prefetch(next);
++ list->func(list);
++ list = next;
++ if (++count >= rdp->blimit)
++ break;
++ }
++ rdp->donelist = list;
++
++ local_irq_save(flags);
++ rdp->qlen -= count;
++ local_irq_restore(flags);
++ if (rdp->blimit == INT_MAX && rdp->qlen <= qlowmark)
++ rdp->blimit = blimit;
++
++ if (!rdp->donelist)
++ rdp->donetail = &rdp->donelist;
++ else
++ raise_rcu_softirq();
++}
++
++/*
++ * Grace period handling:
++ * The grace period handling consists out of two steps:
++ * - A new grace period is started.
++ * This is done by rcu_start_batch. The start is not broadcasted to
++ * all cpus, they must pick this up by comparing rcp->cur with
++ * rdp->quiescbatch. All cpus are recorded in the
++ * rcu_ctrlblk.cpumask bitmap.
++ * - All cpus must go through a quiescent state.
++ * Since the start of the grace period is not broadcasted, at least two
++ * calls to rcu_check_quiescent_state are required:
++ * The first call just notices that a new grace period is running. The
++ * following calls check if there was a quiescent state since the beginning
++ * of the grace period. If so, it updates rcu_ctrlblk.cpumask. If
++ * the bitmap is empty, then the grace period is completed.
++ * rcu_check_quiescent_state calls rcu_start_batch(0) to start the next grace
++ * period (if necessary).
++ */
++
++/*
++ * Register a new batch of callbacks, and start it up if there is currently no
++ * active batch and the batch to be registered has not already occurred.
++ * Caller must hold rcu_ctrlblk.lock.
++ */
++static void rcu_start_batch(struct rcu_ctrlblk *rcp)
++{
++ if (rcp->cur != rcp->pending &&
++ rcp->completed == rcp->cur) {
++ rcp->cur++;
++ record_gp_stall_check_time(rcp);
++
++ /*
++ * Accessing nohz_cpu_mask before incrementing rcp->cur needs a
++ * Barrier Otherwise it can cause tickless idle CPUs to be
++ * included in rcp->cpumask, which will extend graceperiods
++ * unnecessarily.
++ */
++ smp_mb();
++ cpumask_andnot(to_cpumask(rcp->cpumask),
++ cpu_online_mask, nohz_cpu_mask);
++
++ rcp->signaled = 0;
++ }
++}
++
++/*
++ * cpu went through a quiescent state since the beginning of the grace period.
++ * Clear it from the cpu mask and complete the grace period if it was the last
++ * cpu. Start another grace period if someone has further entries pending
++ */
++static void cpu_quiet(int cpu, struct rcu_ctrlblk *rcp)
++{
++ cpumask_clear_cpu(cpu, to_cpumask(rcp->cpumask));
++ if (cpumask_empty(to_cpumask(rcp->cpumask))) {
++ /* batch completed ! */
++ rcp->completed = rcp->cur;
++ rcu_start_batch(rcp);
++ }
++}
++
++/*
++ * Check if the cpu has gone through a quiescent state (say context
++ * switch). If so and if it already hasn't done so in this RCU
++ * quiescent cycle, then indicate that it has done so.
++ */
++static void rcu_check_quiescent_state(struct rcu_ctrlblk *rcp,
++ struct rcu_data *rdp)
++{
++ unsigned long flags;
++
++ if (rdp->quiescbatch != rcp->cur) {
++ /* start new grace period: */
++ rdp->qs_pending = 1;
++ rdp->passed_quiesc = 0;
++ rdp->quiescbatch = rcp->cur;
++ return;
++ }
++
++ /* Grace period already completed for this cpu?
++ * qs_pending is checked instead of the actual bitmap to avoid
++ * cacheline trashing.
++ */
++ if (!rdp->qs_pending)
++ return;
++
++ /*
++ * Was there a quiescent state since the beginning of the grace
++ * period? If no, then exit and wait for the next call.
++ */
++ if (!rdp->passed_quiesc)
++ return;
++ rdp->qs_pending = 0;
++
++ spin_lock_irqsave(&rcp->lock, flags);
++ /*
++ * rdp->quiescbatch/rcp->cur and the cpu bitmap can come out of sync
++ * during cpu startup. Ignore the quiescent state.
++ */
++ if (likely(rdp->quiescbatch == rcp->cur))
++ cpu_quiet(rdp->cpu, rcp);
++
++ spin_unlock_irqrestore(&rcp->lock, flags);
++}
++
++
++#ifdef CONFIG_HOTPLUG_CPU
++
++/* warning! helper for rcu_offline_cpu. do not use elsewhere without reviewing
++ * locking requirements, the list it's pulling from has to belong to a cpu
++ * which is dead and hence not processing interrupts.
++ */
++static void rcu_move_batch(struct rcu_data *this_rdp, struct rcu_head *list,
++ struct rcu_head **tail, long batch)
++{
++ unsigned long flags;
++
++ if (list) {
++ local_irq_save(flags);
++ this_rdp->batch = batch;
++ *this_rdp->nxttail[2] = list;
++ this_rdp->nxttail[2] = tail;
++ local_irq_restore(flags);
++ }
++}
++
++static void __rcu_offline_cpu(struct rcu_data *this_rdp,
++ struct rcu_ctrlblk *rcp, struct rcu_data *rdp)
++{
++ unsigned long flags;
++
++ /*
++ * if the cpu going offline owns the grace period
++ * we can block indefinitely waiting for it, so flush
++ * it here
++ */
++ spin_lock_irqsave(&rcp->lock, flags);
++ if (rcp->cur != rcp->completed)
++ cpu_quiet(rdp->cpu, rcp);
++ rcu_move_batch(this_rdp, rdp->donelist, rdp->donetail, rcp->cur + 1);
++ rcu_move_batch(this_rdp, rdp->nxtlist, rdp->nxttail[2], rcp->cur + 1);
++ spin_unlock(&rcp->lock);
++
++ this_rdp->qlen += rdp->qlen;
++ local_irq_restore(flags);
++}
++
++static void rcu_offline_cpu(int cpu)
++{
++ struct rcu_data *this_rdp = &get_cpu_var(rcu_data);
++ struct rcu_data *this_bh_rdp = &get_cpu_var(rcu_bh_data);
++
++ __rcu_offline_cpu(this_rdp, &rcu_ctrlblk,
++ &per_cpu(rcu_data, cpu));
++ __rcu_offline_cpu(this_bh_rdp, &rcu_bh_ctrlblk,
++ &per_cpu(rcu_bh_data, cpu));
++ put_cpu_var(rcu_data);
++ put_cpu_var(rcu_bh_data);
++}
++
++#else
++
++static void rcu_offline_cpu(int cpu)
++{
++}
++
++#endif
++
++/*
++ * This does the RCU processing work from softirq context.
++ */
++static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp,
++ struct rcu_data *rdp)
++{
++ unsigned long flags;
++ long completed_snap;
++
++ if (rdp->nxtlist) {
++ local_irq_save(flags);
++ completed_snap = ACCESS_ONCE(rcp->completed);
++
++ /*
++ * move the other grace-period-completed entries to
++ * [rdp->nxtlist, *rdp->nxttail[0]) temporarily
++ */
++ if (!rcu_batch_before(completed_snap, rdp->batch))
++ rdp->nxttail[0] = rdp->nxttail[1] = rdp->nxttail[2];
++ else if (!rcu_batch_before(completed_snap, rdp->batch - 1))
++ rdp->nxttail[0] = rdp->nxttail[1];
++
++ /*
++ * the grace period for entries in
++ * [rdp->nxtlist, *rdp->nxttail[0]) has completed and
++ * move these entries to donelist
++ */
++ if (rdp->nxttail[0] != &rdp->nxtlist) {
++ *rdp->donetail = rdp->nxtlist;
++ rdp->donetail = rdp->nxttail[0];
++ rdp->nxtlist = *rdp->nxttail[0];
++ *rdp->donetail = NULL;
++
++ if (rdp->nxttail[1] == rdp->nxttail[0])
++ rdp->nxttail[1] = &rdp->nxtlist;
++ if (rdp->nxttail[2] == rdp->nxttail[0])
++ rdp->nxttail[2] = &rdp->nxtlist;
++ rdp->nxttail[0] = &rdp->nxtlist;
++ }
++
++ local_irq_restore(flags);
++
++ if (rcu_batch_after(rdp->batch, rcp->pending)) {
++ unsigned long flags2;
++
++ /* and start it/schedule start if it's a new batch */
++ spin_lock_irqsave(&rcp->lock, flags2);
++ if (rcu_batch_after(rdp->batch, rcp->pending)) {
++ rcp->pending = rdp->batch;
++ rcu_start_batch(rcp);
++ }
++ spin_unlock_irqrestore(&rcp->lock, flags2);
++ }
++ }
++
++ rcu_check_quiescent_state(rcp, rdp);
++ if (rdp->donelist)
++ rcu_do_batch(rdp);
++}
++
++static void rcu_process_callbacks(struct softirq_action *unused)
++{
++ /*
++ * Memory references from any prior RCU read-side critical sections
++ * executed by the interrupted code must be see before any RCU
++ * grace-period manupulations below.
++ */
++
++ smp_mb(); /* See above block comment. */
++
++ __rcu_process_callbacks(&rcu_ctrlblk, &__get_cpu_var(rcu_data));
++ __rcu_process_callbacks(&rcu_bh_ctrlblk, &__get_cpu_var(rcu_bh_data));
++
++ /*
++ * Memory references from any later RCU read-side critical sections
++ * executed by the interrupted code must be see after any RCU
++ * grace-period manupulations above.
++ */
++
++ smp_mb(); /* See above block comment. */
++}
++
++static int __rcu_pending(struct rcu_ctrlblk *rcp, struct rcu_data *rdp)
++{
++ /* Check for CPU stalls, if enabled. */
++ check_cpu_stall(rcp);
++
++ if (rdp->nxtlist) {
++ long completed_snap = ACCESS_ONCE(rcp->completed);
++
++ /*
++ * This cpu has pending rcu entries and the grace period
++ * for them has completed.
++ */
++ if (!rcu_batch_before(completed_snap, rdp->batch))
++ return 1;
++ if (!rcu_batch_before(completed_snap, rdp->batch - 1) &&
++ rdp->nxttail[0] != rdp->nxttail[1])
++ return 1;
++ if (rdp->nxttail[0] != &rdp->nxtlist)
++ return 1;
++
++ /*
++ * This cpu has pending rcu entries and the new batch
++ * for then hasn't been started nor scheduled start
++ */
++ if (rcu_batch_after(rdp->batch, rcp->pending))
++ return 1;
++ }
++
++ /* This cpu has finished callbacks to invoke */
++ if (rdp->donelist)
++ return 1;
++
++ /* The rcu core waits for a quiescent state from the cpu */
++ if (rdp->quiescbatch != rcp->cur || rdp->qs_pending)
++ return 1;
++
++ /* nothing to do */
++ return 0;
++}
++
++/*
++ * Check to see if there is any immediate RCU-related work to be done
++ * by the current CPU, returning 1 if so. This function is part of the
++ * RCU implementation; it is -not- an exported member of the RCU API.
++ */
++int rcu_pending(int cpu)
++{
++ return __rcu_pending(&rcu_ctrlblk, &per_cpu(rcu_data, cpu)) ||
++ __rcu_pending(&rcu_bh_ctrlblk, &per_cpu(rcu_bh_data, cpu));
++}
++
++/*
++ * Check to see if any future RCU-related work will need to be done
++ * by the current CPU, even if none need be done immediately, returning
++ * 1 if so. This function is part of the RCU implementation; it is -not-
++ * an exported member of the RCU API.
++ */
++int rcu_needs_cpu(int cpu)
++{
++ struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
++ struct rcu_data *rdp_bh = &per_cpu(rcu_bh_data, cpu);
++
++ return !!rdp->nxtlist || !!rdp_bh->nxtlist || rcu_pending(cpu);
++}
++
++/*
++ * Top-level function driving RCU grace-period detection, normally
++ * invoked from the scheduler-clock interrupt. This function simply
++ * increments counters that are read only from softirq by this same
++ * CPU, so there are no memory barriers required.
++ */
++void rcu_check_callbacks(int cpu, int user)
++{
++ if (user ||
++ (idle_cpu(cpu) && rcu_scheduler_active &&
++ !in_softirq() && hardirq_count() <= (1 << HARDIRQ_SHIFT))) {
++
++ /*
++ * Get here if this CPU took its interrupt from user
++ * mode or from the idle loop, and if this is not a
++ * nested interrupt. In this case, the CPU is in
++ * a quiescent state, so count it.
++ *
++ * Also do a memory barrier. This is needed to handle
++ * the case where writes from a preempt-disable section
++ * of code get reordered into schedule() by this CPU's
++ * write buffer. The memory barrier makes sure that
++ * the rcu_qsctr_inc() and rcu_bh_qsctr_inc() are see
++ * by other CPUs to happen after any such write.
++ */
++
++ smp_mb(); /* See above block comment. */
++ rcu_qsctr_inc(cpu);
++ rcu_bh_qsctr_inc(cpu);
++
++ } else if (!in_softirq()) {
++
++ /*
++ * Get here if this CPU did not take its interrupt from
++ * softirq, in other words, if it is not interrupting
++ * a rcu_bh read-side critical section. This is an _bh
++ * critical section, so count it. The memory barrier
++ * is needed for the same reason as is the above one.
++ */
++
++ smp_mb(); /* See above block comment. */
++ rcu_bh_qsctr_inc(cpu);
++ }
++ raise_rcu_softirq();
++}
++
++static void __cpuinit rcu_init_percpu_data(int cpu, struct rcu_ctrlblk *rcp,
++ struct rcu_data *rdp)
++{
++ unsigned long flags;
++
++ spin_lock_irqsave(&rcp->lock, flags);
++ memset(rdp, 0, sizeof(*rdp));
++ rdp->nxttail[0] = rdp->nxttail[1] = rdp->nxttail[2] = &rdp->nxtlist;
++ rdp->donetail = &rdp->donelist;
++ rdp->quiescbatch = rcp->completed;
++ rdp->qs_pending = 0;
++ rdp->cpu = cpu;
++ rdp->blimit = blimit;
++ spin_unlock_irqrestore(&rcp->lock, flags);
++}
++
++static void __cpuinit rcu_online_cpu(int cpu)
++{
++ struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
++ struct rcu_data *bh_rdp = &per_cpu(rcu_bh_data, cpu);
++
++ rcu_init_percpu_data(cpu, &rcu_ctrlblk, rdp);
++ rcu_init_percpu_data(cpu, &rcu_bh_ctrlblk, bh_rdp);
++ open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
++}
++
++static int __cpuinit rcu_cpu_notify(struct notifier_block *self,
++ unsigned long action, void *hcpu)
++{
++ long cpu = (long)hcpu;
++
++ switch (action) {
++ case CPU_UP_PREPARE:
++ case CPU_UP_PREPARE_FROZEN:
++ rcu_online_cpu(cpu);
++ break;
++ case CPU_DEAD:
++ case CPU_DEAD_FROZEN:
++ rcu_offline_cpu(cpu);
++ break;
++ default:
++ break;
++ }
++ return NOTIFY_OK;
++}
++
++static struct notifier_block __cpuinitdata rcu_nb = {
++ .notifier_call = rcu_cpu_notify,
++};
++
++/*
++ * Initializes rcu mechanism. Assumed to be called early.
++ * That is before local timer(SMP) or jiffie timer (uniproc) is setup.
++ * Note that rcu_qsctr and friends are implicitly
++ * initialized due to the choice of ``0'' for RCU_CTR_INVALID.
++ */
++void __init __rcu_init(void)
++{
++#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
++ printk(KERN_INFO "RCU-based detection of stalled CPUs is enabled.\n");
++#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
++ rcu_cpu_notify(&rcu_nb, CPU_UP_PREPARE,
++ (void *)(long)smp_processor_id());
++ /* Register notifier for non-boot CPUs */
++ register_cpu_notifier(&rcu_nb);
++}
++
++module_param(blimit, int, 0);
++module_param(qhimark, int, 0);
++module_param(qlowmark, int, 0);
+diff --git a/libdde_linux26/contrib/kernel/rcupdate.c b/libdde_linux26/contrib/kernel/rcupdate.c
+index cae8a05..c6bfa1a 100644
+--- a/libdde_linux26/contrib/kernel/rcupdate.c
++++ b/libdde_linux26/contrib/kernel/rcupdate.c
+@@ -180,6 +180,7 @@ void __init rcu_init(void)
+ {
+ __rcu_init();
+ }
++core_initcall(rcu_init);
+
+ void rcu_scheduler_starting(void)
+ {
+diff --git a/libdde_linux26/lib/src/Makefile b/libdde_linux26/lib/src/Makefile
+index 358196b..450c4e6 100644
+--- a/libdde_linux26/lib/src/Makefile
++++ b/libdde_linux26/lib/src/Makefile
+@@ -89,6 +89,8 @@ SRC_C_libdde_linux26.o.a += \
+ kernel/kthread.c \
+ kernel/mutex.c \
+ kernel/notifier.c \
++ kernel/rcupdate.c \
++ kernel/rcuclassic.c \
+ kernel/resource.c \
+ kernel/rwsem.c \
+ kernel/sched.c \
generated by cgit v1.2.3 (git 2.46.0) at 2025-04-30 02:05:46 +0000