Re: [PATCH 1/3] RCU: Move some definitions to minimal headers.
From: Pekka Enberg
Date: Mon Dec 29 2008 - 04:42:57 EST
On Mon, Dec 29, 2008 at 3:40 AM, Eduard - Gabriel Munteanu
<eduard.munteanu@xxxxxxxxxxx> wrote:
> linux/rcupdate.h used to include SLAB headers, which got in the way of
> switching kmemtrace to use tracepoints instead of markers. The circular
> header inclusion pattern that appeared was making it impossible to use
> tracepoints in SLAB allocator inlines.
>
> This moves some header code into separate files. As an added bonus,
> preprocessing is faster if care is taken to use these minimal headers,
> since no effort is spent on including SLAB headers.
>
> Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@xxxxxxxxxxx>
I'm okay with this but lets cc Paul for an ack/nak.
> ---
> include/linux/rcuclassic.h | 40 +--------
> include/linux/rcuclassic_min.h | 77 +++++++++++++++
> include/linux/rcupdate.h | 160 +-------------------------------
> include/linux/rcupdate_min.h | 205 ++++++++++++++++++++++++++++++++++++++++
> include/linux/rcupreempt.h | 32 +------
> include/linux/rcupreempt_min.h | 68 +++++++++++++
> 6 files changed, 353 insertions(+), 229 deletions(-)
> create mode 100644 include/linux/rcuclassic_min.h
> create mode 100644 include/linux/rcupdate_min.h
> create mode 100644 include/linux/rcupreempt_min.h
>
> diff --git a/include/linux/rcuclassic.h b/include/linux/rcuclassic.h
> index 5f89b62..32f1512 100644
> --- a/include/linux/rcuclassic.h
> +++ b/include/linux/rcuclassic.h
> @@ -39,6 +39,7 @@
> #include <linux/percpu.h>
> #include <linux/cpumask.h>
> #include <linux/seqlock.h>
> +#include <linux/rcuclassic_min.h>
>
> #ifdef CONFIG_RCU_CPU_STALL_DETECTOR
> #define RCU_SECONDS_TILL_STALL_CHECK ( 3 * HZ) /* for rcp->jiffies_stall */
> @@ -131,45 +132,6 @@ static inline void rcu_bh_qsctr_inc(int cpu)
> extern int rcu_pending(int cpu);
> extern int rcu_needs_cpu(int cpu);
>
> -#ifdef CONFIG_DEBUG_LOCK_ALLOC
> -extern struct lockdep_map rcu_lock_map;
> -# define rcu_read_acquire() \
> - lock_acquire(&rcu_lock_map, 0, 0, 2, 1, NULL, _THIS_IP_)
> -# define rcu_read_release() lock_release(&rcu_lock_map, 1, _THIS_IP_)
> -#else
> -# define rcu_read_acquire() do { } while (0)
> -# define rcu_read_release() do { } while (0)
> -#endif
> -
> -#define __rcu_read_lock() \
> - do { \
> - preempt_disable(); \
> - __acquire(RCU); \
> - rcu_read_acquire(); \
> - } while (0)
> -#define __rcu_read_unlock() \
> - do { \
> - rcu_read_release(); \
> - __release(RCU); \
> - preempt_enable(); \
> - } while (0)
> -#define __rcu_read_lock_bh() \
> - do { \
> - local_bh_disable(); \
> - __acquire(RCU_BH); \
> - rcu_read_acquire(); \
> - } while (0)
> -#define __rcu_read_unlock_bh() \
> - do { \
> - rcu_read_release(); \
> - __release(RCU_BH); \
> - local_bh_enable(); \
> - } while (0)
> -
> -#define __synchronize_sched() synchronize_rcu()
> -
> -#define call_rcu_sched(head, func) call_rcu(head, func)
> -
> extern void __rcu_init(void);
> #define rcu_init_sched() do { } while (0)
> extern void rcu_check_callbacks(int cpu, int user);
> diff --git a/include/linux/rcuclassic_min.h b/include/linux/rcuclassic_min.h
> new file mode 100644
> index 0000000..7ea051b
> --- /dev/null
> +++ b/include/linux/rcuclassic_min.h
> @@ -0,0 +1,77 @@
> +/*
> + * Read-Copy Update mechanism for mutual exclusion (classic version)
> + *
> + * 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
> + *
> + * Author: Dipankar Sarma <dipankar@xxxxxxxxxx>
> + *
> + * Based on the original work by Paul McKenney <paulmck@xxxxxxxxxx>
> + * 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
> + *
> + */
> +
> +#ifndef _LINUX_RCUCLASSIC_MIN_H
> +#define _LINUX_RCUCLASSIC_MIN_H
> +
> +#ifdef CONFIG_DEBUG_LOCK_ALLOC
> +#include <linux/lockdep.h>
> +extern struct lockdep_map rcu_lock_map;
> +# define rcu_read_acquire() \
> + lock_acquire(&rcu_lock_map, 0, 0, 2, 1, NULL, _THIS_IP_)
> +# define rcu_read_release() lock_release(&rcu_lock_map, 1, _THIS_IP_)
> +#else
> +# define rcu_read_acquire() do { } while (0)
> +# define rcu_read_release() do { } while (0)
> +#endif
> +
> +#define __rcu_read_lock() \
> + do { \
> + preempt_disable(); \
> + __acquire(RCU); \
> + rcu_read_acquire(); \
> + } while (0)
> +#define __rcu_read_unlock() \
> + do { \
> + rcu_read_release(); \
> + __release(RCU); \
> + preempt_enable(); \
> + } while (0)
> +#define __rcu_read_lock_bh() \
> + do { \
> + local_bh_disable(); \
> + __acquire(RCU_BH); \
> + rcu_read_acquire(); \
> + } while (0)
> +#define __rcu_read_unlock_bh() \
> + do { \
> + rcu_read_release(); \
> + __release(RCU_BH); \
> + local_bh_enable(); \
> + } while (0)
> +
> +#define __synchronize_sched() synchronize_rcu()
> +
> +#define call_rcu_sched(head, func) call_rcu(head, func)
> +
> +#endif /* _LINUX_RCUCLASSIC_MIN_H */
> +
> diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
> index 86f1f5e..d7659e8 100644
> --- a/include/linux/rcupdate.h
> +++ b/include/linux/rcupdate.h
> @@ -41,16 +41,7 @@
> #include <linux/seqlock.h>
> #include <linux/lockdep.h>
> #include <linux/completion.h>
> -
> -/**
> - * struct rcu_head - callback structure for use with RCU
> - * @next: next update requests in a list
> - * @func: actual update function to call after the grace period.
> - */
> -struct rcu_head {
> - struct rcu_head *next;
> - void (*func)(struct rcu_head *head);
> -};
> +#include <linux/rcupdate_min.h>
>
> #ifdef CONFIG_CLASSIC_RCU
> #include <linux/rcuclassic.h>
> @@ -64,131 +55,6 @@ struct rcu_head {
> (ptr)->next = NULL; (ptr)->func = NULL; \
> } while (0)
>
> -/**
> - * rcu_read_lock - mark the beginning of an RCU read-side critical section.
> - *
> - * When synchronize_rcu() is invoked on one CPU while other CPUs
> - * are within RCU read-side critical sections, then the
> - * synchronize_rcu() is guaranteed to block until after all the other
> - * CPUs exit their critical sections. Similarly, if call_rcu() is invoked
> - * on one CPU while other CPUs are within RCU read-side critical
> - * sections, invocation of the corresponding RCU callback is deferred
> - * until after the all the other CPUs exit their critical sections.
> - *
> - * Note, however, that RCU callbacks are permitted to run concurrently
> - * with RCU read-side critical sections. One way that this can happen
> - * is via the following sequence of events: (1) CPU 0 enters an RCU
> - * read-side critical section, (2) CPU 1 invokes call_rcu() to register
> - * an RCU callback, (3) CPU 0 exits the RCU read-side critical section,
> - * (4) CPU 2 enters a RCU read-side critical section, (5) the RCU
> - * callback is invoked. This is legal, because the RCU read-side critical
> - * section that was running concurrently with the call_rcu() (and which
> - * therefore might be referencing something that the corresponding RCU
> - * callback would free up) has completed before the corresponding
> - * RCU callback is invoked.
> - *
> - * RCU read-side critical sections may be nested. Any deferred actions
> - * will be deferred until the outermost RCU read-side critical section
> - * completes.
> - *
> - * It is illegal to block while in an RCU read-side critical section.
> - */
> -#define rcu_read_lock() __rcu_read_lock()
> -
> -/**
> - * rcu_read_unlock - marks the end of an RCU read-side critical section.
> - *
> - * See rcu_read_lock() for more information.
> - */
> -
> -/*
> - * So where is rcu_write_lock()? It does not exist, as there is no
> - * way for writers to lock out RCU readers. This is a feature, not
> - * a bug -- this property is what provides RCU's performance benefits.
> - * Of course, writers must coordinate with each other. The normal
> - * spinlock primitives work well for this, but any other technique may be
> - * used as well. RCU does not care how the writers keep out of each
> - * others' way, as long as they do so.
> - */
> -#define rcu_read_unlock() __rcu_read_unlock()
> -
> -/**
> - * rcu_read_lock_bh - mark the beginning of a softirq-only RCU critical section
> - *
> - * This is equivalent of rcu_read_lock(), but to be used when updates
> - * are being done using call_rcu_bh(). Since call_rcu_bh() callbacks
> - * consider completion of a softirq handler to be a quiescent state,
> - * a process in RCU read-side critical section must be protected by
> - * disabling softirqs. Read-side critical sections in interrupt context
> - * can use just rcu_read_lock().
> - *
> - */
> -#define rcu_read_lock_bh() __rcu_read_lock_bh()
> -
> -/*
> - * rcu_read_unlock_bh - marks the end of a softirq-only RCU critical section
> - *
> - * See rcu_read_lock_bh() for more information.
> - */
> -#define rcu_read_unlock_bh() __rcu_read_unlock_bh()
> -
> -/**
> - * rcu_read_lock_sched - mark the beginning of a RCU-classic critical section
> - *
> - * Should be used with either
> - * - synchronize_sched()
> - * or
> - * - call_rcu_sched() and rcu_barrier_sched()
> - * on the write-side to insure proper synchronization.
> - */
> -#define rcu_read_lock_sched() preempt_disable()
> -
> -/*
> - * rcu_read_unlock_sched - marks the end of a RCU-classic critical section
> - *
> - * See rcu_read_lock_sched for more information.
> - */
> -#define rcu_read_unlock_sched() preempt_enable()
> -
> -
> -
> -/**
> - * rcu_dereference - fetch an RCU-protected pointer in an
> - * RCU read-side critical section. This pointer may later
> - * be safely dereferenced.
> - *
> - * Inserts memory barriers on architectures that require them
> - * (currently only the Alpha), and, more importantly, documents
> - * exactly which pointers are protected by RCU.
> - */
> -
> -#define rcu_dereference(p) ({ \
> - typeof(p) _________p1 = ACCESS_ONCE(p); \
> - smp_read_barrier_depends(); \
> - (_________p1); \
> - })
> -
> -/**
> - * rcu_assign_pointer - assign (publicize) a pointer to a newly
> - * initialized structure that will be dereferenced by RCU read-side
> - * critical sections. Returns the value assigned.
> - *
> - * Inserts memory barriers on architectures that require them
> - * (pretty much all of them other than x86), and also prevents
> - * the compiler from reordering the code that initializes the
> - * structure after the pointer assignment. More importantly, this
> - * call documents which pointers will be dereferenced by RCU read-side
> - * code.
> - */
> -
> -#define rcu_assign_pointer(p, v) \
> - ({ \
> - if (!__builtin_constant_p(v) || \
> - ((v) != NULL)) \
> - smp_wmb(); \
> - (p) = (v); \
> - })
> -
> /* Infrastructure to implement the synchronize_() primitives. */
>
> struct rcu_synchronize {
> @@ -211,24 +77,6 @@ void name(void) \
> }
>
> /**
> - * synchronize_sched - block until all CPUs have exited any non-preemptive
> - * kernel code sequences.
> - *
> - * This means that all preempt_disable code sequences, including NMI and
> - * hardware-interrupt handlers, in progress on entry will have completed
> - * before this primitive returns. However, this does not guarantee that
> - * softirq handlers will have completed, since in some kernels, these
> - * handlers can run in process context, and can block.
> - *
> - * This primitive provides the guarantees made by the (now removed)
> - * synchronize_kernel() API. In contrast, synchronize_rcu() only
> - * guarantees that rcu_read_lock() sections will have completed.
> - * In "classic RCU", these two guarantees happen to be one and
> - * the same, but can differ in realtime RCU implementations.
> - */
> -#define synchronize_sched() __synchronize_sched()
> -
> -/**
> * 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
> @@ -263,12 +111,6 @@ extern void call_rcu(struct rcu_head *head,
> extern void call_rcu_bh(struct rcu_head *head,
> void (*func)(struct rcu_head *head));
>
> -/* Exported common interfaces */
> -extern void synchronize_rcu(void);
> -extern void rcu_barrier(void);
> -extern void rcu_barrier_bh(void);
> -extern void rcu_barrier_sched(void);
> -
> /* Internal to kernel */
> extern void rcu_init(void);
> extern int rcu_needs_cpu(int cpu);
> diff --git a/include/linux/rcupdate_min.h b/include/linux/rcupdate_min.h
> new file mode 100644
> index 0000000..35ca45d
> --- /dev/null
> +++ b/include/linux/rcupdate_min.h
> @@ -0,0 +1,205 @@
> +/*
> + * 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
> + *
> + * Author: Dipankar Sarma <dipankar@xxxxxxxxxx>
> + *
> + * Based on the original work by Paul McKenney <paulmck@xxxxxxxxxx>
> + * 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)
> + *
> + * This is a minimal header. Use it if you don't require all definitions,
> + * as it doesn't end up including slab stuff and lots of other headers.
> + *
> + * For detailed explanation of Read-Copy Update mechanism see -
> + * http://lse.sourceforge.net/locking/rcupdate.html
> + *
> + */
> +
> +#ifndef __LINUX_RCUPDATE_MIN_H
> +#define __LINUX_RCUPDATE_MIN_H
> +
> +/**
> + * struct rcu_head - callback structure for use with RCU
> + * @next: next update requests in a list
> + * @func: actual update function to call after the grace period.
> + */
> +struct rcu_head {
> + struct rcu_head *next;
> + void (*func)(struct rcu_head *head);
> +};
> +
> +#ifdef CONFIG_CLASSIC_RCU
> +#include <linux/rcuclassic_min.h>
> +#else /* #ifdef CONFIG_CLASSIC_RCU */
> +#include <linux/rcupreempt_min.h>
> +#endif /* #else #ifdef CONFIG_CLASSIC_RCU */
> +
> +/**
> + * rcu_read_lock - mark the beginning of an RCU read-side critical section.
> + *
> + * When synchronize_rcu() is invoked on one CPU while other CPUs
> + * are within RCU read-side critical sections, then the
> + * synchronize_rcu() is guaranteed to block until after all the other
> + * CPUs exit their critical sections. Similarly, if call_rcu() is invoked
> + * on one CPU while other CPUs are within RCU read-side critical
> + * sections, invocation of the corresponding RCU callback is deferred
> + * until after the all the other CPUs exit their critical sections.
> + *
> + * Note, however, that RCU callbacks are permitted to run concurrently
> + * with RCU read-side critical sections. One way that this can happen
> + * is via the following sequence of events: (1) CPU 0 enters an RCU
> + * read-side critical section, (2) CPU 1 invokes call_rcu() to register
> + * an RCU callback, (3) CPU 0 exits the RCU read-side critical section,
> + * (4) CPU 2 enters a RCU read-side critical section, (5) the RCU
> + * callback is invoked. This is legal, because the RCU read-side critical
> + * section that was running concurrently with the call_rcu() (and which
> + * therefore might be referencing something that the corresponding RCU
> + * callback would free up) has completed before the corresponding
> + * RCU callback is invoked.
> + *
> + * RCU read-side critical sections may be nested. Any deferred actions
> + * will be deferred until the outermost RCU read-side critical section
> + * completes.
> + *
> + * It is illegal to block while in an RCU read-side critical section.
> + */
> +#define rcu_read_lock() __rcu_read_lock()
> +
> +/**
> + * rcu_read_unlock - marks the end of an RCU read-side critical section.
> + *
> + * See rcu_read_lock() for more information.
> + */
> +
> +/*
> + * So where is rcu_write_lock()? It does not exist, as there is no
> + * way for writers to lock out RCU readers. This is a feature, not
> + * a bug -- this property is what provides RCU's performance benefits.
> + * Of course, writers must coordinate with each other. The normal
> + * spinlock primitives work well for this, but any other technique may be
> + * used as well. RCU does not care how the writers keep out of each
> + * others' way, as long as they do so.
> + */
> +#define rcu_read_unlock() __rcu_read_unlock()
> +
> +/**
> + * rcu_read_lock_bh - mark the beginning of a softirq-only RCU critical section
> + *
> + * This is equivalent of rcu_read_lock(), but to be used when updates
> + * are being done using call_rcu_bh(). Since call_rcu_bh() callbacks
> + * consider completion of a softirq handler to be a quiescent state,
> + * a process in RCU read-side critical section must be protected by
> + * disabling softirqs. Read-side critical sections in interrupt context
> + * can use just rcu_read_lock().
> + *
> + */
> +#define rcu_read_lock_bh() __rcu_read_lock_bh()
> +
> +/*
> + * rcu_read_unlock_bh - marks the end of a softirq-only RCU critical section
> + *
> + * See rcu_read_lock_bh() for more information.
> + */
> +#define rcu_read_unlock_bh() __rcu_read_unlock_bh()
> +
> +/**
> + * rcu_read_lock_sched - mark the beginning of a RCU-classic critical section
> + *
> + * Should be used with either
> + * - synchronize_sched()
> + * or
> + * - call_rcu_sched() and rcu_barrier_sched()
> + * on the write-side to insure proper synchronization.
> + */
> +#define rcu_read_lock_sched() preempt_disable()
> +
> +/*
> + * rcu_read_unlock_sched - marks the end of a RCU-classic critical section
> + *
> + * See rcu_read_lock_sched for more information.
> + */
> +#define rcu_read_unlock_sched() preempt_enable()
> +
> +
> +
> +/**
> + * rcu_dereference - fetch an RCU-protected pointer in an
> + * RCU read-side critical section. This pointer may later
> + * be safely dereferenced.
> + *
> + * Inserts memory barriers on architectures that require them
> + * (currently only the Alpha), and, more importantly, documents
> + * exactly which pointers are protected by RCU.
> + */
> +
> +#define rcu_dereference(p) ({ \
> + typeof(p) _________p1 = ACCESS_ONCE(p); \
> + smp_read_barrier_depends(); \
> + (_________p1); \
> + })
> +
> +/**
> + * rcu_assign_pointer - assign (publicize) a pointer to a newly
> + * initialized structure that will be dereferenced by RCU read-side
> + * critical sections. Returns the value assigned.
> + *
> + * Inserts memory barriers on architectures that require them
> + * (pretty much all of them other than x86), and also prevents
> + * the compiler from reordering the code that initializes the
> + * structure after the pointer assignment. More importantly, this
> + * call documents which pointers will be dereferenced by RCU read-side
> + * code.
> + */
> +
> +#define rcu_assign_pointer(p, v) \
> + ({ \
> + if (!__builtin_constant_p(v) || \
> + ((v) != NULL)) \
> + smp_wmb(); \
> + (p) = (v); \
> + })
> +
> +/**
> + * synchronize_sched - block until all CPUs have exited any non-preemptive
> + * kernel code sequences.
> + *
> + * This means that all preempt_disable code sequences, including NMI and
> + * hardware-interrupt handlers, in progress on entry will have completed
> + * before this primitive returns. However, this does not guarantee that
> + * softirq handlers will have completed, since in some kernels, these
> + * handlers can run in process context, and can block.
> + *
> + * This primitive provides the guarantees made by the (now removed)
> + * synchronize_kernel() API. In contrast, synchronize_rcu() only
> + * guarantees that rcu_read_lock() sections will have completed.
> + * In "classic RCU", these two guarantees happen to be one and
> + * the same, but can differ in realtime RCU implementations.
> + */
> +#define synchronize_sched() __synchronize_sched()
> +
> +/* Exported common interfaces */
> +extern void synchronize_rcu(void);
> +extern void rcu_barrier(void);
> +extern void rcu_barrier_bh(void);
> +extern void rcu_barrier_sched(void);
> +
> +#endif /* __LINUX_RCUPDATE_MIN_H */
> +
> diff --git a/include/linux/rcupreempt.h b/include/linux/rcupreempt.h
> index 3e05c09..1f1dcf1 100644
> --- a/include/linux/rcupreempt.h
> +++ b/include/linux/rcupreempt.h
> @@ -39,6 +39,7 @@
> #include <linux/percpu.h>
> #include <linux/cpumask.h>
> #include <linux/seqlock.h>
> +#include <linux/rcupreempt_min.h>
>
> struct rcu_dyntick_sched {
> int dynticks;
> @@ -58,37 +59,6 @@ static inline void rcu_qsctr_inc(int cpu)
> }
> #define rcu_bh_qsctr_inc(cpu)
>
> -/*
> - * Someone might want to pass call_rcu_bh as a function pointer.
> - * So this needs to just be a rename and not a macro function.
> - * (no parentheses)
> - */
> -#define call_rcu_bh call_rcu
> -
> -/**
> - * call_rcu_sched - Queue RCU callback for invocation after sched 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
> - * synchronize_sched()-style grace period elapses, in other words after
> - * all currently executing preempt-disabled sections of code (including
> - * hardirq handlers, NMI handlers, and local_irq_save() blocks) have
> - * completed.
> - */
> -extern void call_rcu_sched(struct rcu_head *head,
> - void (*func)(struct rcu_head *head));
> -
> -extern void __rcu_read_lock(void) __acquires(RCU);
> -extern void __rcu_read_unlock(void) __releases(RCU);
> -extern int rcu_pending(int cpu);
> -extern int rcu_needs_cpu(int cpu);
> -
> -#define __rcu_read_lock_bh() { rcu_read_lock(); local_bh_disable(); }
> -#define __rcu_read_unlock_bh() { local_bh_enable(); rcu_read_unlock(); }
> -
> -extern void __synchronize_sched(void);
> -
> extern void __rcu_init(void);
> extern void rcu_init_sched(void);
> extern void rcu_check_callbacks(int cpu, int user);
> diff --git a/include/linux/rcupreempt_min.h b/include/linux/rcupreempt_min.h
> new file mode 100644
> index 0000000..37d3693
> --- /dev/null
> +++ b/include/linux/rcupreempt_min.h
> @@ -0,0 +1,68 @@
> +/*
> + * Read-Copy Update mechanism for mutual exclusion (RT implementation)
> + *
> + * 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 (C) IBM Corporation, 2006
> + *
> + * Author: Paul McKenney <paulmck@xxxxxxxxxx>
> + *
> + * Based on the original work by Paul McKenney <paul.mckenney@xxxxxxxxxx>
> + * 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
> + *
> + */
> +
> +#ifndef __LINUX_RCUPREEMPT_MIN_H
> +#define __LINUX_RCUPREEMPT_MIN_H
> +
> +/*
> + * Someone might want to pass call_rcu_bh as a function pointer.
> + * So this needs to just be a rename and not a macro function.
> + * (no parentheses)
> + */
> +#define call_rcu_bh call_rcu
> +
> +/**
> + * call_rcu_sched - Queue RCU callback for invocation after sched 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
> + * synchronize_sched()-style grace period elapses, in other words after
> + * all currently executing preempt-disabled sections of code (including
> + * hardirq handlers, NMI handlers, and local_irq_save() blocks) have
> + * completed.
> + */
> +extern void call_rcu_sched(struct rcu_head *head,
> + void (*func)(struct rcu_head *head));
> +
> +extern void __rcu_read_lock(void) __acquires(RCU);
> +extern void __rcu_read_unlock(void) __releases(RCU);
> +extern int rcu_pending(int cpu);
> +extern int rcu_needs_cpu(int cpu);
> +
> +#define __rcu_read_lock_bh() { rcu_read_lock(); local_bh_disable(); }
> +#define __rcu_read_unlock_bh() { local_bh_enable(); rcu_read_unlock(); }
> +
> +extern void __synchronize_sched(void);
> +
> +#endif /* __LINUX_RCUPREEMPT_MIN_H */
> +
> --
> 1.6.0.6
>
> --
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