提交 e260be67 编写于 作者: P Paul E. McKenney 提交者: Ingo Molnar

Preempt-RCU: implementation

This patch implements a new version of RCU which allows its read-side
critical sections to be preempted. It uses a set of counter pairs
to keep track of the read-side critical sections and flips them
when all tasks exit read-side critical section. The details
of this implementation can be found in this paper -

	http://www.rdrop.com/users/paulmck/RCU/OLSrtRCU.2006.08.11a.pdf

and the article-

	http://lwn.net/Articles/253651/

This patch was developed as a part of the -rt kernel development and
meant to provide better latencies when read-side critical sections of
RCU don't disable preemption.  As a consequence of keeping track of RCU
readers, the readers have a slight overhead (optimizations in the paper).
This implementation co-exists with the "classic" RCU implementations
and can be switched to at compiler.

Also includes RCU tracing summarized in debugfs.

[ akpm@linux-foundation.org: build fixes on non-preempt architectures ]
Signed-off-by: NGautham R Shenoy <ego@in.ibm.com>
Signed-off-by: NDipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: NPaul E. McKenney <paulmck@us.ibm.com>
Reviewed-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
上级 e0ecfa79
...@@ -2130,4 +2130,3 @@ source "fs/nls/Kconfig" ...@@ -2130,4 +2130,3 @@ source "fs/nls/Kconfig"
source "fs/dlm/Kconfig" source "fs/dlm/Kconfig"
endmenu endmenu
...@@ -157,5 +157,8 @@ extern void __rcu_init(void); ...@@ -157,5 +157,8 @@ extern void __rcu_init(void);
extern void rcu_check_callbacks(int cpu, int user); extern void rcu_check_callbacks(int cpu, int user);
extern void rcu_restart_cpu(int cpu); extern void rcu_restart_cpu(int cpu);
extern long rcu_batches_completed(void);
extern long rcu_batches_completed_bh(void);
#endif /* __KERNEL__ */ #endif /* __KERNEL__ */
#endif /* __LINUX_RCUCLASSIC_H */ #endif /* __LINUX_RCUCLASSIC_H */
...@@ -53,7 +53,11 @@ struct rcu_head { ...@@ -53,7 +53,11 @@ struct rcu_head {
void (*func)(struct rcu_head *head); void (*func)(struct rcu_head *head);
}; };
#ifdef CONFIG_CLASSIC_RCU
#include <linux/rcuclassic.h> #include <linux/rcuclassic.h>
#else /* #ifdef CONFIG_CLASSIC_RCU */
#include <linux/rcupreempt.h>
#endif /* #else #ifdef CONFIG_CLASSIC_RCU */
#define RCU_HEAD_INIT { .next = NULL, .func = NULL } #define RCU_HEAD_INIT { .next = NULL, .func = NULL }
#define RCU_HEAD(head) struct rcu_head head = RCU_HEAD_INIT #define RCU_HEAD(head) struct rcu_head head = RCU_HEAD_INIT
...@@ -231,13 +235,12 @@ extern void call_rcu_bh(struct rcu_head *head, ...@@ -231,13 +235,12 @@ extern void call_rcu_bh(struct rcu_head *head,
/* Exported common interfaces */ /* Exported common interfaces */
extern void synchronize_rcu(void); extern void synchronize_rcu(void);
extern void rcu_barrier(void); extern void rcu_barrier(void);
extern long rcu_batches_completed(void);
extern long rcu_batches_completed_bh(void);
/* Internal to kernel */ /* Internal to kernel */
extern void rcu_init(void); extern void rcu_init(void);
extern void rcu_check_callbacks(int cpu, int user); extern int rcu_needs_cpu(int cpu);
extern long rcu_batches_completed(void);
extern long rcu_batches_completed_bh(void);
#endif /* __KERNEL__ */ #endif /* __KERNEL__ */
#endif /* __LINUX_RCUPDATE_H */ #endif /* __LINUX_RCUPDATE_H */
/*
* 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@us.ibm.com>
*
* Based on the original work by Paul McKenney <paul.mckenney@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
*
*/
#ifndef __LINUX_RCUPREEMPT_H
#define __LINUX_RCUPREEMPT_H
#ifdef __KERNEL__
#include <linux/cache.h>
#include <linux/spinlock.h>
#include <linux/threads.h>
#include <linux/percpu.h>
#include <linux/cpumask.h>
#include <linux/seqlock.h>
#define rcu_qsctr_inc(cpu)
#define rcu_bh_qsctr_inc(cpu)
#define call_rcu_bh(head, rcu) call_rcu(head, rcu)
extern void __rcu_read_lock(void);
extern void __rcu_read_unlock(void);
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_check_callbacks(int cpu, int user);
extern void rcu_restart_cpu(int cpu);
extern long rcu_batches_completed(void);
/*
* Return the number of RCU batches processed thus far. Useful for debug
* and statistic. The _bh variant is identifcal to straight RCU
*/
static inline long rcu_batches_completed_bh(void)
{
return rcu_batches_completed();
}
#ifdef CONFIG_RCU_TRACE
struct rcupreempt_trace;
extern long *rcupreempt_flipctr(int cpu);
extern long rcupreempt_data_completed(void);
extern int rcupreempt_flip_flag(int cpu);
extern int rcupreempt_mb_flag(int cpu);
extern char *rcupreempt_try_flip_state_name(void);
extern struct rcupreempt_trace *rcupreempt_trace_cpu(int cpu);
#endif
struct softirq_action;
#endif /* __KERNEL__ */
#endif /* __LINUX_RCUPREEMPT_H */
/*
* 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@us.ibm.com>
*
* Based on the original work by Paul McKenney <paul.mckenney@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 the Preemptible Read-Copy Update mechanism see -
* http://lwn.net/Articles/253651/
*/
#ifndef __LINUX_RCUPREEMPT_TRACE_H
#define __LINUX_RCUPREEMPT_TRACE_H
#ifdef __KERNEL__
#include <linux/types.h>
#include <linux/kernel.h>
#include <asm/atomic.h>
/*
* PREEMPT_RCU data structures.
*/
struct rcupreempt_trace {
long next_length;
long next_add;
long wait_length;
long wait_add;
long done_length;
long done_add;
long done_remove;
atomic_t done_invoked;
long rcu_check_callbacks;
atomic_t rcu_try_flip_1;
atomic_t rcu_try_flip_e1;
long rcu_try_flip_i1;
long rcu_try_flip_ie1;
long rcu_try_flip_g1;
long rcu_try_flip_a1;
long rcu_try_flip_ae1;
long rcu_try_flip_a2;
long rcu_try_flip_z1;
long rcu_try_flip_ze1;
long rcu_try_flip_z2;
long rcu_try_flip_m1;
long rcu_try_flip_me1;
long rcu_try_flip_m2;
};
#ifdef CONFIG_RCU_TRACE
#define RCU_TRACE(fn, arg) fn(arg);
#else
#define RCU_TRACE(fn, arg)
#endif
extern void rcupreempt_trace_move2done(struct rcupreempt_trace *trace);
extern void rcupreempt_trace_move2wait(struct rcupreempt_trace *trace);
extern void rcupreempt_trace_try_flip_1(struct rcupreempt_trace *trace);
extern void rcupreempt_trace_try_flip_e1(struct rcupreempt_trace *trace);
extern void rcupreempt_trace_try_flip_i1(struct rcupreempt_trace *trace);
extern void rcupreempt_trace_try_flip_ie1(struct rcupreempt_trace *trace);
extern void rcupreempt_trace_try_flip_g1(struct rcupreempt_trace *trace);
extern void rcupreempt_trace_try_flip_a1(struct rcupreempt_trace *trace);
extern void rcupreempt_trace_try_flip_ae1(struct rcupreempt_trace *trace);
extern void rcupreempt_trace_try_flip_a2(struct rcupreempt_trace *trace);
extern void rcupreempt_trace_try_flip_z1(struct rcupreempt_trace *trace);
extern void rcupreempt_trace_try_flip_ze1(struct rcupreempt_trace *trace);
extern void rcupreempt_trace_try_flip_z2(struct rcupreempt_trace *trace);
extern void rcupreempt_trace_try_flip_m1(struct rcupreempt_trace *trace);
extern void rcupreempt_trace_try_flip_me1(struct rcupreempt_trace *trace);
extern void rcupreempt_trace_try_flip_m2(struct rcupreempt_trace *trace);
extern void rcupreempt_trace_check_callbacks(struct rcupreempt_trace *trace);
extern void rcupreempt_trace_done_remove(struct rcupreempt_trace *trace);
extern void rcupreempt_trace_invoke(struct rcupreempt_trace *trace);
extern void rcupreempt_trace_next_add(struct rcupreempt_trace *trace);
#endif /* __KERNEL__ */
#endif /* __LINUX_RCUPREEMPT_TRACE_H */
...@@ -974,6 +974,11 @@ struct task_struct { ...@@ -974,6 +974,11 @@ struct task_struct {
int nr_cpus_allowed; int nr_cpus_allowed;
unsigned int time_slice; unsigned int time_slice;
#ifdef CONFIG_PREEMPT_RCU
int rcu_read_lock_nesting;
int rcu_flipctr_idx;
#endif /* #ifdef CONFIG_PREEMPT_RCU */
#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
struct sched_info sched_info; struct sched_info sched_info;
#endif #endif
......
...@@ -763,3 +763,31 @@ source "block/Kconfig" ...@@ -763,3 +763,31 @@ source "block/Kconfig"
config PREEMPT_NOTIFIERS config PREEMPT_NOTIFIERS
bool bool
choice
prompt "RCU implementation type:"
default CLASSIC_RCU
config CLASSIC_RCU
bool "Classic RCU"
help
This option selects the classic RCU implementation that is
designed for best read-side performance on non-realtime
systems.
Say Y if you are unsure.
config PREEMPT_RCU
bool "Preemptible RCU"
depends on PREEMPT
help
This option reduces the latency of the kernel by making certain
RCU sections preemptible. Normally RCU code is non-preemptible, if
this option is selected then read-only RCU sections become
preemptible. This helps latency, but may expose bugs due to
now-naive assumptions about each RCU read-side critical section
remaining on a given CPU through its execution.
Say N if you are unsure.
endchoice
...@@ -63,3 +63,13 @@ config PREEMPT_BKL ...@@ -63,3 +63,13 @@ config PREEMPT_BKL
Say Y here if you are building a kernel for a desktop system. Say Y here if you are building a kernel for a desktop system.
Say N if you are unsure. Say N if you are unsure.
config RCU_TRACE
bool "Enable tracing for RCU - currently stats in debugfs"
select DEBUG_FS
default y
help
This option provides tracing in RCU which presents stats
in debugfs for debugging RCU implementation.
Say Y here if you want to enable RCU tracing
Say N if you are unsure.
...@@ -6,7 +6,7 @@ obj-y = sched.o fork.o exec_domain.o panic.o printk.o profile.o \ ...@@ -6,7 +6,7 @@ obj-y = sched.o fork.o exec_domain.o panic.o printk.o profile.o \
exit.o itimer.o time.o softirq.o resource.o \ exit.o itimer.o time.o softirq.o resource.o \
sysctl.o capability.o ptrace.o timer.o user.o user_namespace.o \ sysctl.o capability.o ptrace.o timer.o user.o user_namespace.o \
signal.o sys.o kmod.o workqueue.o pid.o \ signal.o sys.o kmod.o workqueue.o pid.o \
rcupdate.o rcuclassic.o extable.o params.o posix-timers.o \ rcupdate.o extable.o params.o posix-timers.o \
kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \ kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
hrtimer.o rwsem.o latency.o nsproxy.o srcu.o \ hrtimer.o rwsem.o latency.o nsproxy.o srcu.o \
utsname.o notifier.o utsname.o notifier.o
...@@ -52,6 +52,11 @@ obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o ...@@ -52,6 +52,11 @@ obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
obj-$(CONFIG_GENERIC_HARDIRQS) += irq/ obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
obj-$(CONFIG_SECCOMP) += seccomp.o obj-$(CONFIG_SECCOMP) += seccomp.o
obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
obj-$(CONFIG_CLASSIC_RCU) += rcuclassic.o
obj-$(CONFIG_PREEMPT_RCU) += rcupreempt.o
ifeq ($(CONFIG_PREEMPT_RCU),y)
obj-$(CONFIG_RCU_TRACE) += rcupreempt_trace.o
endif
obj-$(CONFIG_RELAY) += relay.o obj-$(CONFIG_RELAY) += relay.o
obj-$(CONFIG_SYSCTL) += utsname_sysctl.o obj-$(CONFIG_SYSCTL) += utsname_sysctl.o
obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o
......
...@@ -1045,6 +1045,10 @@ static struct task_struct *copy_process(unsigned long clone_flags, ...@@ -1045,6 +1045,10 @@ static struct task_struct *copy_process(unsigned long clone_flags,
copy_flags(clone_flags, p); copy_flags(clone_flags, p);
INIT_LIST_HEAD(&p->children); INIT_LIST_HEAD(&p->children);
INIT_LIST_HEAD(&p->sibling); INIT_LIST_HEAD(&p->sibling);
#ifdef CONFIG_PREEMPT_RCU
p->rcu_read_lock_nesting = 0;
p->rcu_flipctr_idx = 0;
#endif /* #ifdef CONFIG_PREEMPT_RCU */
p->vfork_done = NULL; p->vfork_done = NULL;
spin_lock_init(&p->alloc_lock); spin_lock_init(&p->alloc_lock);
......
...@@ -45,7 +45,6 @@ ...@@ -45,7 +45,6 @@
#include <linux/moduleparam.h> #include <linux/moduleparam.h>
#include <linux/percpu.h> #include <linux/percpu.h>
#include <linux/notifier.h> #include <linux/notifier.h>
/* #include <linux/rcupdate.h> @@@ */
#include <linux/cpu.h> #include <linux/cpu.h>
#include <linux/mutex.h> #include <linux/mutex.h>
......
此差异已折叠。
/*
* Read-Copy Update tracing for realtime 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 IBM Corporation, 2006
*
* Papers: http://www.rdrop.com/users/paulmck/RCU
*
* For detailed explanation of Read-Copy Update mechanism see -
* Documentation/RCU/ *.txt
*
*/
#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/rcupdate.h>
#include <linux/cpu.h>
#include <linux/mutex.h>
#include <linux/rcupreempt_trace.h>
#include <linux/debugfs.h>
static struct mutex rcupreempt_trace_mutex;
static char *rcupreempt_trace_buf;
#define RCUPREEMPT_TRACE_BUF_SIZE 4096
void rcupreempt_trace_move2done(struct rcupreempt_trace *trace)
{
trace->done_length += trace->wait_length;
trace->done_add += trace->wait_length;
trace->wait_length = 0;
}
void rcupreempt_trace_move2wait(struct rcupreempt_trace *trace)
{
trace->wait_length += trace->next_length;
trace->wait_add += trace->next_length;
trace->next_length = 0;
}
void rcupreempt_trace_try_flip_1(struct rcupreempt_trace *trace)
{
atomic_inc(&trace->rcu_try_flip_1);
}
void rcupreempt_trace_try_flip_e1(struct rcupreempt_trace *trace)
{
atomic_inc(&trace->rcu_try_flip_e1);
}
void rcupreempt_trace_try_flip_i1(struct rcupreempt_trace *trace)
{
trace->rcu_try_flip_i1++;
}
void rcupreempt_trace_try_flip_ie1(struct rcupreempt_trace *trace)
{
trace->rcu_try_flip_ie1++;
}
void rcupreempt_trace_try_flip_g1(struct rcupreempt_trace *trace)
{
trace->rcu_try_flip_g1++;
}
void rcupreempt_trace_try_flip_a1(struct rcupreempt_trace *trace)
{
trace->rcu_try_flip_a1++;
}
void rcupreempt_trace_try_flip_ae1(struct rcupreempt_trace *trace)
{
trace->rcu_try_flip_ae1++;
}
void rcupreempt_trace_try_flip_a2(struct rcupreempt_trace *trace)
{
trace->rcu_try_flip_a2++;
}
void rcupreempt_trace_try_flip_z1(struct rcupreempt_trace *trace)
{
trace->rcu_try_flip_z1++;
}
void rcupreempt_trace_try_flip_ze1(struct rcupreempt_trace *trace)
{
trace->rcu_try_flip_ze1++;
}
void rcupreempt_trace_try_flip_z2(struct rcupreempt_trace *trace)
{
trace->rcu_try_flip_z2++;
}
void rcupreempt_trace_try_flip_m1(struct rcupreempt_trace *trace)
{
trace->rcu_try_flip_m1++;
}
void rcupreempt_trace_try_flip_me1(struct rcupreempt_trace *trace)
{
trace->rcu_try_flip_me1++;
}
void rcupreempt_trace_try_flip_m2(struct rcupreempt_trace *trace)
{
trace->rcu_try_flip_m2++;
}
void rcupreempt_trace_check_callbacks(struct rcupreempt_trace *trace)
{
trace->rcu_check_callbacks++;
}
void rcupreempt_trace_done_remove(struct rcupreempt_trace *trace)
{
trace->done_remove += trace->done_length;
trace->done_length = 0;
}
void rcupreempt_trace_invoke(struct rcupreempt_trace *trace)
{
atomic_inc(&trace->done_invoked);
}
void rcupreempt_trace_next_add(struct rcupreempt_trace *trace)
{
trace->next_add++;
trace->next_length++;
}
static void rcupreempt_trace_sum(struct rcupreempt_trace *sp)
{
struct rcupreempt_trace *cp;
int cpu;
memset(sp, 0, sizeof(*sp));
for_each_possible_cpu(cpu) {
cp = rcupreempt_trace_cpu(cpu);
sp->next_length += cp->next_length;
sp->next_add += cp->next_add;
sp->wait_length += cp->wait_length;
sp->wait_add += cp->wait_add;
sp->done_length += cp->done_length;
sp->done_add += cp->done_add;
sp->done_remove += cp->done_remove;
atomic_set(&sp->done_invoked, atomic_read(&cp->done_invoked));
sp->rcu_check_callbacks += cp->rcu_check_callbacks;
atomic_set(&sp->rcu_try_flip_1,
atomic_read(&cp->rcu_try_flip_1));
atomic_set(&sp->rcu_try_flip_e1,
atomic_read(&cp->rcu_try_flip_e1));
sp->rcu_try_flip_i1 += cp->rcu_try_flip_i1;
sp->rcu_try_flip_ie1 += cp->rcu_try_flip_ie1;
sp->rcu_try_flip_g1 += cp->rcu_try_flip_g1;
sp->rcu_try_flip_a1 += cp->rcu_try_flip_a1;
sp->rcu_try_flip_ae1 += cp->rcu_try_flip_ae1;
sp->rcu_try_flip_a2 += cp->rcu_try_flip_a2;
sp->rcu_try_flip_z1 += cp->rcu_try_flip_z1;
sp->rcu_try_flip_ze1 += cp->rcu_try_flip_ze1;
sp->rcu_try_flip_z2 += cp->rcu_try_flip_z2;
sp->rcu_try_flip_m1 += cp->rcu_try_flip_m1;
sp->rcu_try_flip_me1 += cp->rcu_try_flip_me1;
sp->rcu_try_flip_m2 += cp->rcu_try_flip_m2;
}
}
static ssize_t rcustats_read(struct file *filp, char __user *buffer,
size_t count, loff_t *ppos)
{
struct rcupreempt_trace trace;
ssize_t bcount;
int cnt = 0;
rcupreempt_trace_sum(&trace);
mutex_lock(&rcupreempt_trace_mutex);
snprintf(&rcupreempt_trace_buf[cnt], RCUPREEMPT_TRACE_BUF_SIZE - cnt,
"ggp=%ld rcc=%ld\n",
rcu_batches_completed(),
trace.rcu_check_callbacks);
snprintf(&rcupreempt_trace_buf[cnt], RCUPREEMPT_TRACE_BUF_SIZE - cnt,
"na=%ld nl=%ld wa=%ld wl=%ld da=%ld dl=%ld dr=%ld di=%d\n"
"1=%d e1=%d i1=%ld ie1=%ld g1=%ld a1=%ld ae1=%ld a2=%ld\n"
"z1=%ld ze1=%ld z2=%ld m1=%ld me1=%ld m2=%ld\n",
trace.next_add, trace.next_length,
trace.wait_add, trace.wait_length,
trace.done_add, trace.done_length,
trace.done_remove, atomic_read(&trace.done_invoked),
atomic_read(&trace.rcu_try_flip_1),
atomic_read(&trace.rcu_try_flip_e1),
trace.rcu_try_flip_i1, trace.rcu_try_flip_ie1,
trace.rcu_try_flip_g1,
trace.rcu_try_flip_a1, trace.rcu_try_flip_ae1,
trace.rcu_try_flip_a2,
trace.rcu_try_flip_z1, trace.rcu_try_flip_ze1,
trace.rcu_try_flip_z2,
trace.rcu_try_flip_m1, trace.rcu_try_flip_me1,
trace.rcu_try_flip_m2);
bcount = simple_read_from_buffer(buffer, count, ppos,
rcupreempt_trace_buf, strlen(rcupreempt_trace_buf));
mutex_unlock(&rcupreempt_trace_mutex);
return bcount;
}
static ssize_t rcugp_read(struct file *filp, char __user *buffer,
size_t count, loff_t *ppos)
{
long oldgp = rcu_batches_completed();
ssize_t bcount;
mutex_lock(&rcupreempt_trace_mutex);
synchronize_rcu();
snprintf(rcupreempt_trace_buf, RCUPREEMPT_TRACE_BUF_SIZE,
"oldggp=%ld newggp=%ld\n", oldgp, rcu_batches_completed());
bcount = simple_read_from_buffer(buffer, count, ppos,
rcupreempt_trace_buf, strlen(rcupreempt_trace_buf));
mutex_unlock(&rcupreempt_trace_mutex);
return bcount;
}
static ssize_t rcuctrs_read(struct file *filp, char __user *buffer,
size_t count, loff_t *ppos)
{
int cnt = 0;
int cpu;
int f = rcu_batches_completed() & 0x1;
ssize_t bcount;
mutex_lock(&rcupreempt_trace_mutex);
cnt += snprintf(&rcupreempt_trace_buf[cnt], RCUPREEMPT_TRACE_BUF_SIZE,
"CPU last cur F M\n");
for_each_online_cpu(cpu) {
long *flipctr = rcupreempt_flipctr(cpu);
cnt += snprintf(&rcupreempt_trace_buf[cnt],
RCUPREEMPT_TRACE_BUF_SIZE - cnt,
"%3d %4ld %3ld %d %d\n",
cpu,
flipctr[!f],
flipctr[f],
rcupreempt_flip_flag(cpu),
rcupreempt_mb_flag(cpu));
}
cnt += snprintf(&rcupreempt_trace_buf[cnt],
RCUPREEMPT_TRACE_BUF_SIZE - cnt,
"ggp = %ld, state = %s\n",
rcu_batches_completed(),
rcupreempt_try_flip_state_name());
cnt += snprintf(&rcupreempt_trace_buf[cnt],
RCUPREEMPT_TRACE_BUF_SIZE - cnt,
"\n");
bcount = simple_read_from_buffer(buffer, count, ppos,
rcupreempt_trace_buf, strlen(rcupreempt_trace_buf));
mutex_unlock(&rcupreempt_trace_mutex);
return bcount;
}
static struct file_operations rcustats_fops = {
.owner = THIS_MODULE,
.read = rcustats_read,
};
static struct file_operations rcugp_fops = {
.owner = THIS_MODULE,
.read = rcugp_read,
};
static struct file_operations rcuctrs_fops = {
.owner = THIS_MODULE,
.read = rcuctrs_read,
};
static struct dentry *rcudir, *statdir, *ctrsdir, *gpdir;
static int rcupreempt_debugfs_init(void)
{
rcudir = debugfs_create_dir("rcu", NULL);
if (!rcudir)
goto out;
statdir = debugfs_create_file("rcustats", 0444, rcudir,
NULL, &rcustats_fops);
if (!statdir)
goto free_out;
gpdir = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
if (!gpdir)
goto free_out;
ctrsdir = debugfs_create_file("rcuctrs", 0444, rcudir,
NULL, &rcuctrs_fops);
if (!ctrsdir)
goto free_out;
return 0;
free_out:
if (statdir)
debugfs_remove(statdir);
if (gpdir)
debugfs_remove(gpdir);
debugfs_remove(rcudir);
out:
return 1;
}
static int __init rcupreempt_trace_init(void)
{
mutex_init(&rcupreempt_trace_mutex);
rcupreempt_trace_buf = kmalloc(RCUPREEMPT_TRACE_BUF_SIZE, GFP_KERNEL);
if (!rcupreempt_trace_buf)
return 1;
return rcupreempt_debugfs_init();
}
static void __exit rcupreempt_trace_cleanup(void)
{
debugfs_remove(statdir);
debugfs_remove(gpdir);
debugfs_remove(ctrsdir);
debugfs_remove(rcudir);
kfree(rcupreempt_trace_buf);
}
module_init(rcupreempt_trace_init);
module_exit(rcupreempt_trace_cleanup);
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