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Commit 6b3ef48a authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Ingo Molnar
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rcu: Remove CONFIG_PREEMPT_RCU 

Now that CONFIG_TREE_PREEMPT_RCU is in place, there is no
further need for CONFIG_PREEMPT_RCU.  Remove it, along with
whatever subtle bugs it may (or may not) contain.
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: mathieu.desnoyers@polymtl.ca
Cc: josht@linux.vnet.ibm.com
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
LKML-Reference: <125097461396-git-send-email->
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent f41d911f
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Showing with 13 additions and 2142 deletions
Documentation/RCU/rcu.txt
View file @ 6b3ef48a
......@@ -36,7 +36,7 @@ o How can the updater tell when a grace period has completed
executed in user mode, or executed in the idle loop, we can
safely free up that item.
Preemptible variants of RCU (CONFIG_PREEMPT_RCU) get the
Preemptible variants of RCU (CONFIG_TREE_PREEMPT_RCU) get the
same effect, but require that the readers manipulate CPU-local
counters. These counters allow limited types of blocking
within RCU read-side critical sections. SRCU also uses
......@@ -79,10 +79,10 @@ o I hear that RCU is patented? What is with that?
o I hear that RCU needs work in order to support realtime kernels?
This work is largely completed. Realtime-friendly RCU can be
enabled via the CONFIG_PREEMPT_RCU kernel configuration parameter.
However, work is in progress for enabling priority boosting of
preempted RCU read-side critical sections. This is needed if you
have CPU-bound realtime threads.
enabled via the CONFIG_TREE_PREEMPT_RCU kernel configuration
parameter. However, work is in progress for enabling priority
boosting of preempted RCU read-side critical sections. This is
needed if you have CPU-bound realtime threads.
o Where can I find more information on RCU?
......
Documentation/RCU/whatisRCU.txt
View file @ 6b3ef48a
......@@ -136,10 +136,10 @@ rcu_read_lock()
Used by a reader to inform the reclaimer that the reader is
entering an RCU read-side critical section. It is illegal
to block while in an RCU read-side critical section, though
kernels built with CONFIG_PREEMPT_RCU can preempt RCU read-side
critical sections. Any RCU-protected data structure accessed
during an RCU read-side critical section is guaranteed to remain
unreclaimed for the full duration of that critical section.
kernels built with CONFIG_TREE_PREEMPT_RCU can preempt RCU
read-side critical sections. Any RCU-protected data structure
accessed during an RCU read-side critical section is guaranteed to
remain unreclaimed for the full duration of that critical section.
Reference counts may be used in conjunction with RCU to maintain
longer-term references to data structures.
......
include/linux/init_task.h
View file @ 6b3ef48a
......@@ -94,11 +94,7 @@ extern struct group_info init_groups;
# define CAP_INIT_BSET CAP_INIT_EFF_SET
#endif
#ifdef CONFIG_PREEMPT_RCU
#define INIT_TASK_RCU_PREEMPT(tsk) \
.rcu_read_lock_nesting = 0, \
.rcu_flipctr_idx = 0,
#elif defined(CONFIG_TREE_PREEMPT_RCU)
#ifdef CONFIG_TREE_PREEMPT_RCU
#define INIT_TASK_RCU_PREEMPT(tsk) \
.rcu_read_lock_nesting = 0, \
.rcu_read_unlock_special = 0, \
......
include/linux/rcupdate.h
View file @ 6b3ef48a
......@@ -68,11 +68,9 @@ extern int rcu_scheduler_active;
#if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU)
#include <linux/rcutree.h>
#elif defined(CONFIG_PREEMPT_RCU)
#include <linux/rcupreempt.h>
#else
#error "Unknown RCU implementation specified to kernel configuration"
#endif /* #else #if defined(CONFIG_CLASSIC_RCU) */
#endif
#define RCU_HEAD_INIT { .next = NULL, .func = NULL }
#define RCU_HEAD(head) struct rcu_head head = RCU_HEAD_INIT
......
include/linux/rcupreempt.h deleted 100644 → 0
View file @ f41d911f
/*
* 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
#include <linux/cache.h>
#include <linux/spinlock.h>
#include <linux/threads.h>
#include <linux/smp.h>
#include <linux/cpumask.h>
#include <linux/seqlock.h>
extern void rcu_sched_qs(int cpu);
static inline void rcu_bh_qs(int 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);
extern void __rcu_read_unlock(void);
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);
static inline void synchronize_rcu_expedited(void)
{
synchronize_rcu(); /* Placeholder for new rcupreempt implementation. */
}
static inline void synchronize_rcu_bh_expedited(void)
{
synchronize_rcu_bh(); /* Placeholder for new rcupreempt impl. */
}
extern void __rcu_init(void);
extern void rcu_init_sched(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();
}
static inline void exit_rcu(void)
{
}
#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;
#ifdef CONFIG_NO_HZ
extern void rcu_enter_nohz(void);
extern void rcu_exit_nohz(void);
#else
# define rcu_enter_nohz() do { } while (0)
# define rcu_exit_nohz() do { } while (0)
#endif
/*
* A context switch is a grace period for rcupreempt synchronize_rcu()
* only during early boot, before the scheduler has been initialized.
* So, how the heck do we get a context switch? Well, if the caller
* invokes synchronize_rcu(), they are willing to accept a context
* switch, so we simply pretend that one happened.
*
* After boot, there might be a blocked or preempted task in an RCU
* read-side critical section, so we cannot then take the fastpath.
*/
static inline int rcu_blocking_is_gp(void)
{
return num_online_cpus() == 1 && !rcu_scheduler_active;
}
#endif /* __LINUX_RCUPREEMPT_H */
include/linux/rcupreempt_trace.h deleted 100644 → 0
View file @ f41d911f
/*
* 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
#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 /* __LINUX_RCUPREEMPT_TRACE_H */
include/linux/sched.h
View file @ 6b3ef48a
......@@ -1205,11 +1205,6 @@ struct task_struct {
unsigned int policy;
cpumask_t cpus_allowed;
#ifdef CONFIG_PREEMPT_RCU
int rcu_read_lock_nesting;
int rcu_flipctr_idx;
#endif /* #ifdef CONFIG_PREEMPT_RCU */
#ifdef CONFIG_TREE_PREEMPT_RCU
int rcu_read_lock_nesting;
char rcu_read_unlock_special;
......@@ -1744,14 +1739,6 @@ static inline void rcu_copy_process(struct task_struct *p)
INIT_LIST_HEAD(&p->rcu_node_entry);
}
#elif defined(CONFIG_PREEMPT_RCU)
static inline void rcu_copy_process(struct task_struct *p)
{
p->rcu_read_lock_nesting = 0;
p->rcu_flipctr_idx = 0;
}
#else
static inline void rcu_copy_process(struct task_struct *p)
......
init/Kconfig
View file @ 6b3ef48a
......@@ -324,17 +324,6 @@ config TREE_RCU
thousands of CPUs. It also scales down nicely to
smaller systems.
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.
config TREE_PREEMPT_RCU
bool "Preemptable tree-based hierarchical RCU"
depends on PREEMPT
......@@ -348,7 +337,7 @@ endchoice
config RCU_TRACE
bool "Enable tracing for RCU"
depends on TREE_RCU || PREEMPT_RCU || TREE_PREEMPT_RCU
depends on TREE_RCU || TREE_PREEMPT_RCU
help
This option provides tracing in RCU which presents stats
in debugfs for debugging RCU implementation.
......@@ -395,13 +384,6 @@ config TREE_RCU_TRACE
TREE_PREEMPT_RCU implementations, permitting Makefile to
trivially select kernel/rcutree_trace.c.
config PREEMPT_RCU_TRACE
def_bool RCU_TRACE && PREEMPT_RCU
select DEBUG_FS
help
This option provides tracing for the PREEMPT_RCU implementation,
permitting Makefile to trivially select kernel/rcupreempt_trace.c.
endmenu # "RCU Subsystem"
config IKCONFIG
......
kernel/Makefile
View file @ 6b3ef48a
......@@ -82,9 +82,7 @@ obj-$(CONFIG_SECCOMP) += seccomp.o
obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
obj-$(CONFIG_TREE_RCU) += rcutree.o
obj-$(CONFIG_TREE_PREEMPT_RCU) += rcutree.o
obj-$(CONFIG_PREEMPT_RCU) += rcupreempt.o
obj-$(CONFIG_TREE_RCU_TRACE) += rcutree_trace.o
obj-$(CONFIG_PREEMPT_RCU_TRACE) += rcupreempt_trace.o
obj-$(CONFIG_RELAY) += relay.o
obj-$(CONFIG_SYSCTL) += utsname_sysctl.o
obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o
......
kernel/rcupreempt.c deleted 100644 → 0
View file @ f41d911f
This diff is collapsed.
kernel/rcupreempt_trace.c deleted 100644 → 0
View file @ f41d911f
/*
* 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/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_add(atomic_read(&cp->done_invoked), &sp->done_invoked);
sp->rcu_check_callbacks += cp->rcu_check_callbacks;
atomic_add(atomic_read(&cp->rcu_try_flip_1),
&sp->rcu_try_flip_1);
atomic_add(atomic_read(&cp->rcu_try_flip_e1),
&sp->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_possible_cpu(cpu) {
long *flipctr = rcupreempt_flipctr(cpu);
cnt += snprintf(&rcupreempt_trace_buf[cnt],
RCUPREEMPT_TRACE_BUF_SIZE - cnt,
"%3d%c %4ld %3ld %d %d\n",
cpu,
cpu_is_offline(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)
{
int ret;
mutex_init(&rcupreempt_trace_mutex);
rcupreempt_trace_buf = kmalloc(RCUPREEMPT_TRACE_BUF_SIZE, GFP_KERNEL);
if (!rcupreempt_trace_buf)
return 1;
ret = rcupreempt_debugfs_init();
if (ret)
kfree(rcupreempt_trace_buf);
return ret;
}
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);
lib/Kconfig.debug
View file @ 6b3ef48a
......@@ -725,7 +725,7 @@ config RCU_TORTURE_TEST_RUNNABLE
config RCU_CPU_STALL_DETECTOR
bool "Check for stalled CPUs delaying RCU grace periods"
depends on CLASSIC_RCU || TREE_RCU || TREE_PREEMPT_RCU
depends on TREE_RCU || TREE_PREEMPT_RCU
default n
help
This option causes RCU to printk information on which
......
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