mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-05 10:26:42 +07:00
bdfa97bf72
The file rcutiny.c does not need moduleparam.h header, as there are no modparams in this file. However rcutiny_plugin.h does define a module_init() and a module_exit() and it uses the various MODULE_ macros, so it really does need module.h included. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
255 lines
6.7 KiB
C
255 lines
6.7 KiB
C
/*
|
|
* Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
|
|
*
|
|
* Copyright IBM Corporation, 2008
|
|
*
|
|
* Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
|
|
*
|
|
* For detailed explanation of Read-Copy Update mechanism see -
|
|
* Documentation/RCU
|
|
*/
|
|
#include <linux/completion.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/notifier.h>
|
|
#include <linux/rcupdate.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/export.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/types.h>
|
|
#include <linux/init.h>
|
|
#include <linux/time.h>
|
|
#include <linux/cpu.h>
|
|
#include <linux/prefetch.h>
|
|
|
|
#ifdef CONFIG_RCU_TRACE
|
|
#include <trace/events/rcu.h>
|
|
#endif /* #else #ifdef CONFIG_RCU_TRACE */
|
|
|
|
#include "rcu.h"
|
|
|
|
/* Forward declarations for rcutiny_plugin.h. */
|
|
struct rcu_ctrlblk;
|
|
static void invoke_rcu_callbacks(void);
|
|
static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp);
|
|
static void rcu_process_callbacks(struct softirq_action *unused);
|
|
static void __call_rcu(struct rcu_head *head,
|
|
void (*func)(struct rcu_head *rcu),
|
|
struct rcu_ctrlblk *rcp);
|
|
|
|
#include "rcutiny_plugin.h"
|
|
|
|
#ifdef CONFIG_NO_HZ
|
|
|
|
static long rcu_dynticks_nesting = 1;
|
|
|
|
/*
|
|
* Enter dynticks-idle mode, which is an extended quiescent state
|
|
* if we have fully entered that mode (i.e., if the new value of
|
|
* dynticks_nesting is zero).
|
|
*/
|
|
void rcu_enter_nohz(void)
|
|
{
|
|
if (--rcu_dynticks_nesting == 0)
|
|
rcu_sched_qs(0); /* implies rcu_bh_qsctr_inc(0) */
|
|
}
|
|
|
|
/*
|
|
* Exit dynticks-idle mode, so that we are no longer in an extended
|
|
* quiescent state.
|
|
*/
|
|
void rcu_exit_nohz(void)
|
|
{
|
|
rcu_dynticks_nesting++;
|
|
}
|
|
|
|
#endif /* #ifdef CONFIG_NO_HZ */
|
|
|
|
/*
|
|
* Helper function for rcu_sched_qs() and rcu_bh_qs().
|
|
* Also irqs are disabled to avoid confusion due to interrupt handlers
|
|
* invoking call_rcu().
|
|
*/
|
|
static int rcu_qsctr_help(struct rcu_ctrlblk *rcp)
|
|
{
|
|
if (rcp->rcucblist != NULL &&
|
|
rcp->donetail != rcp->curtail) {
|
|
rcp->donetail = rcp->curtail;
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Record an rcu quiescent state. And an rcu_bh quiescent state while we
|
|
* are at it, given that any rcu quiescent state is also an rcu_bh
|
|
* quiescent state. Use "+" instead of "||" to defeat short circuiting.
|
|
*/
|
|
void rcu_sched_qs(int cpu)
|
|
{
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
if (rcu_qsctr_help(&rcu_sched_ctrlblk) +
|
|
rcu_qsctr_help(&rcu_bh_ctrlblk))
|
|
invoke_rcu_callbacks();
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
/*
|
|
* Record an rcu_bh quiescent state.
|
|
*/
|
|
void rcu_bh_qs(int cpu)
|
|
{
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
if (rcu_qsctr_help(&rcu_bh_ctrlblk))
|
|
invoke_rcu_callbacks();
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
/*
|
|
* Check to see if the scheduling-clock interrupt came from an extended
|
|
* quiescent state, and, if so, tell RCU about it.
|
|
*/
|
|
void rcu_check_callbacks(int cpu, int user)
|
|
{
|
|
if (user ||
|
|
(idle_cpu(cpu) &&
|
|
!in_softirq() &&
|
|
hardirq_count() <= (1 << HARDIRQ_SHIFT)))
|
|
rcu_sched_qs(cpu);
|
|
else if (!in_softirq())
|
|
rcu_bh_qs(cpu);
|
|
rcu_preempt_check_callbacks();
|
|
}
|
|
|
|
/*
|
|
* Invoke the RCU callbacks on the specified rcu_ctrlkblk structure
|
|
* whose grace period has elapsed.
|
|
*/
|
|
static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp)
|
|
{
|
|
char *rn = NULL;
|
|
struct rcu_head *next, *list;
|
|
unsigned long flags;
|
|
RCU_TRACE(int cb_count = 0);
|
|
|
|
/* If no RCU callbacks ready to invoke, just return. */
|
|
if (&rcp->rcucblist == rcp->donetail) {
|
|
RCU_TRACE(trace_rcu_batch_start(rcp->name, 0, -1));
|
|
RCU_TRACE(trace_rcu_batch_end(rcp->name, 0));
|
|
return;
|
|
}
|
|
|
|
/* Move the ready-to-invoke callbacks to a local list. */
|
|
local_irq_save(flags);
|
|
RCU_TRACE(trace_rcu_batch_start(rcp->name, 0, -1));
|
|
list = rcp->rcucblist;
|
|
rcp->rcucblist = *rcp->donetail;
|
|
*rcp->donetail = NULL;
|
|
if (rcp->curtail == rcp->donetail)
|
|
rcp->curtail = &rcp->rcucblist;
|
|
rcu_preempt_remove_callbacks(rcp);
|
|
rcp->donetail = &rcp->rcucblist;
|
|
local_irq_restore(flags);
|
|
|
|
/* Invoke the callbacks on the local list. */
|
|
RCU_TRACE(rn = rcp->name);
|
|
while (list) {
|
|
next = list->next;
|
|
prefetch(next);
|
|
debug_rcu_head_unqueue(list);
|
|
local_bh_disable();
|
|
__rcu_reclaim(rn, list);
|
|
local_bh_enable();
|
|
list = next;
|
|
RCU_TRACE(cb_count++);
|
|
}
|
|
RCU_TRACE(rcu_trace_sub_qlen(rcp, cb_count));
|
|
RCU_TRACE(trace_rcu_batch_end(rcp->name, cb_count));
|
|
}
|
|
|
|
static void rcu_process_callbacks(struct softirq_action *unused)
|
|
{
|
|
__rcu_process_callbacks(&rcu_sched_ctrlblk);
|
|
__rcu_process_callbacks(&rcu_bh_ctrlblk);
|
|
rcu_preempt_process_callbacks();
|
|
}
|
|
|
|
/*
|
|
* Wait for a grace period to elapse. But it is illegal to invoke
|
|
* synchronize_sched() from within an RCU read-side critical section.
|
|
* Therefore, any legal call to synchronize_sched() is a quiescent
|
|
* state, and so on a UP system, synchronize_sched() need do nothing.
|
|
* Ditto for synchronize_rcu_bh(). (But Lai Jiangshan points out the
|
|
* benefits of doing might_sleep() to reduce latency.)
|
|
*
|
|
* Cool, huh? (Due to Josh Triplett.)
|
|
*
|
|
* But we want to make this a static inline later. The cond_resched()
|
|
* currently makes this problematic.
|
|
*/
|
|
void synchronize_sched(void)
|
|
{
|
|
cond_resched();
|
|
}
|
|
EXPORT_SYMBOL_GPL(synchronize_sched);
|
|
|
|
/*
|
|
* Helper function for call_rcu() and call_rcu_bh().
|
|
*/
|
|
static void __call_rcu(struct rcu_head *head,
|
|
void (*func)(struct rcu_head *rcu),
|
|
struct rcu_ctrlblk *rcp)
|
|
{
|
|
unsigned long flags;
|
|
|
|
debug_rcu_head_queue(head);
|
|
head->func = func;
|
|
head->next = NULL;
|
|
|
|
local_irq_save(flags);
|
|
*rcp->curtail = head;
|
|
rcp->curtail = &head->next;
|
|
RCU_TRACE(rcp->qlen++);
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
/*
|
|
* Post an RCU callback to be invoked after the end of an RCU-sched grace
|
|
* period. But since we have but one CPU, that would be after any
|
|
* quiescent state.
|
|
*/
|
|
void call_rcu_sched(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
|
|
{
|
|
__call_rcu(head, func, &rcu_sched_ctrlblk);
|
|
}
|
|
EXPORT_SYMBOL_GPL(call_rcu_sched);
|
|
|
|
/*
|
|
* Post an RCU bottom-half callback to be invoked after any subsequent
|
|
* quiescent state.
|
|
*/
|
|
void call_rcu_bh(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
|
|
{
|
|
__call_rcu(head, func, &rcu_bh_ctrlblk);
|
|
}
|
|
EXPORT_SYMBOL_GPL(call_rcu_bh);
|