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Merge branch 'core/rcu' into core/rcu-for-linus

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This commit is contained in:
Ingo Molnar
2008-07-15 21:10:12 +02:00
parent b9d2252c1e 199a952876
commit 6c9fcaf2ee
33 changed files with 1347 additions and 530 deletions
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1
include/linux/dcache.h
View File

@@ -3,6 +3,7 @@
#include <asm/atomic.h>
#include <linux/list.h>
#include <linux/rculist.h>
#include <linux/spinlock.h>
#include <linux/cache.h>
#include <linux/rcupdate.h>

367
include/linux/list.h
View File

@@ -84,65 +84,6 @@ static inline void list_add_tail(struct list_head *new, struct list_head *head)
__list_add(new, head->prev, head);
}
/*
* Insert a new entry between two known consecutive entries.
*
* This is only for internal list manipulation where we know
* the prev/next entries already!
*/
static inline void __list_add_rcu(struct list_head * new,
struct list_head * prev, struct list_head * next)
{
new->next = next;
new->prev = prev;
smp_wmb();
next->prev = new;
prev->next = new;
}
/**
* list_add_rcu - add a new entry to rcu-protected list
* @new: new entry to be added
* @head: list head to add it after
*
* Insert a new entry after the specified head.
* This is good for implementing stacks.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as list_add_rcu()
* or list_del_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* list_for_each_entry_rcu().
*/
static inline void list_add_rcu(struct list_head *new, struct list_head *head)
{
__list_add_rcu(new, head, head->next);
}
/**
* list_add_tail_rcu - add a new entry to rcu-protected list
* @new: new entry to be added
* @head: list head to add it before
*
* Insert a new entry before the specified head.
* This is useful for implementing queues.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as list_add_tail_rcu()
* or list_del_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* list_for_each_entry_rcu().
*/
static inline void list_add_tail_rcu(struct list_head *new,
struct list_head *head)
{
__list_add_rcu(new, head->prev, head);
}
/*
* Delete a list entry by making the prev/next entries
* point to each other.
@@ -173,36 +114,6 @@ static inline void list_del(struct list_head *entry)
extern void list_del(struct list_head *entry);
#endif
/**
* list_del_rcu - deletes entry from list without re-initialization
* @entry: the element to delete from the list.
*
* Note: list_empty() on entry does not return true after this,
* the entry is in an undefined state. It is useful for RCU based
* lockfree traversal.
*
* In particular, it means that we can not poison the forward
* pointers that may still be used for walking the list.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as list_del_rcu()
* or list_add_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* list_for_each_entry_rcu().
*
* Note that the caller is not permitted to immediately free
* the newly deleted entry. Instead, either synchronize_rcu()
* or call_rcu() must be used to defer freeing until an RCU
* grace period has elapsed.
*/
static inline void list_del_rcu(struct list_head *entry)
{
__list_del(entry->prev, entry->next);
entry->prev = LIST_POISON2;
}
/**
* list_replace - replace old entry by new one
* @old : the element to be replaced
@@ -226,25 +137,6 @@ static inline void list_replace_init(struct list_head *old,
INIT_LIST_HEAD(old);
}
/**
* list_replace_rcu - replace old entry by new one
* @old : the element to be replaced
* @new : the new element to insert
*
* The @old entry will be replaced with the @new entry atomically.
* Note: @old should not be empty.
*/
static inline void list_replace_rcu(struct list_head *old,
struct list_head *new)
{
new->next = old->next;
new->prev = old->prev;
smp_wmb();
new->next->prev = new;
new->prev->next = new;
old->prev = LIST_POISON2;
}
/**
* list_del_init - deletes entry from list and reinitialize it.
* @entry: the element to delete from the list.
@@ -368,62 +260,6 @@ static inline void list_splice_init(struct list_head *list,
}
}
/**
* list_splice_init_rcu - splice an RCU-protected list into an existing list.
* @list: the RCU-protected list to splice
* @head: the place in the list to splice the first list into
* @sync: function to sync: synchronize_rcu(), synchronize_sched(), ...
*
* @head can be RCU-read traversed concurrently with this function.
*
* Note that this function blocks.
*
* Important note: the caller must take whatever action is necessary to
* prevent any other updates to @head. In principle, it is possible
* to modify the list as soon as sync() begins execution.
* If this sort of thing becomes necessary, an alternative version
* based on call_rcu() could be created. But only if -really-
* needed -- there is no shortage of RCU API members.
*/
static inline void list_splice_init_rcu(struct list_head *list,
struct list_head *head,
void (*sync)(void))
{
struct list_head *first = list->next;
struct list_head *last = list->prev;
struct list_head *at = head->next;
if (list_empty(head))
return;
/* "first" and "last" tracking list, so initialize it. */
INIT_LIST_HEAD(list);
/*
* At this point, the list body still points to the source list.
* Wait for any readers to finish using the list before splicing
* the list body into the new list. Any new readers will see
* an empty list.
*/
sync();
/*
* Readers are finished with the source list, so perform splice.
* The order is important if the new list is global and accessible
* to concurrent RCU readers. Note that RCU readers are not
* permitted to traverse the prev pointers without excluding
* this function.
*/
last->next = at;
smp_wmb();
head->next = first;
first->prev = head;
at->prev = last;
}
/**
* list_entry - get the struct for this entry
* @ptr: the &struct list_head pointer.
@@ -629,57 +465,6 @@ static inline void list_splice_init_rcu(struct list_head *list,
&pos->member != (head); \
pos = n, n = list_entry(n->member.prev, typeof(*n), member))
/**
* list_for_each_rcu - iterate over an rcu-protected list
* @pos: the &struct list_head to use as a loop cursor.
* @head: the head for your list.
*
* This list-traversal primitive may safely run concurrently with
* the _rcu list-mutation primitives such as list_add_rcu()
* as long as the traversal is guarded by rcu_read_lock().
*/
#define list_for_each_rcu(pos, head) \
for (pos = rcu_dereference((head)->next); \
prefetch(pos->next), pos != (head); \
pos = rcu_dereference(pos->next))
#define __list_for_each_rcu(pos, head) \
for (pos = rcu_dereference((head)->next); \
pos != (head); \
pos = rcu_dereference(pos->next))
/**
* list_for_each_entry_rcu - iterate over rcu list of given type
* @pos: the type * to use as a loop cursor.
* @head: the head for your list.
* @member: the name of the list_struct within the struct.
*
* This list-traversal primitive may safely run concurrently with
* the _rcu list-mutation primitives such as list_add_rcu()
* as long as the traversal is guarded by rcu_read_lock().
*/
#define list_for_each_entry_rcu(pos, head, member) \
for (pos = list_entry(rcu_dereference((head)->next), typeof(*pos), member); \
prefetch(pos->member.next), &pos->member != (head); \
pos = list_entry(rcu_dereference(pos->member.next), typeof(*pos), member))
/**
* list_for_each_continue_rcu
* @pos: the &struct list_head to use as a loop cursor.
* @head: the head for your list.
*
* Iterate over an rcu-protected list, continuing after current point.
*
* This list-traversal primitive may safely run concurrently with
* the _rcu list-mutation primitives such as list_add_rcu()
* as long as the traversal is guarded by rcu_read_lock().
*/
#define list_for_each_continue_rcu(pos, head) \
for ((pos) = rcu_dereference((pos)->next); \
prefetch((pos)->next), (pos) != (head); \
(pos) = rcu_dereference((pos)->next))
/*
* Double linked lists with a single pointer list head.
* Mostly useful for hash tables where the two pointer list head is
@@ -730,31 +515,6 @@ static inline void hlist_del(struct hlist_node *n)
n->pprev = LIST_POISON2;
}
/**
* hlist_del_rcu - deletes entry from hash list without re-initialization
* @n: the element to delete from the hash list.
*
* Note: list_unhashed() on entry does not return true after this,
* the entry is in an undefined state. It is useful for RCU based
* lockfree traversal.
*
* In particular, it means that we can not poison the forward
* pointers that may still be used for walking the hash list.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as hlist_add_head_rcu()
* or hlist_del_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* hlist_for_each_entry().
*/
static inline void hlist_del_rcu(struct hlist_node *n)
{
__hlist_del(n);
n->pprev = LIST_POISON2;
}
static inline void hlist_del_init(struct hlist_node *n)
{
if (!hlist_unhashed(n)) {
@@ -763,27 +523,6 @@ static inline void hlist_del_init(struct hlist_node *n)
}
}
/**
* hlist_replace_rcu - replace old entry by new one
* @old : the element to be replaced
* @new : the new element to insert
*
* The @old entry will be replaced with the @new entry atomically.
*/
static inline void hlist_replace_rcu(struct hlist_node *old,
struct hlist_node *new)
{
struct hlist_node *next = old->next;
new->next = next;
new->pprev = old->pprev;
smp_wmb();
if (next)
new->next->pprev = &new->next;
*new->pprev = new;
old->pprev = LIST_POISON2;
}
static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
{
struct hlist_node *first = h->first;
@@ -794,38 +533,6 @@ static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
n->pprev = &h->first;
}
/**
* hlist_add_head_rcu
* @n: the element to add to the hash list.
* @h: the list to add to.
*
* Description:
* Adds the specified element to the specified hlist,
* while permitting racing traversals.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as hlist_add_head_rcu()
* or hlist_del_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* hlist_for_each_entry_rcu(), used to prevent memory-consistency
* problems on Alpha CPUs. Regardless of the type of CPU, the
* list-traversal primitive must be guarded by rcu_read_lock().
*/
static inline void hlist_add_head_rcu(struct hlist_node *n,
struct hlist_head *h)
{
struct hlist_node *first = h->first;
n->next = first;
n->pprev = &h->first;
smp_wmb();
if (first)
first->pprev = &n->next;
h->first = n;
}
/* next must be != NULL */
static inline void hlist_add_before(struct hlist_node *n,
struct hlist_node *next)
@@ -847,63 +554,6 @@ static inline void hlist_add_after(struct hlist_node *n,
next->next->pprev = &next->next;
}
/**
* hlist_add_before_rcu
* @n: the new element to add to the hash list.
* @next: the existing element to add the new element before.
*
* Description:
* Adds the specified element to the specified hlist
* before the specified node while permitting racing traversals.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as hlist_add_head_rcu()
* or hlist_del_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* hlist_for_each_entry_rcu(), used to prevent memory-consistency
* problems on Alpha CPUs.
*/
static inline void hlist_add_before_rcu(struct hlist_node *n,
struct hlist_node *next)
{
n->pprev = next->pprev;
n->next = next;
smp_wmb();
next->pprev = &n->next;
*(n->pprev) = n;
}
/**
* hlist_add_after_rcu
* @prev: the existing element to add the new element after.
* @n: the new element to add to the hash list.
*
* Description:
* Adds the specified element to the specified hlist
* after the specified node while permitting racing traversals.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as hlist_add_head_rcu()
* or hlist_del_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* hlist_for_each_entry_rcu(), used to prevent memory-consistency
* problems on Alpha CPUs.
*/
static inline void hlist_add_after_rcu(struct hlist_node *prev,
struct hlist_node *n)
{
n->next = prev->next;
n->pprev = &prev->next;
smp_wmb();
prev->next = n;
if (n->next)
n->next->pprev = &n->next;
}
#define hlist_entry(ptr, type, member) container_of(ptr,type,member)
#define hlist_for_each(pos, head) \
@@ -964,21 +614,4 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev,
({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
pos = n)
/**
* hlist_for_each_entry_rcu - iterate over rcu list of given type
* @tpos: the type * to use as a loop cursor.
* @pos: the &struct hlist_node to use as a loop cursor.
* @head: the head for your list.
* @member: the name of the hlist_node within the struct.
*
* This list-traversal primitive may safely run concurrently with
* the _rcu list-mutation primitives such as hlist_add_head_rcu()
* as long as the traversal is guarded by rcu_read_lock().
*/
#define hlist_for_each_entry_rcu(tpos, pos, head, member) \
for (pos = rcu_dereference((head)->first); \
pos && ({ prefetch(pos->next); 1;}) && \
({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
pos = rcu_dereference(pos->next))
#endif

3
include/linux/rcuclassic.h
View File

@@ -151,7 +151,10 @@ extern struct lockdep_map rcu_lock_map;
#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);
extern void rcu_restart_cpu(int cpu);

371
include/linux/rculist.h
View File

@@ -1,6 +1,373 @@
#ifndef _LINUX_RCULIST_H
#define _LINUX_RCULIST_H
#include <linux/list.h>
#ifdef __KERNEL__
#endif /* _LINUX_RCULIST_H */
/*
* RCU-protected list version
*/
#include <linux/list.h>
#include <linux/rcupdate.h>
/*
* Insert a new entry between two known consecutive entries.
*
* This is only for internal list manipulation where we know
* the prev/next entries already!
*/
static inline void __list_add_rcu(struct list_head *new,
struct list_head *prev, struct list_head *next)
{
new->next = next;
new->prev = prev;
rcu_assign_pointer(prev->next, new);
next->prev = new;
}
/**
* list_add_rcu - add a new entry to rcu-protected list
* @new: new entry to be added
* @head: list head to add it after
*
* Insert a new entry after the specified head.
* This is good for implementing stacks.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as list_add_rcu()
* or list_del_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* list_for_each_entry_rcu().
*/
static inline void list_add_rcu(struct list_head *new, struct list_head *head)
{
__list_add_rcu(new, head, head->next);
}
/**
* list_add_tail_rcu - add a new entry to rcu-protected list
* @new: new entry to be added
* @head: list head to add it before
*
* Insert a new entry before the specified head.
* This is useful for implementing queues.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as list_add_tail_rcu()
* or list_del_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* list_for_each_entry_rcu().
*/
static inline void list_add_tail_rcu(struct list_head *new,
struct list_head *head)
{
__list_add_rcu(new, head->prev, head);
}
/**
* list_del_rcu - deletes entry from list without re-initialization
* @entry: the element to delete from the list.
*
* Note: list_empty() on entry does not return true after this,
* the entry is in an undefined state. It is useful for RCU based
* lockfree traversal.
*
* In particular, it means that we can not poison the forward
* pointers that may still be used for walking the list.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as list_del_rcu()
* or list_add_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* list_for_each_entry_rcu().
*
* Note that the caller is not permitted to immediately free
* the newly deleted entry. Instead, either synchronize_rcu()
* or call_rcu() must be used to defer freeing until an RCU
* grace period has elapsed.
*/
static inline void list_del_rcu(struct list_head *entry)
{
__list_del(entry->prev, entry->next);
entry->prev = LIST_POISON2;
}
/**
* list_replace_rcu - replace old entry by new one
* @old : the element to be replaced
* @new : the new element to insert
*
* The @old entry will be replaced with the @new entry atomically.
* Note: @old should not be empty.
*/
static inline void list_replace_rcu(struct list_head *old,
struct list_head *new)
{
new->next = old->next;
new->prev = old->prev;
rcu_assign_pointer(new->prev->next, new);
new->next->prev = new;
old->prev = LIST_POISON2;
}
/**
* list_splice_init_rcu - splice an RCU-protected list into an existing list.
* @list: the RCU-protected list to splice
* @head: the place in the list to splice the first list into
* @sync: function to sync: synchronize_rcu(), synchronize_sched(), ...
*
* @head can be RCU-read traversed concurrently with this function.
*
* Note that this function blocks.
*
* Important note: the caller must take whatever action is necessary to
* prevent any other updates to @head. In principle, it is possible
* to modify the list as soon as sync() begins execution.
* If this sort of thing becomes necessary, an alternative version
* based on call_rcu() could be created. But only if -really-
* needed -- there is no shortage of RCU API members.
*/
static inline void list_splice_init_rcu(struct list_head *list,
struct list_head *head,
void (*sync)(void))
{
struct list_head *first = list->next;
struct list_head *last = list->prev;
struct list_head *at = head->next;
if (list_empty(head))
return;
/* "first" and "last" tracking list, so initialize it. */
INIT_LIST_HEAD(list);
/*
* At this point, the list body still points to the source list.
* Wait for any readers to finish using the list before splicing
* the list body into the new list. Any new readers will see
* an empty list.
*/
sync();
/*
* Readers are finished with the source list, so perform splice.
* The order is important if the new list is global and accessible
* to concurrent RCU readers. Note that RCU readers are not
* permitted to traverse the prev pointers without excluding
* this function.
*/
last->next = at;
rcu_assign_pointer(head->next, first);
first->prev = head;
at->prev = last;
}
/**
* list_for_each_rcu - iterate over an rcu-protected list
* @pos: the &struct list_head to use as a loop cursor.
* @head: the head for your list.
*
* This list-traversal primitive may safely run concurrently with
* the _rcu list-mutation primitives such as list_add_rcu()
* as long as the traversal is guarded by rcu_read_lock().
*/
#define list_for_each_rcu(pos, head) \
for (pos = rcu_dereference((head)->next); \
prefetch(pos->next), pos != (head); \
pos = rcu_dereference(pos->next))
#define __list_for_each_rcu(pos, head) \
for (pos = rcu_dereference((head)->next); \
pos != (head); \
pos = rcu_dereference(pos->next))
/**
* list_for_each_entry_rcu - iterate over rcu list of given type
* @pos: the type * to use as a loop cursor.
* @head: the head for your list.
* @member: the name of the list_struct within the struct.
*
* This list-traversal primitive may safely run concurrently with
* the _rcu list-mutation primitives such as list_add_rcu()
* as long as the traversal is guarded by rcu_read_lock().
*/
#define list_for_each_entry_rcu(pos, head, member) \
for (pos = list_entry(rcu_dereference((head)->next), typeof(*pos), member); \
prefetch(pos->member.next), &pos->member != (head); \
pos = list_entry(rcu_dereference(pos->member.next), typeof(*pos), member))
/**
* list_for_each_continue_rcu
* @pos: the &struct list_head to use as a loop cursor.
* @head: the head for your list.
*
* Iterate over an rcu-protected list, continuing after current point.
*
* This list-traversal primitive may safely run concurrently with
* the _rcu list-mutation primitives such as list_add_rcu()
* as long as the traversal is guarded by rcu_read_lock().
*/
#define list_for_each_continue_rcu(pos, head) \
for ((pos) = rcu_dereference((pos)->next); \
prefetch((pos)->next), (pos) != (head); \
(pos) = rcu_dereference((pos)->next))
/**
* hlist_del_rcu - deletes entry from hash list without re-initialization
* @n: the element to delete from the hash list.
*
* Note: list_unhashed() on entry does not return true after this,
* the entry is in an undefined state. It is useful for RCU based
* lockfree traversal.
*
* In particular, it means that we can not poison the forward
* pointers that may still be used for walking the hash list.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as hlist_add_head_rcu()
* or hlist_del_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* hlist_for_each_entry().
*/
static inline void hlist_del_rcu(struct hlist_node *n)
{
__hlist_del(n);
n->pprev = LIST_POISON2;
}
/**
* hlist_replace_rcu - replace old entry by new one
* @old : the element to be replaced
* @new : the new element to insert
*
* The @old entry will be replaced with the @new entry atomically.
*/
static inline void hlist_replace_rcu(struct hlist_node *old,
struct hlist_node *new)
{
struct hlist_node *next = old->next;
new->next = next;
new->pprev = old->pprev;
rcu_assign_pointer(*new->pprev, new);
if (next)
new->next->pprev = &new->next;
old->pprev = LIST_POISON2;
}
/**
* hlist_add_head_rcu
* @n: the element to add to the hash list.
* @h: the list to add to.
*
* Description:
* Adds the specified element to the specified hlist,
* while permitting racing traversals.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as hlist_add_head_rcu()
* or hlist_del_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* hlist_for_each_entry_rcu(), used to prevent memory-consistency
* problems on Alpha CPUs. Regardless of the type of CPU, the
* list-traversal primitive must be guarded by rcu_read_lock().
*/
static inline void hlist_add_head_rcu(struct hlist_node *n,
struct hlist_head *h)
{
struct hlist_node *first = h->first;
n->next = first;
n->pprev = &h->first;
rcu_assign_pointer(h->first, n);
if (first)
first->pprev = &n->next;
}
/**
* hlist_add_before_rcu
* @n: the new element to add to the hash list.
* @next: the existing element to add the new element before.
*
* Description:
* Adds the specified element to the specified hlist
* before the specified node while permitting racing traversals.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as hlist_add_head_rcu()
* or hlist_del_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* hlist_for_each_entry_rcu(), used to prevent memory-consistency
* problems on Alpha CPUs.
*/
static inline void hlist_add_before_rcu(struct hlist_node *n,
struct hlist_node *next)
{
n->pprev = next->pprev;
n->next = next;
rcu_assign_pointer(*(n->pprev), n);
next->pprev = &n->next;
}
/**
* hlist_add_after_rcu
* @prev: the existing element to add the new element after.
* @n: the new element to add to the hash list.
*
* Description:
* Adds the specified element to the specified hlist
* after the specified node while permitting racing traversals.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as hlist_add_head_rcu()
* or hlist_del_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* hlist_for_each_entry_rcu(), used to prevent memory-consistency
* problems on Alpha CPUs.
*/
static inline void hlist_add_after_rcu(struct hlist_node *prev,
struct hlist_node *n)
{
n->next = prev->next;
n->pprev = &prev->next;
rcu_assign_pointer(prev->next, n);
if (n->next)
n->next->pprev = &n->next;
}
/**
* hlist_for_each_entry_rcu - iterate over rcu list of given type
* @tpos: the type * to use as a loop cursor.
* @pos: the &struct hlist_node to use as a loop cursor.
* @head: the head for your list.
* @member: the name of the hlist_node within the struct.
*
* This list-traversal primitive may safely run concurrently with
* the _rcu list-mutation primitives such as hlist_add_head_rcu()
* as long as the traversal is guarded by rcu_read_lock().
*/
#define hlist_for_each_entry_rcu(tpos, pos, head, member) \
for (pos = rcu_dereference((head)->first); \
pos && ({ prefetch(pos->next); 1; }) && \
({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \
pos = rcu_dereference(pos->next))
#endif /* __KERNEL__ */
#endif

26
include/linux/rcupdate.h
View File

@@ -40,6 +40,7 @@
#include <linux/cpumask.h>
#include <linux/seqlock.h>
#include <linux/lockdep.h>
#include <linux/completion.h>
/**
* struct rcu_head - callback structure for use with RCU
@@ -168,6 +169,27 @@ struct rcu_head {
(p) = (v); \
})
/* Infrastructure to implement the synchronize_() primitives. */
struct rcu_synchronize {
struct rcu_head head;
struct completion completion;
};
extern void wakeme_after_rcu(struct rcu_head *head);
#define synchronize_rcu_xxx(name, func) \
void name(void) \
{ \
struct rcu_synchronize rcu; \
\
init_completion(&rcu.completion); \
/* Will wake me after RCU finished. */ \
func(&rcu.head, wakeme_after_rcu); \
/* Wait for it. */ \
wait_for_completion(&rcu.completion); \
}
/**
* synchronize_sched - block until all CPUs have exited any non-preemptive
* kernel code sequences.
@@ -224,8 +246,8 @@ extern void call_rcu_bh(struct rcu_head *head,
/* Exported common interfaces */
extern void synchronize_rcu(void);
extern void rcu_barrier(void);
extern long rcu_batches_completed(void);
extern long rcu_batches_completed_bh(void);
extern void rcu_barrier_bh(void);
extern void rcu_barrier_sched(void);
/* Internal to kernel */
extern void rcu_init(void);

42
include/linux/rcupreempt.h
View File

@@ -40,10 +40,39 @@
#include <linux/cpumask.h>
#include <linux/seqlock.h>
#define rcu_qsctr_inc(cpu)
struct rcu_dyntick_sched {
int dynticks;
int dynticks_snap;
int sched_qs;
int sched_qs_snap;
int sched_dynticks_snap;
};
DECLARE_PER_CPU(struct rcu_dyntick_sched, rcu_dyntick_sched);
static inline void rcu_qsctr_inc(int cpu)
{
struct rcu_dyntick_sched *rdssp = &per_cpu(rcu_dyntick_sched, cpu);
rdssp->sched_qs++;
}
#define rcu_bh_qsctr_inc(cpu)
#define call_rcu_bh(head, rcu) call_rcu(head, 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);
@@ -55,6 +84,7 @@ extern int rcu_needs_cpu(int cpu);
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);
extern void rcu_restart_cpu(int cpu);
extern long rcu_batches_completed(void);
@@ -81,20 +111,20 @@ extern struct rcupreempt_trace *rcupreempt_trace_cpu(int cpu);
struct softirq_action;
#ifdef CONFIG_NO_HZ
DECLARE_PER_CPU(long, dynticks_progress_counter);
DECLARE_PER_CPU(struct rcu_dyntick_sched, rcu_dyntick_sched);
static inline void rcu_enter_nohz(void)
{
smp_mb(); /* CPUs seeing ++ must see prior RCU read-side crit sects */
__get_cpu_var(dynticks_progress_counter)++;
WARN_ON(__get_cpu_var(dynticks_progress_counter) & 0x1);
__get_cpu_var(rcu_dyntick_sched).dynticks++;
WARN_ON(__get_cpu_var(rcu_dyntick_sched).dynticks & 0x1);
}
static inline void rcu_exit_nohz(void)
{
__get_cpu_var(dynticks_progress_counter)++;
smp_mb(); /* CPUs seeing ++ must see later RCU read-side crit sects */
WARN_ON(!(__get_cpu_var(dynticks_progress_counter) & 0x1));
__get_cpu_var(rcu_dyntick_sched).dynticks++;
WARN_ON(!(__get_cpu_var(rcu_dyntick_sched).dynticks & 0x1));
}
#else /* CONFIG_NO_HZ */