Re: [PATCH RESEND v4 1/3] lib/plist: Provide plist_add_head() for nodes with the same prio

2015-03-10 Thread Dan Streetman 
On Mon, Mar 9, 2015 at 3:32 AM, Xunlei Pang  wrote:
> From: Xunlei Pang 
>
> If there're multiple nodes with the same prio as @node, currently
> plist_add() will add @node behind all of them. Now we need to add
> @node before all of these nodes for SMP RT scheduler.
>
> This patch adds a common __plist_add() for adding @node before or
> after existing nodes with the same prio, then adds plist_add_head()
> and plist_add_tail() inline wrapper functions for convenient uses.
>
> Finally, define plist_add() as plist_add_tail() which has the same
> behaviour as before.
>
> cc: Andrew Morton 
> cc: Dan Streetman 
> Signed-off-by: Xunlei Pang 
> ---
>  include/linux/plist.h | 30 +-
>  lib/plist.c   | 24 +---
>  2 files changed, 50 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/plist.h b/include/linux/plist.h
> index 9788360..10c834c 100644
> --- a/include/linux/plist.h
> +++ b/include/linux/plist.h
> @@ -138,7 +138,35 @@ static inline void plist_node_init(struct plist_node 
> *node, int prio)
> INIT_LIST_HEAD(>node_list);
>  }
>
> -extern void plist_add(struct plist_node *node, struct plist_head *head);
> +extern void __plist_add(struct plist_node *node,
> +   struct plist_head *head, bool is_head);
> +
> +/**
> + * plist_add_head - add @node to @head, before all existing same-prio nodes
> + *
> + * @node:   plist_node pointer
> + * @head:   plist_head pointer
> + */
> +static inline
> +void plist_add_head(struct plist_node *node, struct plist_head *head)
> +{
> +   __plist_add(node, head, true);
> +}
> +
> +/**
> + * plist_add_tail - add @node to @head, after all existing same-prio nodes
> + *
> + * @node:   plist_node pointer
> + * @head:   plist_head pointer
> + */
> +static inline
> +void plist_add_tail(struct plist_node *node, struct plist_head *head)
> +{
> +   __plist_add(node, head, false);
> +}
> +
> +#define plist_add plist_add_tail
> +
>  extern void plist_del(struct plist_node *node, struct plist_head *head);
>
>  extern void plist_requeue(struct plist_node *node, struct plist_head *head);
> diff --git a/lib/plist.c b/lib/plist.c
> index 3a30c53..d3ebac6 100644
> --- a/lib/plist.c
> +++ b/lib/plist.c
> @@ -66,12 +66,16 @@ static void plist_check_head(struct plist_head *head)
>  #endif
>
>  /**
> - * plist_add - add @node to @head
> + * __plist_add - add @node to @head
>   *
>   * @node:   plist_node pointer
>   * @head:   plist_head pointer
> + * @is_head:   bool
> + *
> + * If there're any nodes with the same prio, add @node
> + * behind or before all of them according to @is_head.
>   */
> -void plist_add(struct plist_node *node, struct plist_head *head)
> +void __plist_add(struct plist_node *node, struct plist_head *head, bool 
> is_head)
>  {
> struct plist_node *first, *iter, *prev = NULL;
> struct list_head *node_next = >node_list;
> @@ -96,8 +100,22 @@ void plist_add(struct plist_node *node, struct plist_head 
> *head)
> struct plist_node, prio_list);
> } while (iter != first);
>
> -   if (!prev || prev->prio != node->prio)
> +   if (!prev || prev->prio != node->prio) {
> list_add_tail(>prio_list, >prio_list);
> +   } else if (is_head) {
> +   /*
> +* prev has the same priority as the node that is
> +* being added. It is also the first node for this
> +* priority, but the new node needs to be added ahead of
> +* it. To accomplish this, insert node right after prev
> +* in the prio_list and then remove prev from that list.
> +* Then set node_next to prev->node_list so that the
> +* new node gets added before prev and not iter.
> +*/
> +   list_add(>prio_list, >prio_list);
> +   list_del_init(>prio_list);

I think this can just be

list_replace_init(>prio_list, >prio_list);

besides that,
Reviewed-by: Dan Streetman 

> +   node_next = >node_list;
> +   }
>  ins_node:
> list_add_tail(>node_list, node_next);
>
> --
> 1.9.1
>
>
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Re: [PATCH RESEND v4 1/3] lib/plist: Provide plist_add_head() for nodes with the same prio

2015-03-10 Thread Dan Streetman 
On Mon, Mar 9, 2015 at 3:32 AM, Xunlei Pang xlp...@126.com wrote:
 From: Xunlei Pang pang.xun...@linaro.org

 If there're multiple nodes with the same prio as @node, currently
 plist_add() will add @node behind all of them. Now we need to add
 @node before all of these nodes for SMP RT scheduler.

 This patch adds a common __plist_add() for adding @node before or
 after existing nodes with the same prio, then adds plist_add_head()
 and plist_add_tail() inline wrapper functions for convenient uses.

 Finally, define plist_add() as plist_add_tail() which has the same
 behaviour as before.

 cc: Andrew Morton a...@linux-foundation.org
 cc: Dan Streetman ddstr...@ieee.org
 Signed-off-by: Xunlei Pang pang.xun...@linaro.org
 ---
  include/linux/plist.h | 30 +-
  lib/plist.c   | 24 +---
  2 files changed, 50 insertions(+), 4 deletions(-)

 diff --git a/include/linux/plist.h b/include/linux/plist.h
 index 9788360..10c834c 100644
 --- a/include/linux/plist.h
 +++ b/include/linux/plist.h
 @@ -138,7 +138,35 @@ static inline void plist_node_init(struct plist_node 
 *node, int prio)
 INIT_LIST_HEAD(node-node_list);
  }

 -extern void plist_add(struct plist_node *node, struct plist_head *head);
 +extern void __plist_add(struct plist_node *node,
 +   struct plist_head *head, bool is_head);
 +
 +/**
 + * plist_add_head - add @node to @head, before all existing same-prio nodes
 + *
 + * @node:  struct plist_node pointer
 + * @head:  struct plist_head pointer
 + */
 +static inline
 +void plist_add_head(struct plist_node *node, struct plist_head *head)
 +{
 +   __plist_add(node, head, true);
 +}
 +
 +/**
 + * plist_add_tail - add @node to @head, after all existing same-prio nodes
 + *
 + * @node:  struct plist_node pointer
 + * @head:  struct plist_head pointer
 + */
 +static inline
 +void plist_add_tail(struct plist_node *node, struct plist_head *head)
 +{
 +   __plist_add(node, head, false);
 +}
 +
 +#define plist_add plist_add_tail
 +
  extern void plist_del(struct plist_node *node, struct plist_head *head);

  extern void plist_requeue(struct plist_node *node, struct plist_head *head);
 diff --git a/lib/plist.c b/lib/plist.c
 index 3a30c53..d3ebac6 100644
 --- a/lib/plist.c
 +++ b/lib/plist.c
 @@ -66,12 +66,16 @@ static void plist_check_head(struct plist_head *head)
  #endif

  /**
 - * plist_add - add @node to @head
 + * __plist_add - add @node to @head
   *
   * @node:  struct plist_node pointer
   * @head:  struct plist_head pointer
 + * @is_head:   bool
 + *
 + * If there're any nodes with the same prio, add @node
 + * behind or before all of them according to @is_head.
   */
 -void plist_add(struct plist_node *node, struct plist_head *head)
 +void __plist_add(struct plist_node *node, struct plist_head *head, bool 
 is_head)
  {
 struct plist_node *first, *iter, *prev = NULL;
 struct list_head *node_next = head-node_list;
 @@ -96,8 +100,22 @@ void plist_add(struct plist_node *node, struct plist_head 
 *head)
 struct plist_node, prio_list);
 } while (iter != first);

 -   if (!prev || prev-prio != node-prio)
 +   if (!prev || prev-prio != node-prio) {
 list_add_tail(node-prio_list, iter-prio_list);
 +   } else if (is_head) {
 +   /*
 +* prev has the same priority as the node that is
 +* being added. It is also the first node for this
 +* priority, but the new node needs to be added ahead of
 +* it. To accomplish this, insert node right after prev
 +* in the prio_list and then remove prev from that list.
 +* Then set node_next to prev-node_list so that the
 +* new node gets added before prev and not iter.
 +*/
 +   list_add(node-prio_list, prev-prio_list);
 +   list_del_init(prev-prio_list);

I think this can just be

list_replace_init(prev-prio_list, node-prio_list);

besides that,
Reviewed-by: Dan Streetman ddstr...@ieee.org

 +   node_next = prev-node_list;
 +   }
  ins_node:
 list_add_tail(node-node_list, node_next);

 --
 1.9.1


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[PATCH RESEND v4 1/3] lib/plist: Provide plist_add_head() for nodes with the same prio

2015-03-09 Thread Xunlei Pang 
From: Xunlei Pang 

If there're multiple nodes with the same prio as @node, currently
plist_add() will add @node behind all of them. Now we need to add
@node before all of these nodes for SMP RT scheduler.

This patch adds a common __plist_add() for adding @node before or
after existing nodes with the same prio, then adds plist_add_head()
and plist_add_tail() inline wrapper functions for convenient uses.

Finally, define plist_add() as plist_add_tail() which has the same
behaviour as before.

cc: Andrew Morton 
cc: Dan Streetman 
Signed-off-by: Xunlei Pang 
---
 include/linux/plist.h | 30 +-
 lib/plist.c   | 24 +---
 2 files changed, 50 insertions(+), 4 deletions(-)

diff --git a/include/linux/plist.h b/include/linux/plist.h
index 9788360..10c834c 100644
--- a/include/linux/plist.h
+++ b/include/linux/plist.h
@@ -138,7 +138,35 @@ static inline void plist_node_init(struct plist_node 
*node, int prio)
INIT_LIST_HEAD(>node_list);
 }
 
-extern void plist_add(struct plist_node *node, struct plist_head *head);
+extern void __plist_add(struct plist_node *node,
+   struct plist_head *head, bool is_head);
+
+/**
+ * plist_add_head - add @node to @head, before all existing same-prio nodes
+ *
+ * @node:   plist_node pointer
+ * @head:   plist_head pointer
+ */
+static inline
+void plist_add_head(struct plist_node *node, struct plist_head *head)
+{
+   __plist_add(node, head, true);
+}
+
+/**
+ * plist_add_tail - add @node to @head, after all existing same-prio nodes
+ *
+ * @node:   plist_node pointer
+ * @head:   plist_head pointer
+ */
+static inline
+void plist_add_tail(struct plist_node *node, struct plist_head *head)
+{
+   __plist_add(node, head, false);
+}
+
+#define plist_add plist_add_tail
+
 extern void plist_del(struct plist_node *node, struct plist_head *head);
 
 extern void plist_requeue(struct plist_node *node, struct plist_head *head);
diff --git a/lib/plist.c b/lib/plist.c
index 3a30c53..d3ebac6 100644
--- a/lib/plist.c
+++ b/lib/plist.c
@@ -66,12 +66,16 @@ static void plist_check_head(struct plist_head *head)
 #endif
 
 /**
- * plist_add - add @node to @head
+ * __plist_add - add @node to @head
  *
  * @node:   plist_node pointer
  * @head:   plist_head pointer
+ * @is_head:   bool
+ *
+ * If there're any nodes with the same prio, add @node
+ * behind or before all of them according to @is_head.
  */
-void plist_add(struct plist_node *node, struct plist_head *head)
+void __plist_add(struct plist_node *node, struct plist_head *head, bool 
is_head)
 {
struct plist_node *first, *iter, *prev = NULL;
struct list_head *node_next = >node_list;
@@ -96,8 +100,22 @@ void plist_add(struct plist_node *node, struct plist_head 
*head)
struct plist_node, prio_list);
} while (iter != first);
 
-   if (!prev || prev->prio != node->prio)
+   if (!prev || prev->prio != node->prio) {
list_add_tail(>prio_list, >prio_list);
+   } else if (is_head) {
+   /*
+* prev has the same priority as the node that is
+* being added. It is also the first node for this
+* priority, but the new node needs to be added ahead of
+* it. To accomplish this, insert node right after prev
+* in the prio_list and then remove prev from that list.
+* Then set node_next to prev->node_list so that the
+* new node gets added before prev and not iter.
+*/
+   list_add(>prio_list, >prio_list);
+   list_del_init(>prio_list);
+   node_next = >node_list;
+   }
 ins_node:
list_add_tail(>node_list, node_next);
 
-- 
1.9.1


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[PATCH RESEND v4 1/3] lib/plist: Provide plist_add_head() for nodes with the same prio

2015-03-09 Thread Xunlei Pang 
From: Xunlei Pang pang.xun...@linaro.org

If there're multiple nodes with the same prio as @node, currently
plist_add() will add @node behind all of them. Now we need to add
@node before all of these nodes for SMP RT scheduler.

This patch adds a common __plist_add() for adding @node before or
after existing nodes with the same prio, then adds plist_add_head()
and plist_add_tail() inline wrapper functions for convenient uses.

Finally, define plist_add() as plist_add_tail() which has the same
behaviour as before.

cc: Andrew Morton a...@linux-foundation.org
cc: Dan Streetman ddstr...@ieee.org
Signed-off-by: Xunlei Pang pang.xun...@linaro.org
---
 include/linux/plist.h | 30 +-
 lib/plist.c   | 24 +---
 2 files changed, 50 insertions(+), 4 deletions(-)

diff --git a/include/linux/plist.h b/include/linux/plist.h
index 9788360..10c834c 100644
--- a/include/linux/plist.h
+++ b/include/linux/plist.h
@@ -138,7 +138,35 @@ static inline void plist_node_init(struct plist_node 
*node, int prio)
INIT_LIST_HEAD(node-node_list);
 }
 
-extern void plist_add(struct plist_node *node, struct plist_head *head);
+extern void __plist_add(struct plist_node *node,
+   struct plist_head *head, bool is_head);
+
+/**
+ * plist_add_head - add @node to @head, before all existing same-prio nodes
+ *
+ * @node:  struct plist_node pointer
+ * @head:  struct plist_head pointer
+ */
+static inline
+void plist_add_head(struct plist_node *node, struct plist_head *head)
+{
+   __plist_add(node, head, true);
+}
+
+/**
+ * plist_add_tail - add @node to @head, after all existing same-prio nodes
+ *
+ * @node:  struct plist_node pointer
+ * @head:  struct plist_head pointer
+ */
+static inline
+void plist_add_tail(struct plist_node *node, struct plist_head *head)
+{
+   __plist_add(node, head, false);
+}
+
+#define plist_add plist_add_tail
+
 extern void plist_del(struct plist_node *node, struct plist_head *head);
 
 extern void plist_requeue(struct plist_node *node, struct plist_head *head);
diff --git a/lib/plist.c b/lib/plist.c
index 3a30c53..d3ebac6 100644
--- a/lib/plist.c
+++ b/lib/plist.c
@@ -66,12 +66,16 @@ static void plist_check_head(struct plist_head *head)
 #endif
 
 /**
- * plist_add - add @node to @head
+ * __plist_add - add @node to @head
  *
  * @node:  struct plist_node pointer
  * @head:  struct plist_head pointer
+ * @is_head:   bool
+ *
+ * If there're any nodes with the same prio, add @node
+ * behind or before all of them according to @is_head.
  */
-void plist_add(struct plist_node *node, struct plist_head *head)
+void __plist_add(struct plist_node *node, struct plist_head *head, bool 
is_head)
 {
struct plist_node *first, *iter, *prev = NULL;
struct list_head *node_next = head-node_list;
@@ -96,8 +100,22 @@ void plist_add(struct plist_node *node, struct plist_head 
*head)
struct plist_node, prio_list);
} while (iter != first);
 
-   if (!prev || prev-prio != node-prio)
+   if (!prev || prev-prio != node-prio) {
list_add_tail(node-prio_list, iter-prio_list);
+   } else if (is_head) {
+   /*
+* prev has the same priority as the node that is
+* being added. It is also the first node for this
+* priority, but the new node needs to be added ahead of
+* it. To accomplish this, insert node right after prev
+* in the prio_list and then remove prev from that list.
+* Then set node_next to prev-node_list so that the
+* new node gets added before prev and not iter.
+*/
+   list_add(node-prio_list, prev-prio_list);
+   list_del_init(prev-prio_list);
+   node_next = prev-node_list;
+   }
 ins_node:
list_add_tail(node-node_list, node_next);
 
-- 
1.9.1


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