[PATCH -mm -v2 1/5] llist, Make all llist functions inline

Huang Ying
2011-09-08T06:00:59Z

Because llist may be used in performance critical code path, make all
llist functions inline to avoid function calling overhead.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
---
drivers/acpi/apei/Kconfig | 1
include/linux/llist.h | 122 +++++++++++++++++++++++++++++++++++++++++--
lib/Kconfig | 3 -
lib/Makefile | 2
lib/llist.c | 129 ----------------------------------------------
5 files changed, 116 insertions(+), 141 deletions(-)
delete mode 100644 lib/llist.c

--- a/drivers/acpi/apei/Kconfig
+++ b/drivers/acpi/apei/Kconfig
@@ -14,7 +14,6 @@ config ACPI_APEI_GHES
depends on ACPI_APEI && X86
select ACPI_HED
select IRQ_WORK
- select LLIST
select GENERIC_ALLOCATOR
help
Generic Hardware Error Source provides a way to report
--- a/include/linux/llist.h
+++ b/include/linux/llist.h
@@ -37,8 +37,28 @@
* architectures that don't have NMI-safe cmpxchg implementation, the
* list can NOT be used in NMI handler. So code uses the list in NMI
* handler should depend on CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG.
+ *
+ * Copyright 2010,2011 Intel Corp.
+ * Author: Huang Ying <ying.huang@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation;
+ *
+ * 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
*/

+#include <linux/kernel.h>
+#include <asm/system.h>
+#include <asm/processor.h>
+
struct llist_head {
struct llist_node *first;
};
@@ -113,14 +133,104 @@ static inline void init_llist_head(struc
* test whether the list is empty without deleting something from the
* list.
*/
-static inline int llist_empty(const struct llist_head *head)
+static inline bool llist_empty(const struct llist_head *head)
{
return ACCESS_ONCE(head->first) == NULL;
}

-void llist_add(struct llist_node *new, struct llist_head *head);
-void llist_add_batch(struct llist_node *new_first, struct llist_node *new_last,
- struct llist_head *head);
-struct llist_node *llist_del_first(struct llist_head *head);
-struct llist_node *llist_del_all(struct llist_head *head);
+/**
+ * llist_add - add a new entry
+ * @new: new entry to be added
+ * @head: the head for your lock-less list
+ */
+static inline void llist_add(struct llist_node *new, struct llist_head *head)
+{
+ struct llist_node *entry, *old_entry;
+
+#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
+ BUG_ON(in_nmi());
+#endif
+
+ entry = head->first;
+ do {
+ old_entry = entry;
+ new->next = entry;
+ cpu_relax();
+ } while ((entry = cmpxchg(&head->first, old_entry, new)) != old_entry);
+}
+
+/**
+ * llist_add_batch - add several linked entries in batch
+ * @new_first: first entry in batch to be added
+ * @new_last: last entry in batch to be added
+ * @head: the head for your lock-less list
+ */
+static inline void llist_add_batch(struct llist_node *new_first,
+ struct llist_node *new_last,
+ struct llist_head *head)
+{
+ struct llist_node *entry, *old_entry;
+
+#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
+ BUG_ON(in_nmi());
+#endif
+
+ entry = head->first;
+ do {
+ old_entry = entry;
+ new_last->next = entry;
+ cpu_relax();
+ } while ((entry = cmpxchg(&head->first, old_entry, new_first)) != old_entry);
+}
+
+/**
+ * llist_del_first - delete the first entry of lock-less list
+ * @head: the head for your lock-less list
+ *
+ * If list is empty, return NULL, otherwise, return the first entry
+ * deleted, this is the newest added one.
+ *
+ * Only one llist_del_first user can be used simultaneously with
+ * multiple llist_add users without lock. Because otherwise
+ * llist_del_first, llist_add, llist_add (or llist_del_all, llist_add,
+ * llist_add) sequence in another user may change @head->first->next,
+ * but keep @head->first. If multiple consumers are needed, please
+ * use llist_del_all or use lock between consumers.
+ */
+static inline struct llist_node *llist_del_first(struct llist_head *head)
+{
+ struct llist_node *entry, *old_entry, *next;
+
+#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
+ BUG_ON(in_nmi());
+#endif
+
+ entry = head->first;
+ do {
+ if (entry == NULL)
+ return NULL;
+ old_entry = entry;
+ next = entry->next;
+ cpu_relax();
+ } while ((entry = cmpxchg(&head->first, old_entry, next)) != old_entry);
+
+ return entry;
+}
+
+/**
+ * llist_del_all - delete all entries from lock-less list
+ * @head: the head of lock-less list to delete all entries
+ *
+ * If list is empty, return NULL, otherwise, delete all entries and
+ * return the pointer to the first entry. The order of entries
+ * deleted is from the newest to the oldest added one.
+ */
+static inline struct llist_node *llist_del_all(struct llist_head *head)
+{
+#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
+ BUG_ON(in_nmi());
+#endif
+
+ return xchg(&head->first, NULL);
+}
#endif /* LLIST_H */
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -276,7 +276,4 @@ config CORDIC
so its calculations are in fixed point. Modules can select this
when they require this function. Module will be called cordic.

-config LLIST
- bool
-
endmenu
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -116,8 +116,6 @@ obj-$(CONFIG_CPU_RMAP) += cpu_rmap.o

obj-$(CONFIG_CORDIC) += cordic.o

-obj-$(CONFIG_LLIST) += llist.o
-
hostprogs-y := gen_crc32table
clean-files := crc32table.h

--- a/lib/llist.c
+++ /dev/null
@@ -1,129 +0,0 @@
-/*
- * Lock-less NULL terminated single linked list
- *
- * The basic atomic operation of this list is cmpxchg on long. On
- * architectures that don't have NMI-safe cmpxchg implementation, the
- * list can NOT be used in NMI handler. So code uses the list in NMI
- * handler should depend on CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG.
- *
- * Copyright 2010,2011 Intel Corp.
- * Author: Huang Ying <ying.huang@intel.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License version
- * 2 as published by the Free Software Foundation;
- *
- * 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
- */
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/interrupt.h>
-#include <linux/llist.h>
-
-#include <asm/system.h>
-
-/**
- * llist_add - add a new entry
- * @new: new entry to be added
- * @head: the head for your lock-less list
- */
-void llist_add(struct llist_node *new, struct llist_head *head)
-{
- struct llist_node *entry, *old_entry;
-
-#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
- BUG_ON(in_nmi());
-#endif
-
- entry = head->first;
- do {
- old_entry = entry;
- new->next = entry;
- cpu_relax();
- } while ((entry = cmpxchg(&head->first, old_entry, new)) != old_entry);
-}
-EXPORT_SYMBOL_GPL(llist_add);
-
-/**
- * llist_add_batch - add several linked entries in batch
- * @new_first: first entry in batch to be added
- * @new_last: last entry in batch to be added
- * @head: the head for your lock-less list
- */
-void llist_add_batch(struct llist_node *new_first, struct llist_node *new_last,
- struct llist_head *head)
-{
- struct llist_node *entry, *old_entry;
-
-#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
- BUG_ON(in_nmi());
-#endif
-
- entry = head->first;
- do {
- old_entry = entry;
- new_last->next = entry;
- cpu_relax();
- } while ((entry = cmpxchg(&head->first, old_entry, new_first)) != old_entry);
-}
-EXPORT_SYMBOL_GPL(llist_add_batch);
-
-/**
- * llist_del_first - delete the first entry of lock-less list
- * @head: the head for your lock-less list
- *
- * If list is empty, return NULL, otherwise, return the first entry
- * deleted, this is the newest added one.
- *
- * Only one llist_del_first user can be used simultaneously with
- * multiple llist_add users without lock. Because otherwise
- * llist_del_first, llist_add, llist_add (or llist_del_all, llist_add,
- * llist_add) sequence in another user may change @head->first->next,
- * but keep @head->first. If multiple consumers are needed, please
- * use llist_del_all or use lock between consumers.
- */
-struct llist_node *llist_del_first(struct llist_head *head)
-{
- struct llist_node *entry, *old_entry, *next;
-
-#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
- BUG_ON(in_nmi());
-#endif
-
- entry = head->first;
- do {
- if (entry == NULL)
- return NULL;
- old_entry = entry;
- next = entry->next;
- cpu_relax();
- } while ((entry = cmpxchg(&head->first, old_entry, next)) != old_entry);
-
- return entry;
-}
-EXPORT_SYMBOL_GPL(llist_del_first);
-
-/**
- * llist_del_all - delete all entries from lock-less list
- * @head: the head of lock-less list to delete all entries
- *
- * If list is empty, return NULL, otherwise, delete all entries and
- * return the pointer to the first entry. The order of entries
- * deleted is from the newest to the oldest added one.
- */
-struct llist_node *llist_del_all(struct llist_head *head)
-{
-#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
- BUG_ON(in_nmi());
-#endif
-
- return xchg(&head->first, NULL);
-}
-EXPORT_SYMBOL_GPL(llist_del_all);