Skip to contentSkip to conversation

expunge lingering references to CONFIG_CLASSIC_RCU

PATCH In review Paul E. McKenney 1 participant 2 messages Aug 22, 2009 Page cache

lore
Share & tools
lore

Paul E. McKenney

author
#0 lore raw

PATCH 1/1 expunge lingering references to CONFIG_CLASSIC_RCU

A couple of references to CONFIG_CLASSIC_RCU have survived. Although these are harmless, it is past time for them to go. The one in hardirq.h is strictly a readability problem. The two in pagemap.h appear to disable a !SMP performance optimization (which this patch re-enables).

This does raise the issue as to whether pagemap.h should really be referring to the CPU implementation. Long term, I intend to make the RCU implementation driven by CONFIG_PREEMPT, at which point these should change from defined(CONFIG_TREE_RCU) to !defined(CONFIG_PREEMPT). In the meantime, is there something else that could be done in pagemap.h?

Signed-off-by Paul E. McKenney <[email protected]>

---

 hardirq.h |    4 ++--
 pagemap.h |    4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)
include/linux/hardirq.h +2 -2
index 8246c69..330cb31 100644
@@ -132,7 +132,7 @@ static inline void account_system_vtime(struct task_struct *tsk)
 }
 #endif
 
-#if defined(CONFIG_NO_HZ) && !defined(CONFIG_CLASSIC_RCU)
+#if defined(CONFIG_NO_HZ)
 extern void rcu_irq_enter(void);
 extern void rcu_irq_exit(void);
 extern void rcu_nmi_enter(void);

@@ -142,7 +142,7 @@ extern void rcu_nmi_exit(void);
 # define rcu_irq_exit() do { } while (0)
 # define rcu_nmi_enter() do { } while (0)
 # define rcu_nmi_exit() do { } while (0)
-#endif /* #if defined(CONFIG_NO_HZ) && !defined(CONFIG_CLASSIC_RCU) */
+#endif /* #if defined(CONFIG_NO_HZ) */
 
 /*
  * It is safe to do non-atomic ops on ->hardirq_context,
include/linux/pagemap.h +2 -2
index aec3252..ed5d750 100644
@@ -132,7 +132,7 @@ static inline int page_cache_get_speculative(struct page *page)
 {
 	VM_BUG_ON(in_interrupt());
 
-#if !defined(CONFIG_SMP) && defined(CONFIG_CLASSIC_RCU)
+#if !defined(CONFIG_SMP) && defined(CONFIG_TREE_RCU)
 # ifdef CONFIG_PREEMPT
 	VM_BUG_ON(!in_atomic());
 # endif

@@ -170,7 +170,7 @@ static inline int page_cache_add_speculative(struct page *page, int count)
 {
 	VM_BUG_ON(in_interrupt());
 
-#if !defined(CONFIG_SMP) && defined(CONFIG_CLASSIC_RCU)
+#if !defined(CONFIG_SMP) && defined(CONFIG_TREE_RCU)
 # ifdef CONFIG_PREEMPT
 	VM_BUG_ON(!in_atomic());
 # endif
author
#1 lore raw

[tip:core/rcu] rcu: Expunge lingering references to CONFIG_CLASSIC_RCU, optimize on !SMP

Commit-ID:  b560d8ad8583803978aaaeba50ef29dc8e97a610
Gitweb:     http://git.kernel.org/tip/b560d8ad8583803978aaaeba50ef29dc8e97a610
Author:     Paul E. McKenney <[email protected]>
AuthorDate: Fri, 21 Aug 2009 22:08:51 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Sat, 22 Aug 2009 13:07:09 +0200

rcu: Expunge lingering references to CONFIG_CLASSIC_RCU, optimize on !SMP

A couple of references to CONFIG_CLASSIC_RCU have survived. Although these are harmless, it is past time for them to go. The one in hardirq.h is strictly a readability problem.

The two in pagemap.h appear to disable a !SMP performance optimization (which this patch re-enables).

This does raise the issue as to whether pagemap.h should really be referring to the CPU implementation. Long term, I intend to make the RCU implementation driven by CONFIG_PREEMPT, at which point these should change from defined(CONFIG_TREE_RCU) to !defined(CONFIG_PREEMPT). In the meantime, is there something else that could be done in pagemap.h?

Signed-off-by Paul E. McKenney <[email protected]>
Cc [email protected]
Cc [email protected]
Cc [email protected]
Cc [email protected]
Cc [email protected]
Cc [email protected]
Cc [email protected]
Cc [email protected]
Cc [email protected]

LKML-Reference: <[email protected]>

Signed-off-by Ingo Molnar <[email protected]>
---
 include/linux/hardirq.h |    4 ++--
 include/linux/pagemap.h |    4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)
include/linux/hardirq.h +2 -2
index 8246c69..330cb31 100644
@@ -132,7 +132,7 @@ static inline void account_system_vtime(struct task_struct *tsk)
 }
 #endif
 
-#if defined(CONFIG_NO_HZ) && !defined(CONFIG_CLASSIC_RCU)
+#if defined(CONFIG_NO_HZ)
 extern void rcu_irq_enter(void);
 extern void rcu_irq_exit(void);
 extern void rcu_nmi_enter(void);

@@ -142,7 +142,7 @@ extern void rcu_nmi_exit(void);
 # define rcu_irq_exit() do { } while (0)
 # define rcu_nmi_enter() do { } while (0)
 # define rcu_nmi_exit() do { } while (0)
-#endif /* #if defined(CONFIG_NO_HZ) && !defined(CONFIG_CLASSIC_RCU) */
+#endif /* #if defined(CONFIG_NO_HZ) */
 
 /*
  * It is safe to do non-atomic ops on ->hardirq_context,
include/linux/pagemap.h +2 -2
index aec3252..ed5d750 100644
@@ -132,7 +132,7 @@ static inline int page_cache_get_speculative(struct page *page)
 {
 	VM_BUG_ON(in_interrupt());
 
-#if !defined(CONFIG_SMP) && defined(CONFIG_CLASSIC_RCU)
+#if !defined(CONFIG_SMP) && defined(CONFIG_TREE_RCU)
 # ifdef CONFIG_PREEMPT
 	VM_BUG_ON(!in_atomic());
 # endif

@@ -170,7 +170,7 @@ static inline int page_cache_add_speculative(struct page *page, int count)
 {
 	VM_BUG_ON(in_interrupt());
 
-#if !defined(CONFIG_SMP) && defined(CONFIG_CLASSIC_RCU)
+#if !defined(CONFIG_SMP) && defined(CONFIG_TREE_RCU)
 # ifdef CONFIG_PREEMPT
 	VM_BUG_ON(!in_atomic());
 # endif