[(resend)patch 3/7] Notify page fault call chain for ia64

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 

Overloading of page fault notification with the
notify_die() has performance issues(since the
only interested components for page fault is
kprobes and/or kdb) and hence this patch introduces 
the new notifier call chain exclusively for page 
fault notifications their by avoiding notifying
unnecessary components in the do_page_fault() code
path.

Signed-off-by: Anil S Keshavamurthy <[email protected]>

---
 arch/ia64/kernel/traps.c  |   11 +++++++++++
 arch/ia64/mm/fault.c      |    2 +-
 include/asm-ia64/kdebug.h |   16 ++++++++++++++++
 3 files changed, 28 insertions(+), 1 deletion(-)

Index: linux-2.6.17-rc1-mm3/arch/ia64/kernel/traps.c
===================================================================
--- linux-2.6.17-rc1-mm3.orig/arch/ia64/kernel/traps.c
+++ linux-2.6.17-rc1-mm3/arch/ia64/kernel/traps.c
@@ -31,6 +31,7 @@ fpswa_interface_t *fpswa_interface;
 EXPORT_SYMBOL(fpswa_interface);
 
 ATOMIC_NOTIFIER_HEAD(ia64die_chain);
+ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain);
 
 int
 register_die_notifier(struct notifier_block *nb)
@@ -46,6 +47,16 @@ unregister_die_notifier(struct notifier_
 }
 EXPORT_SYMBOL_GPL(unregister_die_notifier);
 
+int register_page_fault_notifier(struct notifier_block *nb)
+{
+	return atomic_notifier_chain_register(&notify_page_fault_chain, nb);
+}
+
+int unregister_page_fault_notifier(struct notifier_block *nb)
+{
+	return atomic_notifier_chain_unregister(&notify_page_fault_chain, nb);
+}
+
 void __init
 trap_init (void)
 {
Index: linux-2.6.17-rc1-mm3/arch/ia64/mm/fault.c
===================================================================
--- linux-2.6.17-rc1-mm3.orig/arch/ia64/mm/fault.c
+++ linux-2.6.17-rc1-mm3/arch/ia64/mm/fault.c
@@ -84,7 +84,7 @@ ia64_do_page_fault (unsigned long addres
 	/*
 	 * This is to handle the kprobes on user space access instructions
 	 */
-	if (notify_die(DIE_PAGE_FAULT, "page fault", regs, code, TRAP_BRKPT,
+	if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, code, TRAP_BRKPT,
 					SIGSEGV) == NOTIFY_STOP)
 		return;
 
Index: linux-2.6.17-rc1-mm3/include/asm-ia64/kdebug.h
===================================================================
--- linux-2.6.17-rc1-mm3.orig/include/asm-ia64/kdebug.h
+++ linux-2.6.17-rc1-mm3/include/asm-ia64/kdebug.h
@@ -40,7 +40,10 @@ struct die_args {
 
 extern int register_die_notifier(struct notifier_block *);
 extern int unregister_die_notifier(struct notifier_block *);
+extern int register_page_fault_notifier(struct notifier_block *);
+extern int unregister_page_fault_notifier(struct notifier_block *);
 extern struct atomic_notifier_head ia64die_chain;
+extern struct atomic_notifier_head notify_page_fault_chain;
 
 enum die_val {
 	DIE_BREAK = 1,
@@ -86,4 +89,17 @@ static inline int notify_die(enum die_va
 	return atomic_notifier_call_chain(&ia64die_chain, val, &args);
 }
 
+static inline int notify_page_fault(enum die_val val, char *str, struct pt_regs *regs,
+			     long err, int trap, int sig)
+{
+	struct die_args args = {
+		.regs   = regs,
+		.str    = str,
+		.err    = err,
+		.trapnr = trap,
+		.signr  = sig
+	};
+
+	return atomic_notifier_call_chain(&notify_page_fault_chain, val, &args);
+}
 #endif

--
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/
[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux