Messages in this thread Patch in this message | | | Date | Wed, 19 Apr 2006 15:14:21 -0700 | From | Anil S Keshavamurthy <> | Subject | [(resend)patch 2/7] Notify page fault call chain for x86_64 |
| |
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 <anil.s.keshavamurthy@intel.com>
--- arch/x86_64/kernel/traps.c | 12 ++++++++++++ arch/x86_64/mm/fault.c | 4 ++-- include/asm-x86_64/kdebug.h | 16 ++++++++++++++++ 3 files changed, 30 insertions(+), 2 deletions(-)
Index: linux-2.6.17-rc1-mm3/arch/x86_64/kernel/traps.c =================================================================== --- linux-2.6.17-rc1-mm3.orig/arch/x86_64/kernel/traps.c +++ linux-2.6.17-rc1-mm3/arch/x86_64/kernel/traps.c @@ -71,6 +71,7 @@ asmlinkage void machine_check(void); asmlinkage void spurious_interrupt_bug(void); ATOMIC_NOTIFIER_HEAD(die_chain); +ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain); int register_die_notifier(struct notifier_block *nb) { @@ -85,6 +86,17 @@ int unregister_die_notifier(struct notif } EXPORT_SYMBOL(unregister_die_notifier); +int register_page_fault_notifier(struct notifier_block *nb) +{ + vmalloc_sync_all(); + return atomic_notifier_chain_register(¬ify_page_fault_chain, nb); +} + +int unregister_page_fault_notifier(struct notifier_block *nb) +{ + return atomic_notifier_chain_unregister(¬ify_page_fault_chain, nb); +} + static inline void conditional_sti(struct pt_regs *regs) { if (regs->eflags & X86_EFLAGS_IF) Index: linux-2.6.17-rc1-mm3/arch/x86_64/mm/fault.c =================================================================== --- linux-2.6.17-rc1-mm3.orig/arch/x86_64/mm/fault.c +++ linux-2.6.17-rc1-mm3/arch/x86_64/mm/fault.c @@ -348,7 +348,7 @@ asmlinkage void __kprobes do_page_fault( if (vmalloc_fault(address) >= 0) return; } - if (notify_die(DIE_PAGE_FAULT, "page fault", regs, error_code, 14, + if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, error_code, 14, SIGSEGV) == NOTIFY_STOP) return; /* @@ -358,7 +358,7 @@ asmlinkage void __kprobes do_page_fault( goto bad_area_nosemaphore; } - if (notify_die(DIE_PAGE_FAULT, "page fault", regs, error_code, 14, + if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, error_code, 14, SIGSEGV) == NOTIFY_STOP) return; Index: linux-2.6.17-rc1-mm3/include/asm-x86_64/kdebug.h =================================================================== --- linux-2.6.17-rc1-mm3.orig/include/asm-x86_64/kdebug.h +++ linux-2.6.17-rc1-mm3/include/asm-x86_64/kdebug.h @@ -15,7 +15,10 @@ 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 die_chain; +extern struct atomic_notifier_head notify_page_fault_chain; /* Grossly misnamed. */ enum die_val { @@ -47,6 +50,19 @@ static inline int notify_die(enum die_va return atomic_notifier_call_chain(&die_chain, val, &args); } +static inline int notify_page_fault(enum die_val val, const 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(¬ify_page_fault_chain, val, &args); +} + extern int printk_address(unsigned long address); extern void die(const char *,struct pt_regs *,long); extern void __die(const char *,struct pt_regs *,long); -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |