commit 5be3492f972b73051ead7ecbac6fb9efd1e8e0ec
author Anton Blanchard <anton@samba.org> Tue Jan 12 00:50:14 2010 +0000
committer Benjamin Herrenschmidt <benh@kernel.crashing.org> Wed Feb 03 17:39:48 2010 +1100
tree c0c66a38665af53673792246f21198c119e8c7d4
parent 61c03ddbdff2e080702521bc1b757854ca58c46a

powerpc: Mark some variables in the page fault path __read_mostly

Using perf to trace L1 dcache misses and dumping data addresses I found a few
variables taking a lot of misses. Since they are almost never written, they
should go into the __read_mostly section.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/traps.c

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index d069ff8..4588d1e 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -60,13 +60,13 @@
 #endif
 
 #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
-int (*__debugger)(struct pt_regs *regs);
-int (*__debugger_ipi)(struct pt_regs *regs);
-int (*__debugger_bpt)(struct pt_regs *regs);
-int (*__debugger_sstep)(struct pt_regs *regs);
-int (*__debugger_iabr_match)(struct pt_regs *regs);
-int (*__debugger_dabr_match)(struct pt_regs *regs);
-int (*__debugger_fault_handler)(struct pt_regs *regs);
+int (*__debugger)(struct pt_regs *regs) __read_mostly;
+int (*__debugger_ipi)(struct pt_regs *regs) __read_mostly;
+int (*__debugger_bpt)(struct pt_regs *regs) __read_mostly;
+int (*__debugger_sstep)(struct pt_regs *regs) __read_mostly;
+int (*__debugger_iabr_match)(struct pt_regs *regs) __read_mostly;
+int (*__debugger_dabr_match)(struct pt_regs *regs) __read_mostly;
+int (*__debugger_fault_handler)(struct pt_regs *regs) __read_mostly;
 
 EXPORT_SYMBOL(__debugger);
 EXPORT_SYMBOL(__debugger_ipi);

arch/powerpc/xmon/xmon.c

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 4e6152c..8bad7d5 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -61,7 +61,7 @@
 static int xmon_gate;
 #endif /* CONFIG_SMP */
 
-static unsigned long in_xmon = 0;
+static unsigned long in_xmon __read_mostly = 0;
 
 static unsigned long adrs;
 static int size = 1;