[PATCH] x86: introduce and use percpu_inc()

From: Jan Beulich
Date: Wed Apr 21 2010 - 10:21:57 EST


... generating slightly smaller code.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

---
arch/x86/include/asm/hardirq.h | 2 +-
arch/x86/include/asm/percpu.h | 24 ++++++++++++++++++++++++
arch/x86/kernel/cpu/mcheck/mce.c | 4 ++--
3 files changed, 27 insertions(+), 3 deletions(-)

--- linux-2.6.34-rc5/arch/x86/include/asm/hardirq.h 2010-02-24 19:52:17.000000000 +0100
+++ 2.6.34-rc5-x86-inc-percpu/arch/x86/include/asm/hardirq.h 2010-04-15 11:58:06.000000000 +0200
@@ -35,7 +35,7 @@ DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpust

#define __ARCH_IRQ_STAT

-#define inc_irq_stat(member) percpu_add(irq_stat.member, 1)
+#define inc_irq_stat(member) percpu_inc(irq_stat.member)

#define local_softirq_pending() percpu_read(irq_stat.__softirq_pending)

--- linux-2.6.34-rc5/arch/x86/include/asm/percpu.h 2010-04-20 16:07:41.000000000 +0200
+++ 2.6.34-rc5-x86-inc-percpu/arch/x86/include/asm/percpu.h 2010-04-15 11:58:06.000000000 +0200
@@ -190,6 +190,29 @@ do { \
pfo_ret__; \
})

+#define percpu_unary_op(op, var) \
+({ \
+ switch (sizeof(var)) { \
+ case 1: \
+ asm(op "b "__percpu_arg(0) \
+ : "+m" (var)); \
+ break; \
+ case 2: \
+ asm(op "w "__percpu_arg(0) \
+ : "+m" (var)); \
+ break; \
+ case 4: \
+ asm(op "l "__percpu_arg(0) \
+ : "+m" (var)); \
+ break; \
+ case 8: \
+ asm(op "q "__percpu_arg(0) \
+ : "+m" (var)); \
+ break; \
+ default: __bad_percpu_size(); \
+ } \
+})
+
/*
* percpu_read() makes gcc load the percpu variable every time it is
* accessed while percpu_read_stable() allows the value to be cached.
@@ -207,6 +230,7 @@ do { \
#define percpu_and(var, val) percpu_to_op("and", var, val)
#define percpu_or(var, val) percpu_to_op("or", var, val)
#define percpu_xor(var, val) percpu_to_op("xor", var, val)
+#define percpu_inc(var) percpu_unary_op("inc", var)

#define __this_cpu_read_1(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
#define __this_cpu_read_2(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
--- linux-2.6.34-rc5/arch/x86/kernel/cpu/mcheck/mce.c 2010-04-20 16:07:42.000000000 +0200
+++ 2.6.34-rc5-x86-inc-percpu/arch/x86/kernel/cpu/mcheck/mce.c 2010-04-15 11:58:06.000000000 +0200
@@ -539,7 +539,7 @@ void machine_check_poll(enum mcp_flags f
struct mce m;
int i;

- __get_cpu_var(mce_poll_count)++;
+ percpu_inc(mce_poll_count);

mce_setup(&m);

@@ -934,7 +934,7 @@ void do_machine_check(struct pt_regs *re

atomic_inc(&mce_entry);

- __get_cpu_var(mce_exception_count)++;
+ percpu_inc(mce_exception_count);

if (notify_die(DIE_NMI, "machine check", regs, error_code,
18, SIGKILL) == NOTIFY_STOP)



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