__get_cpu_var() can be replaced with this_cpu_read and will then use a single read instruction with implied address calculation to access the correct per cpu instance. However, the address of a per cpu variable passed to __this_cpu_read() cannot be determed (since its an implied address conversion through segment prefixes). Therefore apply this only to uses of __get_cpu_var where the addres of the variable is not used. Cc: Neil Horman Cc: Martin Schwidefsky Signed-off-by: Christoph Lameter --- drivers/acpi/processor_idle.c | 6 +++--- drivers/char/random.c | 2 +- drivers/cpuidle/cpuidle.c | 2 +- drivers/s390/cio/cio.c | 2 +- drivers/staging/speakup/fakekey.c | 4 ++-- 5 files changed, 8 insertions(+), 8 deletions(-) Index: linux-2.6/drivers/acpi/processor_idle.c =================================================================== --- linux-2.6.orig/drivers/acpi/processor_idle.c 2010-11-30 12:40:22.000000000 -0600 +++ linux-2.6/drivers/acpi/processor_idle.c 2010-11-30 12:40:47.000000000 -0600 @@ -746,7 +746,7 @@ static int acpi_idle_enter_c1(struct cpu struct acpi_processor *pr; struct acpi_processor_cx *cx = cpuidle_get_statedata(state); - pr = __get_cpu_var(processors); + pr = __this_cpu_read(processors); if (unlikely(!pr)) return 0; @@ -787,7 +787,7 @@ static int acpi_idle_enter_simple(struct s64 idle_time_ns; s64 idle_time; - pr = __get_cpu_var(processors); + pr = __this_cpu_read(processors); if (unlikely(!pr)) return 0; @@ -864,7 +864,7 @@ static int acpi_idle_enter_bm(struct cpu s64 idle_time; - pr = __get_cpu_var(processors); + pr = __this_cpu_read(processors); if (unlikely(!pr)) return 0; Index: linux-2.6/drivers/char/random.c =================================================================== --- linux-2.6.orig/drivers/char/random.c 2010-11-30 12:40:22.000000000 -0600 +++ linux-2.6/drivers/char/random.c 2010-11-30 12:40:47.000000000 -0600 @@ -626,7 +626,7 @@ static void add_timer_randomness(struct preempt_disable(); /* if over the trickle threshold, use only 1 in 4096 samples */ if (input_pool.entropy_count > trickle_thresh && - (__get_cpu_var(trickle_count)++ & 0xfff)) + (__this_cpu_inc_return(trickle_count) & 0xfff)) goto out; sample.jiffies = jiffies; Index: linux-2.6/drivers/cpuidle/cpuidle.c =================================================================== --- linux-2.6.orig/drivers/cpuidle/cpuidle.c 2010-11-30 12:40:22.000000000 -0600 +++ linux-2.6/drivers/cpuidle/cpuidle.c 2010-11-30 12:40:47.000000000 -0600 @@ -49,7 +49,7 @@ static int __cpuidle_register_device(str */ static void cpuidle_idle_call(void) { - struct cpuidle_device *dev = __get_cpu_var(cpuidle_devices); + struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); struct cpuidle_state *target_state; int next_state; Index: linux-2.6/drivers/s390/cio/cio.c =================================================================== --- linux-2.6.orig/drivers/s390/cio/cio.c 2010-11-30 12:40:22.000000000 -0600 +++ linux-2.6/drivers/s390/cio/cio.c 2010-11-30 12:40:47.000000000 -0600 @@ -619,7 +619,7 @@ void __irq_entry do_IRQ(struct pt_regs * s390_idle_check(regs, S390_lowcore.int_clock, S390_lowcore.async_enter_timer); irq_enter(); - __get_cpu_var(s390_idle).nohz_delay = 1; + __this_cpu_write(s390_idle.nohz_delay, 1); if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator) /* Serve timer interrupts first. */ clock_comparator_work(); Index: linux-2.6/drivers/staging/speakup/fakekey.c =================================================================== --- linux-2.6.orig/drivers/staging/speakup/fakekey.c 2010-11-30 12:40:22.000000000 -0600 +++ linux-2.6/drivers/staging/speakup/fakekey.c 2010-11-30 12:40:47.000000000 -0600 @@ -79,10 +79,10 @@ void speakup_fake_down_arrow(void) /* don't change CPU */ preempt_disable(); - __get_cpu_var(reporting_keystroke) = true; + __this_cpu_write(reporting_keystroke), true); input_report_key(virt_keyboard, KEY_DOWN, PRESSED); input_report_key(virt_keyboard, KEY_DOWN, RELEASED); - __get_cpu_var(reporting_keystroke) = false; + __this_cpu_write(reporting_keystroke, false); /* reenable preemption */ preempt_enable(); -- 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/