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authorTejun Heo <tj@kernel.org>2009-08-03 14:12:19 +0900
committerTejun Heo <tj@kernel.org>2009-08-04 01:29:34 +0900
commitbdf977b37418cdf8a2252504779a7e12a09b7575 (patch)
tree0f3896a5b39c35f3018d3cb16f797ae7d6c4a66b /arch/x86/kernel/process_64.c
parent3e352aa8ee2bd48f1a19c7742810b3a4a7ba605e (diff)
x86, percpu: Collect hot percpu variables into one cacheline
On x86_64, percpu variables current_task and kernel_stack are used for get_current() and current_thread_info() respectively and thus are often used close to each other. Move definition of current_task to kernel/cpu/common.c right above kernel_stack definition and align it to cacheline so that they always fall into the same cacheline. Two percpu variables defined there together - irq_stack_ptr and irq_count - are also pretty hot and will benefit from sharing the cacheline. For consistency, current_task definition for x86_32 is also moved to kernel/cpu/common.c. Putting current_task and kernel_stack into the same cacheline was suggested by Linus Torvalds. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/kernel/process_64.c')
-rw-r--r--arch/x86/kernel/process_64.c3
1 files changed, 0 insertions, 3 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index ebefb5407b9d..c4c675d5ba1a 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -55,9 +55,6 @@
asmlinkage extern void ret_from_fork(void);
-DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task;
-EXPORT_PER_CPU_SYMBOL(current_task);
-
DEFINE_PER_CPU(unsigned long, old_rsp);
static DEFINE_PER_CPU(unsigned char, is_idle);