[PATCH 02/27] smpboot: Add provisions for arch-specific locking around cpu_online_mask
From: Srivatsa S. Bhat <hidden>
Date: 2012-06-01 10:04:00
Also in:
lkml
Subsystem:
cpu hotplug, the rest · Maintainers:
Thomas Gleixner, Peter Zijlstra, Linus Torvalds
We want to make smp booting as generic as possible and remove code duplication in arch/ directories. While manipulating the cpu_online_mask, x86 uses an additional lock, i.e., 'vector_lock'. So provide a generic way to implement such arch-specific extra locking, by providing weakly defined functions arch_vector_lock() and arch_vector_unlock() which can be overriden by different architectures suitably. Cc: Thomas Gleixner <redacted> Cc: Suresh Siddha <redacted> Cc: Venkatesh Pallipadi <redacted> Signed-off-by: Srivatsa S. Bhat <redacted> --- kernel/smpboot.c | 11 ++++++++++- 1 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/kernel/smpboot.c b/kernel/smpboot.c
index 6c26133..5ae1805 100644
--- a/kernel/smpboot.c
+++ b/kernel/smpboot.c@@ -107,6 +107,13 @@ void __weak __cpu_pre_online(void *arg) {} void __weak __cpu_post_online(void *arg) {} #endif +/* + * Optional arch-specific locking for manipulating cpu_online_mask while + * bringing up secondary CPUs. + */ +void __weak arch_vector_lock(void) {} +void __weak arch_vector_unlock(void) {} + /** * smpboot_start_secondary - Generic way to boot secondary processors
@@ -129,8 +136,10 @@ void __cpuinit smpboot_start_secondary(void *arg) __cpu_pre_online(arg); - /* Set the CPU in the cpu_online_mask */ + /* Set the CPU in the cpu_online_mask with required locks held */ + arch_vector_lock(); set_cpu_online(cpu, true); + arch_vector_unlock(); __cpu_post_online(arg);