xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

remove sched notifier for cross-cpu migrations

Browse Source 
Linux as a guest on KVM hypervisor, the only user of the pvclock
vsyscall interface, does not require notification on task migration
because:

1. cpu ID number maps 1:1 to per-CPU pvclock time info.
2. per-CPU pvclock time info is updated if the
   underlying CPU changes.
3. that version is increased whenever underlying CPU
   changes.

Which is sufficient to guarantee nanoseconds counter
is calculated properly.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
This commit is contained in:
Marcelo Tosatti
2013-07-10 22:21:57 -03:00
committed by Paolo Bonzini
parent b3897a49e2
commit e04c5d76b0
5 changed files with 8 additions and 76 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
include/linux/sched.h
View File

@@ -107,14 +107,6 @@ extern unsigned long this_cpu_load(void);
extern void calc_global_load(unsigned long ticks);
extern void update_cpu_load_nohz(void);
/* Notifier for when a task gets migrated to a new CPU */
struct task_migration_notifier {
struct task_struct *task;
int from_cpu;
int to_cpu;
};
extern void register_task_migration_notifier(struct notifier_block *n);
extern unsigned long get_parent_ip(unsigned long addr);
extern void dump_cpu_task(int cpu);