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Subject[PATCH v2 0/4] implement vcpu preempted check
change fomr v1:
a simplier definition of default vcpu_is_preempted
skip mahcine type check on ppc, and add config. remove dedicated macro.
add one patch to drop overload of rwsem_spin_on_owner and mutex_spin_on_owner.
add more comments
thanks boqun and Peter's suggestion.

This patch set aims to fix lock holder preemption issues.

perf record -a perf bench sched messaging -g 400 -p && perf report

18.09% sched-messaging [kernel.vmlinux] [k] osq_lock
12.28% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner
5.27% sched-messaging [kernel.vmlinux] [k] mutex_unlock
3.89% sched-messaging [kernel.vmlinux] [k] wait_consider_task
3.64% sched-messaging [kernel.vmlinux] [k] _raw_write_lock_irq
3.41% sched-messaging [kernel.vmlinux] [k]
2.49% sched-messaging [kernel.vmlinux] [k] system_call

We introduce interface bool vcpu_is_preempted(int cpu) and use it in some spin
loops of osq_lock, rwsem_spin_on_owner and mutex_spin_on_owner.
These spin_on_onwer variant also cause rcu stall before we apply this patch set

Pan Xinhui (4):
kernel/sched: introduce vcpu preempted check interface
powerpc/spinlock: support vcpu preempted check
locking/osq: Drop the overload of osq_lock()
kernel/locking: Drop the overload of {mutex,rwsem}_spin_on_owner

arch/powerpc/include/asm/spinlock.h | 18 ++++++++++++++++++
include/linux/sched.h | 12 ++++++++++++
kernel/locking/mutex.c | 15 +++++++++++++--
kernel/locking/osq_lock.c | 10 +++++++++-
kernel/locking/rwsem-xadd.c | 16 +++++++++++++---
5 files changed, 65 insertions(+), 6 deletions(-)


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