lkml.org 
[lkml]   [2017]   [May]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[tip:smp/hotplug] KVM/PPC/Book3S HV: Use cpuhp_setup_state_nocalls_cpuslocked()
    Commit-ID:  419af25fa4d0974fd758a668c08c369c19392a47
    Gitweb: http://git.kernel.org/tip/419af25fa4d0974fd758a668c08c369c19392a47
    Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
    AuthorDate: Wed, 24 May 2017 10:15:21 +0200
    Committer: Thomas Gleixner <tglx@linutronix.de>
    CommitDate: Fri, 26 May 2017 10:10:39 +0200

    KVM/PPC/Book3S HV: Use cpuhp_setup_state_nocalls_cpuslocked()

    kvmppc_alloc_host_rm_ops() holds get_online_cpus() while invoking
    cpuhp_setup_state_nocalls().

    cpuhp_setup_state_nocalls() invokes get_online_cpus() as well. This is
    correct, but prevents the conversion of the hotplug locking to a percpu
    rwsem.

    Use cpuhp_setup_state_nocalls_cpuslocked() to avoid the nested
    call. Convert *_online_cpus() to the new interfaces while at it.

    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Acked-by: Ingo Molnar <mingo@kernel.org>
    Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
    Cc: kvm@vger.kernel.org
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    Cc: Steven Rostedt <rostedt@goodmis.org>
    Cc: kvm-ppc@vger.kernel.org
    Cc: Michael Ellerman <mpe@ellerman.id.au>
    Cc: linuxppc-dev@lists.ozlabs.org
    Cc: Alexander Graf <agraf@suse.com>
    Link: http://lkml.kernel.org/r/20170524081547.809616236@linutronix.de

    ---
    arch/powerpc/kvm/book3s_hv.c | 14 +++++++-------
    1 file changed, 7 insertions(+), 7 deletions(-)

    diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
    index 42b7a4f..48a6bd1 100644
    --- a/arch/powerpc/kvm/book3s_hv.c
    +++ b/arch/powerpc/kvm/book3s_hv.c
    @@ -3317,7 +3317,7 @@ void kvmppc_alloc_host_rm_ops(void)
    return;
    }

    - get_online_cpus();
    + cpus_read_lock();

    for (cpu = 0; cpu < nr_cpu_ids; cpu += threads_per_core) {
    if (!cpu_online(cpu))
    @@ -3339,17 +3339,17 @@ void kvmppc_alloc_host_rm_ops(void)
    l_ops = (unsigned long) ops;

    if (cmpxchg64((unsigned long *)&kvmppc_host_rm_ops_hv, 0, l_ops)) {
    - put_online_cpus();
    + cpus_read_unlock();
    kfree(ops->rm_core);
    kfree(ops);
    return;
    }

    - cpuhp_setup_state_nocalls(CPUHP_KVM_PPC_BOOK3S_PREPARE,
    - "ppc/kvm_book3s:prepare",
    - kvmppc_set_host_core,
    - kvmppc_clear_host_core);
    - put_online_cpus();
    + cpuhp_setup_state_nocalls_cpuslocked(CPUHP_KVM_PPC_BOOK3S_PREPARE,
    + "ppc/kvm_book3s:prepare",
    + kvmppc_set_host_core,
    + kvmppc_clear_host_core);
    + cpus_read_unlock();
    }

    void kvmppc_free_host_rm_ops(void)
    \
     
     \ /
      Last update: 2017-05-26 10:41    [W:4.078 / U:0.080 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site