Map "xen_nopvspin" to "nopvspin", fix stale description of "xen_nopvspin"
as we use qspinlock now.
Signed-off-by: Zhenzhong Duan <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Boris Ostrovsky <[email protected]>
Cc: Juergen Gross <[email protected]>
Cc: Stefano Stabellini <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
---
Documentation/admin-guide/kernel-parameters.txt | 7 ++++---
arch/x86/xen/spinlock.c | 3 +++
2 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 89d77ea..df1eacc 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5303,8 +5303,9 @@
never -- do not unplug even if version check succeeds
xen_nopvspin [X86,XEN]
- Disables the ticketlock slowpath using Xen PV
- optimizations.
+ Disables the qspinlock slowpath using Xen PV optimizations.
+ This parameter is obsoleted by "nopvspin" parameter, which
+ has equivalent effect for XEN platform.
xen_nopv [X86]
Disables the PV optimizations forcing the HVM guest to
@@ -5330,7 +5331,7 @@
as generic guest with no PV drivers. Currently support
XEN HVM, KVM, HYPER_V and VMWARE guest.
- nopvspin [X86,KVM]
+ nopvspin [X86,XEN,KVM]
Disables the qspinlock slow path using PV optimizations
which allow the hypervisor to 'idle' the guest on lock
contention.
diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
index 6deb490..bae29a4 100644
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -114,6 +114,8 @@ void xen_uninit_lock_cpu(int cpu)
*/
void __init xen_init_spinlocks(void)
{
+ if (nopvspin)
+ xen_pvspin = false;
/* Don't need to use pvqspinlock code if there is only 1 vCPU. */
if (num_possible_cpus() == 1)
@@ -137,6 +139,7 @@ void __init xen_init_spinlocks(void)
static __init int xen_parse_nopvspin(char *arg)
{
+ pr_notice("\"xen_nopvspin\" is deprecated, please use \"nopvspin\" instead\n");
xen_pvspin = false;
return 0;
}
--
1.8.3.1
On 10/3/19 10:02 AM, Zhenzhong Duan wrote:
> Map "xen_nopvspin" to "nopvspin", fix stale description of "xen_nopvspin"
> as we use qspinlock now.
>
> Signed-off-by: Zhenzhong Duan <[email protected]>
> Cc: Jonathan Corbet <[email protected]>
> Cc: Boris Ostrovsky <[email protected]>
> Cc: Juergen Gross <[email protected]>
> Cc: Stefano Stabellini <[email protected]>
> Cc: Thomas Gleixner <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: Borislav Petkov <[email protected]>
> Cc: "H. Peter Anvin" <[email protected]>
Reviewed-by: Boris Ostrovsky <[email protected]>
with a small nit
> void __init xen_init_spinlocks(void)
> {
> + if (nopvspin)
> + xen_pvspin = false;
>
> /* Don't need to use pvqspinlock code if there is only 1 vCPU. */
> if (num_possible_cpus() == 1)
I'd fold the change into this 'if' statement, I think it will still be
clear what the comment refers to.
-boris
On 2019/10/4 22:57, Boris Ostrovsky wrote:
> On 10/3/19 10:02 AM, Zhenzhong Duan wrote:
>> Map "xen_nopvspin" to "nopvspin", fix stale description of "xen_nopvspin"
>> as we use qspinlock now.
>>
>> Signed-off-by: Zhenzhong Duan <[email protected]>
>> Cc: Jonathan Corbet <[email protected]>
>> Cc: Boris Ostrovsky <[email protected]>
>> Cc: Juergen Gross <[email protected]>
>> Cc: Stefano Stabellini <[email protected]>
>> Cc: Thomas Gleixner <[email protected]>
>> Cc: Ingo Molnar <[email protected]>
>> Cc: Borislav Petkov <[email protected]>
>> Cc: "H. Peter Anvin" <[email protected]>
> Reviewed-by: Boris Ostrovsky <[email protected]>
>
> with a small nit
>
>> void __init xen_init_spinlocks(void)
>> {
>> + if (nopvspin)
>> + xen_pvspin = false;
>>
>> /* Don't need to use pvqspinlock code if there is only 1 vCPU. */
>> if (num_possible_cpus() == 1)
> I'd fold the change into this 'if' statement, I think it will still be
> clear what the comment refers to.
Good suggestion, will do that. Thanks
Zhenzhong