hi, Andrea
thanks for your reply. :)
在 2016/12/19 19:42, Andrea Arcangeli 写道:
Hello,
On Wed, Nov 02, 2016 at 05:08:35AM -0400, Pan Xinhui wrote:
Support the vcpu_is_preempted() functionality under KVM. This will
enhance lock performance on overcommitted hosts (more runnable vcpus
than
hi, Peter
I think I know the point.
then could we just let __eax rettype(here is bool), not unsigned long?
I does not do tests for my thoughts.
@@ -461,7 +461,9 @@ int paravirt_disable_iospace(void);
#define PVOP_VCALL_ARGS
\
in the hash table might not be the correct lock holder, as for
performace issue, we does not take care of hash conflict.
Also introduce spin_lock_holder, which tells who owns the lock now.
currently the only user is spin_unlock_wait.
Signed-off-by: Pan Xinhui
---
arch/powerpc/include/asm
Avoid a function call under native version of qspinlock. On powerNV,
bafore applying this patch, every unlock is expensive. This small
optimizes enhance the performance.
We use static_key with jump_lable which removes unnecessary loads of
lppaca and its stuff.
Signed-off-by: Pan Xinhui
will introduce latency and a little overhead. And we
do NOT want to suffer any latency on some cases, e.g. in interrupt handler.
The second parameter *confer* can indicate such case.
__spin_wake_cpu is simpiler, it will wake up one vcpu regardless of its
current vcpu state.
Signed-off-by: Pan
pSeries/powerNV will use qspinlock from now on.
Signed-off-by: Pan Xinhui
---
arch/powerpc/platforms/Kconfig | 9 +
1 file changed, 9 insertions(+)
diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig
index fbdae83..3559bbf 100644
--- a/arch/powerpc/platforms
pSeries run as a guest and might need pv-qspinlock.
Signed-off-by: Pan Xinhui
---
arch/powerpc/kernel/Makefile | 1 +
arch/powerpc/platforms/pseries/Kconfig | 8
2 files changed, 9 insertions(+)
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index
1050.6
----
Pan Xinhui (6):
powerpc/qspinlock: powerpc support qspinlock
powerpc: platforms/Kconfig: Add qspinlock build config
powerpc: lib/locks.c: Add cpu yield/wake helper function
powerpc/pv-qspinlock: powerpc support pv-qspinlo
endianness
system.
We override some arch_spin_XXX as powerpc has io_sync stuff which makes
sure the io operations are protected by the lock correctly.
There is another special case, see commit
2c610022711 ("locking/qspinlock: Fix spin_unlock_wait() some more")
Signed-off-by: Pan Xinhui
在 2016/12/6 09:24, Pan Xinhui 写道:
在 2016/12/6 08:58, Boqun Feng 写道:
On Mon, Dec 05, 2016 at 10:19:22AM -0500, Pan Xinhui wrote:
pSeries/powerNV will use qspinlock from now on.
Signed-off-by: Pan Xinhui
---
arch/powerpc/platforms/pseries/Kconfig | 8
1 file changed, 8 insertions
在 2016/12/6 09:23, Boqun Feng 写道:
On Mon, Dec 05, 2016 at 10:19:23AM -0500, Pan Xinhui wrote:
Add two corresponding helper functions to support pv-qspinlock.
For normal use, __spin_yield_cpu will confer current vcpu slices to the
target vcpu(say, a lock holder). If target vcpu is not
在 2016/12/6 08:58, Boqun Feng 写道:
On Mon, Dec 05, 2016 at 10:19:22AM -0500, Pan Xinhui wrote:
pSeries/powerNV will use qspinlock from now on.
Signed-off-by: Pan Xinhui
---
arch/powerpc/platforms/pseries/Kconfig | 8
1 file changed, 8 insertions(+)
diff --git a/arch/powerpc
correct waiman's address.
在 2016/12/6 08:47, Boqun Feng 写道:
On Mon, Dec 05, 2016 at 10:19:21AM -0500, Pan Xinhui wrote:
This patch add basic code to enable qspinlock on powerpc. qspinlock is
one kind of fairlock implementation. And seen some performance improvement
under some scen
in the hash table might not be the correct lock holder, as for
performace issue, we does not take care of hash conflict.
Also introduce spin_lock_holder, which tells who owns the lock now.
currently the only user is spin_unlock_wait.
Signed-off-by: Pan Xinhui
---
arch/powerpc/include/asm
Avoid a function call under native version of qspinlock. On powerNV,
bafore applying this patch, every unlock is expensive. This small
optimizes enhance the performance.
We use static_key with jump_label which removes unnecessary loads of
lppaca and its stuff.
Signed-off-by: Pan Xinhui
pSeries run as a guest and might need pv-qspinlock.
Signed-off-by: Pan Xinhui
---
arch/powerpc/kernel/Makefile | 1 +
arch/powerpc/platforms/pseries/Kconfig | 8
2 files changed, 9 insertions(+)
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index
will introduce latency and a little overhead. And we
do NOT want to suffer any latency on some cases, e.g. in interrupt handler.
The second parameter *confer* can indicate such case.
__spin_wake_cpu is simpiler, it will wake up one vcpu regardless of its
current vcpu state.
Signed-off-by: Pan
pSeries/powerNV will use qspinlock from now on.
Signed-off-by: Pan Xinhui
---
arch/powerpc/platforms/pseries/Kconfig | 8
1 file changed, 8 insertions(+)
diff --git a/arch/powerpc/platforms/pseries/Kconfig
b/arch/powerpc/platforms/pseries/Kconfig
index bec90fb..8a87d06 100644
--- a
endianness
system.
We override some arch_spin_XXX as powerpc has io_sync stuff which makes
sure the io operations are protected by the lock correctly.
There is another special case, see commit
2c610022711 ("locking/qspinlock: Fix spin_unlock_wait() some more")
Signed-off-by: Pan Xinhui
1134.2
=
System Benchmarks Index Score 1072.0 1108.91050.6
--------
Pan Xinhui (6):
powerpc/qspinlock: powerpc support qspinlock
powerpc
在 2016/11/16 18:23, Peter Zijlstra 写道:
On Wed, Nov 16, 2016 at 12:19:09PM +0800, Pan Xinhui wrote:
Hi, Peter.
I think we can avoid a function call in a simpler way. How about below
static inline bool vcpu_is_preempted(int cpu)
{
/* only set in pv case*/
if
在 2016/11/15 23:47, Peter Zijlstra 写道:
On Wed, Nov 02, 2016 at 05:08:33AM -0400, Pan Xinhui wrote:
diff --git a/arch/x86/include/asm/paravirt_types.h
b/arch/x86/include/asm/paravirt_types.h
index 0f400c0..38c3bb7 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm
u has been preempted.
Signed-off-by: Pan Xinhui
Acked-by: Radim Krčmář
Acked-by: Paolo Bonzini
---
Documentation/virtual/kvm/msr.txt | 9 -
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/Documentation/virtual/kvm/msr.txt
b/Documentation/virtual/kvm/msr.txt
index 2a71c8f..
quick test (4 vcpus on 1 physical cpu doing a parallel build job
with "make -j 8") reduced system time by about 5% with this patch.
Signed-off-by: Juergen Gross
Signed-off-by: Pan Xinhui
---
arch/x86/xen/spinlock.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/ar
concurrent) | 3531.4 lpm | 3211.9 lpm
System Call Overhead | 10385653.0 lps | 10419979.0 lps
Signed-off-by: Pan Xinhui
Acked-by: Paolo Bonzini
---
arch/x86/kernel/kvm.c | 12
1 file changed, 12 insertions(+)
diff --git a/arch/x86/kernel/kvm.c
kvm_steal_time ::preempted to indicate that if
one vcpu is running or not.
Signed-off-by: Pan Xinhui
Acked-by: Paolo Bonzini
---
arch/x86/include/uapi/asm/kvm_para.h | 4 +++-
arch/x86/kvm/x86.c | 16
2 files changed, 19 insertions(+), 1 deletion(-)
diff --git a
It allows us to update some status or field of one struct partially.
We can also save one kvm_read_guest_cached if we just update one filed
of the struct regardless of its current value.
Signed-off-by: Pan Xinhui
Acked-by: Paolo Bonzini
---
include/linux/kvm_host.h | 2 ++
virt/kvm
From: Christian Borntraeger
this implements the s390 backend for commit
"kernel/sched: introduce vcpu preempted check interface"
by reworking the existing smp_vcpu_scheduled into
arch_vcpu_is_preempted. We can then also get rid of the
local cpu_is_preempted function by moving the
CIF_ENABLED_WAIT
spin loops upon the retval of
vcpu_is_preempted.
As kernel has used this interface, So lets support it.
To deal with kernel and kvm/xen, add vcpu_is_preempted into struct
pv_lock_ops.
Then kvm or xen could provide their own implementation to support
vcpu_is_preempted.
Signed-off-by: Pan Xinhui
.
Suggested-by: Peter Zijlstra (Intel)
Signed-off-by: Pan Xinhui
Acked-by: Christian Borntraeger
Acked-by: Paolo Bonzini
Tested-by: Juergen Gross
---
include/linux/sched.h | 12
1 file changed, 12 insertions(+)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index
essaging [kernel.vmlinux] [k] system_call
2.69% sched-messaging [kernel.vmlinux] [k] wait_consider_task
Signed-off-by: Pan Xinhui
Acked-by: Christian Borntraeger
Acked-by: Paolo Bonzini
Tested-by: Juergen Gross
---
kernel/locking/mutex.c | 13 +++--
kernel/locking/rwsem-xad
->yiled_count keeps zero on
PowerNV. So we can just skip the machine type check.
Suggested-by: Boqun Feng
Suggested-by: Peter Zijlstra (Intel)
Signed-off-by: Pan Xinhui
---
arch/powerpc/include/asm/spinlock.h | 8
1 file changed, 8 insertions(+)
diff --git a/arch/powerpc/include/asm/spinloc
call_common
2.83% sched-messaging [kernel.vmlinux] [k] copypage_power7
2.64% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner
2.00% sched-messaging [kernel.vmlinux] [k] osq_lock
Suggested-by: Boqun Feng
Signed-off-by: Pan Xinhui
Acked-by: Christian Borntraeger
Acked-by: Pa
System Call Overhead | 10385653.0 lps | 10419979.0 lps
Christian Borntraeger (1):
s390/spinlock: Provide vcpu_is_preempted
Juergen Gross (1):
x86, xen: support vcpu preempted check
Pan Xinhui (9):
kernel/sched: introduce vcpu preempted check interface
locking/
在 2016/10/30 00:52, Davidlohr Bueso 写道:
On Fri, 28 Oct 2016, Pan Xinhui wrote:
/*
* If we need to reschedule bail... so we can block.
+ * Use vcpu_is_preempted to detech lock holder preemption issue
^^ detect
ok. thanks for
在 2016/10/29 03:38, Konrad Rzeszutek Wilk 写道:
On Fri, Oct 28, 2016 at 04:11:16AM -0400, Pan Xinhui wrote:
change from v5:
spilt x86/kvm patch into guest/host part.
introduce kvm_write_guest_offset_cached.
fix some typos.
rebase patch onto 4.9.2
change from v4
在 2016/10/29 03:43, Konrad Rzeszutek Wilk 写道:
On Fri, Oct 28, 2016 at 04:11:26AM -0400, Pan Xinhui wrote:
From: Juergen Gross
Support the vcpu_is_preempted() functionality under Xen. This will
enhance lock performance on overcommitted hosts (more runnable vcpus
than physical cpus in the
u has been preempted.
Signed-off-by: Pan Xinhui
Acked-by: Radim Krčmář
---
Documentation/virtual/kvm/msr.txt | 9 -
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/Documentation/virtual/kvm/msr.txt
b/Documentation/virtual/kvm/msr.txt
index 2a71c8f..ab2ab76 100644
--- a/Docum
quick test (4 vcpus on 1 physical cpu doing a parallel build job
with "make -j 8") reduced system time by about 5% with this patch.
Signed-off-by: Juergen Gross
Signed-off-by: Pan Xinhui
---
arch/x86/xen/spinlock.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/ar
kvm_steal_time ::preempted to indicate that if
one vcpu is running or not.
Signed-off-by: Pan Xinhui
---
arch/x86/include/uapi/asm/kvm_para.h | 4 +++-
arch/x86/kvm/x86.c | 16
2 files changed, 19 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/uapi
concurrent) | 3531.4 lpm | 3211.9 lpm
System Call Overhead | 10385653.0 lps | 10419979.0 lps
Signed-off-by: Pan Xinhui
---
arch/x86/kernel/kvm.c | 12
1 file changed, 12 insertions(+)
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
ind
It allows us to update some status or field of one struct partially.
We can also save one kvm_read_guest_cached if we just update one filed
of the struct regardless of its current value.
Signed-off-by: Pan Xinhui
---
include/linux/kvm_host.h | 2 ++
virt/kvm/kvm_main.c | 20
spin loops upon on the retval of
vcpu_is_preempted.
As kernel has used this interface, So lets support it.
To deal with kernel and kvm/xen, add vcpu_is_preempted into struct
pv_lock_ops.
Then kvm or xen could provide their own implementation to support
vcpu_is_preempted.
Signed-off-by: Pan
.
Suggested-by: Peter Zijlstra (Intel)
Signed-off-by: Pan Xinhui
Acked-by: Christian Borntraeger
Tested-by: Juergen Gross
---
include/linux/sched.h | 12
1 file changed, 12 insertions(+)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 348f51b..44c1ce7 100644
From: Christian Borntraeger
this implements the s390 backend for commit
"kernel/sched: introduce vcpu preempted check interface"
by reworking the existing smp_vcpu_scheduled into
arch_vcpu_is_preempted. We can then also get rid of the
local cpu_is_preempted function by moving the
CIF_ENABLED_WAIT
->yiled_count keeps zero on
powerNV. So we can just skip the machine type check.
Suggested-by: Boqun Feng
Suggested-by: Peter Zijlstra (Intel)
Signed-off-by: Pan Xinhui
---
arch/powerpc/include/asm/spinlock.h | 8
1 file changed, 8 insertions(+)
diff --git a/arch/powerpc/include/
essaging [kernel.vmlinux] [k] system_call
2.69% sched-messaging [kernel.vmlinux] [k] wait_consider_task
Signed-off-by: Pan Xinhui
Acked-by: Christian Borntraeger
Tested-by: Juergen Gross
---
kernel/locking/mutex.c | 15 +--
kernel/locking/rwsem-xadd.c | 16 +---
call_common
2.83% sched-messaging [kernel.vmlinux] [k] copypage_power7
2.64% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner
2.00% sched-messaging [kernel.vmlinux] [k] osq_lock
Suggested-by: Boqun Feng
Signed-off-by: Pan Xinhui
Acked-by: Christian Borntraeger
Tested-by: Ju
0419979.0 lps
Christian Borntraeger (1):
s390/spinlock: Provide vcpu_is_preempted
Juergen Gross (1):
x86, xen: support vcpu preempted check
Pan Xinhui (9):
kernel/sched: introduce vcpu preempted check interface
locking/osq: Drop the overload of osq_lock()
kernel/locking: Drop the overl
在 2016/10/24 23:18, Paolo Bonzini 写道:
On 24/10/2016 17:14, Radim Krčmář wrote:
2016-10-24 16:39+0200, Paolo Bonzini:
On 19/10/2016 19:24, Radim Krčmář wrote:
+ if (vcpu->arch.st.msr_val & KVM_MSR_ENABLED)
+ if (kvm_read_guest_cached(vcpu->kvm, &vcpu->arch.st.stime,
+
在 2016/10/21 09:23, Boqun Feng 写道:
On Thu, Oct 20, 2016 at 05:27:54PM -0400, Pan Xinhui wrote:
Commit ("x86, kvm: support vcpu preempted check") add one field "__u8
preempted" into struct kvm_steal_time. This field tells if one vcpu is
running or not.
It is zero if 1) s
n preempted.
Signed-off-by: Pan Xinhui
---
Documentation/virtual/kvm/msr.txt | 8 +++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/Documentation/virtual/kvm/msr.txt
b/Documentation/virtual/kvm/msr.txt
index 2a71c8f..3376f13 100644
--- a/Documentation/virtual/kvm/msr.txt
quick test (4 vcpus on 1 physical cpu doing a parallel build job
with "make -j 8") reduced system time by about 5% with this patch.
Signed-off-by: Juergen Gross
Signed-off-by: Pan Xinhui
---
arch/x86/xen/spinlock.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/ar
From: Christian Borntraeger
this implements the s390 backend for commit
"kernel/sched: introduce vcpu preempted check interface"
by reworking the existing smp_vcpu_scheduled into
arch_vcpu_is_preempted. We can then also get rid of the
local cpu_is_preempted function by moving the
CIF_ENABLED_WAIT
Call Overhead | 10385653.0 lps | 10419979.0 lps
Signed-off-by: Pan Xinhui
---
arch/x86/include/uapi/asm/kvm_para.h | 3 ++-
arch/x86/kernel/kvm.c| 12
arch/x86/kvm/x86.c | 18 ++
3 files changed, 32 insertions(+), 1
spin loops upon on the retval of
vcpu_is_preempted.
As kernel has used this interface, So lets support it.
To deal with kernel and kvm/xen, add vcpu_is_preempted into struct
pv_lock_ops.
Then kvm or xen could provide their own implementation to support
vcpu_is_preempted.
Signed-off-by: Pan
essaging [kernel.vmlinux] [k] system_call
2.69% sched-messaging [kernel.vmlinux] [k] wait_consider_task
Signed-off-by: Pan Xinhui
Acked-by: Christian Borntraeger
Tested-by: Juergen Gross
---
kernel/locking/mutex.c | 15 +--
kernel/locking/rwsem-xadd.c | 16 +---
->yiled_count keeps zero on
powerNV. So we can just skip the machine type check.
Suggested-by: Boqun Feng
Suggested-by: Peter Zijlstra (Intel)
Signed-off-by: Pan Xinhui
---
arch/powerpc/include/asm/spinlock.h | 8
1 file changed, 8 insertions(+)
diff --git a/arch/powerpc/include/
call_common
2.83% sched-messaging [kernel.vmlinux] [k] copypage_power7
2.64% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner
2.00% sched-messaging [kernel.vmlinux] [k] osq_lock
Suggested-by: Boqun Feng
Signed-off-by: Pan Xinhui
Acked-by: Christian Borntraeger
Tested-by: Ju
.
Suggested-by: Peter Zijlstra (Intel)
Signed-off-by: Pan Xinhui
Acked-by: Christian Borntraeger
Tested-by: Juergen Gross
---
include/linux/sched.h | 12
1 file changed, 12 insertions(+)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 348f51b..44c1ce7 100644
ll Scripts (8 concurrent) | 3531.4 lpm | 3211.9 lpm
System Call Overhead | 10385653.0 lps | 10419979.0 lps
Christian Borntraeger (1):
s390/spinlock: Provide vcpu_is_preempted
Juergen Gross (1):
x86, xen: support vcpu preempted check
Pan Xinhui (7):
kernel/sch
在 2016/10/20 01:24, Radim Krčmář 写道:
2016-10-19 06:20-0400, Pan Xinhui:
This is to fix some lock holder preemption issues. Some other locks
implementation do a spin loop before acquiring the lock itself.
Currently kernel has an interface of bool vcpu_is_preempted(int cpu). It
takes the cpu as
在 2016/10/19 23:58, Juergen Gross 写道:
On 19/10/16 12:20, Pan Xinhui wrote:
change from v3:
add x86 vcpu preempted check patch
change from v2:
no code change, fix typos, update some comments
change from v1:
a simplier definition of default vcpu_is_preempted
skip
在 2016/10/19 14:47, Christian Borntraeger 写道:
On 10/19/2016 12:20 PM, Pan Xinhui wrote:
change from v3:
add x86 vcpu preempted check patch
If you want you could add the s390 patch that I provided for your last version.
I also gave my Acked-by for all previous patches.
hi
->yiled_count keeps zero on
powerNV. So we can just skip the machine type check.
Suggested-by: Boqun Feng
Suggested-by: Peter Zijlstra (Intel)
Signed-off-by: Pan Xinhui
---
arch/powerpc/include/asm/spinlock.h | 8
1 file changed, 8 insertions(+)
diff --git a/arch/powerpc/include/
Scripts (1 concurrent) |23224.3 lpm |22607.4 lpm
Shell Scripts (8 concurrent) | 3531.4 lpm | 3211.9 lpm
System Call Overhead | 10385653.0 lps | 10419979.0 lps
Signed-off-by: Pan Xinhui
---
arch/x86/include/asm/paravirt_types.h | 6
essaging [kernel.vmlinux] [k] system_call
2.69% sched-messaging [kernel.vmlinux] [k] wait_consider_task
Signed-off-by: Pan Xinhui
---
kernel/locking/mutex.c | 15 +--
kernel/locking/rwsem-xadd.c | 16 +---
2 files changed, 26 insertions(+), 5 deletions(-)
diff --git
.
Suggested-by: Peter Zijlstra (Intel)
Signed-off-by: Pan Xinhui
---
include/linux/sched.h | 12
1 file changed, 12 insertions(+)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 348f51b..44c1ce7 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
call_common
2.83% sched-messaging [kernel.vmlinux] [k] copypage_power7
2.64% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner
2.00% sched-messaging [kernel.vmlinux] [k] osq_lock
Suggested-by: Boqun Feng
Signed-off-by: Pan Xinhui
---
kernel/locking/osq_lock.c | 10 +-
1 f
(1 concurrent) |23224.3 lpm |22607.4 lpm
Shell Scripts (8 concurrent) | 3531.4 lpm | 3211.9 lpm
System Call Overhead | 10385653.0 lps | 10419979.0 lps
Pan Xinhui (5):
kernel/sched: introduce vcpu preempted check interface
locking/osq: Drop
在 2016/9/30 17:08, Paolo Bonzini 写道:
On 30/09/2016 10:52, Pan Xinhui wrote:
x86 has no hypervisor support, and I'd like to understand the desired
semantics first, so I don't think it should block this series. In
Once a guest do a hypercall or something similar, IOW,
hi, Paolo
thanks for your reply.
在 2016/9/30 14:58, Paolo Bonzini 写道:
Please consider s390 and (x86/arm) KVM. Once we have a few, more can
follow later, but I think its important to not only have PPC support for
this.
Actually the s390 preemted check via sigp sense running is availab
在 2016/9/30 13:52, Boqun Feng 写道:
On Fri, Sep 30, 2016 at 12:49:52PM +0800, Pan Xinhui wrote:
在 2016/9/29 23:51, Christian Borntraeger 写道:
this implements the s390 backend for commit
"kernel/sched: introduce vcpu preempted check interface"
by reworking the existing smp_vcpu_sche
在 2016/9/29 18:31, Peter Zijlstra 写道:
On Thu, Sep 29, 2016 at 12:23:19PM +0200, Christian Borntraeger wrote:
On 09/29/2016 12:10 PM, Peter Zijlstra wrote:
On Thu, Jul 21, 2016 at 07:45:10AM -0400, Pan Xinhui wrote:
change from v2:
no code change, fix typos, update some comments
在 2016/9/29 23:51, Christian Borntraeger 写道:
this implements the s390 backend for commit
"kernel/sched: introduce vcpu preempted check interface"
by reworking the existing smp_vcpu_scheduled into
arch_vcpu_is_preempted. We can then also get rid of the
local cpu_is_preempted function by moving t
在 2016/9/29 18:10, Peter Zijlstra 写道:
On Thu, Jul 21, 2016 at 07:45:10AM -0400, Pan Xinhui wrote:
change from v2:
no code change, fix typos, update some comments
change from v1:
a simplier definition of default vcpu_is_preempted
skip mahcine type check on ppc, and add
pSeries run as a guest and might need pv-qspinlock.
Signed-off-by: Pan Xinhui
---
arch/powerpc/kernel/Makefile | 1 +
arch/powerpc/platforms/pseries/Kconfig | 8
2 files changed, 9 insertions(+)
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index
in the hash table might not be the correct lock holder, as for
performace issue, we does not take care of hash conflict.
Also introduce spin_lock_holder, which tells who owns the lock now.
currently the only user is spin_unlock_wait.
Signed-off-by: Pan Xinhui
---
arch/powerpc/include/asm
will introduce latency and a little overhead. And
we do NOT want to suffer any latency on some cases, e.g. in interrupt handler.
The second parameter *confer* can indicate such case.
__spin_wake_cpu is simpiler, it will wake up one vcpu regardless of its
current vcpu state.
Signed-off-by: Pan
two endianness
system.
We override some arch_spin_xxx as powerpc has io_sync stuff which makes
sure the io operations are protected by the lock correctly.
There is another special case, see commit
2c610022711 ("locking/qspinlock: Fix spin_unlock_wait() some more")
Signed-off-by: Pan Xinh
pseries will use qspinlock by default.
Signed-off-by: Pan Xinhui
---
arch/powerpc/platforms/pseries/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/powerpc/platforms/pseries/Kconfig
b/arch/powerpc/platforms/pseries/Kconfig
index bec90fb..f669323 100644
--- a/arch/powerpc
ed-by: Boqun Feng
Signed-off-by: Pan Xinhui
---
kernel/locking/qspinlock_paravirt.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/locking/qspinlock_paravirt.h
b/kernel/locking/qspinlock_paravirt.h
index 8a99abf..ce655aa 100644
--- a/kernel/locking/qspinlock_parav
1008.3 1122.61134.2
=
System Benchmarks Index Score 1072.0 1108.91050.6
--------
Pan Xinhui (6):
pv-qspin
essaging [kernel.vmlinux] [k] system_call
2.69% sched-messaging [kernel.vmlinux] [k] wait_consider_task
Signed-off-by: Pan Xinhui
---
kernel/locking/mutex.c | 15 +--
kernel/locking/rwsem-xadd.c | 16 +---
2 files changed, 26 insertions(+), 5 deletions(-)
diff --git
call_common
2.83% sched-messaging [kernel.vmlinux] [k] copypage_power7
2.64% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner
2.00% sched-messaging [kernel.vmlinux] [k] osq_lock
Suggested-by: Boqun Feng
Signed-off-by: Pan Xinhui
---
kernel/locking/osq_lock.c | 10 +-
1 f
nterface 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 v
->yield_count keeps zero on
powerNV. So we can just skip the machine type check.
Suggested-by: Boqun Feng
Suggested-by: Peter Zijlstra (Intel)
Signed-off-by: Pan Xinhui
---
arch/powerpc/include/asm/spinlock.h | 18 ++
1 file changed, 18 insertions(+)
diff --git a/arch/powerpc/incl
check.
Suggested-by: Peter Zijlstra (Intel)
Signed-off-by: Pan Xinhui
---
include/linux/sched.h | 12
1 file changed, 12 insertions(+)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 6e42ada..cbe0574 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
Hi, Baibir
sorry for late responce, I missed reading your mail.
在 16/7/6 18:54, Balbir Singh 写道:
On Tue, 2016-06-28 at 10:43 -0400, Pan Xinhui wrote:
This is to fix some lock holder preemption issues. Some other locks
implementation do a spin loop before acquiring the lock itself
essaging [kernel.vmlinux] [k] system_call
2.69% sched-messaging [kernel.vmlinux] [k] wait_consider_task
Signed-off-by: Pan Xinhui
---
kernel/locking/mutex.c | 15 +--
kernel/locking/rwsem-xadd.c | 16 +---
2 files changed, 26 insertions(+), 5 deletions(-)
diff --git
call_common
2.83% sched-messaging [kernel.vmlinux] [k] copypage_power7
2.64% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner
2.00% sched-messaging [kernel.vmlinux] [k] osq_lock
Suggested-by: Boqun Feng
Signed-off-by: Pan Xinhui
---
kernel/locking/osq_lock.c | 10 +-
1 f
->yiled_count keeps zero on
powerNV. So we can just skip the machine type.
Suggested-by: Boqun Feng
Suggested-by: Peter Zijlstra (Intel)
Signed-off-by: Pan Xinhui
---
arch/powerpc/include/asm/spinlock.h | 18 ++
1 file changed, 18 insertions(+)
diff --git a/arch/powerpc/include/
] 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 ch
.
Suggested-by: Peter Zijlstra (Intel)
Signed-off-by: Pan Xinhui
---
include/linux/sched.h | 12
1 file changed, 12 insertions(+)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 6e42ada..cbe0574 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
pseries will use qspinlock by default.
Signed-off-by: Pan Xinhui
---
arch/powerpc/platforms/pseries/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/powerpc/platforms/pseries/Kconfig
b/arch/powerpc/platforms/pseries/Kconfig
index bec90fb..f669323 100644
--- a/arch/powerpc
cmpxchg_release is light-wight than cmpxchg, On some arch like ppc,
barrier impact the performace too much.
Suggested-by: Boqun Feng
Signed-off-by: Pan Xinhui
---
kernel/locking/qspinlock_paravirt.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/locking
pseries has PowerVM support, the default option is Y.
Signed-off-by: Pan Xinhui
---
arch/powerpc/kernel/Makefile | 1 +
arch/powerpc/platforms/pseries/Kconfig | 8
2 files changed, 9 insertions(+)
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index
[patch]locking/pvqspinlock: Add lock holder CPU argument to pv_wait() from
Waiman
Some other patches in Waiman's "locking/pvqspinlock: Fix missed PV wakeup &
support PPC" are not applied for now.
Pan Xinhui (6):
qspinlock: powerpc support qspinlock
powerpc: pseries/Kconfig: Add
pv-qspinlock core has pv_wait/pv_kick which will give a better
performace by yielding and kicking cpu at some cases.
lets support them by adding two corresponding helper functions.
Signed-off-by: Pan Xinhui
---
arch/powerpc/include/asm/spinlock.h | 4
arch/powerpc/lib/locks.c
Base code to enable qspinlock on powerpc. this patch add some #ifdef
here and there. Although there is no paravirt related code, we can
successfully build a qspinlock kernel after apply this patch.
Signed-off-by: Pan Xinhui
---
arch/powerpc/include/asm/qspinlock.h | 26
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