Re: [PATCH RFC V9 9/19] Split out rate limiting from jump_label.h
On 06/03/2013 09:26 PM, Konrad Rzeszutek Wilk wrote:
On Sun, Jun 02, 2013 at 12:54:22AM +0530, Raghavendra K T wrote:
Split jumplabel ratelimit
I would change the title a bit, perhaps prefix it with: "jump_label: "
From: Andrew Jones
Commit b202952075f62603bea9bfb6ebc6b0420db11949 introduced rate limiting
Also please add right after the git id this:
("perf, core: Rate limit perf_sched_events jump_label patching")
Agreed.
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Re: [PATCH RFC V9 12/19] xen: Enable PV ticketlocks on HVM Xen
On 06/03/2013 09:27 PM, Konrad Rzeszutek Wilk wrote: On Sun, Jun 02, 2013 at 12:55:03AM +0530, Raghavendra K T wrote: xen: Enable PV ticketlocks on HVM Xen There is more to it. You should also revert 70dd4998cb85f0ecd6ac892cc7232abefa432efb Yes, true. Do you expect the revert to be folded into this patch itself? ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [PATCH RFC V9 5/19] xen/pvticketlock: Xen implementation for PV ticket locks
On 06/03/2013 09:33 PM, Konrad Rzeszutek Wilk wrote:
On Sat, Jun 01, 2013 at 12:23:14PM -0700, Raghavendra K T wrote:
xen/pvticketlock: Xen implementation for PV ticket locks
From: Jeremy Fitzhardinge
Replace the old Xen implementation of PV spinlocks with and implementation
of xen_lock_spinning and xen_unlock_kick.
xen_lock_spinning simply registers the cpu in its entry in lock_waiting,
adds itself to the waiting_cpus set, and blocks on an event channel
until the channel becomes pending.
xen_unlock_kick searches the cpus in waiting_cpus looking for the one
which next wants this lock with the next ticket, if any. If found,
it kicks it by making its event channel pending, which wakes it up.
We need to make sure interrupts are disabled while we're relying on the
contents of the per-cpu lock_waiting values, otherwise an interrupt
handler could come in, try to take some other lock, block, and overwrite
our values.
Raghu: use function + enum instead of macro, cmpxchg for zero status reset
Signed-off-by: Jeremy Fitzhardinge
Reviewed-by: Konrad Rzeszutek Wilk
Signed-off-by: Raghavendra K T
---
arch/x86/xen/spinlock.c | 347 +++
1 file changed, 78 insertions(+), 269 deletions(-)
diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
index d6481a9..860e190 100644
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -16,45 +16,44 @@
#include "xen-ops.h"
#include "debugfs.h"
-#ifdef CONFIG_XEN_DEBUG_FS
-static struct xen_spinlock_stats
-{
- u64 taken;
- u32 taken_slow;
- u32 taken_slow_nested;
- u32 taken_slow_pickup;
- u32 taken_slow_spurious;
- u32 taken_slow_irqenable;
+enum xen_contention_stat {
+ TAKEN_SLOW,
+ TAKEN_SLOW_PICKUP,
+ TAKEN_SLOW_SPURIOUS,
+ RELEASED_SLOW,
+ RELEASED_SLOW_KICKED,
+ NR_CONTENTION_STATS
+};
- u64 released;
- u32 released_slow;
- u32 released_slow_kicked;
+#ifdef CONFIG_XEN_DEBUG_FS
#define HISTO_BUCKETS 30
- u32 histo_spin_total[HISTO_BUCKETS+1];
- u32 histo_spin_spinning[HISTO_BUCKETS+1];
+static struct xen_spinlock_stats
+{
+ u32 contention_stats[NR_CONTENTION_STATS];
u32 histo_spin_blocked[HISTO_BUCKETS+1];
-
- u64 time_total;
- u64 time_spinning;
u64 time_blocked;
} spinlock_stats;
static u8 zero_stats;
-static unsigned lock_timeout = 1 << 10;
-#define TIMEOUT lock_timeout
-
static inline void check_zero(void)
{
- if (unlikely(zero_stats)) {
- memset(&spinlock_stats, 0, sizeof(spinlock_stats));
- zero_stats = 0;
+ u8 ret;
+ u8 old = ACCESS_ONCE(zero_stats);
+ if (unlikely(old)) {
+ ret = cmpxchg(&zero_stats, old, 0);
+ /* This ensures only one fellow resets the stat */
+ if (ret == old)
+ memset(&spinlock_stats, 0, sizeof(spinlock_stats));
}
}
-#define ADD_STATS(elem, val) \
- do { check_zero(); spinlock_stats.elem += (val); } while(0)
+static inline void add_stats(enum xen_contention_stat var, u32 val)
+{
+ check_zero();
+ spinlock_stats.contention_stats[var] += val;
+}
static inline u64 spin_time_start(void)
{
@@ -73,22 +72,6 @@ static void __spin_time_accum(u64 delta, u32 *array)
array[HISTO_BUCKETS]++;
}
-static inline void spin_time_accum_spinning(u64 start)
-{
- u32 delta = xen_clocksource_read() - start;
-
- __spin_time_accum(delta, spinlock_stats.histo_spin_spinning);
- spinlock_stats.time_spinning += delta;
-}
-
-static inline void spin_time_accum_total(u64 start)
-{
- u32 delta = xen_clocksource_read() - start;
-
- __spin_time_accum(delta, spinlock_stats.histo_spin_total);
- spinlock_stats.time_total += delta;
-}
-
static inline void spin_time_accum_blocked(u64 start)
{
u32 delta = xen_clocksource_read() - start;
@@ -98,19 +81,15 @@ static inline void spin_time_accum_blocked(u64 start)
}
#else /* !CONFIG_XEN_DEBUG_FS */
#define TIMEOUT (1 << 10)
-#define ADD_STATS(elem, val) do { (void)(val); } while(0)
+static inline void add_stats(enum xen_contention_stat var, u32 val)
+{
+}
static inline u64 spin_time_start(void)
{
return 0;
}
-static inline void spin_time_accum_total(u64 start)
-{
-}
-static inline void spin_time_accum_spinning(u64 start)
-{
-}
static inline void spin_time_accum_blocked(u64 start)
{
}
@@ -133,229 +112,82 @@ typedef u16 xen_spinners_t;
asm(LOCK_PREFIX " decw %0" : "+m" ((xl)->spinners) : : "memory");
#endif
-struct xen_spinlock {
- unsigned char lock; /* 0 -> free; 1 -> locked */
- xen_spinners_t spinners;/* count of waiting cpus */
+struct xen_lock_waiting {
+ struct arch_spinlock *lock;
+ __ticket_t want;
};
static DEFINE_PER_CPU(int, lock_kicker_irq) = -1;
+static DEFINE_PER_
Re: [PATCH RFC V9 18/19] Documentation/kvm : Add documentation on Hypercalls and features used for PV spinlock
On 06/03/2013 09:34 PM, Konrad Rzeszutek Wilk wrote: On Sun, Jun 02, 2013 at 12:56:24AM +0530, Raghavendra K T wrote: Documentation/kvm : Add documentation on Hypercalls and features used for PV spinlock From: Raghavendra K T KVM_HC_KICK_CPU hypercall added to wakeup halted vcpu in paravirtual spinlock enabled guest. KVM_FEATURE_PV_UNHALT enables guest to check whether pv spinlock can be enabled in guest. Thanks Vatsa for rewriting KVM_HC_KICK_CPU Signed-off-by: Srivatsa Vaddagiri Signed-off-by: Raghavendra K T --- Documentation/virtual/kvm/cpuid.txt |4 Documentation/virtual/kvm/hypercalls.txt | 13 + 2 files changed, 17 insertions(+) diff --git a/Documentation/virtual/kvm/cpuid.txt b/Documentation/virtual/kvm/cpuid.txt index 83afe65..654f43c 100644 --- a/Documentation/virtual/kvm/cpuid.txt +++ b/Documentation/virtual/kvm/cpuid.txt @@ -43,6 +43,10 @@ KVM_FEATURE_CLOCKSOURCE2 || 3 || kvmclock available at msrs KVM_FEATURE_ASYNC_PF || 4 || async pf can be enabled by || || writing to msr 0x4b564d02 -- +KVM_FEATURE_PV_UNHALT || 6 || guest checks this feature bit + || || before enabling paravirtualized + || || spinlock support. +-- KVM_FEATURE_CLOCKSOURCE_STABLE_BIT ||24 || host will warn if no guest-side || || per-cpu warps are expected in || || kvmclock. diff --git a/Documentation/virtual/kvm/hypercalls.txt b/Documentation/virtual/kvm/hypercalls.txt index ea113b5..2a4da11 100644 --- a/Documentation/virtual/kvm/hypercalls.txt +++ b/Documentation/virtual/kvm/hypercalls.txt @@ -64,3 +64,16 @@ Purpose: To enable communication between the hypervisor and guest there is a shared page that contains parts of supervisor visible register state. The guest can map this shared page to access its supervisor register through memory using this hypercall. + +5. KVM_HC_KICK_CPU + +Architecture: x86 +Status: active +Purpose: Hypercall used to wakeup a vcpu from HLT state +Usage example : A vcpu of a paravirtualized guest that is busywaiting in guest +kernel mode for an event to occur (ex: a spinlock to become available) can +execute HLT instruction once it has busy-waited for more than a threshold +time-interval. Execution of HLT instruction would cause the hypervisor to put +the vcpu to sleep until occurence of an appropriate event. Another vcpu of the +same guest can wakeup the sleeping vcpu by issuing KVM_HC_KICK_CPU hypercall, +specifying APIC ID of the vcpu to be wokenup. woken up. Yep. :) ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [PATCH RFC V9 19/19] kvm hypervisor: Add directed yield in vcpu block path
On 06/03/2013 09:35 PM, Konrad Rzeszutek Wilk wrote:
On Sun, Jun 02, 2013 at 12:56:45AM +0530, Raghavendra K T wrote:
kvm hypervisor: Add directed yield in vcpu block path
From: Raghavendra K T
We use the improved PLE handler logic in vcpu block patch for
scheduling rather than plain schedule, so that we can make
intelligent decisions
You are missing '.' there, and
Yep.
Signed-off-by: Raghavendra K T
---
arch/ia64/include/asm/kvm_host.h|5 +
arch/powerpc/include/asm/kvm_host.h |5 +
arch/s390/include/asm/kvm_host.h|5 +
arch/x86/include/asm/kvm_host.h |2 +-
arch/x86/kvm/x86.c |8
include/linux/kvm_host.h|2 +-
virt/kvm/kvm_main.c |6 --
7 files changed, 29 insertions(+), 4 deletions(-)
diff --git a/arch/ia64/include/asm/kvm_host.h b/arch/ia64/include/asm/kvm_host.h
index 989dd3f..999ab15 100644
--- a/arch/ia64/include/asm/kvm_host.h
+++ b/arch/ia64/include/asm/kvm_host.h
@@ -595,6 +595,11 @@ int kvm_emulate_halt(struct kvm_vcpu *vcpu);
int kvm_pal_emul(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run);
void kvm_sal_emul(struct kvm_vcpu *vcpu);
+static inline void kvm_do_schedule(struct kvm_vcpu *vcpu)
+{
+ schedule();
+}
+
#define __KVM_HAVE_ARCH_VM_ALLOC 1
struct kvm *kvm_arch_alloc_vm(void);
void kvm_arch_free_vm(struct kvm *kvm);
diff --git a/arch/powerpc/include/asm/kvm_host.h
b/arch/powerpc/include/asm/kvm_host.h
index af326cd..1aeecc0 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -628,4 +628,9 @@ struct kvm_vcpu_arch {
#define __KVM_HAVE_ARCH_WQP
#define __KVM_HAVE_CREATE_DEVICE
+static inline void kvm_do_schedule(struct kvm_vcpu *vcpu)
+{
+ schedule();
+}
+
#endif /* __POWERPC_KVM_HOST_H__ */
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 16bd5d1..db09a56 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -266,4 +266,9 @@ struct kvm_arch{
};
extern int sie64a(struct kvm_s390_sie_block *, u64 *);
+static inline void kvm_do_schedule(struct kvm_vcpu *vcpu)
+{
+ schedule();
+}
+
#endif
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 95702de..72ff791 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1042,5 +1042,5 @@ int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct
msr_data *msr_info);
int kvm_pmu_read_pmc(struct kvm_vcpu *vcpu, unsigned pmc, u64 *data);
void kvm_handle_pmu_event(struct kvm_vcpu *vcpu);
void kvm_deliver_pmi(struct kvm_vcpu *vcpu);
-
+void kvm_do_schedule(struct kvm_vcpu *vcpu);
#endif /* _ASM_X86_KVM_HOST_H */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b963c86..d26c4be 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7281,6 +7281,14 @@ bool kvm_arch_can_inject_async_page_present(struct
kvm_vcpu *vcpu)
kvm_x86_ops->interrupt_allowed(vcpu);
}
+void kvm_do_schedule(struct kvm_vcpu *vcpu)
+{
+ /* We try to yield to a kikced vcpu else do a schedule */
s/kikced/kicked/
:(. Thanks .. will change that.
[...]
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Re: [PATCH RFC V9 16/19] kvm : Paravirtual ticketlocks support for linux guests running on KVM hypervisor
On 06/03/2013 09:30 PM, Konrad Rzeszutek Wilk wrote:
On Sun, Jun 02, 2013 at 12:55:57AM +0530, Raghavendra K T wrote:
kvm : Paravirtual ticketlocks support for linux guests running on KVM hypervisor
From: Srivatsa Vaddagiri
During smp_boot_cpus paravirtualied KVM guest detects if the hypervisor has
required feature (KVM_FEATURE_PV_UNHALT) to support pv-ticketlocks. If so,
support for pv-ticketlocks is registered via pv_lock_ops.
Use KVM_HC_KICK_CPU hypercall to wakeup waiting/halted vcpu.
Signed-off-by: Srivatsa Vaddagiri
Signed-off-by: Suzuki Poulose
[Raghu: check_zero race fix, enum for kvm_contention_stat
jumplabel related changes ]
Signed-off-by: Raghavendra K T
---
arch/x86/include/asm/kvm_para.h | 14 ++
arch/x86/kernel/kvm.c | 256 +++
2 files changed, 268 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
index 695399f..427afcb 100644
--- a/arch/x86/include/asm/kvm_para.h
+++ b/arch/x86/include/asm/kvm_para.h
@@ -118,10 +118,20 @@ void kvm_async_pf_task_wait(u32 token);
void kvm_async_pf_task_wake(u32 token);
u32 kvm_read_and_reset_pf_reason(void);
extern void kvm_disable_steal_time(void);
-#else
-#define kvm_guest_init() do { } while (0)
+
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+void __init kvm_spinlock_init(void);
+#else /* !CONFIG_PARAVIRT_SPINLOCKS */
+static inline void kvm_spinlock_init(void)
+{
+}
+#endif /* CONFIG_PARAVIRT_SPINLOCKS */
+
+#else /* CONFIG_KVM_GUEST */
+#define kvm_guest_init() do {} while (0)
#define kvm_async_pf_task_wait(T) do {} while(0)
#define kvm_async_pf_task_wake(T) do {} while(0)
+
static inline u32 kvm_read_and_reset_pf_reason(void)
{
return 0;
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index cd6d9a5..2715b92 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -34,6 +34,7 @@
#include
#include
#include
+#include
#include
#include
#include
@@ -419,6 +420,7 @@ static void __init kvm_smp_prepare_boot_cpu(void)
WARN_ON(kvm_register_clock("primary cpu clock"));
kvm_guest_cpu_init();
native_smp_prepare_boot_cpu();
+ kvm_spinlock_init();
}
static void __cpuinit kvm_guest_cpu_online(void *dummy)
@@ -523,3 +525,257 @@ static __init int activate_jump_labels(void)
return 0;
}
arch_initcall(activate_jump_labels);
+
+/* Kick a cpu by its apicid. Used to wake up a halted vcpu */
+void kvm_kick_cpu(int cpu)
+{
+ int apicid;
+
+ apicid = per_cpu(x86_cpu_to_apicid, cpu);
+ kvm_hypercall1(KVM_HC_KICK_CPU, apicid);
+}
+
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+
+enum kvm_contention_stat {
+ TAKEN_SLOW,
+ TAKEN_SLOW_PICKUP,
+ RELEASED_SLOW,
+ RELEASED_SLOW_KICKED,
+ NR_CONTENTION_STATS
+};
+
+#ifdef CONFIG_KVM_DEBUG_FS
+#define HISTO_BUCKETS 30
+
+static struct kvm_spinlock_stats
+{
+ u32 contention_stats[NR_CONTENTION_STATS];
+ u32 histo_spin_blocked[HISTO_BUCKETS+1];
+ u64 time_blocked;
+} spinlock_stats;
+
+static u8 zero_stats;
+
+static inline void check_zero(void)
+{
+ u8 ret;
+ u8 old;
+
+ old = ACCESS_ONCE(zero_stats);
+ if (unlikely(old)) {
+ ret = cmpxchg(&zero_stats, old, 0);
+ /* This ensures only one fellow resets the stat */
+ if (ret == old)
+ memset(&spinlock_stats, 0, sizeof(spinlock_stats));
+ }
+}
+
+static inline void add_stats(enum kvm_contention_stat var, u32 val)
+{
+ check_zero();
+ spinlock_stats.contention_stats[var] += val;
+}
+
+
+static inline u64 spin_time_start(void)
+{
+ return sched_clock();
+}
+
+static void __spin_time_accum(u64 delta, u32 *array)
+{
+ unsigned index;
+
+ index = ilog2(delta);
+ check_zero();
+
+ if (index < HISTO_BUCKETS)
+ array[index]++;
+ else
+ array[HISTO_BUCKETS]++;
+}
+
+static inline void spin_time_accum_blocked(u64 start)
+{
+ u32 delta;
+
+ delta = sched_clock() - start;
+ __spin_time_accum(delta, spinlock_stats.histo_spin_blocked);
+ spinlock_stats.time_blocked += delta;
+}
+
+static struct dentry *d_spin_debug;
+static struct dentry *d_kvm_debug;
+
+struct dentry *kvm_init_debugfs(void)
+{
+ d_kvm_debug = debugfs_create_dir("kvm", NULL);
+ if (!d_kvm_debug)
+ printk(KERN_WARNING "Could not create 'kvm' debugfs
directory\n");
+
+ return d_kvm_debug;
+}
+
+static int __init kvm_spinlock_debugfs(void)
+{
+ struct dentry *d_kvm;
+
+ d_kvm = kvm_init_debugfs();
+ if (d_kvm == NULL)
+ return -ENOMEM;
+
+ d_spin_debug = debugfs_create_dir("spinlocks", d_kvm);
+
+ debugfs_create_u8("zero_stats", 0644, d_spin_debug, &zero_stats);
+
+ debugfs_create_u32("taken_slow", 0444, d_spin_debug,
+ &spinlock_stats.contention_stats[TAKEN_SLOW]);
+ debugf
Re: [PATCH 2/2] xen: remove bm_rld_set of xen_processor_flags
>>> On 04.06.13 at 10:05, liguang wrote:
> bm_rld_set seems obsolete now
>
> Signed-off-by: liguang
> ---
> include/xen/interface/platform.h |1 -
> 1 files changed, 0 insertions(+), 1 deletions(-)
>
> diff --git a/include/xen/interface/platform.h
> b/include/xen/interface/platform.h
> index c57d5f6..733 100644
> --- a/include/xen/interface/platform.h
> +++ b/include/xen/interface/platform.h
> @@ -240,7 +240,6 @@ struct xen_processor_flags {
> uint32_t bm_check:1;
> uint32_t has_cst:1;
> uint32_t power_setup_done:1;
> - uint32_t bm_rld_set:1;
> };
>
> struct xen_processor_power {
Any such patch would need to be submitted against the master copy
of the header (in the Xen repo), and by recognizing that you'd also
notice that this is part of a public ABI, and hence can't be removed,
but at best can be documented as obsolete. Of course you'd first
need to check whether the hypervisor makes any use of that bit
when passed down from Dom0.
Jan
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Re: [PATCH RFC V9 0/19] Paravirtualized ticket spinlocks
On 06/02/2013 01:44 AM, Andi Kleen wrote: FWIW I use the paravirt spinlock ops for adding lock elision to the spinlocks. This needs to be done at the top level (so the level you're removing) However I don't like the pv mechanism very much and would be fine with using an static key hook in the main path like I do for all the other lock types. It also uses interrupt ops patching, for that it would be still needed though. Hi Andi, IIUC, you are okay with the current approach overall right? ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [PATCH RFC V9 12/19] xen: Enable PV ticketlocks on HVM Xen
On Tue, Jun 04, 2013 at 12:46:53PM +0530, Raghavendra K T wrote: > On 06/03/2013 09:27 PM, Konrad Rzeszutek Wilk wrote: > >On Sun, Jun 02, 2013 at 12:55:03AM +0530, Raghavendra K T wrote: > >>xen: Enable PV ticketlocks on HVM Xen > > > >There is more to it. You should also revert > >70dd4998cb85f0ecd6ac892cc7232abefa432efb > > > > Yes, true. Do you expect the revert to be folded into this patch itself? > I can do them. I would drop this patch and just mention in the cover letter that Konrad would have to revert two git commits to re-enable it on PVHVM. ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [PATCH RFC V9 12/19] xen: Enable PV ticketlocks on HVM Xen
On 06/04/2013 08:14 PM, Konrad Rzeszutek Wilk wrote: On Tue, Jun 04, 2013 at 12:46:53PM +0530, Raghavendra K T wrote: On 06/03/2013 09:27 PM, Konrad Rzeszutek Wilk wrote: On Sun, Jun 02, 2013 at 12:55:03AM +0530, Raghavendra K T wrote: xen: Enable PV ticketlocks on HVM Xen There is more to it. You should also revert 70dd4998cb85f0ecd6ac892cc7232abefa432efb Yes, true. Do you expect the revert to be folded into this patch itself? I can do them. I would drop this patch and just mention in the cover letter that Konrad would have to revert two git commits to re-enable it on PVHVM. Thanks. will do that. ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
