[Xen-devel] [PATCH 4/5] xen: use masking operation instead of test_bit for VPF bits

[Juergen Gross <jgross@xxxxxxxx>]

Use a bit mask for testing of a set bit instead of test_bit in case no
atomic operation is needed, as this will lead to smaller and more
effective code.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 xen/arch/x86/domctl.c  |  2 +-
 xen/arch/x86/hvm/hvm.c |  4 ++--
 xen/arch/x86/hvm/vpt.c |  2 +-
 xen/common/domain.c    |  4 ++--
 xen/common/domctl.c    |  8 ++++----
 xen/common/schedule.c  | 16 ++++++++--------
 6 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index 6172c0d..f8a559c 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -1213,7 +1213,7 @@ void arch_get_info_guest(struct vcpu *v, 
vcpu_guest_context_u c)
     c(flags = v->arch.vgc_flags & ~(VGCF_i387_valid|VGCF_in_kernel));
     if ( v->fpu_initialised )
         c(flags |= VGCF_i387_valid);
-    if ( !test_bit(_VPF_down, &v->pause_flags) )
+    if ( !(v->pause_flags & VPF_down) )
         c(flags |= VGCF_online);
     if ( !compat )
     {
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 6afc344..3fa2280 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -1728,7 +1728,7 @@ static int hvm_save_cpu_ctxt(struct domain *d, 
hvm_domain_context_t *h)
     {
         /* We don't need to save state for a vcpu that is down; the restore 
          * code will leave it down if there is nothing saved. */
-        if ( test_bit(_VPF_down, &v->pause_flags) ) 
+        if ( v->pause_flags & VPF_down )
             continue;
 
         /* Architecture-specific vmcs/vmcb bits */
@@ -2512,7 +2512,7 @@ void hvm_vcpu_down(struct vcpu *v)
     /* Any other VCPUs online? ... */
     domain_lock(d);
     for_each_vcpu ( d, v )
-        if ( !test_bit(_VPF_down, &v->pause_flags) )
+        if ( !(v->pause_flags & VPF_down) )
             online_count++;
     domain_unlock(d);
 
diff --git a/xen/arch/x86/hvm/vpt.c b/xen/arch/x86/hvm/vpt.c
index 0c8b22e..4fa6566 100644
--- a/xen/arch/x86/hvm/vpt.c
+++ b/xen/arch/x86/hvm/vpt.c
@@ -178,7 +178,7 @@ void pt_save_timer(struct vcpu *v)
     struct list_head *head = &v->arch.hvm_vcpu.tm_list;
     struct periodic_time *pt;
 
-    if ( test_bit(_VPF_blocked, &v->pause_flags) )
+    if ( v->pause_flags & VPF_blocked )
         return;
 
     spin_lock(&v->arch.hvm_vcpu.tm_lock);
diff --git a/xen/common/domain.c b/xen/common/domain.c
index cda60a9..7c362eb 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -1135,7 +1135,7 @@ int map_vcpu_info(struct vcpu *v, unsigned long gfn, 
unsigned offset)
         return -EINVAL;
 
     /* Run this command on yourself or on other offline VCPUS. */
-    if ( (v != current) && !test_bit(_VPF_down, &v->pause_flags) )
+    if ( (v != current) && !(v->pause_flags & VPF_down) )
         return -EINVAL;
 
     page = get_page_from_gfn(d, gfn, NULL, P2M_ALLOC);
@@ -1263,7 +1263,7 @@ long do_vcpu_op(int cmd, unsigned int vcpuid, 
XEN_GUEST_HANDLE_PARAM(void) arg)
         break;
 
     case VCPUOP_is_up:
-        rc = !test_bit(_VPF_down, &v->pause_flags);
+        rc = !(v->pause_flags & VPF_down);
         break;
 
     case VCPUOP_get_runstate_info:
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index 08de32d..46b967e 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -170,7 +170,7 @@ void getdomaininfo(struct domain *d, struct 
xen_domctl_getdomaininfo *info)
         vcpu_runstate_get(v, &runstate);
         cpu_time += runstate.time[RUNSTATE_running];
         info->max_vcpu_id = v->vcpu_id;
-        if ( !test_bit(_VPF_down, &v->pause_flags) )
+        if ( !(v->pause_flags & VPF_down) )
         {
             if ( !(v->pause_flags & VPF_blocked) )
                 flags &= ~XEN_DOMINF_blocked;
@@ -231,7 +231,7 @@ static unsigned int default_vcpu0_location(cpumask_t 
*online)
         rcu_read_lock(&domlist_read_lock);
         for_each_domain ( d )
             for_each_vcpu ( d, v )
-                if ( !test_bit(_VPF_down, &v->pause_flags)
+                if ( !(v->pause_flags & VPF_down)
                      && ((cpu = v->processor) < nr_cpus) )
                     cnt[cpu]++;
         rcu_read_unlock(&domlist_read_lock);
@@ -944,8 +944,8 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) 
u_domctl)
 
         vcpu_runstate_get(v, &runstate);
 
-        op->u.getvcpuinfo.online   = !test_bit(_VPF_down, &v->pause_flags);
-        op->u.getvcpuinfo.blocked  = test_bit(_VPF_blocked, &v->pause_flags);
+        op->u.getvcpuinfo.online   = !(v->pause_flags & VPF_down);
+        op->u.getvcpuinfo.blocked  = !!(v->pause_flags & VPF_blocked);
         op->u.getvcpuinfo.running  = v->is_running;
         op->u.getvcpuinfo.cpu_time = runstate.time[RUNSTATE_running];
         op->u.getvcpuinfo.cpu      = v->processor;
diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index 5ffa1a1..c5f640f 100644
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -119,7 +119,7 @@ static inline void vcpu_urgent_count_update(struct vcpu *v)
 
     if ( unlikely(v->is_urgent) )
     {
-        if ( !test_bit(_VPF_blocked, &v->pause_flags) ||
+        if ( !(v->pause_flags & VPF_blocked) ||
              !test_bit(v->vcpu_id, v->domain->poll_mask) )
         {
             v->is_urgent = 0;
@@ -128,8 +128,8 @@ static inline void vcpu_urgent_count_update(struct vcpu *v)
     }
     else
     {
-        if ( unlikely(test_bit(_VPF_blocked, &v->pause_flags) &&
-                      test_bit(v->vcpu_id, v->domain->poll_mask)) )
+        if ( unlikely(v->pause_flags & VPF_blocked) &&
+             unlikely(test_bit(v->vcpu_id, v->domain->poll_mask)) )
         {
             v->is_urgent = 1;
             atomic_inc(&per_cpu(schedule_data,v->processor).urgent_count);
@@ -418,7 +418,7 @@ void vcpu_wake(struct vcpu *v)
             vcpu_runstate_change(v, RUNSTATE_runnable, NOW());
         SCHED_OP(VCPU2OP(v), wake, v);
     }
-    else if ( !test_bit(_VPF_blocked, &v->pause_flags) )
+    else if ( !(v->pause_flags & VPF_blocked) )
     {
         if ( v->runstate.state == RUNSTATE_blocked )
             vcpu_runstate_change(v, RUNSTATE_offline, NOW());
@@ -595,7 +595,7 @@ void vcpu_force_reschedule(struct vcpu *v)
         set_bit(_VPF_migrating, &v->pause_flags);
     vcpu_schedule_unlock_irq(lock, v);
 
-    if ( test_bit(_VPF_migrating, &v->pause_flags) )
+    if ( v->pause_flags & VPF_migrating )
     {
         vcpu_sleep_nosync(v);
         vcpu_migrate(v);
@@ -763,7 +763,7 @@ static int vcpu_set_affinity(
 
     domain_update_node_affinity(v->domain);
 
-    if ( test_bit(_VPF_migrating, &v->pause_flags) )
+    if ( v->pause_flags & VPF_migrating )
     {
         vcpu_sleep_nosync(v);
         vcpu_migrate(v);
@@ -1285,7 +1285,7 @@ static void schedule(void)
 
     vcpu_runstate_change(
         prev,
-        (test_bit(_VPF_blocked, &prev->pause_flags) ? RUNSTATE_blocked :
+        ((prev->pause_flags & VPF_blocked) ? RUNSTATE_blocked :
          (vcpu_runnable(prev) ? RUNSTATE_runnable : RUNSTATE_offline)),
         now);
     prev->last_run_time = now;
@@ -1327,7 +1327,7 @@ void context_saved(struct vcpu *prev)
 
     SCHED_OP(VCPU2OP(prev), context_saved, prev);
 
-    if ( unlikely(test_bit(_VPF_migrating, &prev->pause_flags)) )
+    if ( unlikely(prev->pause_flags & VPF_migrating) )
         vcpu_migrate(prev);
 }
 
-- 
2.1.4


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