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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen-unstable] Wait queues, allowing conditional sleep in hypervisor context.
# HG changeset patch
# User Keir Fraser <keir@xxxxxxx>
# Date 1290012157 0
# Node ID c1b7aae86cf51c7a80925d050a3b7b3ef08e7cc2
# Parent deb438d43e79943643914f708b37354dc53f79f4
Wait queues, allowing conditional sleep in hypervisor context.
Signed-off-by: Keir Fraser <keir@xxxxxxx>
---
xen/arch/x86/domain.c | 2
xen/arch/x86/hvm/hvm.c | 3
xen/common/Makefile | 1
xen/common/domain.c | 5 +
xen/common/schedule.c | 5 +
xen/common/wait.c | 165 ++++++++++++++++++++++++++++++++++++++++++++++++
xen/include/xen/sched.h | 4 +
xen/include/xen/wait.h | 54 +++++++++++++++
8 files changed, 239 insertions(+)
diff -r deb438d43e79 -r c1b7aae86cf5 xen/arch/x86/domain.c
--- a/xen/arch/x86/domain.c Tue Nov 16 15:41:28 2010 +0000
+++ b/xen/arch/x86/domain.c Wed Nov 17 16:42:37 2010 +0000
@@ -33,6 +33,7 @@
#include <xen/pci.h>
#include <xen/paging.h>
#include <xen/cpu.h>
+#include <xen/wait.h>
#include <public/sysctl.h>
#include <asm/regs.h>
#include <asm/mc146818rtc.h>
@@ -77,6 +78,7 @@ static void continue_idle_domain(struct
static void continue_nonidle_domain(struct vcpu *v)
{
+ check_wakeup_from_wait();
reset_stack_and_jump(ret_from_intr);
}
diff -r deb438d43e79 -r c1b7aae86cf5 xen/arch/x86/hvm/hvm.c
--- a/xen/arch/x86/hvm/hvm.c Tue Nov 16 15:41:28 2010 +0000
+++ b/xen/arch/x86/hvm/hvm.c Wed Nov 17 16:42:37 2010 +0000
@@ -34,6 +34,7 @@
#include <xen/event.h>
#include <xen/paging.h>
#include <xen/cpu.h>
+#include <xen/wait.h>
#include <asm/shadow.h>
#include <asm/hap.h>
#include <asm/current.h>
@@ -282,6 +283,8 @@ void hvm_do_resume(struct vcpu *v)
ioreq_t *p;
pt_restore_timer(v);
+
+ check_wakeup_from_wait();
/* NB. Optimised for common case (p->state == STATE_IOREQ_NONE). */
p = get_ioreq(v);
diff -r deb438d43e79 -r c1b7aae86cf5 xen/common/Makefile
--- a/xen/common/Makefile Tue Nov 16 15:41:28 2010 +0000
+++ b/xen/common/Makefile Wed Nov 17 16:42:37 2010 +0000
@@ -31,6 +31,7 @@ obj-y += trace.o
obj-y += trace.o
obj-y += version.o
obj-y += vsprintf.o
+obj-y += wait.o
obj-y += xmalloc_tlsf.o
obj-y += rcupdate.o
obj-y += tmem.o
diff -r deb438d43e79 -r c1b7aae86cf5 xen/common/domain.c
--- a/xen/common/domain.c Tue Nov 16 15:41:28 2010 +0000
+++ b/xen/common/domain.c Wed Nov 17 16:42:37 2010 +0000
@@ -27,6 +27,7 @@
#include <xen/percpu.h>
#include <xen/multicall.h>
#include <xen/rcupdate.h>
+#include <xen/wait.h>
#include <acpi/cpufreq/cpufreq.h>
#include <asm/debugger.h>
#include <public/sched.h>
@@ -162,10 +163,12 @@ struct vcpu *alloc_vcpu(
v->vcpu_info = ((vcpu_id < XEN_LEGACY_MAX_VCPUS)
? (vcpu_info_t *)&shared_info(d, vcpu_info[vcpu_id])
: &dummy_vcpu_info);
+ init_waitqueue_vcpu(v);
}
if ( sched_init_vcpu(v, cpu_id) != 0 )
{
+ destroy_waitqueue_vcpu(v);
free_vcpu_struct(v);
return NULL;
}
@@ -173,6 +176,7 @@ struct vcpu *alloc_vcpu(
if ( vcpu_initialise(v) != 0 )
{
sched_destroy_vcpu(v);
+ destroy_waitqueue_vcpu(v);
free_vcpu_struct(v);
return NULL;
}
@@ -617,6 +621,7 @@ static void complete_domain_destroy(stru
tasklet_kill(&v->continue_hypercall_tasklet);
vcpu_destroy(v);
sched_destroy_vcpu(v);
+ destroy_waitqueue_vcpu(v);
}
grant_table_destroy(d);
diff -r deb438d43e79 -r c1b7aae86cf5 xen/common/schedule.c
--- a/xen/common/schedule.c Tue Nov 16 15:41:28 2010 +0000
+++ b/xen/common/schedule.c Wed Nov 17 16:42:37 2010 +0000
@@ -1396,6 +1396,11 @@ void sched_tick_resume(void)
SCHED_OP(sched, tick_resume, cpu);
}
+void wait(void)
+{
+ schedule();
+}
+
#ifdef CONFIG_COMPAT
#include "compat/schedule.c"
#endif
diff -r deb438d43e79 -r c1b7aae86cf5 xen/common/wait.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/xen/common/wait.c Wed Nov 17 16:42:37 2010 +0000
@@ -0,0 +1,165 @@
+/******************************************************************************
+ * wait.c
+ *
+ * Sleep in hypervisor context for some event to occur.
+ */
+
+#include <xen/config.h>
+#include <xen/sched.h>
+#include <xen/wait.h>
+
+struct waitqueue_vcpu {
+ struct list_head list;
+ struct vcpu *vcpu;
+#ifdef CONFIG_X86
+ /*
+ * Xen/x86 does not have per-vcpu hypervisor stacks. So we must save the
+ * hypervisor context before sleeping (descheduling), setjmp/longjmp-style.
+ */
+ void *esp;
+ char stack[1500];
+#endif
+};
+
+int init_waitqueue_vcpu(struct vcpu *v)
+{
+ struct waitqueue_vcpu *wqv;
+
+ wqv = xmalloc(struct waitqueue_vcpu);
+ if ( wqv == NULL )
+ return -ENOMEM;
+
+ memset(wqv, 0, sizeof(*wqv));
+ INIT_LIST_HEAD(&wqv->list);
+ wqv->vcpu = v;
+
+ v->waitqueue_vcpu = wqv;
+
+ return 0;
+}
+
+void destroy_waitqueue_vcpu(struct vcpu *v)
+{
+ struct waitqueue_vcpu *wqv;
+
+ wqv = v->waitqueue_vcpu;
+ if ( wqv == NULL )
+ return;
+
+ BUG_ON(!list_empty(&wqv->list));
+ xfree(wqv);
+
+ v->waitqueue_vcpu = NULL;
+}
+
+void init_waitqueue_head(struct waitqueue_head *wq)
+{
+ spin_lock_init(&wq->lock);
+ INIT_LIST_HEAD(&wq->list);
+}
+
+void wake_up(struct waitqueue_head *wq)
+{
+ struct waitqueue_vcpu *wqv;
+
+ spin_lock(&wq->lock);
+
+ while ( !list_empty(&wq->list) )
+ {
+ wqv = list_entry(wq->list.next, struct waitqueue_vcpu, list);
+ list_del_init(&wqv->list);
+ vcpu_unpause(wqv->vcpu);
+ }
+
+ spin_unlock(&wq->lock);
+}
+
+#ifdef CONFIG_X86
+
+static void __prepare_to_wait(struct waitqueue_vcpu *wqv)
+{
+ char *cpu_info = (char *)get_cpu_info();
+ asm volatile (
+#ifdef CONFIG_X86_64
+ "push %%rax; push %%rbx; push %%rcx; push %%rdx; push %%rdi; "
+ "push %%rbp; push %%r8; push %%r9; push %%r10; push %%r11; "
+ "push %%r12; push %%r13; push %%r14; push %%r15; call 1f; "
+ "1: mov 80(%%rsp),%%rdi; mov 96(%%rsp),%%rcx; mov %%rsp,%%rsi; "
+ "sub %%rsi,%%rcx; rep movsb; mov %%rsp,%%rsi; pop %%rax; "
+ "pop %%r15; pop %%r14; pop %%r13; pop %%r12; "
+ "pop %%r11; pop %%r10; pop %%r9; pop %%r8; "
+ "pop %%rbp; pop %%rdi; pop %%rdx; pop %%rcx; pop %%rbx; pop %%rax"
+#else
+ "push %%eax; push %%ebx; push %%ecx; push %%edx; push %%edi; "
+ "push %%ebp; call 1f; "
+ "1: mov 8(%%esp),%%edi; mov 16(%%esp),%%ecx; mov %%esp,%%esi; "
+ "sub %%esi,%%ecx; rep movsb; mov %%esp,%%esi; pop %%eax; "
+ "pop %%ebp; pop %%edi; pop %%edx; pop %%ecx; pop %%ebx; pop %%eax"
+#endif
+ : "=S" (wqv->esp)
+ : "c" (cpu_info), "D" (wqv->stack)
+ : "memory" );
+ BUG_ON((cpu_info - (char *)wqv->esp) > sizeof(wqv->stack));
+}
+
+static void __finish_wait(struct waitqueue_vcpu *wqv)
+{
+ wqv->esp = NULL;
+}
+
+void check_wakeup_from_wait(void)
+{
+ struct waitqueue_vcpu *wqv = current->waitqueue_vcpu;
+
+ ASSERT(list_empty(&wqv->list));
+
+ if ( likely(wqv->esp == NULL) )
+ return;
+
+ asm volatile (
+ "mov %1,%%"__OP"sp; rep movsb; jmp *(%%"__OP"sp)"
+ : : "S" (wqv->stack), "D" (wqv->esp),
+ "c" ((char *)get_cpu_info() - (char *)wqv->esp)
+ : "memory" );
+}
+
+#else /* !CONFIG_X86 */
+
+#define __prepare_to_wait(wqv) ((void)0)
+#define __finish_wait(wqv) ((void)0)
+
+#endif
+
+void prepare_to_wait(struct waitqueue_head *wq)
+{
+ struct vcpu *curr = current;
+ struct waitqueue_vcpu *wqv = curr->waitqueue_vcpu;
+
+ ASSERT(list_empty(&wqv->list));
+
+ spin_lock(&wq->lock);
+ list_add_tail(&wqv->list, &wq->list);
+ vcpu_pause_nosync(curr);
+ spin_unlock(&wq->lock);
+
+ __prepare_to_wait(wqv);
+}
+
+void finish_wait(struct waitqueue_head *wq)
+{
+ struct vcpu *curr = current;
+ struct waitqueue_vcpu *wqv = curr->waitqueue_vcpu;
+
+ __finish_wait(wqv);
+
+ if ( list_empty(&wqv->list) )
+ return;
+
+ spin_lock(&wq->lock);
+ if ( !list_empty(&wqv->list) )
+ {
+ list_del_init(&wqv->list);
+ vcpu_unpause(curr);
+ }
+ spin_unlock(&wq->lock);
+}
diff -r deb438d43e79 -r c1b7aae86cf5 xen/include/xen/sched.h
--- a/xen/include/xen/sched.h Tue Nov 16 15:41:28 2010 +0000
+++ b/xen/include/xen/sched.h Wed Nov 17 16:42:37 2010 +0000
@@ -80,6 +80,8 @@ void evtchn_destroy(struct domain *d); /
void evtchn_destroy(struct domain *d); /* from domain_kill */
void evtchn_destroy_final(struct domain *d); /* from complete_domain_destroy */
+struct waitqueue_vcpu;
+
struct vcpu
{
int vcpu_id;
@@ -172,6 +174,8 @@ struct vcpu
/* Multicall information. */
struct mc_state mc_state;
+
+ struct waitqueue_vcpu *waitqueue_vcpu;
struct arch_vcpu arch;
};
diff -r deb438d43e79 -r c1b7aae86cf5 xen/include/xen/wait.h
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/xen/include/xen/wait.h Wed Nov 17 16:42:37 2010 +0000
@@ -0,0 +1,54 @@
+/******************************************************************************
+ * wait.h
+ *
+ * Sleep in hypervisor context for some event to occur.
+ */
+
+#ifndef __XEN_WAIT_H__
+#define __XEN_WAIT_H__
+
+#include <xen/types.h>
+#include <xen/list.h>
+#include <xen/spinlock.h>
+
+struct waitqueue_head {
+ spinlock_t lock;
+ struct list_head list;
+};
+
+/* Statically define and initialise a waitqueue. */
+#define DEFINE_WAITQUEUE_HEAD(name) \
+ struct waitqueue_head name = { \
+ .lock = SPIN_LOCK_UNLOCKED, \
+ .list = LIST_HEAD_INIT((name).list) \
+ }
+
+/* Dynamically initialise a waitqueue. */
+void init_waitqueue_head(struct waitqueue_head *wq);
+
+/* Wake all VCPUs waiting on specified waitqueue. */
+void wake_up(struct waitqueue_head *wq);
+
+/* Wait on specified waitqueue until @condition is true. */
+#define wait_event(wq, condition) \
+do { \
+ if ( condition ) \
+ break; \
+ for ( ; ; ) { \
+ prepare_to_wait(&wq); \
+ if ( condition ) \
+ break; \
+ wait(); \
+ } \
+ finish_wait(&wq); \
+} while (0)
+
+/* Private functions. */
+int init_waitqueue_vcpu(struct vcpu *v);
+void destroy_waitqueue_vcpu(struct vcpu *v);
+void prepare_to_wait(struct waitqueue_head *wq);
+void wait(void);
+void finish_wait(struct waitqueue_head *wq);
+void check_wakeup_from_wait(void);
+
+#endif /* __XEN_WAIT_H__ */
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