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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] Fix lazy state switching when context-switching to/from the idle
ChangeSet 1.1390, 2005/03/29 22:10:08+01:00, kaf24@xxxxxxxxxxxxxxxxxxxx
Fix lazy state switching when context-switching to/from the idle
domain. Track which domain's state is on each CPU and, for each
domain, which CPUs are running on its page tables.
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
arch/ia64/xenmisc.c | 2
arch/x86/domain.c | 187 +++++++++++++++++++++--------------
arch/x86/domain_build.c | 4
arch/x86/mm.c | 13 --
arch/x86/shadow.c | 1
arch/x86/smp.c | 254 ++++++++++++++++++------------------------------
arch/x86/x86_32/mm.c | 16 ---
arch/x86/x86_64/mm.c | 17 ---
common/dom0_ops.c | 1
common/page_alloc.c | 7 -
common/schedule.c | 1
include/asm-x86/mm.h | 6 -
include/public/xen.h | 28 +++--
include/xen/sched.h | 38 ++++---
include/xen/smp.h | 9 +
15 files changed, 276 insertions(+), 308 deletions(-)
diff -Nru a/xen/arch/ia64/xenmisc.c b/xen/arch/ia64/xenmisc.c
--- a/xen/arch/ia64/xenmisc.c 2005-03-29 17:03:07 -05:00
+++ b/xen/arch/ia64/xenmisc.c 2005-03-29 17:03:07 -05:00
@@ -53,7 +53,7 @@
}
/* calls in xen/common code that are unused on ia64 */
-void synchronise_pagetables(unsigned long cpu_mask) { return; }
+void synchronise_execution_state(unsigned long cpu_mask) { }
int grant_table_create(struct domain *d) { return 0; }
void grant_table_destroy(struct domain *d)
diff -Nru a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
--- a/xen/arch/x86/domain.c 2005-03-29 17:03:07 -05:00
+++ b/xen/arch/x86/domain.c 2005-03-29 17:03:07 -05:00
@@ -45,13 +45,18 @@
static int opt_noreboot = 0;
boolean_param("noreboot", opt_noreboot);
+struct percpu_ctxt {
+ struct exec_domain *curr_ed;
+} __cacheline_aligned;
+static struct percpu_ctxt percpu_ctxt[NR_CPUS];
+
static void default_idle(void)
{
- __cli();
+ local_irq_disable();
if ( !softirq_pending(smp_processor_id()) )
safe_halt();
else
- __sti();
+ local_irq_enable();
}
static __attribute_used__ void idle_loop(void)
@@ -73,6 +78,8 @@
{
/* Just some sanity to ensure that the scheduler is set up okay. */
ASSERT(current->domain->id == IDLE_DOMAIN_ID);
+ percpu_ctxt[smp_processor_id()].curr_ed = current;
+ set_bit(smp_processor_id(), ¤t->domain->cpuset);
domain_unpause_by_systemcontroller(current->domain);
raise_softirq(SCHEDULE_SOFTIRQ);
do_softirq();
@@ -110,7 +117,7 @@
safe_halt();
}
- __sti();
+ local_irq_enable();
/* Ensure we are the boot CPU. */
if ( GET_APIC_ID(apic_read(APIC_ID)) != boot_cpu_physical_apicid )
@@ -307,10 +314,10 @@
struct pfn_info *mmfn_info;
struct domain *d = ed->domain;
- ASSERT(!pagetable_val(ed->arch.monitor_table)); /* we should only get
called once */
+ ASSERT(pagetable_val(ed->arch.monitor_table) == 0);
mmfn_info = alloc_domheap_page(NULL);
- ASSERT( mmfn_info );
+ ASSERT(mmfn_info != NULL);
mmfn = (unsigned long) (mmfn_info - frame_table);
mpl2e = (l2_pgentry_t *) map_domain_mem(mmfn << PAGE_SHIFT);
@@ -326,7 +333,7 @@
ed->arch.monitor_vtable = mpl2e;
- // map the phys_to_machine map into the Read-Only MPT space for this domain
+ /* Map the p2m map into the Read-Only MPT space for this domain. */
mpl2e[l2_table_offset(RO_MPT_VIRT_START)] =
mk_l2_pgentry(pagetable_val(ed->arch.phys_table) | __PAGE_HYPERVISOR);
@@ -578,19 +585,10 @@
: "=r" (__r) : "r" (value), "0" (__r) );\
__r; })
-static void switch_segments(
- struct xen_regs *regs, struct exec_domain *p, struct exec_domain *n)
+static void load_segments(struct exec_domain *p, struct exec_domain *n)
{
int all_segs_okay = 1;
- if ( !is_idle_task(p->domain) )
- {
- __asm__ __volatile__ ( "movl %%ds,%0" : "=m" (p->arch.user_ctxt.ds) );
- __asm__ __volatile__ ( "movl %%es,%0" : "=m" (p->arch.user_ctxt.es) );
- __asm__ __volatile__ ( "movl %%fs,%0" : "=m" (p->arch.user_ctxt.fs) );
- __asm__ __volatile__ ( "movl %%gs,%0" : "=m" (p->arch.user_ctxt.gs) );
- }
-
/* Either selector != 0 ==> reload. */
if ( unlikely(p->arch.user_ctxt.ds |
n->arch.user_ctxt.ds) )
@@ -654,7 +652,8 @@
if ( unlikely(!all_segs_okay) )
{
- unsigned long *rsp =
+ struct xen_regs *regs = get_execution_context();
+ unsigned long *rsp =
(n->arch.flags & TF_kernel_mode) ?
(unsigned long *)regs->rsp :
(unsigned long *)n->arch.kernel_sp;
@@ -689,6 +688,24 @@
}
}
+static void save_segments(struct exec_domain *p)
+{
+ __asm__ __volatile__ ( "movl %%ds,%0" : "=m" (p->arch.user_ctxt.ds) );
+ __asm__ __volatile__ ( "movl %%es,%0" : "=m" (p->arch.user_ctxt.es) );
+ __asm__ __volatile__ ( "movl %%fs,%0" : "=m" (p->arch.user_ctxt.fs) );
+ __asm__ __volatile__ ( "movl %%gs,%0" : "=m" (p->arch.user_ctxt.gs) );
+}
+
+static void clear_segments(void)
+{
+ __asm__ __volatile__ (
+ "movl %0,%%ds; "
+ "movl %0,%%es; "
+ "movl %0,%%fs; "
+ "movl %0,%%gs; swapgs; movl %0,%%gs"
+ : : "r" (0) );
+}
+
long do_switch_to_user(void)
{
struct xen_regs *regs = get_execution_context();
@@ -720,80 +737,96 @@
#elif defined(__i386__)
-#define switch_segments(_r, _p, _n) ((void)0)
+#define load_segments(_p, _n) ((void)0)
+#define save_segments(_p) ((void)0)
+#define clear_segments() ((void)0)
#endif
-/*
- * This special macro can be used to load a debugging register
- */
#define loaddebug(_ed,_reg) \
- __asm__("mov %0,%%db" #_reg \
- : /* no output */ \
- :"r" ((_ed)->debugreg[_reg]))
+ __asm__ __volatile__ ("mov %0,%%db" #_reg : : "r"
((_ed)->debugreg[_reg]))
-void context_switch(struct exec_domain *prev_p, struct exec_domain *next_p)
+static void __context_switch(void)
{
-#ifdef __i386__
- struct tss_struct *tss = init_tss + smp_processor_id();
-#endif
execution_context_t *stack_ec = get_execution_context();
+ unsigned int cpu = smp_processor_id();
+ struct exec_domain *p = percpu_ctxt[cpu].curr_ed;
+ struct exec_domain *n = current;
- __cli();
-
- /* Switch guest general-register state. */
- if ( !is_idle_task(prev_p->domain) )
+ if ( !is_idle_task(p->domain) )
{
- memcpy(&prev_p->arch.user_ctxt,
+ memcpy(&p->arch.user_ctxt,
stack_ec,
sizeof(*stack_ec));
- unlazy_fpu(prev_p);
- CLEAR_FAST_TRAP(&prev_p->arch);
+ unlazy_fpu(p);
+ CLEAR_FAST_TRAP(&p->arch);
+ save_segments(p);
}
- if ( !is_idle_task(next_p->domain) )
- {
- memcpy(stack_ec,
- &next_p->arch.user_ctxt,
- sizeof(*stack_ec));
+ memcpy(stack_ec,
+ &n->arch.user_ctxt,
+ sizeof(*stack_ec));
- /* Maybe switch the debug registers. */
- if ( unlikely(next_p->arch.debugreg[7]) )
- {
- loaddebug(&next_p->arch, 0);
- loaddebug(&next_p->arch, 1);
- loaddebug(&next_p->arch, 2);
- loaddebug(&next_p->arch, 3);
- /* no 4 and 5 */
- loaddebug(&next_p->arch, 6);
- loaddebug(&next_p->arch, 7);
- }
+ /* Maybe switch the debug registers. */
+ if ( unlikely(n->arch.debugreg[7]) )
+ {
+ loaddebug(&n->arch, 0);
+ loaddebug(&n->arch, 1);
+ loaddebug(&n->arch, 2);
+ loaddebug(&n->arch, 3);
+ /* no 4 and 5 */
+ loaddebug(&n->arch, 6);
+ loaddebug(&n->arch, 7);
+ }
- if ( !VMX_DOMAIN(next_p) )
- {
- SET_FAST_TRAP(&next_p->arch);
+ if ( !VMX_DOMAIN(n) )
+ {
+ SET_FAST_TRAP(&n->arch);
#ifdef __i386__
+ {
/* Switch the kernel ring-1 stack. */
- tss->esp1 = next_p->arch.kernel_sp;
- tss->ss1 = next_p->arch.kernel_ss;
-#endif
+ struct tss_struct *tss = &init_tss[cpu];
+ tss->esp1 = n->arch.kernel_sp;
+ tss->ss1 = n->arch.kernel_ss;
}
-
- /* Switch page tables. */
- write_ptbase(next_p);
+#endif
}
- set_current(next_p);
+ set_bit(cpu, &n->domain->cpuset);
+ write_ptbase(n);
+ clear_bit(cpu, &p->domain->cpuset);
+
+ __asm__ __volatile__ ( "lgdt %0" : "=m" (*n->arch.gdt) );
+
+ percpu_ctxt[cpu].curr_ed = n;
+}
+
- __asm__ __volatile__ ("lgdt %0" : "=m" (*next_p->arch.gdt));
+void context_switch(struct exec_domain *prev, struct exec_domain *next)
+{
+ struct exec_domain *realprev;
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