# HG changeset patch
# User yamahata@xxxxxxxxxxxxx
# Date 1197362515 -32400
# Node ID 576af13d0fa037504baaada7bb5b790ab84e678d
# Parent 612d0d9e3c53e20f54c079b075186bf697f0cabe
various fixes on xen/arch/ia64/linux-xen/perfmon.c
- fix starting/stopping sampling.
So far IPI is used. but psr.pp isn't preserved when nested interrupt case
with VTi domain. Instead timer is used.
- redefines ia64_set_pmc() to enable sampling of
all xen VMM/guest kernel/guest user process.
It supports only generic pmc/pmd.
- twist xenpfm_write_pmcs()
It is also used when turning on pmcs. So bailing out when error is not
appropriate. Even when error occures, it should continue to update next
cpu's pmcs.
- add gdprintk(XENLOG_DEUBG) and BUG_ON()s.
PATCHNAME: various_fix_linux_xen_perfmon_c
Signed-off-by: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
diff -r 612d0d9e3c53 -r 576af13d0fa0 xen/arch/ia64/linux-xen/perfmon.c
--- a/xen/arch/ia64/linux-xen/perfmon.c Tue Dec 11 17:41:09 2007 +0900
+++ b/xen/arch/ia64/linux-xen/perfmon.c Tue Dec 11 17:41:55 2007 +0900
@@ -69,6 +69,35 @@
#define pid vcpu_id
#define thread arch._thread
#define task_pt_regs vcpu_regs
+
+#define PMC_USER (1UL << 3)
+#define PMC_KERNEL (1UL << 0)
+#define PMC_XEN_AND_GUEST ((1UL << 0) | (1UL << 1) | (1UL << 2))
+#define PMC_PRIV_MONITOR (1UL << 6)
+
+#undef ia64_set_pmc
+#define ia64_set_pmc(index, val) \
+do { \
+ u64 __index = (index); \
+ u64 __val = (val); \
+ /* bad hack! \
+ * At this moment Linux perfmon knows only kernel and user \
+ * so that it sets only pmc.plm[0] and pmc.plm[3]. \
+ * On the other hand what we want is to sample on the whole \
+ * system. i.e. user, guest kernel and xen VMM. \
+ * Thus here we enable pmc.plm[2:1] too for generic pmc/pmd. \
+ * \
+ * But we can not do it genericly for the implementation \
+ * dependent pmc/pmd. \
+ * Probably such knowlege should be taught to the oprofiled or \
+ * the xenified perfmon. \
+ */ \
+ if (pmu_conf != NULL && PMC_IS_COUNTING(__index) && \
+ (__val & PMC_KERNEL)) \
+ __val |= PMC_XEN_AND_GUEST | PMC_PRIV_MONITOR; \
+ asm volatile ("mov pmc[%0]=%1" :: \
+ "r"(__index), "r"(__val) : "memory"); \
+} while (0)
#endif
#ifdef CONFIG_PERFMON
@@ -1214,7 +1243,7 @@ xenpfm_restore_pmcs(pfm_context_t* ctx)
{
int i;
unsigned long mask = ctx->ctx_all_pmcs[0];
-
+
for (i = 0; mask; i++, mask >>= 1) {
if ((mask & 0x1) == 0)
continue;
@@ -3073,6 +3102,7 @@ pfm_write_pmcs(pfm_context_t *ctx, void
#else
/* XXX FIXME */
if (state != PFM_CTX_UNLOADED) {
+ gdprintk(XENLOG_DEBUG, "%s state %d\n", __func__, state);
return -EBUSY;
}
#endif
@@ -3334,6 +3364,7 @@ pfm_write_pmds(pfm_context_t *ctx, void
#else
/* XXX FIXME */
if (state != PFM_CTX_UNLOADED) {
+ gdprintk(XENLOG_DEBUG, "%s state %d\n", __func__, state);
return -EBUSY;
}
#endif
@@ -7387,13 +7418,12 @@ xenpfm_write_pmcs(XEN_GUEST_HANDLE(pfarg
spin_lock_irqsave(&xenpfm_context_lock, flags);
for_each_online_cpu(cpu) {
pfm_context_t* ctx = per_cpu(xenpfm_context, cpu);
+ BUG_ON(ctx == NULL);
PROTECT_CTX_NOIRQ(ctx);
error |= pfm_write_pmcs(ctx, (void *)&kreq, 1, NULL);
UNPROTECT_CTX_NOIRQ(ctx);
}
spin_unlock_irqrestore(&xenpfm_context_lock, flags);
- if (error)
- break;
}
/* XXX if is loaded, change all physical cpus pmcs. */
@@ -7420,6 +7450,7 @@ xenpfm_write_pmds(XEN_GUEST_HANDLE(pfarg
spin_lock_irqsave(&xenpfm_context_lock, flags);
for_each_online_cpu(cpu) {
pfm_context_t* ctx = per_cpu(xenpfm_context, cpu);
+ BUG_ON(ctx == NULL);
PROTECT_CTX_NOIRQ(ctx);
error |= pfm_write_pmds(ctx, &kreq, 1, NULL);
UNPROTECT_CTX_NOIRQ(ctx);
@@ -7444,6 +7475,8 @@ xenpfm_context_load_cpu(void* info)
unsigned long flags;
struct xenpfm_context_load_arg* arg = (struct
xenpfm_context_load_arg*)info;
pfm_context_t* ctx = __get_cpu_var(xenpfm_context);
+
+ BUG_ON(ctx == NULL);
PROTECT_CTX(ctx, flags);
arg->error[smp_processor_id()] = pfm_context_load(ctx, arg->req, 0,
NULL);
UNPROTECT_CTX(ctx, flags);
@@ -7490,6 +7523,7 @@ xenpfm_context_unload_cpu(void* info)
unsigned long flags;
struct xenpfm_context_unload_arg* arg = (struct
xenpfm_context_unload_arg*)info;
pfm_context_t* ctx = __get_cpu_var(xenpfm_context);
+ BUG_ON(ctx == NULL);
PROTECT_CTX(ctx, flags);
arg->error[smp_processor_id()] = pfm_context_unload(ctx, NULL, 0, NULL);
UNPROTECT_CTX(ctx, flags);
@@ -7500,19 +7534,25 @@ xenpfm_context_unload(void)
{
int cpu;
struct xenpfm_context_unload_arg arg;
+ unsigned long flags;
int error = 0;
for_each_online_cpu(cpu)
arg.error[cpu] = 0;
BUG_ON(in_irq());
- spin_lock(&xenpfm_context_lock);
+ local_irq_save(flags);
+ if (!spin_trylock(&xenpfm_context_lock)) {
+ local_irq_restore(flags);
+ return -EAGAIN;
+ }
error = xenpfm_start_stop_locked(0);
+ local_irq_restore(flags);
if (error) {
spin_unlock(&xenpfm_context_lock);
return error;
}
-
+
smp_call_function(&xenpfm_context_unload_cpu, &arg, 1, 1);
xenpfm_context_unload_cpu(&arg);
spin_unlock(&xenpfm_context_lock);
@@ -7533,10 +7573,12 @@ __xenpfm_start(void)
int state;
int error = 0;
+ BUG_ON(ctx == NULL);
BUG_ON(local_irq_is_enabled());
PROTECT_CTX_NOIRQ(ctx);
state = ctx->ctx_state;
if (state != PFM_CTX_LOADED) {
+ gdprintk(XENLOG_DEBUG, "%s state %d\n", __func__, state);
error = -EINVAL;
goto out;
}
@@ -7566,9 +7608,18 @@ __xenpfm_stop(void)
int error = 0;
BUG_ON(local_irq_is_enabled());
+ if (ctx == NULL) {
+ gdprintk(XENLOG_DEBUG, "%s ctx=NULL p:%2d v:%2d\n",
+ __func__, smp_processor_id(), current->vcpu_id);
+ return 0;
+ }
+
PROTECT_CTX_NOIRQ(ctx);
state = ctx->ctx_state;
if (state != PFM_CTX_LOADED) {
+ gdprintk(XENLOG_DEBUG, "%s state %d p:%2d v:%2d\n",
+ __func__, state,
+ smp_processor_id(), current->vcpu_id);
error = -EINVAL;
goto out;
}
@@ -7640,7 +7691,7 @@ xenpfm_start_stop_vcpu(struct vcpu* v, i
ia64_psr(regs)->up = 1;
/* don't allow user level control */
- ia64_psr(regs)->sp = 0;
+ ia64_psr(regs)->sp = 1;
} else {
/*
* stop monitoring in the caller
@@ -7656,18 +7707,32 @@ xenpfm_start_stop_vcpu(struct vcpu* v, i
/*
* cancel user level control
*/
- ia64_psr(regs)->sp = 1;
-#endif
- }
-}
-
+ ia64_psr(regs)->sp = 0;
+#endif
+ }
+}
+
+/*
+ * This is the trickiest part.
+ * Here we want to enable/disable wide performance monitor including
+ * all xen context and all guest.
+ * For interrupt context and running vcpu, set dcr.pp = 1
+ * For blocked vcpu and idle vcpu, set psr.pp = 1 using timer via softirq.
+ * (Here IPI doesn't work because psr doesn't preserved over interruption
+ * when VTi domain.
+ * If IPI is used, we need to unwind the stack to the interrupt frame
+ * and set cr_ipsr.pp = 1. but using timer via do_softirq() is easier.)
+ * For guest set all vcpu_regs(v)->cr_ipsr.pp = 1.
+ */
static int
xenpfm_start_stop_locked(int is_start)
{
+ /* avoid stack over flow. protected by xenpfm_context_lock*/
+ static struct timer xenpfm_timer[NR_CPUS];
+
struct xenpfm_start_arg arg;
int cpus = num_online_cpus();
int cpu;
- unsigned long flags;
struct domain* d;
struct vcpu* v;
int error = 0;
@@ -7679,8 +7744,14 @@ xenpfm_start_stop_locked(int is_start)
arg.error[cpu] = 0;
BUG_ON(!spin_is_locked(&xenpfm_context_lock));
- smp_call_function(&xenpfm_start_stop_cpu, &arg, 1, 0);
- local_irq_save(flags);
+ for_each_online_cpu(cpu) {
+ struct timer* start_stop_timer = &xenpfm_timer[cpu];
+ if (cpu == smp_processor_id())
+ continue;
+ init_timer(start_stop_timer, &xenpfm_start_stop_cpu,
+ &arg, cpu);
+ set_timer(start_stop_timer, 0);/* fire it ASAP */
+ }
while (atomic_read(&arg.started) != cpus)
cpu_relax();
@@ -7696,9 +7767,13 @@ xenpfm_start_stop_locked(int is_start)
while (atomic_read(&arg.finished) != cpus)
cpu_relax();
- local_irq_restore(flags);
for_each_online_cpu(cpu) {
+ if (cpu == smp_processor_id())
+ continue;
+ /* xenpfm_timer[] is global so that we have to wait
+ * for xen timer subsystem to finish them. */
+ kill_timer(&xenpfm_timer[cpu]);
if (arg.error[cpu]) {
gdprintk(XENLOG_INFO, "%s: cpu %d error %d\n",
__func__, cpu, arg.error[cpu]);
@@ -7711,12 +7786,22 @@ static int
static int
xenpfm_start_stop(int is_start)
{
+ unsigned long flags;
int error;
BUG_ON(in_irq());
- spin_lock(&xenpfm_context_lock);
+ local_irq_save(flags);
+ /*
+ * Avoid dead lock. At this moment xen has only spin locks and
+ * doesn't have blocking mutex.
+ */
+ if (!spin_trylock(&xenpfm_context_lock)) {
+ local_irq_restore(flags);
+ gdprintk(XENLOG_DEBUG, "%s EAGAIN\n", __func__);
+ return -EAGAIN;
+ }
error = xenpfm_start_stop_locked(is_start);
- spin_unlock(&xenpfm_context_lock);
+ spin_unlock_irqrestore(&xenpfm_context_lock, flags);
return error;
}
16582_576af13d0fa0_various_fix_linux_xen_perfmon_c.patch
Description: Text Data
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