# HG changeset patch
# User George Dunlap <george.dunlap@xxxxxxxxxxxxx>
# Date 1295274253 0
# Node ID 97ab84aca65cdcbce2ddccc51629fb24adb056cf
# Parent d1631540bcc4d369d7e7ec1d87e54e1a8f5d5f78
PoD: Allow pod_set_cache_target hypercall to be preempted
For very large VMs, setting the cache target can take long enough that
dom0 complains of soft lockups. Allow the hypercall to be preempted.
Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
Acked-by: Tim Deegan <Tim.Deegan@xxxxxxxxxx>
---
xen/arch/x86/domain.c | 4 ++--
xen/arch/x86/mm.c | 26 +++++++++++++++++---------
xen/arch/x86/mm/p2m.c | 18 +++++++++++++++---
xen/arch/x86/x86_64/compat/mm.c | 3 +++
4 files changed, 37 insertions(+), 14 deletions(-)
diff -r d1631540bcc4 -r 97ab84aca65c xen/arch/x86/domain.c
--- a/xen/arch/x86/domain.c Tue Jan 18 17:23:24 2011 +0000
+++ b/xen/arch/x86/domain.c Mon Jan 17 14:24:13 2011 +0000
@@ -1653,8 +1653,8 @@ int hypercall_xlat_continuation(unsigned
unsigned long nval = 0;
va_list args;
- BUG_ON(*id > 5);
- BUG_ON(mask & (1U << *id));
+ BUG_ON(id && *id > 5);
+ BUG_ON(id && (mask & (1U << *id)));
va_start(args, mask);
diff -r d1631540bcc4 -r 97ab84aca65c xen/arch/x86/mm.c
--- a/xen/arch/x86/mm.c Tue Jan 18 17:23:24 2011 +0000
+++ b/xen/arch/x86/mm.c Mon Jan 17 14:24:13 2011 +0000
@@ -4799,15 +4799,23 @@ long arch_memory_op(int op, XEN_GUEST_HA
rc = p2m_pod_set_mem_target(d, target.target_pages);
}
- p2m = p2m_get_hostp2m(d);
- target.tot_pages = d->tot_pages;
- target.pod_cache_pages = p2m->pod.count;
- target.pod_entries = p2m->pod.entry_count;
-
- if ( copy_to_guest(arg, &target, 1) )
- {
- rc= -EFAULT;
- goto pod_target_out_unlock;
+ if ( rc == -EAGAIN )
+ {
+ rc = hypercall_create_continuation(
+ __HYPERVISOR_memory_op, "lh", op, arg);
+ }
+ else if ( rc >= 0 )
+ {
+ p2m = p2m_get_hostp2m(d);
+ target.tot_pages = d->tot_pages;
+ target.pod_cache_pages = p2m->pod.count;
+ target.pod_entries = p2m->pod.entry_count;
+
+ if ( copy_to_guest(arg, &target, 1) )
+ {
+ rc= -EFAULT;
+ goto pod_target_out_unlock;
+ }
}
pod_target_out_unlock:
diff -r d1631540bcc4 -r 97ab84aca65c xen/arch/x86/mm/p2m.c
--- a/xen/arch/x86/mm/p2m.c Tue Jan 18 17:23:24 2011 +0000
+++ b/xen/arch/x86/mm/p2m.c Mon Jan 17 14:24:13 2011 +0000
@@ -435,7 +435,7 @@ static struct page_info * p2m_pod_cache_
/* Set the size of the cache, allocating or freeing as necessary. */
static int
-p2m_pod_set_cache_target(struct p2m_domain *p2m, unsigned long pod_target)
+p2m_pod_set_cache_target(struct p2m_domain *p2m, unsigned long pod_target, int
preemptible)
{
struct domain *d = p2m->domain;
int ret = 0;
@@ -468,6 +468,12 @@ p2m_pod_set_cache_target(struct p2m_doma
}
p2m_pod_cache_add(p2m, page, order);
+
+ if ( hypercall_preempt_check() && preemptible )
+ {
+ ret = -EAGAIN;
+ goto out;
+ }
}
/* Decreasing the target */
@@ -512,6 +518,12 @@ p2m_pod_set_cache_target(struct p2m_doma
put_page(page+i);
put_page(page+i);
+
+ if ( hypercall_preempt_check() && preemptible )
+ {
+ ret = -EAGAIN;
+ goto out;
+ }
}
}
@@ -589,7 +601,7 @@ p2m_pod_set_mem_target(struct domain *d,
ASSERT( pod_target >= p2m->pod.count );
- ret = p2m_pod_set_cache_target(p2m, pod_target);
+ ret = p2m_pod_set_cache_target(p2m, pod_target, 1/*preemptible*/);
out:
p2m_unlock(p2m);
@@ -753,7 +765,7 @@ out_entry_check:
/* If we've reduced our "liabilities" beyond our "assets", free some */
if ( p2m->pod.entry_count < p2m->pod.count )
{
- p2m_pod_set_cache_target(p2m, p2m->pod.entry_count);
+ p2m_pod_set_cache_target(p2m, p2m->pod.entry_count, 0/*can't
preempt*/);
}
out_unlock:
diff -r d1631540bcc4 -r 97ab84aca65c xen/arch/x86/x86_64/compat/mm.c
--- a/xen/arch/x86/x86_64/compat/mm.c Tue Jan 18 17:23:24 2011 +0000
+++ b/xen/arch/x86/x86_64/compat/mm.c Mon Jan 17 14:24:13 2011 +0000
@@ -126,6 +126,9 @@ int compat_arch_memory_op(int op, XEN_GU
rc = arch_memory_op(op, guest_handle_from_ptr(nat, void));
if ( rc < 0 )
break;
+
+ if ( rc == __HYPERVISOR_memory_op )
+ hypercall_xlat_continuation(NULL, 0x2, nat, arg);
XLAT_pod_target(&cmp, nat);
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