[Xen-changelog] [xen master] grant_table: implement grant_table_warn_active_grants()

[patchbot@xxxxxxx]

commit 502a592704ca782ba4fde0746464b68c52e6de7e
Author:     Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
AuthorDate: Thu Sep 10 16:53:36 2015 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Sep 10 16:53:36 2015 +0200

    grant_table: implement grant_table_warn_active_grants()
    
    Log first 10 active grants for a domain. This function is going to be used
    for soft reset, active grants on this path usually mean misbehaving backends
    refusing to release their mappings on shutdown. We need that in addition to
    the already existent 'g' keyhandler as such misbehaving backends can cause a
    domain to crash right after the soft reset operation and 'g' option won't be
    available in this case.
    
    Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
    Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/common/grant_table.c      |   35 +++++++++++++++++++++++++++++++++++
 xen/include/xen/grant_table.h |    5 +++++
 2 files changed, 40 insertions(+), 0 deletions(-)

diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c
index 2b449d5..23185e7 100644
--- a/xen/common/grant_table.c
+++ b/xen/common/grant_table.c
@@ -3352,6 +3352,41 @@ gnttab_release_mappings(
     }
 }
 
+void grant_table_warn_active_grants(struct domain *d)
+{
+    struct grant_table *gt = d->grant_table;
+    struct active_grant_entry *act;
+    grant_ref_t ref;
+    unsigned int nr_active = 0;
+
+#define WARN_GRANT_MAX 10
+
+    read_lock(&gt->lock);
+
+    for ( ref = 0; ref != nr_grant_entries(gt); ref++ )
+    {
+        act = active_entry_acquire(gt, ref);
+        if ( !act->pin )
+        {
+            active_entry_release(act);
+            continue;
+        }
+
+        nr_active++;
+        if ( nr_active <= WARN_GRANT_MAX )
+            printk(XENLOG_G_DEBUG "Dom%d has an active grant: GFN: %lx (MFN: 
%lx)\n",
+                   d->domain_id, act->gfn, act->frame);
+        active_entry_release(act);
+    }
+
+    if ( nr_active > WARN_GRANT_MAX )
+        printk(XENLOG_G_DEBUG "Dom%d has too many (%d) active grants to 
report\n",
+               d->domain_id, nr_active);
+
+    read_unlock(&gt->lock);
+
+#undef WARN_GRANT_MAX
+}
 
 void
 grant_table_destroy(
diff --git a/xen/include/xen/grant_table.h b/xen/include/xen/grant_table.h
index 5263fd6..1c29cee 100644
--- a/xen/include/xen/grant_table.h
+++ b/xen/include/xen/grant_table.h
@@ -89,6 +89,11 @@ void grant_table_destroy(
     struct domain *d);
 void grant_table_init_vcpu(struct vcpu *v);
 
+/*
+ * Check if domain has active grants and log first 10 of them.
+ */
+void grant_table_warn_active_grants(struct domain *d);
+
 /* Domain death release of granted mappings of other domains' memory. */
 void
 gnttab_release_mappings(
--
generated by git-patchbot for /home/xen/git/xen.git#master

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