[Xen-devel] [PATCH 2/5] x86/mm: warn if we ever run out of shadow/hap pool for p2m/lgd ops.

[Tim Deegan <tim@xxxxxxx>]

Even if the error propagates up through the p2m ops to the caller,
it'll look like ENOMEM, which won't be obviously a shadow-pool problem.

Warn on the console, once per domain.

Signed-off-by: Tim Deegan <tim@xxxxxxx>
---
 xen/arch/x86/mm/hap/hap.c       |    6 ++++++
 xen/arch/x86/mm/shadow/common.c |    8 +++++++-
 xen/include/asm-x86/domain.h    |    2 ++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/mm/hap/hap.c b/xen/arch/x86/mm/hap/hap.c
index 055833d..bff05d9 100644
--- a/xen/arch/x86/mm/hap/hap.c
+++ b/xen/arch/x86/mm/hap/hap.c
@@ -258,6 +258,12 @@ static struct page_info *hap_alloc_p2m_page(struct domain 
*d)
         page_set_owner(pg, d);
         pg->count_info |= 1;
     }
+    else if ( !d->arch.paging.p2m_alloc_failed )
+    {
+        d->arch.paging.p2m_alloc_failed = 1;
+        dprintk(XENLOG_ERR, "d%i failed to allocate from HAP pool",
+                d->domain_id);
+    }
 
     paging_unlock(d);
     return pg;
diff --git a/xen/arch/x86/mm/shadow/common.c b/xen/arch/x86/mm/shadow/common.c
index 691776c..4b576ac 100644
--- a/xen/arch/x86/mm/shadow/common.c
+++ b/xen/arch/x86/mm/shadow/common.c
@@ -1591,10 +1591,16 @@ shadow_alloc_p2m_page(struct domain *d)
     if ( d->arch.paging.shadow.total_pages 
          < shadow_min_acceptable_pages(d) + 1 )
     {
+        if ( !d->arch.paging.p2m_alloc_failed )
+        {
+            d->arch.paging.p2m_alloc_failed = 1;
+            dprintk(XENLOG_ERR, "d%i failed to allocate from shadow pool",
+                    d->domain_id);
+        }
         paging_unlock(d);
         return NULL;
     }
- 
+
     shadow_prealloc(d, SH_type_p2m_table, 1);
     pg = mfn_to_page(shadow_alloc(d, SH_type_p2m_table, 0));
     d->arch.paging.shadow.p2m_pages++;
diff --git a/xen/include/asm-x86/domain.h b/xen/include/asm-x86/domain.h
index fd9fa0f..6f9744a 100644
--- a/xen/include/asm-x86/domain.h
+++ b/xen/include/asm-x86/domain.h
@@ -190,6 +190,8 @@ struct paging_domain {
      * (used by p2m and log-dirty code for their tries) */
     struct page_info * (*alloc_page)(struct domain *d);
     void (*free_page)(struct domain *d, struct page_info *pg);
+    /* Has that pool ever run out of memory? */
+    bool_t p2m_alloc_failed;
 };
 
 struct paging_vcpu {
-- 
1.7.10.4


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