[Xen-devel] [PATCH] x86/mm: Provide more useful information in diagnostics

Andrew Cooper posted 1 patch 4 years, 9 months ago
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/xen tags/patchew/20190716172801.11518-1-andrew.cooper3@citrix.com
xen/arch/x86/mm.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
[Xen-devel] [PATCH] x86/mm: Provide more useful information in diagnostics
Posted by Andrew Cooper 4 years, 9 months ago
 * alloc_l?_table() should identify the failure, not just state that there is
   one.
 * get_page() should use %pd for the two domains, to render system domains in
   a more obvious way.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
---
 xen/arch/x86/mm.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 138662e777..0f0761d624 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -1407,7 +1407,8 @@ static int alloc_l1_table(struct page_info *page)
     return 0;
 
  fail:
-    gdprintk(XENLOG_WARNING, "Failure in alloc_l1_table: slot %#x\n", i);
+    gdprintk(XENLOG_WARNING,
+             "Failure in alloc_l1_table: slot %#x, ret %d\n", i, ret);
  out:
     while ( i-- > 0 )
         put_page_from_l1e(pl1e[i], d);
@@ -1505,7 +1506,8 @@ static int alloc_l2_table(struct page_info *page, unsigned long type)
         }
         else if ( rc < 0 && rc != -EINTR )
         {
-            gdprintk(XENLOG_WARNING, "Failure in alloc_l2_table: slot %#x\n", i);
+            gdprintk(XENLOG_WARNING,
+                     "Failure in alloc_l2_table: slot %#x, rc %d\n", i, rc);
             if ( i )
             {
                 page->nr_validated_ptes = i;
@@ -1599,7 +1601,8 @@ static int alloc_l3_table(struct page_info *page)
         rc = -EINVAL;
     if ( rc < 0 && rc != -ERESTART && rc != -EINTR )
     {
-        gdprintk(XENLOG_WARNING, "Failure in alloc_l3_table: slot %#x\n", i);
+        gdprintk(XENLOG_WARNING,
+                 "Failure in alloc_l3_table: slot %#x, rc %d\n", i, rc);
         if ( i )
         {
             page->nr_validated_ptes = i;
@@ -1767,7 +1770,7 @@ static int alloc_l4_table(struct page_info *page)
         {
             if ( rc != -EINTR )
                 gdprintk(XENLOG_WARNING,
-                         "Failure in alloc_l4_table: slot %#x\n", i);
+                         "Failure in alloc_l4_table: slot %#x, rc %d\n", i, rc);
             if ( i )
             {
                 page->nr_validated_ptes = i;
@@ -2482,9 +2485,8 @@ int get_page(struct page_info *page, struct domain *domain)
 
     if ( !paging_mode_refcounts(domain) && !domain->is_dying )
         gprintk(XENLOG_INFO,
-                "Error mfn %"PRI_mfn": rd=%d od=%d caf=%08lx taf=%" PRtype_info "\n",
-                mfn_x(page_to_mfn(page)), domain->domain_id,
-                owner ? owner->domain_id : DOMID_INVALID,
+                "Error mfn %"PRI_mfn": rd=%pd od=%pd caf=%08lx taf=%"PRtype_info"\n",
+                mfn_x(page_to_mfn(page)), domain, owner,
                 page->count_info - !!owner, page->u.inuse.type_info);
 
     if ( owner )
-- 
2.11.0


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Re: [Xen-devel] [PATCH] x86/mm: Provide more useful information in diagnostics
Posted by Jan Beulich 4 years, 9 months ago
On 16.07.2019 19:28, Andrew Cooper wrote:
> --- a/xen/arch/x86/mm.c
> +++ b/xen/arch/x86/mm.c
> @@ -1407,7 +1407,8 @@ static int alloc_l1_table(struct page_info *page)
>       return 0;
>   
>    fail:
> -    gdprintk(XENLOG_WARNING, "Failure in alloc_l1_table: slot %#x\n", i);
> +    gdprintk(XENLOG_WARNING,
> +             "Failure in alloc_l1_table: slot %#x, ret %d\n", i, ret);

To make it slightly less output without losing information, in cases
like this I generally prefer "Failure %d in alloc_l1_table: slot %#x\n".
Seeing ...

> @@ -1505,7 +1506,8 @@ static int alloc_l2_table(struct page_info *page, unsigned long type)
>           }
>           else if ( rc < 0 && rc != -EINTR )
>           {
> -            gdprintk(XENLOG_WARNING, "Failure in alloc_l2_table: slot %#x\n", i);
> +            gdprintk(XENLOG_WARNING,
> +                     "Failure in alloc_l2_table: slot %#x, rc %d\n", i, rc);

... this for comparison it is, imo, not relevant to actually have names
of local variables in logged messages.

Preferably with this adjusted
Acked-by: Jan Beulich <jbeulich@suse.com>

Jan
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