[PATCH 1 of 4] p2m: Keep statistics on order of p2m entries

[George Dunlap <george.dunlap@eu.citrix.com>]

Count the number of 4kiB, 2MiB, and 1GiB p2m entries.

Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>

diff -r 4b0692880dfa -r be5d93d38f28 xen/arch/x86/mm/hap/p2m-ept.c
--- a/xen/arch/x86/mm/hap/p2m-ept.c	Thu May 05 17:40:34 2011 +0100
+++ b/xen/arch/x86/mm/hap/p2m-ept.c	Fri May 06 15:01:08 2011 +0100
@@ -39,6 +39,8 @@
 
 #define is_epte_present(ept_entry)      ((ept_entry)->epte & 0x7)
 #define is_epte_superpage(ept_entry)    ((ept_entry)->sp)
+#define is_epte_countable(ept_entry)    (is_epte_present(ept_entry) \
+                                         || ((ept_entry)->sa_p2mt == p2m_populate_on_demand))
 
 /* Non-ept "lock-and-check" wrapper */
 static int ept_pod_check_and_populate(struct p2m_domain *p2m, unsigned long gfn,
@@ -167,11 +169,14 @@
 void ept_free_entry(struct p2m_domain *p2m, ept_entry_t *ept_entry, int level)
 {
     /* End if the entry is a leaf entry. */
-    if ( level == 0 || !is_epte_present(ept_entry) ||
-         is_epte_superpage(ept_entry) )
+    if ( level == 0 || !is_epte_present(ept_entry) || is_epte_superpage(ept_entry) )
+    {
+        if ( is_epte_countable(ept_entry) )
+            p2m->stats.entries[level]--;
         return;
+    }
 
-    if ( level > 1 )
+    if ( level > 0 )
     {
         ept_entry_t *epte = map_domain_page(ept_entry->mfn);
         for ( int i = 0; i < EPT_PAGETABLE_ENTRIES; i++ )
@@ -217,7 +222,10 @@
         ept_p2m_type_to_flags(epte, epte->sa_p2mt, epte->access);
 
         if ( (level - 1) == target )
+        {
+            p2m->stats.entries[target]++;
             continue;
+        }
 
         ASSERT(is_epte_superpage(epte));
 
@@ -400,6 +408,10 @@
             ept_p2m_type_to_flags(&new_entry, p2mt, p2ma);
         }
 
+        /* old_entry will be handled by ept_free_entry below */
+        if ( is_epte_countable(&new_entry) )
+            p2m->stats.entries[i]++;
+
         atomic_write_ept_entry(ept_entry, new_entry);
     }
     else
@@ -412,12 +424,16 @@
 
         split_ept_entry = atomic_read_ept_entry(ept_entry);
 
+        /* Accounting should be OK here; split_ept_entry bump the counts,
+         * free_entry will reduce them. */
         if ( !ept_split_super_page(p2m, &split_ept_entry, i, target) )
         {
             ept_free_entry(p2m, &split_ept_entry, i);
             goto out;
         }
 
+        /* We know this was countable or we wouldn't be here.*/
+        p2m->stats.entries[i]--;
         /* now install the newly split ept sub-tree */
         /* NB: please make sure domian is paused and no in-fly VT-d DMA. */
         atomic_write_ept_entry(ept_entry, split_ept_entry);
@@ -449,9 +465,13 @@
 
         ept_p2m_type_to_flags(&new_entry, p2mt, p2ma);
 
+        /* old_entry will be handled by ept_free_entry below */
+        if ( is_epte_countable(&new_entry) )
+            p2m->stats.entries[i]++;
+
         atomic_write_ept_entry(ept_entry, new_entry);
     }
-
+ 
     /* Track the highest gfn for which we have ever had a valid mapping */
     if ( mfn_valid(mfn_x(mfn)) &&
          (gfn + (1UL << order) - 1 > p2m->max_mapped_pfn) )
diff -r 4b0692880dfa -r be5d93d38f28 xen/arch/x86/mm/p2m.c
--- a/xen/arch/x86/mm/p2m.c	Thu May 05 17:40:34 2011 +0100
+++ b/xen/arch/x86/mm/p2m.c	Fri May 06 15:01:08 2011 +0100
@@ -184,11 +184,15 @@
 {
     /* End if the entry is a leaf entry. */
     if ( page_order == 0
-         || !(l1e_get_flags(*p2m_entry) & _PAGE_PRESENT)
+         || !(l1e_get_flags(*p2m_entry) & _PAGE_PRESENT) 
          || (l1e_get_flags(*p2m_entry) & _PAGE_PSE) )
+    {
+        if ( l1e_get_flags(*p2m_entry) )
+            p2m->stats.entries[page_order/9]--;
         return;
-
-    if ( page_order > 9 )
+    }
+
+    if ( page_order )
     {
         l1_pgentry_t *l3_table = map_domain_page(l1e_get_pfn(*p2m_entry));
         for ( int i = 0; i < L3_PAGETABLE_ENTRIES; i++ )
@@ -242,6 +246,7 @@
         new_entry = l1e_from_pfn(mfn_x(page_to_mfn(pg)),
                                  __PAGE_HYPERVISOR | _PAGE_USER);
 
+        /* Stats: Empty entry, no mods needed */
         switch ( type ) {
         case PGT_l3_page_table:
             p2m_add_iommu_flags(&new_entry, 3, IOMMUF_readable|IOMMUF_writable);
@@ -285,10 +290,12 @@
         {
             new_entry = l1e_from_pfn(pfn + (i * L1_PAGETABLE_ENTRIES), flags);
             p2m_add_iommu_flags(&new_entry, 1, IOMMUF_readable|IOMMUF_writable);
+            p2m->stats.entries[1]++;
             p2m->write_p2m_entry(p2m, gfn,
                 l1_entry+i, *table_mfn, new_entry, 2);
         }
         unmap_domain_page(l1_entry);
+        p2m->stats.entries[2]--;
         new_entry = l1e_from_pfn(mfn_x(page_to_mfn(pg)),
                                  __PAGE_HYPERVISOR|_PAGE_USER); //disable PSE
         p2m_add_iommu_flags(&new_entry, 2, IOMMUF_readable|IOMMUF_writable);
@@ -320,6 +327,7 @@
         {
             new_entry = l1e_from_pfn(pfn + i, flags);
             p2m_add_iommu_flags(&new_entry, 0, 0);
+            p2m->stats.entries[0]++;
             p2m->write_p2m_entry(p2m, gfn,
                 l1_entry+i, *table_mfn, new_entry, 1);
         }
@@ -328,6 +336,7 @@
         new_entry = l1e_from_pfn(mfn_x(page_to_mfn(pg)),
                                  __PAGE_HYPERVISOR|_PAGE_USER);
         p2m_add_iommu_flags(&new_entry, 1, IOMMUF_readable|IOMMUF_writable);
+        p2m->stats.entries[1]--;
         p2m->write_p2m_entry(p2m, gfn,
             p2m_entry, *table_mfn, new_entry, 2);
     }
@@ -908,6 +917,15 @@
 void
 p2m_pod_dump_data(struct p2m_domain *p2m)
 {
+    int i;
+    long entries;
+    printk("    P2M entry stats:\n");
+    for ( i=0; i<3; i++)
+        if ( (entries=p2m->stats.entries[i]) )
+            printk("     L%d: %8ld entries, %ld bytes\n",
+                   i+1,
+                   entries,
+                   entries<<(i*9+12));
     printk("    PoD entries=%d cachesize=%d\n",
            p2m->pod.entry_count, p2m->pod.count);
 }
@@ -1475,6 +1493,12 @@
             old_mfn = l1e_get_pfn(*p2m_entry);
         }
 
+        /* Adjust count for present/not-present entries added */
+        if ( l1e_get_flags(*p2m_entry) )
+            p2m->stats.entries[page_order/9]--;
+        if ( l1e_get_flags(entry_content) )
+            p2m->stats.entries[page_order/9]++;
+
         p2m->write_p2m_entry(p2m, gfn, p2m_entry, table_mfn, entry_content, 3);
         /* NB: paging_write_p2m_entry() handles tlb flushes properly */
 
@@ -1519,6 +1543,13 @@
             p2m_add_iommu_flags(&entry_content, 0, iommu_pte_flags);
             old_mfn = l1e_get_pfn(*p2m_entry);
         }
+
+        /* Adjust count for present/not-present entries added */
+        if ( l1e_get_flags(*p2m_entry) )
+            p2m->stats.entries[page_order/9]--;
+        if ( l1e_get_flags(entry_content) )
+            p2m->stats.entries[page_order/9]++;
+
         /* level 1 entry */
         p2m->write_p2m_entry(p2m, gfn, p2m_entry, table_mfn, entry_content, 1);
         /* NB: paging_write_p2m_entry() handles tlb flushes properly */
@@ -1556,6 +1587,12 @@
             old_mfn = l1e_get_pfn(*p2m_entry);
         }
 
+        /* Adjust count for present/not-present entries added */
+        if ( l1e_get_flags(*p2m_entry) )
+            p2m->stats.entries[page_order/9]--;
+        if ( l1e_get_flags(entry_content) )
+            p2m->stats.entries[page_order/9]++;
+
         p2m->write_p2m_entry(p2m, gfn, p2m_entry, table_mfn, entry_content, 2);
         /* NB: paging_write_p2m_entry() handles tlb flushes properly */
 
@@ -2750,6 +2787,8 @@
                 continue;
             }
 
+            /* STATS: Should change only type; no stats should need adjustment */
+
             l2mfn = _mfn(l3e_get_pfn(l3e[i3]));
             l2e = map_domain_page(l3e_get_pfn(l3e[i3]));
             for ( i2 = 0; i2 < L2_PAGETABLE_ENTRIES; i2++ )
diff -r 4b0692880dfa -r be5d93d38f28 xen/include/asm-x86/p2m.h
--- a/xen/include/asm-x86/p2m.h	Thu May 05 17:40:34 2011 +0100
+++ b/xen/include/asm-x86/p2m.h	Fri May 06 15:01:08 2011 +0100
@@ -278,6 +278,10 @@
         unsigned         reclaim_single; /* Last gpfn of a scan */
         unsigned         max_guest;    /* gpfn of max guest demand-populate */
     } pod;
+
+    struct {
+        long entries[3]; 
+    } stats;
 };
 
 /* get host p2m table */