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Re: [Xen-devel] [PATCH 1 of 4] p2m: Keep statistics on order of p2m entries
On 05/06/11 17:00, Tim Deegan wrote:
Hello,
At 15:40 +0100 on 06 May (1304696401), Christoph Egger wrote:
Can you please use defines for the indexes of p2m->stats.entries[],
please? That makes it easier to read what you are counting.
I'm not sure that's a great idea. The array is indexed in several
places by integer already, and the defines are unlikely to be much more
illuminating unless you can think of some better naming scheme than
"#define LEVEL_0 0" etc.
What about this:
#define PAGE_ORDER_4K 0
#define PAGE_ORDER_2M 9
#define PAGE_ORDER_1G 18
On the other hand, maybe the array itself could have a more descriptive
name than "stats.entries".
Tim.
On 05/06/11 16:01, George Dunlap wrote:
Count the number of 4kiB, 2MiB, and 1GiB p2m entries.
Signed-off-by: George Dunlap<george.dunlap@xxxxxxxxxxxxx>
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 */
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