Segment dirty log for performance

diff -r 9bdb3e7a99c9 xen/arch/x86/mm/p2m.c
@@ -241,9 +241,12 @@ set_p2m_entry(struct domain *d, unsigned
                                0, L1_PAGETABLE_ENTRIES);
     ASSERT(p2m_entry);
 
-    /* Track the highest gfn for which we have ever had a valid mapping */
-    if ( mfn_valid(mfn) && (gfn > d->arch.p2m.max_mapped_pfn) )
-        d->arch.p2m.max_mapped_pfn = gfn;
+    if ( mfn_valid(mfn) ) {
+        paging_pfn_range_append(d, gfn);
+        /* Track the highest gfn for which we have ever had a valid mapping */
+        if (gfn > d->arch.p2m.max_mapped_pfn ) 
+            d->arch.p2m.max_mapped_pfn = gfn;
+    }
 
     if ( mfn_valid(mfn) || (p2mt == p2m_mmio_direct) )
         entry_content = l1e_from_pfn(mfn_x(mfn), p2m_type_to_flags(p2mt));

299 lines not on this page · raw message

diff -r 9bdb3e7a99c9 xen/arch/x86/mm/shadow/private.h
@@ -491,17 +491,22 @@ sh_mfn_is_dirty(struct domain *d, mfn_t 
 /* Is this guest page dirty?  Call only in log-dirty mode. */
 {
     unsigned long pfn;
+    struct pfn_range *pr, *pr0 = d->arch.paging.log_dirty.pfn_range;
+    
     ASSERT(shadow_mode_log_dirty(d));
-    ASSERT(d->arch.paging.log_dirty.bitmap != NULL);
 
     /* We /really/ mean PFN here, even for non-translated guests. */
     pfn = get_gpfn_from_mfn(mfn_x(gmfn));
-    if ( likely(VALID_M2P(pfn))
-         && likely(pfn < d->arch.paging.log_dirty.bitmap_size) 
-         && test_bit(pfn, d->arch.paging.log_dirty.bitmap) )
-        return 1;
-
-    return 0;
+    if ( unlikely(!VALID_M2P(pfn)) )
+         return 0;
+         
+    for (pr = pr0; likely(pr - pr0 != PFN_RANGE_NR && pr->len > 0); pr++)
+    {
+        ASSERT(pr->dirty_bitmap != NULL);
+        if ( likely(pr->start <= pfn && pfn < pr->start + pr->len) )
+            return test_bit(pfn - pr->start, pr->dirty_bitmap);
+    }
+    return 0; /* shouldn't get here */
 }
 
 

diff -r 9bdb3e7a99c9 xen/include/asm-x86/domain.h
@@ -158,13 +158,18 @@ struct log_dirty_domain {
     int            locker; /* processor that holds the lock */
     const char    *locker_function; /* func that took it */
 
-    /* log-dirty bitmap to record dirty pages */
-    unsigned long *bitmap;
-    unsigned int   bitmap_size;  /* in pages, bit per page */
-
     /* log-dirty mode stats */
     unsigned int   fault_count;
     unsigned int   dirty_count;
+
+    /* segmented log-dirty bitmap to record dirty pages */
+#define PFN_RANGE_NR 4
+    struct pfn_range {
+        unsigned long start;
+        unsigned long len;
+        uint8_t *dirty_bitmap;
+        unsigned int dirty_bitmap_size;  /* in pages, bit per page */
+    } pfn_range[PFN_RANGE_NR];
 
     /* functions which are paging mode specific */
     int            (*enable_log_dirty   )(struct domain *d);

diff -r 9bdb3e7a99c9 xen/include/asm-x86/paging.h
@@ -258,6 +258,8 @@ static inline int paging_cmpxchg_guest_e
         return (!cmpxchg_user(p, *old, new));
 }
 
+void paging_pfn_range_append(struct domain *d, unsigned long gfn);
+
 /* Helper function that writes a pte in such a way that a concurrent read 
  * never sees a half-written entry that has _PAGE_PRESENT set */
 static inline void safe_write_pte(l1_pgentry_t *p, l1_pgentry_t new)