[PATCH v3 1/2] exec/ram_addr: return nr of dirty pages in cpu_physical_memory_set_dirty_lebitmap()

[Joao Martins <joao.m.martins@oracle.com>]

In preparation for including the number of dirty pages in the
vfio_get_dirty_bitmap() tracepoint, return the number of dirty pages in
cpu_physical_memory_set_dirty_lebitmap() similar to
cpu_physical_memory_sync_dirty_bitmap().

To avoid counting twice when GLOBAL_DIRTY_RATE is enabled, stash the
number of bits set per bitmap quad in a variable (@nbits) and reuse it
there.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
---
 include/exec/ram_addr.h | 28 ++++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)

diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
index 90a82692904f..9f2e3893f562 100644
--- a/include/exec/ram_addr.h
+++ b/include/exec/ram_addr.h
@@ -334,14 +334,23 @@ static inline void cpu_physical_memory_set_dirty_range(ram_addr_t start,
 }
 
 #if !defined(_WIN32)
-static inline void cpu_physical_memory_set_dirty_lebitmap(unsigned long *bitmap,
-                                                          ram_addr_t start,
-                                                          ram_addr_t pages)
+
+/*
+ * Contrary to cpu_physical_memory_sync_dirty_bitmap() this function returns
+ * the number of dirty pages in @bitmap passed as argument. On the other hand,
+ * cpu_physical_memory_sync_dirty_bitmap() returns newly dirtied pages that
+ * weren't set in the global migration bitmap.
+ */
+static inline
+uint64_t cpu_physical_memory_set_dirty_lebitmap(unsigned long *bitmap,
+                                                ram_addr_t start,
+                                                ram_addr_t pages)
 {
     unsigned long i, j;
-    unsigned long page_number, c;
+    unsigned long page_number, c, nbits;
     hwaddr addr;
     ram_addr_t ram_addr;
+    uint64_t num_dirty = 0;
     unsigned long len = (pages + HOST_LONG_BITS - 1) / HOST_LONG_BITS;
     unsigned long hpratio = qemu_real_host_page_size() / TARGET_PAGE_SIZE;
     unsigned long page = BIT_WORD(start >> TARGET_PAGE_BITS);
@@ -369,6 +378,7 @@ static inline void cpu_physical_memory_set_dirty_lebitmap(unsigned long *bitmap,
                 if (bitmap[k]) {
                     unsigned long temp = leul_to_cpu(bitmap[k]);
 
+                    nbits = ctpopl(temp);
                     qatomic_or(&blocks[DIRTY_MEMORY_VGA][idx][offset], temp);
 
                     if (global_dirty_tracking) {
@@ -377,10 +387,12 @@ static inline void cpu_physical_memory_set_dirty_lebitmap(unsigned long *bitmap,
                                 temp);
                         if (unlikely(
                             global_dirty_tracking & GLOBAL_DIRTY_DIRTY_RATE)) {
-                            total_dirty_pages += ctpopl(temp);
+                            total_dirty_pages += nbits;
                         }
                     }
 
+                    num_dirty += nbits;
+
                     if (tcg_enabled()) {
                         qatomic_or(&blocks[DIRTY_MEMORY_CODE][idx][offset],
                                    temp);
@@ -409,9 +421,11 @@ static inline void cpu_physical_memory_set_dirty_lebitmap(unsigned long *bitmap,
         for (i = 0; i < len; i++) {
             if (bitmap[i] != 0) {
                 c = leul_to_cpu(bitmap[i]);
+                nbits = ctpopl(c);
                 if (unlikely(global_dirty_tracking & GLOBAL_DIRTY_DIRTY_RATE)) {
-                    total_dirty_pages += ctpopl(c);
+                    total_dirty_pages += nbits;
                 }
+                num_dirty += nbits;
                 do {
                     j = ctzl(c);
                     c &= ~(1ul << j);
@@ -424,6 +438,8 @@ static inline void cpu_physical_memory_set_dirty_lebitmap(unsigned long *bitmap,
             }
         }
     }
+
+    return num_dirty;
 }
 #endif /* not _WIN32 */
 
-- 
2.39.3