[PATCH v4 02/11] migration: Extract blocktime marking helper

[Aadeshveer Singh <aadeshveer07@gmail.com>]

Use new function try_mark_postcopy_blocktim_begin() to call
mark_postcopy_blocktime_begin if page was not received and return if it
actually marked it.

This will help in having a cleaner API to call
mark_postcopy_blocktime_begin as it requires the page to not be received
by asserting on it's existance in RAMBlock->receivedmap.

Signed-off-by: Aadeshveer Singh <aadeshveer07@gmail.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
---
 migration/migration.c    | 24 ++----------------------
 migration/postcopy-ram.c | 31 +++++++++++++++++++++++++++++++
 migration/postcopy-ram.h |  3 +++
 3 files changed, 36 insertions(+), 22 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 074d3f2c69..07394d8eea 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -577,32 +577,12 @@ int migrate_send_rp_req_pages(MigrationIncomingState *mis,
                               RAMBlock *rb, ram_addr_t start, uint64_t haddr,
                               uint32_t tid)
 {
-    void *aligned = (void *)(uintptr_t)ROUND_DOWN(haddr, qemu_ram_pagesize(rb));
-    bool received = false;
-
-    WITH_QEMU_LOCK_GUARD(&mis->page_request_mutex) {
-        received = ramblock_recv_bitmap_test_byte_offset(rb, start);
-        if (!received) {
-            if (!g_tree_lookup(mis->page_requested, aligned)) {
-                /*
-                 * The page has not been received, and it's not yet in the
-                 * page request list.  Queue it.  Set the value of element
-                 * to 1, so that things like g_tree_lookup() will return
-                 * TRUE (1) when found.
-                 */
-                g_tree_insert(mis->page_requested, aligned, (gpointer)1);
-                qatomic_inc(&mis->page_requested_count);
-                trace_postcopy_page_req_add(aligned, mis->page_requested_count);
-            }
-            mark_postcopy_blocktime_begin(haddr, tid, rb);
-        }
-    }
-
     /*
+     * If not able to mark page for blocktime it must already be present.
      * If the page is there, skip sending the message.  We don't even need the
      * lock because as long as the page arrived, it'll be there forever.
      */
-    if (received) {
+    if (!try_mark_postcopy_blocktime_begin(mis, rb, start, haddr, tid)) {
         return 0;
     }
 
diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
index 96a65aa976..4b8f882e1e 100644
--- a/migration/postcopy-ram.c
+++ b/migration/postcopy-ram.c
@@ -1057,6 +1057,37 @@ static void blocktime_fault_inject(PostcopyBlocktimeContext *ctx,
     trace_postcopy_blocktime_begin(addr, time, cpu, !!head);
 }
 
+/*
+ * Take @page_request_mutex and try marking postcopy blocktime begin.
+ * Return true if marking is successful and false if page alredy exists.
+ */
+bool try_mark_postcopy_blocktime_begin(MigrationIncomingState *mis,
+                                       RAMBlock *rb, ram_addr_t start,
+                                       uint64_t haddr, uint32_t tid)
+{
+    bool received = false;
+    void *aligned = (void *)(uintptr_t)ROUND_DOWN(haddr, qemu_ram_pagesize(rb));
+
+    WITH_QEMU_LOCK_GUARD(&mis->page_request_mutex) {
+        received = ramblock_recv_bitmap_test_byte_offset(rb, start);
+        if (!received) {
+            if (!g_tree_lookup(mis->page_requested, aligned)) {
+                /*
+                 * The page has not been received, and it's not yet in the
+                 * page request list.  Queue it.  Set the value of element
+                 * to 1, so that things like g_tree_lookup() will return
+                 * TRUE (1) when found.
+                 */
+                g_tree_insert(mis->page_requested, aligned, (gpointer)1);
+                qatomic_inc(&mis->page_requested_count);
+                trace_postcopy_page_req_add(aligned, mis->page_requested_count);
+            }
+            mark_postcopy_blocktime_begin((uint64_t)aligned, tid, rb);
+        }
+    }
+    return !received;
+}
+
 /*
  * This function is being called when pagefault occurs. It tracks down vCPU
  * blocking time.  It's protected by @page_request_mutex.
diff --git a/migration/postcopy-ram.h b/migration/postcopy-ram.h
index 98d918713f..ea879f0bc6 100644
--- a/migration/postcopy-ram.h
+++ b/migration/postcopy-ram.h
@@ -196,6 +196,9 @@ void postcopy_preempt_new_channel(MigrationIncomingState *mis, QEMUFile *file);
 void postcopy_preempt_setup(MigrationState *s);
 int postcopy_preempt_establish_channel(MigrationState *s);
 bool postcopy_is_paused(MigrationStatus status);
+bool try_mark_postcopy_blocktime_begin(MigrationIncomingState *mis,
+                                       RAMBlock *rb, ram_addr_t start,
+                                       uint64_t haddr, uint32_t tid);
 void mark_postcopy_blocktime_begin(uintptr_t addr, uint32_t ptid,
                                    RAMBlock *rb);
 
-- 
2.55.0