[v6,10/19] migration/multifd: Isolate ram pages packet data

Commit Message

Fabiano Rosas Aug. 27, 2024, 5:45 p.m. UTC

While we cannot yet disentangle the multifd packet from page data, we
can make the code a bit cleaner by setting the page-related fields in
a separate function.

Reviewed-by: Philippe Mathieu-Daudé <[e-mail]>
Reviewed-by: Peter Xu <[e-mail]>
Signed-off-by: Fabiano Rosas <[e-mail]>
---
 migration/multifd.c    | 99 +++++++++++++++++++++++++-----------------
 migration/trace-events |  5 ++-
 2 files changed, 63 insertions(+), 41 deletions(-)

Patch

diff --git a/migration/multifd.c b/migration/multifd.c
index df8dfcc98f..d64fcdf4ac 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -424,65 +424,61 @@  static int multifd_recv_initial_packet(QIOChannel *c, Error **errp)
     return msg.id;
 }
 
-void multifd_send_fill_packet(MultiFDSendParams *p)
+static void multifd_ram_fill_packet(MultiFDSendParams *p)
 {
     MultiFDPacket_t *packet = p->packet;
     MultiFDPages_t *pages = &p->data->u.ram;
-    uint64_t packet_num;
     uint32_t zero_num = pages->num - pages->normal_num;
-    int i;
 
-    packet->flags = cpu_to_be32(p->flags);
     packet->pages_alloc = cpu_to_be32(multifd_ram_page_count());
     packet->normal_pages = cpu_to_be32(pages->normal_num);
     packet->zero_pages = cpu_to_be32(zero_num);
-    packet->next_packet_size = cpu_to_be32(p->next_packet_size);
-
-    packet_num = qatomic_fetch_inc(&multifd_send_state->packet_num);
-    packet->packet_num = cpu_to_be64(packet_num);
 
     if (pages->block) {
         strncpy(packet->ramblock, pages->block->idstr, 256);
     }
 
-    for (i = 0; i < pages->num; i++) {
+    for (int i = 0; i < pages->num; i++) {
         /* there are architectures where ram_addr_t is 32 bit */
         uint64_t temp = pages->offset[i];
 
         packet->offset[i] = cpu_to_be64(temp);
     }
 
+    trace_multifd_send_ram_fill(p->id, pages->normal_num, zero_num);
+}
+
+void multifd_send_fill_packet(MultiFDSendParams *p)
+{
+    MultiFDPacket_t *packet = p->packet;
+    uint64_t packet_num;
+
+    memset(packet, 0, p->packet_len);
+
+    packet->magic = cpu_to_be32(MULTIFD_MAGIC);
+    packet->version = cpu_to_be32(MULTIFD_VERSION);
+
+    packet->flags = cpu_to_be32(p->flags);
+    packet->next_packet_size = cpu_to_be32(p->next_packet_size);
+
+    packet_num = qatomic_fetch_inc(&multifd_send_state->packet_num);
+    packet->packet_num = cpu_to_be64(packet_num);
+
     p->packets_sent++;
 
-    trace_multifd_send(p->id, packet_num, pages->normal_num, zero_num,
-                       p->flags, p->next_packet_size);
+    multifd_ram_fill_packet(p);
+
+    trace_multifd_send_fill(p->id, packet_num,
+                            p->flags, p->next_packet_size);
 }
 
-static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp)
+static int multifd_ram_unfill_packet(MultiFDRecvParams *p, Error **errp)
 {
     MultiFDPacket_t *packet = p->packet;
     uint32_t page_count = multifd_ram_page_count();
     uint32_t page_size = multifd_ram_page_size();
     int i;
 
-    packet->magic = be32_to_cpu(packet->magic);
-    if (packet->magic != MULTIFD_MAGIC) {
-        error_setg(errp, "multifd: received packet "
-                   "magic %x and expected magic %x",
-                   packet->magic, MULTIFD_MAGIC);
-        return -1;
-    }
-
-    packet->version = be32_to_cpu(packet->version);
-    if (packet->version != MULTIFD_VERSION) {
-        error_setg(errp, "multifd: received packet "
-                   "version %u and expected version %u",
-                   packet->version, MULTIFD_VERSION);
-        return -1;
-    }
-
-    p->flags = be32_to_cpu(packet->flags);
-
     packet->pages_alloc = be32_to_cpu(packet->pages_alloc);
     /*
      * If we received a packet that is 100 times bigger than expected
@@ -511,13 +507,6 @@  static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp)
         return -1;
     }
 
-    p->next_packet_size = be32_to_cpu(packet->next_packet_size);
-    p->packet_num = be64_to_cpu(packet->packet_num);
-    p->packets_recved++;
-
-    trace_multifd_recv(p->id, p->packet_num, p->normal_num, p->zero_num,
-                       p->flags, p->next_packet_size);
-
     if (p->normal_num == 0 && p->zero_num == 0) {
         return 0;
     }
@@ -559,6 +548,40 @@  static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp)
     return 0;
 }
 
+static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp)
+{
+    MultiFDPacket_t *packet = p->packet;
+    int ret = 0;
+
+    packet->magic = be32_to_cpu(packet->magic);
+    if (packet->magic != MULTIFD_MAGIC) {
+        error_setg(errp, "multifd: received packet "
+                   "magic %x and expected magic %x",
+                   packet->magic, MULTIFD_MAGIC);
+        return -1;
+    }
+
+    packet->version = be32_to_cpu(packet->version);
+    if (packet->version != MULTIFD_VERSION) {
+        error_setg(errp, "multifd: received packet "
+                   "version %u and expected version %u",
+                   packet->version, MULTIFD_VERSION);
+        return -1;
+    }
+
+    p->flags = be32_to_cpu(packet->flags);
+    p->next_packet_size = be32_to_cpu(packet->next_packet_size);
+    p->packet_num = be64_to_cpu(packet->packet_num);
+    p->packets_recved++;
+
+    ret = multifd_ram_unfill_packet(p, errp);
+
+    trace_multifd_recv_unfill(p->id, p->packet_num, p->flags,
+                              p->next_packet_size);
+
+    return ret;
+}
+
 static bool multifd_send_should_exit(void)
 {
     return qatomic_read(&multifd_send_state->exiting);
@@ -1203,8 +1226,6 @@  bool multifd_send_setup(void)
             p->packet_len = sizeof(MultiFDPacket_t)
                           + sizeof(uint64_t) * page_count;
             p->packet = g_malloc0(p->packet_len);
-            p->packet->magic = cpu_to_be32(MULTIFD_MAGIC);
-            p->packet->version = cpu_to_be32(MULTIFD_VERSION);
         }
         p->name = g_strdup_printf("mig/src/send_%d", i);
         p->write_flags = 0;
diff --git a/migration/trace-events b/migration/trace-events
index 0887cef912..c65902f042 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -128,7 +128,7 @@  postcopy_preempt_reset_channel(void) ""
 # multifd.c
 multifd_new_send_channel_async(uint8_t id) "channel %u"
 multifd_new_send_channel_async_error(uint8_t id, void *err) "channel=%u err=%p"
-multifd_recv(uint8_t id, uint64_t packet_num, uint32_t normal, uint32_t zero, uint32_t flags, uint32_t next_packet_size) "channel %u packet_num %" PRIu64 " normal pages %u zero pages %u flags 0x%x next packet size %u"
+multifd_recv_unfill(uint8_t id, uint64_t packet_num, uint32_t flags, uint32_t next_packet_size) "channel %u packet_num %" PRIu64 " flags 0x%x next packet size %u"
 multifd_recv_new_channel(uint8_t id) "channel %u"
 multifd_recv_sync_main(long packet_num) "packet num %ld"
 multifd_recv_sync_main_signal(uint8_t id) "channel %u"
@@ -136,7 +136,8 @@  multifd_recv_sync_main_wait(uint8_t id) "iter %u"
 multifd_recv_terminate_threads(bool error) "error %d"
 multifd_recv_thread_end(uint8_t id, uint64_t packets) "channel %u packets %" PRIu64
 multifd_recv_thread_start(uint8_t id) "%u"
-multifd_send(uint8_t id, uint64_t packet_num, uint32_t normal_pages, uint32_t zero_pages, uint32_t flags, uint32_t next_packet_size) "channel %u packet_num %" PRIu64 " normal pages %u zero pages %u flags 0x%x next packet size %u"
+multifd_send_fill(uint8_t id, uint64_t packet_num, uint32_t flags, uint32_t next_packet_size) "channel %u packet_num %" PRIu64 " flags 0x%x next packet size %u"
+multifd_send_ram_fill(uint8_t id, uint32_t normal, uint32_t zero) "channel %u normal pages %u zero pages %u"
 multifd_send_error(uint8_t id) "channel %u"
 multifd_send_sync_main(long packet_num) "packet num %ld"
 multifd_send_sync_main_signal(uint8_t id) "channel %u"