[PATCH 06/11] migration: Move iov from pages to params

[Juan Quintela]

This will allow us to reduce the number of system calls on the next patch.

Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 migration/multifd.h |  8 ++++++--
 migration/multifd.c | 30 +++++++++++++++++++++---------
 2 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/migration/multifd.h b/migration/multifd.h
index 15c50ca0b2..67f9104051 100644
--- a/migration/multifd.h
+++ b/migration/multifd.h
@@ -62,8 +62,6 @@ typedef struct {
     uint64_t packet_num;
     /* offset of each page */
     ram_addr_t *offset;
-    /* pointer to each page */
-    struct iovec *iov;
     RAMBlock *block;
 } MultiFDPages_t;
 
@@ -110,6 +108,10 @@ typedef struct {
     uint64_t num_pages;
     /* syncs main thread and channels */
     QemuSemaphore sem_sync;
+    /* buffers to send */
+    struct iovec *iov;
+    /* used for compression methods */
+    uint32_t iovs_used;
     /* used for compression methods */
     void *data;
 }  MultiFDSendParams;
@@ -149,6 +151,8 @@ typedef struct {
     uint64_t num_pages;
     /* syncs main thread and channels */
     QemuSemaphore sem_sync;
+    /* buffers to recv */
+    struct iovec *iov;
     /* used for de-compression methods */
     void *data;
 } MultiFDRecvParams;
diff --git a/migration/multifd.c b/migration/multifd.c
index e2adcdffa1..4368b7f855 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -87,6 +87,14 @@ static void nocomp_send_cleanup(MultiFDSendParams *p, Error 
**errp)
 static int nocomp_send_prepare(MultiFDSendParams *p, uint32_t used,
                                Error **errp)
 {
+    MultiFDPages_t *pages = p->pages;
+
+    for (int i = 0; i < used; i++) {
+        p->iov[p->iovs_used].iov_base = pages->block->host + pages->offset[i];
+        p->iov[p->iovs_used].iov_len = qemu_target_page_size();
+        p->iovs_used++;
+    }
+
     p->next_packet_size = used * qemu_target_page_size();
     p->flags |= MULTIFD_FLAG_NOCOMP;
     return 0;
@@ -105,7 +113,7 @@ static int nocomp_send_prepare(MultiFDSendParams *p, 
uint32_t used,
  */
 static int nocomp_send_write(MultiFDSendParams *p, uint32_t used, Error **errp)
 {
-    return qio_channel_writev_all(p->c, p->pages->iov, used, errp);
+    return qio_channel_writev_all(p->c, p->iov, p->iovs_used, errp);
 }
 
 /**
@@ -154,7 +162,11 @@ static int nocomp_recv_pages(MultiFDRecvParams *p, 
uint32_t used, Error **errp)
                    p->id, flags, MULTIFD_FLAG_NOCOMP);
         return -1;
     }
-    return qio_channel_readv_all(p->c, p->pages->iov, used, errp);
+    for (int i = 0; i < p->pages->used; i++) {
+        p->iov[i].iov_base = p->pages->block->host + p->pages->offset[i];
+        p->iov[i].iov_len = qemu_target_page_size();
+    }
+    return qio_channel_readv_all(p->c, p->iov, used, errp);
 }
 
 static MultiFDMethods multifd_nocomp_ops = {
@@ -244,7 +256,6 @@ static MultiFDPages_t *multifd_pages_init(size_t size)
     MultiFDPages_t *pages = g_new0(MultiFDPages_t, 1);
 
     pages->allocated = size;
-    pages->iov = g_new0(struct iovec, size);
     pages->offset = g_new0(ram_addr_t, size);
 
     return pages;
@@ -256,8 +267,6 @@ static void multifd_pages_clear(MultiFDPages_t *pages)
     pages->allocated = 0;
     pages->packet_num = 0;
     pages->block = NULL;
-    g_free(pages->iov);
-    pages->iov = NULL;
     g_free(pages->offset);
     pages->offset = NULL;
     g_free(pages);
@@ -366,8 +375,6 @@ static int multifd_recv_unfill_packet(MultiFDRecvParams *p, 
Error **errp)
         }
         p->pages->offset[i] = offset;
         p->pages->block = block;
-        p->pages->iov[i].iov_base = block->host + offset;
-        p->pages->iov[i].iov_len = qemu_target_page_size();
     }
 
     return 0;
@@ -471,8 +478,6 @@ int multifd_queue_page(QEMUFile *f, RAMBlock *block, 
ram_addr_t offset)
 
     if (pages->block == block) {
         pages->offset[pages->used] = offset;
-        pages->iov[pages->used].iov_base = block->host + offset;
-        pages->iov[pages->used].iov_len = qemu_target_page_size();
         pages->used++;
 
         if (pages->used < pages->allocated) {
@@ -565,6 +570,8 @@ void multifd_save_cleanup(void)
         p->packet_len = 0;
         g_free(p->packet);
         p->packet = NULL;
+        g_free(p->iov);
+        p->iov = NULL;
         multifd_send_state->ops->send_cleanup(p, &local_err);
         if (local_err) {
             migrate_set_error(migrate_get_current(), local_err);
@@ -653,6 +660,7 @@ static void *multifd_send_thread(void *opaque)
             uint32_t used = p->pages->used;
             uint64_t packet_num = p->packet_num;
             flags = p->flags;
+            p->iovs_used = 0;
 
             if (used) {
                 ret = multifd_send_state->ops->send_prepare(p, used,
@@ -922,6 +930,7 @@ int multifd_save_setup(Error **errp)
         p->packet->version = cpu_to_be32(MULTIFD_VERSION);
         p->name = g_strdup_printf("multifdsend_%d", i);
         p->tls_hostname = g_strdup(s->hostname);
+        p->iov = g_new0(struct iovec, page_count);
         socket_send_channel_create(multifd_new_send_channel_async, p);
     }
 
@@ -1021,6 +1030,8 @@ int multifd_load_cleanup(Error **errp)
         p->packet_len = 0;
         g_free(p->packet);
         p->packet = NULL;
+        g_free(p->iov);
+        p->iov = NULL;
         multifd_recv_state->ops->recv_cleanup(p);
     }
     qemu_sem_destroy(&multifd_recv_state->sem_sync);
@@ -1161,6 +1172,7 @@ int multifd_load_setup(Error **errp)
                       + sizeof(uint64_t) * page_count;
         p->packet = g_malloc0(p->packet_len);
         p->name = g_strdup_printf("multifdrecv_%d", i);
+        p->iov = g_new0(struct iovec, page_count);
     }
 
     for (i = 0; i < thread_count; i++) {
-- 
2.33.1