[Qemu-devel] [PATCH v2 09/12] Rework ram block hash

["Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

RDMA uses a hash from block offset->RAM Block; this isn't needed
on the destination, and it becomes harder to maintain after the next
patch in the series that sorts the block list.

Split the hash so that it's only generated on the source.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 migration/rdma.c | 32 ++++++++++++++++++++------------
 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/migration/rdma.c b/migration/rdma.c
index 8d99378..f541586 100644
--- a/migration/rdma.c
+++ b/migration/rdma.c
@@ -533,23 +533,22 @@ static int rdma_add_block(RDMAContext *rdma, const char *block_name,
                          ram_addr_t block_offset, uint64_t length)
 {
     RDMALocalBlocks *local = &rdma->local_ram_blocks;
-    RDMALocalBlock *block = g_hash_table_lookup(rdma->blockmap,
-        (void *)(uintptr_t)block_offset);
+    RDMALocalBlock *block;
     RDMALocalBlock *old = local->block;
 
-    assert(block == NULL);
-
     local->block = g_malloc0(sizeof(RDMALocalBlock) * (local->nb_blocks + 1));
 
     if (local->nb_blocks) {
         int x;
 
-        for (x = 0; x < local->nb_blocks; x++) {
-            g_hash_table_remove(rdma->blockmap,
-                                (void *)(uintptr_t)old[x].offset);
-            g_hash_table_insert(rdma->blockmap,
-                                (void *)(uintptr_t)old[x].offset,
-                                &local->block[x]);
+        if (rdma->blockmap) {
+            for (x = 0; x < local->nb_blocks; x++) {
+                g_hash_table_remove(rdma->blockmap,
+                                    (void *)(uintptr_t)old[x].offset);
+                g_hash_table_insert(rdma->blockmap,
+                                    (void *)(uintptr_t)old[x].offset,
+                                    &local->block[x]);
+            }
         }
         memcpy(local->block, old, sizeof(RDMALocalBlock) * local->nb_blocks);
         g_free(old);
@@ -571,7 +570,9 @@ static int rdma_add_block(RDMAContext *rdma, const char *block_name,
 
     block->is_ram_block = local->init ? false : true;
 
-    g_hash_table_insert(rdma->blockmap, (void *) block_offset, block);
+    if (rdma->blockmap) {
+        g_hash_table_insert(rdma->blockmap, (void *) block_offset, block);
+    }
 
     trace_rdma_add_block(block_name, local->nb_blocks,
                          (uintptr_t) block->local_host_addr,
@@ -607,7 +608,6 @@ static int qemu_rdma_init_ram_blocks(RDMAContext *rdma)
     RDMALocalBlocks *local = &rdma->local_ram_blocks;
 
     assert(rdma->blockmap == NULL);
-    rdma->blockmap = g_hash_table_new(g_direct_hash, g_direct_equal);
     memset(local, 0, sizeof *local);
     qemu_ram_foreach_block(qemu_rdma_init_one_block, rdma);
     trace_qemu_rdma_init_ram_blocks(local->nb_blocks);
@@ -2292,6 +2292,14 @@ static int qemu_rdma_source_init(RDMAContext *rdma, Error **errp, bool pin_all)
         goto err_rdma_source_init;
     }
 
+    /* Build the hash that maps from offset to RAMBlock */
+    rdma->blockmap = g_hash_table_new(g_direct_hash, g_direct_equal);
+    for (idx = 0; idx < rdma->local_ram_blocks.nb_blocks; idx++) {
+        g_hash_table_insert(rdma->blockmap,
+                (void *)(uintptr_t)rdma->local_ram_blocks.block[idx].offset,
+                &rdma->local_ram_blocks.block[idx]);
+    }
+
     for (idx = 0; idx < RDMA_WRID_MAX; idx++) {
         ret = qemu_rdma_reg_control(rdma, idx);
         if (ret) {
-- 
2.4.2