exec: Change RAMBlockIterFunc definition

Currently, qemu_ram_foreach_* calls RAMBlockIterFunc with many
block-specific arguments. But often iter func needs RAMBlock*.
This refactoring is needed for fast access to RAMBlock flags from
qemu_ram_foreach_block's callback. The only way to achieve this now
is to call qemu_ram_block_from_host (which also enumerates blocks).

So, this patch reduces complexity of
qemu_ram_foreach_block() -> cb() -> qemu_ram_block_from_host()
from O(n^2) to O(n).

Fix RAMBlockIterFunc definition and add some functions to read
RAMBlock* fields witch were passed.

Signed-off-by: Yury Kotov <yury-kotov@yandex-team.ru>
Message-Id: <20190215174548.2630-2-yury-kotov@yandex-team.ru>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

1 files changed, 21 insertions, 15 deletions

diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
index fa09dba534..b098816221 100644
--- a/migration/postcopy-ram.c
+++ b/migration/postcopy-ram.c
@@ -319,10 +319,10 @@ static bool ufd_check_and_apply(int ufd, MigrationIncomingState *mis)
 
 /* Callback from postcopy_ram_supported_by_host block iterator.
  */
-static int test_ramblock_postcopiable(const char *block_name, void *host_addr,
-                             ram_addr_t offset, ram_addr_t length, void *opaque)
+static int test_ramblock_postcopiable(RAMBlock *rb, void *opaque)
 {
-    RAMBlock *rb = qemu_ram_block_by_name(block_name);
+    const char *block_name = qemu_ram_get_idstr(rb);
+    ram_addr_t length = qemu_ram_get_used_length(rb);
     size_t pagesize = qemu_ram_pagesize(rb);
 
     if (length % pagesize) {
@@ -443,9 +443,12 @@ out:
  * must be done right at the start prior to pre-copy.
  * opaque should be the MIS.
  */
-static int init_range(const char *block_name, void *host_addr,
-                      ram_addr_t offset, ram_addr_t length, void *opaque)
+static int init_range(RAMBlock *rb, void *opaque)
 {
+    const char *block_name = qemu_ram_get_idstr(rb);
+    void *host_addr = qemu_ram_get_host_addr(rb);
+    ram_addr_t offset = qemu_ram_get_offset(rb);
+    ram_addr_t length = qemu_ram_get_used_length(rb);
     trace_postcopy_init_range(block_name, host_addr, offset, length);
 
     /*
@@ -465,9 +468,12 @@ static int init_range(const char *block_name, void *host_addr,
  * At the end of migration, undo the effects of init_range
  * opaque should be the MIS.
  */
-static int cleanup_range(const char *block_name, void *host_addr,
-                        ram_addr_t offset, ram_addr_t length, void *opaque)
+static int cleanup_range(RAMBlock *rb, void *opaque)
 {
+    const char *block_name = qemu_ram_get_idstr(rb);
+    void *host_addr = qemu_ram_get_host_addr(rb);
+    ram_addr_t offset = qemu_ram_get_offset(rb);
+    ram_addr_t length = qemu_ram_get_used_length(rb);
     MigrationIncomingState *mis = opaque;
     struct uffdio_range range_struct;
     trace_postcopy_cleanup_range(block_name, host_addr, offset, length);
@@ -586,9 +592,12 @@ int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis)
 /*
  * Disable huge pages on an area
  */
-static int nhp_range(const char *block_name, void *host_addr,
-                    ram_addr_t offset, ram_addr_t length, void *opaque)
+static int nhp_range(RAMBlock *rb, void *opaque)
 {
+    const char *block_name = qemu_ram_get_idstr(rb);
+    void *host_addr = qemu_ram_get_host_addr(rb);
+    ram_addr_t offset = qemu_ram_get_offset(rb);
+    ram_addr_t length = qemu_ram_get_used_length(rb);
     trace_postcopy_nhp_range(block_name, host_addr, offset, length);
 
     /*
@@ -626,15 +635,13 @@ int postcopy_ram_prepare_discard(MigrationIncomingState *mis)
  *   opaque: MigrationIncomingState pointer
  * Returns 0 on success
  */
-static int ram_block_enable_notify(const char *block_name, void *host_addr,
-                                   ram_addr_t offset, ram_addr_t length,
-                                   void *opaque)
+static int ram_block_enable_notify(RAMBlock *rb, void *opaque)
 {
     MigrationIncomingState *mis = opaque;
     struct uffdio_register reg_struct;
 
-    reg_struct.range.start = (uintptr_t)host_addr;
-    reg_struct.range.len = length;
+    reg_struct.range.start = (uintptr_t)qemu_ram_get_host_addr(rb);
+    reg_struct.range.len = qemu_ram_get_used_length(rb);
     reg_struct.mode = UFFDIO_REGISTER_MODE_MISSING;
 
     /* Now tell our userfault_fd that it's responsible for this area */
@@ -647,7 +654,6 @@ static int ram_block_enable_notify(const char *block_name, void *host_addr,
         return -1;
     }
     if (reg_struct.ioctls & ((__u64)1 << _UFFDIO_ZEROPAGE)) {
-        RAMBlock *rb = qemu_ram_block_by_name(block_name);
         qemu_ram_set_uf_zeroable(rb);
     }