From 6d52c264fa9a7a78ee532f45d24704491ce4c431 Mon Sep 17 00:00:00 2001

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

Date: Wed, 1 Aug 2018 13:55:09 +0100

Subject: [PATCH 05/21] migration: introduce control_save_page()

RH-Author: Dr. David Alan Gilbert <dgilbert@redhat.com>

Message-id: <20180801135522.11658-6-dgilbert@redhat.com>

Patchwork-id: 81581

O-Subject: [qemu-kvm RHEL8/virt212 PATCH 05/18] migration: introduce control_save_page()

Bugzilla: 1594384

RH-Acked-by: Peter Xu <peterx@redhat.com>

RH-Acked-by: John Snow <jsnow@redhat.com>

RH-Acked-by: Juan Quintela <quintela@redhat.com>

From: Xiao Guangrong <xiaoguangrong@tencent.com>

Abstract the common function control_save_page() to cleanup the code,

no logic is changed

Reviewed-by: Peter Xu <peterx@redhat.com>

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Signed-off-by: Xiao Guangrong <xiaoguangrong@tencent.com>

Message-Id: <20180330075128.26919-6-xiaoguangrong@tencent.com>

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

(cherry picked from commit 059ff0fb29dd3a56ac2843676915efc279938c6b)

Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>

---

 migration/ram.c | 174 +++++++++++++++++++++++++++++---------------------------

 1 file changed, 89 insertions(+), 85 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c

index cd6d98a..8dc98a5 100644

--- a/migration/ram.c

+++ b/migration/ram.c

@@ -975,6 +975,44 @@ static void ram_release_pages(const char *rbname, uint64_t offset, int pages)

     ram_discard_range(rbname, offset, pages << TARGET_PAGE_BITS);

 }

+/*

+ * @pages: the number of pages written by the control path,

+ *        < 0 - error

+ *        > 0 - number of pages written

+ *

+ * Return true if the pages has been saved, otherwise false is returned.

+ */

+static bool control_save_page(RAMState *rs, RAMBlock *block, ram_addr_t offset,

+                              int *pages)

+{

+    uint64_t bytes_xmit = 0;

+    int ret;

+

+    *pages = -1;

+    ret = ram_control_save_page(rs->f, block->offset, offset, TARGET_PAGE_SIZE,

+                                &bytes_xmit);

+    if (ret == RAM_SAVE_CONTROL_NOT_SUPP) {

+        return false;

+    }

+

+    if (bytes_xmit) {

+        ram_counters.transferred += bytes_xmit;

+        *pages = 1;

+    }

+

+    if (ret == RAM_SAVE_CONTROL_DELAYED) {

+        return true;

+    }

+

+    if (bytes_xmit > 0) {

+        ram_counters.normal++;

+    } else if (bytes_xmit == 0) {

+        ram_counters.duplicate++;

+    }

+

+    return true;

+}

+

 /**

  * ram_save_page: send the given page to the stream

  *

@@ -991,56 +1029,36 @@ static void ram_release_pages(const char *rbname, uint64_t offset, int pages)

 static int ram_save_page(RAMState *rs, PageSearchStatus *pss, bool last_stage)

 {

     int pages = -1;

-    uint64_t bytes_xmit;

-    ram_addr_t current_addr;

     uint8_t *p;

-    int ret;

     bool send_async = true;

     RAMBlock *block = pss->block;

     ram_addr_t offset = pss->page << TARGET_PAGE_BITS;

+    ram_addr_t current_addr = block->offset + offset;

     p = block->host + offset;

     trace_ram_save_page(block->idstr, (uint64_t)offset, p);

-    /* In doubt sent page as normal */

-    bytes_xmit = 0;

-    ret = ram_control_save_page(rs->f, block->offset,

-                           offset, TARGET_PAGE_SIZE, &bytes_xmit);

-    if (bytes_xmit) {

-        ram_counters.transferred += bytes_xmit;

-        pages = 1;

+    if (control_save_page(rs, block, offset, &pages)) {

+        return pages;

     }

     XBZRLE_cache_lock();

-

-    current_addr = block->offset + offset;

-

-    if (ret != RAM_SAVE_CONTROL_NOT_SUPP) {

-        if (ret != RAM_SAVE_CONTROL_DELAYED) {

-            if (bytes_xmit > 0) {

-                ram_counters.normal++;

-            } else if (bytes_xmit == 0) {

-                ram_counters.duplicate++;

-            }

-        }

-    } else {

-        pages = save_zero_page(rs, block, offset);

-        if (pages > 0) {

-            /* Must let xbzrle know, otherwise a previous (now 0'd) cached

-             * page would be stale

+    pages = save_zero_page(rs, block, offset);

+    if (pages > 0) {

+        /* Must let xbzrle know, otherwise a previous (now 0'd) cached

+         * page would be stale

+         */

+        xbzrle_cache_zero_page(rs, current_addr);

+        ram_release_pages(block->idstr, offset, pages);

+    } else if (!rs->ram_bulk_stage &&

+               !migration_in_postcopy() && migrate_use_xbzrle()) {

+        pages = save_xbzrle_page(rs, &p, current_addr, block,

+                                 offset, last_stage);

+        if (!last_stage) {

+            /* Can't send this cached data async, since the cache page

+             * might get updated before it gets to the wire

              */

-            xbzrle_cache_zero_page(rs, current_addr);

-            ram_release_pages(block->idstr, offset, pages);

-        } else if (!rs->ram_bulk_stage &&

-                   !migration_in_postcopy() && migrate_use_xbzrle()) {

-            pages = save_xbzrle_page(rs, &p, current_addr, block,

-                                     offset, last_stage);

-            if (!last_stage) {

-                /* Can't send this cached data async, since the cache page

-                 * might get updated before it gets to the wire

-                 */

-                send_async = false;

-            }

+            send_async = false;

         }

     }

@@ -1175,63 +1193,49 @@ static int ram_save_compressed_page(RAMState *rs, PageSearchStatus *pss,

                                     bool last_stage)

 {

     int pages = -1;

-    uint64_t bytes_xmit = 0;

     uint8_t *p;

-    int ret;

     RAMBlock *block = pss->block;

     ram_addr_t offset = pss->page << TARGET_PAGE_BITS;

     p = block->host + offset;

-    ret = ram_control_save_page(rs->f, block->offset,

-                                offset, TARGET_PAGE_SIZE, &bytes_xmit);

-    if (bytes_xmit) {

-        ram_counters.transferred += bytes_xmit;

-        pages = 1;

+    if (control_save_page(rs, block, offset, &pages)) {

+        return pages;

     }

-    if (ret != RAM_SAVE_CONTROL_NOT_SUPP) {

-        if (ret != RAM_SAVE_CONTROL_DELAYED) {

-            if (bytes_xmit > 0) {

-                ram_counters.normal++;

-            } else if (bytes_xmit == 0) {

-                ram_counters.duplicate++;

-            }

+

+    /* When starting the process of a new block, the first page of

+     * the block should be sent out before other pages in the same

+     * block, and all the pages in last block should have been sent

+     * out, keeping this order is important, because the 'cont' flag

+     * is used to avoid resending the block name.

+     */

+    if (block != rs->last_sent_block) {

+        flush_compressed_data(rs);

+        pages = save_zero_page(rs, block, offset);

+        if (pages > 0) {

+            ram_release_pages(block->idstr, offset, pages);

+        } else {

+            /*

+             * Make sure the first page is sent out before other pages.

+             *

+             * we post it as normal page as compression will take much

+             * CPU resource.

+             */

+            ram_counters.transferred += save_page_header(rs, rs->f, block,

+                                            offset | RAM_SAVE_FLAG_PAGE);

+            qemu_put_buffer_async(rs->f, p, TARGET_PAGE_SIZE,

+                                  migrate_release_ram() &

+                                  migration_in_postcopy());

+            ram_counters.transferred += TARGET_PAGE_SIZE;

+            ram_counters.normal++;

+            pages = 1;

         }

     } else {

-        /* When starting the process of a new block, the first page of

-         * the block should be sent out before other pages in the same

-         * block, and all the pages in last block should have been sent

-         * out, keeping this order is important, because the 'cont' flag

-         * is used to avoid resending the block name.

-         */

-        if (block != rs->last_sent_block) {

-            flush_compressed_data(rs);

-            pages = save_zero_page(rs, block, offset);

-            if (pages > 0) {

-                ram_release_pages(block->idstr, offset, pages);

-            } else {

-                /*

-                 * Make sure the first page is sent out before other pages.

-                 *

-                 * we post it as normal page as compression will take much

-                 * CPU resource.

-                 */

-                ram_counters.transferred += save_page_header(rs, rs->f, block,

-                                                offset | RAM_SAVE_FLAG_PAGE);

-                qemu_put_buffer_async(rs->f, p, TARGET_PAGE_SIZE,

-                                      migrate_release_ram() &

-                                      migration_in_postcopy());

-                ram_counters.transferred += TARGET_PAGE_SIZE;

-                ram_counters.normal++;

-                pages = 1;

-            }

+        pages = save_zero_page(rs, block, offset);

+        if (pages == -1) {

+            pages = compress_page_with_multi_thread(rs, block, offset);

         } else {

-            pages = save_zero_page(rs, block, offset);

-            if (pages == -1) {

-                pages = compress_page_with_multi_thread(rs, block, offset);

-            } else {

-                ram_release_pages(block->idstr, offset, pages);

-            }

+            ram_release_pages(block->idstr, offset, pages);

         }

     }

-- 

1.8.3.1