From: Juan Quintela <quintela@redhat.com>
Date: Tue, 10 May 2022 17:37:36 +0000 (+0200)
Subject: migration: Calculate ram size once
X-Git-Tag: xenpvh-tag~10^2~8
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=bb63c3aec89df85422de066ca47b84485df9451d;p=users%2Fdwmw2%2Fqemu.git

migration: Calculate ram size once

We are recalculating ram size continously, when we know that it don't
change during migration.  Create a field in RAMState to track it.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---

diff --git a/migration/ram.c b/migration/ram.c
index 4dd9cf87ea..d108bf6951 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -330,6 +330,8 @@ struct RAMState {
     PageSearchStatus pss[RAM_CHANNEL_MAX];
     /* UFFD file descriptor, used in 'write-tracking' migration */
     int uffdio_fd;
+    /* total ram size in bytes */
+    uint64_t ram_bytes_total;
     /* Last block that we have visited searching for dirty pages */
     RAMBlock *last_seen_block;
     /* Last dirty target page we have sent */
@@ -2546,7 +2548,7 @@ static int ram_find_and_save_block(RAMState *rs)
     int pages = 0;
 
     /* No dirty page as there is zero RAM */
-    if (!ram_bytes_total()) {
+    if (!rs->ram_bytes_total) {
         return pages;
     }
 
@@ -3009,13 +3011,14 @@ static int ram_state_init(RAMState **rsp)
     qemu_mutex_init(&(*rsp)->bitmap_mutex);
     qemu_mutex_init(&(*rsp)->src_page_req_mutex);
     QSIMPLEQ_INIT(&(*rsp)->src_page_requests);
+    (*rsp)->ram_bytes_total = ram_bytes_total();
 
     /*
      * Count the total number of pages used by ram blocks not including any
      * gaps due to alignment or unplugs.
      * This must match with the initial values of dirty bitmap.
      */
-    (*rsp)->migration_dirty_pages = ram_bytes_total() >> TARGET_PAGE_BITS;
+    (*rsp)->migration_dirty_pages = (*rsp)->ram_bytes_total >> TARGET_PAGE_BITS;
     ram_state_reset(*rsp);
 
     return 0;