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[09/15] postcopy: Load huge pages in one go

Message ID 20170106182823.1960-10-dgilbert@redhat.com
State New
Headers show

Commit Message

Dr. David Alan Gilbert Jan. 6, 2017, 6:28 p.m. UTC 
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

The existing postcopy RAM load loop already ensures that it
glues together whole host-pages from the target page size chunks sent
over the wire.  Modify the definition of host page that it uses
to be the RAM block page size and thus be huge pages where appropriate.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 migration/ram.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

Comments

Juan Quintela Jan. 25, 2017, 10:31 a.m. UTC | #1 
"Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote:
> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
>
> The existing postcopy RAM load loop already ensures that it
> glues together whole host-pages from the target page size chunks sent
> over the wire.  Modify the definition of host page that it uses
> to be the RAM block page size and thus be huge pages where appropriate.
>
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Reviewed-by: Juan Quintela <quintela@redhat.com>
diff mbox

Patch

diff --git a/migration/ram.c b/migration/ram.c
index ebcf740..9c9e8a2 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -2395,7 +2395,7 @@  static int ram_load_postcopy(QEMUFile *f)
 {
     int flags = 0, ret = 0;
     bool place_needed = false;
-    bool matching_page_sizes = qemu_host_page_size == TARGET_PAGE_SIZE;
+    bool matching_page_sizes = false;
     MigrationIncomingState *mis = migration_incoming_get_current();
     /* Temporary page that is later 'placed' */
     void *postcopy_host_page = postcopy_get_tmp_page(mis);
@@ -2425,8 +2425,11 @@  static int ram_load_postcopy(QEMUFile *f)
                 ret = -EINVAL;
                 break;
             }
+            matching_page_sizes = block->page_size == TARGET_PAGE_SIZE;
             /*
-             * Postcopy requires that we place whole host pages atomically.
+             * Postcopy requires that we place whole host pages atomically;
+             * these may be huge pages for RAMBlocks that are backed by
+             * hugetlbfs.
              * To make it atomic, the data is read into a temporary page
              * that's moved into place later.
              * The migration protocol uses,  possibly smaller, target-pages
@@ -2434,9 +2437,9 @@  static int ram_load_postcopy(QEMUFile *f)
              * of a host page in order.
              */
             page_buffer = postcopy_host_page +
-                          ((uintptr_t)host & ~qemu_host_page_mask);
+                          ((uintptr_t)host & (block->page_size - 1));
             /* If all TP are zero then we can optimise the place */
-            if (!((uintptr_t)host & ~qemu_host_page_mask)) {
+            if (!((uintptr_t)host & (block->page_size - 1))) {
                 all_zero = true;
             } else {
                 /* not the 1st TP within the HP */
@@ -2454,7 +2457,7 @@  static int ram_load_postcopy(QEMUFile *f)
              * page
              */
             place_needed = (((uintptr_t)host + TARGET_PAGE_SIZE) &
-                                     ~qemu_host_page_mask) == 0;
+                                     (block->page_size - 1)) == 0;
             place_source = postcopy_host_page;
         }
         last_host = host;