diff mbox

[v8,47/54] Round up RAMBlock sizes to host page sizes

Message ID 1443515898-3594-48-git-send-email-dgilbert@redhat.com
State New
Headers show

Commit Message

Dr. David Alan Gilbert Sept. 29, 2015, 8:38 a.m. UTC 
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

RAMBlocks that are not a multiple of host pages in length
cause problems for postcopy (I've seen an ACPI table on aarch64
be 5k in length - i.e. 5x target-page), so round RAMBlock sizes
up to a host-page.

This potentially breaks migration compatibility due to changes
in RAMBlock sizes; however:
   1) x86 and s390 I think always have host=target page size
   2) When I've tried on Power the block sizes already seem aligned.
   3) I don't think there's anything else that maintains per-version
      machine-types for compatibility.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 exec.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Comments

Juan Quintela Oct. 28, 2015, 11:28 a.m. UTC | #1 
"Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote:
> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
>
> RAMBlocks that are not a multiple of host pages in length
> cause problems for postcopy (I've seen an ACPI table on aarch64
> be 5k in length - i.e. 5x target-page), so round RAMBlock sizes
> up to a host-page.
>
> This potentially breaks migration compatibility due to changes
> in RAMBlock sizes; however:
>    1) x86 and s390 I think always have host=target page size
>    2) When I've tried on Power the block sizes already seem aligned.
>    3) I don't think there's anything else that maintains per-version
>       machine-types for compatibility.
>
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

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

We had this problem on the past when we moved the machines to be
Megabyte rounded size, some machines where not.  But in this particular
case, I will clame that having a size that is _not_ of the size of the
host pages is just asking for trouble.
diff mbox

Patch

diff --git a/exec.c b/exec.c
index d7c50e3..f746409 100644
--- a/exec.c
+++ b/exec.c
@@ -1425,7 +1425,7 @@  int qemu_ram_resize(ram_addr_t base, ram_addr_t newsize, Error **errp)
 
     assert(block);
 
-    newsize = TARGET_PAGE_ALIGN(newsize);
+    newsize = HOST_PAGE_ALIGN(newsize);
 
     if (block->used_length == newsize) {
         return 0;
@@ -1569,7 +1569,7 @@  ram_addr_t qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr,
         return -1;
     }
 
-    size = TARGET_PAGE_ALIGN(size);
+    size = HOST_PAGE_ALIGN(size);
     new_block = g_malloc0(sizeof(*new_block));
     new_block->mr = mr;
     new_block->used_length = size;
@@ -1604,8 +1604,8 @@  ram_addr_t qemu_ram_alloc_internal(ram_addr_t size, ram_addr_t max_size,
     ram_addr_t addr;
     Error *local_err = NULL;
 
-    size = TARGET_PAGE_ALIGN(size);
-    max_size = TARGET_PAGE_ALIGN(max_size);
+    size = HOST_PAGE_ALIGN(size);
+    max_size = HOST_PAGE_ALIGN(max_size);
     new_block = g_malloc0(sizeof(*new_block));
     new_block->mr = mr;
     new_block->resized = resized;