[2/3] migration/postcopy: break the loop when there is no more page to discard
diff mbox series

Message ID 20190627020822.15485-3-richardw.yang@linux.intel.com
State New
Headers show
Series
  • migration/postcopy: cleanup function postcopy_send_discard_bm_ram
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Commit Message

Wei Yang June 27, 2019, 2:08 a.m. UTC
When one is equal or bigger then end, it means there is no page to
discard. Just break the loop in this case instead of processing it.

No functional change, just refactor it a little.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
---
 migration/ram.c | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

Comments

Dr. David Alan Gilbert June 28, 2019, 3:15 p.m. UTC | #1
* Wei Yang (richardw.yang@linux.intel.com) wrote:
> When one is equal or bigger then end, it means there is no page to
> discard. Just break the loop in this case instead of processing it.
> 
> No functional change, just refactor it a little.
> 
> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>

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

> ---
>  migration/ram.c | 26 +++++++++++++-------------
>  1 file changed, 13 insertions(+), 13 deletions(-)
> 
> diff --git a/migration/ram.c b/migration/ram.c
> index b78169e811..b41b58ee54 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -2776,23 +2776,23 @@ static int postcopy_send_discard_bm_ram(MigrationState *ms,
>  
>      for (current = 0; current < end; ) {
>          unsigned long one = find_next_bit(unsentmap, end, current);
> +        unsigned long zero, discard_length;
>  
> -        if (one < end) {
> -            unsigned long zero = find_next_zero_bit(unsentmap, end, one + 1);
> -            unsigned long discard_length;
> +        if (one >= end) {
> +            break;
> +        }
>  
> -            if (zero >= end) {
> -                discard_length = end - one;
> -            } else {
> -                discard_length = zero - one;
> -            }
> -            if (discard_length) {
> -                postcopy_discard_send_range(ms, pds, one, discard_length);
> -            }
> -            current = one + discard_length;
> +        zero = find_next_zero_bit(unsentmap, end, one + 1);
> +
> +        if (zero >= end) {
> +            discard_length = end - one;
>          } else {
> -            current = one;
> +            discard_length = zero - one;
> +        }
> +        if (discard_length) {
> +            postcopy_discard_send_range(ms, pds, one, discard_length);
>          }
> +        current = one + discard_length;
>      }
>  
>      return 0;
> -- 
> 2.19.1
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

Patch
diff mbox series

diff --git a/migration/ram.c b/migration/ram.c
index b78169e811..b41b58ee54 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -2776,23 +2776,23 @@  static int postcopy_send_discard_bm_ram(MigrationState *ms,
 
     for (current = 0; current < end; ) {
         unsigned long one = find_next_bit(unsentmap, end, current);
+        unsigned long zero, discard_length;
 
-        if (one < end) {
-            unsigned long zero = find_next_zero_bit(unsentmap, end, one + 1);
-            unsigned long discard_length;
+        if (one >= end) {
+            break;
+        }
 
-            if (zero >= end) {
-                discard_length = end - one;
-            } else {
-                discard_length = zero - one;
-            }
-            if (discard_length) {
-                postcopy_discard_send_range(ms, pds, one, discard_length);
-            }
-            current = one + discard_length;
+        zero = find_next_zero_bit(unsentmap, end, one + 1);
+
+        if (zero >= end) {
+            discard_length = end - one;
         } else {
-            current = one;
+            discard_length = zero - one;
+        }
+        if (discard_length) {
+            postcopy_discard_send_range(ms, pds, one, discard_length);
         }
+        current = one + discard_length;
     }
 
     return 0;