[Qemu-devel] [PATCH 0/2] migration/postcopy: cleanup function postcopy_chunk_hostpages_pass

[Qemu-devel] [PATCH 0/2] migration/postcopy: cleanup function postcopy_chunk_hostpages_pass

[Wei Yang]

Here are two trivial function cleanup.

BTW, I didn't test them since TPS == HPS. How could I setup a guest with
TPS != HPS?

Wei Yang (2):
  migration/postcopy: reduce one operation to calculate fixup_start_addr
  migration/postcopy: do_fixup is true when host_offset is non-zero

 migration/ram.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

-- 
2.17.1

[Qemu-devel] [PATCH 1/2] migration/postcopy: reduce one operation to calculate fixup_start_addr

[Wei Yang]

Use the same way for run_end to calculate run_start, which saves one
operation.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
---
 migration/ram.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index 410e0f89fe..c4dc36e525 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -2884,10 +2884,12 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass,
         host_offset = run_start % host_ratio;
         if (host_offset) {
             do_fixup = true;
-            run_start -= host_offset;
-            fixup_start_addr = run_start;
-            /* For the next pass */
-            run_start = run_start + host_ratio;
+            fixup_start_addr = run_start - host_offset;
+            /*
+             * This host page has gone, the next loop iteration starts
+             * from after the fixup
+             */
+            run_start = fixup_start_addr + host_ratio;
         } else {
             /* Find the end of this run */
             unsigned long run_end;
-- 
2.17.1

[Qemu-devel] [PATCH 2/2] migration/postcopy: do_fixup is true when host_offset is non-zero

[Wei Yang]

This means it is not necessary to spare an extra variable to hold this
condition. Use host_offset directly is fine.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
---
 migration/ram.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index c4dc36e525..b0ca0059c4 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -2873,7 +2873,6 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass,
     }
 
     while (run_start < pages) {
-        bool do_fixup = false;
         unsigned long fixup_start_addr;
         unsigned long host_offset;
 
@@ -2883,7 +2882,6 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass,
          */
         host_offset = run_start % host_ratio;
         if (host_offset) {
-            do_fixup = true;
             fixup_start_addr = run_start - host_offset;
             /*
              * This host page has gone, the next loop iteration starts
@@ -2905,7 +2903,6 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass,
              */
             host_offset = run_end % host_ratio;
             if (host_offset) {
-                do_fixup = true;
                 fixup_start_addr = run_end - host_offset;
                 /*
                  * This host page has gone, the next loop iteration starts
@@ -2921,7 +2918,7 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass,
             }
         }
 
-        if (do_fixup) {
+        if (host_offset) {
             unsigned long page;
 
             /* Tell the destination to discard this page */
-- 
2.17.1

Re: [Qemu-devel] [PATCH 1/2] migration/postcopy: reduce one operation to calculate fixup_start_addr

[Dr. David Alan Gilbert]

* Wei Yang (richardw.yang@linux.intel.com) wrote:
> Use the same way for run_end to calculate run_start, which saves one
> operation.
> 
> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>

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

> ---
>  migration/ram.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/migration/ram.c b/migration/ram.c
> index 410e0f89fe..c4dc36e525 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -2884,10 +2884,12 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass,
>          host_offset = run_start % host_ratio;
>          if (host_offset) {
>              do_fixup = true;
> -            run_start -= host_offset;
> -            fixup_start_addr = run_start;
> -            /* For the next pass */
> -            run_start = run_start + host_ratio;
> +            fixup_start_addr = run_start - host_offset;
> +            /*
> +             * This host page has gone, the next loop iteration starts
> +             * from after the fixup
> +             */
> +            run_start = fixup_start_addr + host_ratio;
>          } else {
>              /* Find the end of this run */
>              unsigned long run_end;
> -- 
> 2.17.1
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

Re: [Qemu-devel] [PATCH 2/2] migration/postcopy: do_fixup is true when host_offset is non-zero

[Dr. David Alan Gilbert]

* Wei Yang (richardw.yang@linux.intel.com) wrote:
> This means it is not necessary to spare an extra variable to hold this
> condition. Use host_offset directly is fine.
> 
> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>

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

> ---
>  migration/ram.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/migration/ram.c b/migration/ram.c
> index c4dc36e525..b0ca0059c4 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -2873,7 +2873,6 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass,
>      }
>  
>      while (run_start < pages) {
> -        bool do_fixup = false;
>          unsigned long fixup_start_addr;
>          unsigned long host_offset;
>  
> @@ -2883,7 +2882,6 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass,
>           */
>          host_offset = run_start % host_ratio;
>          if (host_offset) {
> -            do_fixup = true;
>              fixup_start_addr = run_start - host_offset;
>              /*
>               * This host page has gone, the next loop iteration starts
> @@ -2905,7 +2903,6 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass,
>               */
>              host_offset = run_end % host_ratio;
>              if (host_offset) {
> -                do_fixup = true;
>                  fixup_start_addr = run_end - host_offset;
>                  /*
>                   * This host page has gone, the next loop iteration starts
> @@ -2921,7 +2918,7 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass,
>              }
>          }
>  
> -        if (do_fixup) {
> +        if (host_offset) {
>              unsigned long page;
>  
>              /* Tell the destination to discard this page */
> -- 
> 2.17.1
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

Re: [Qemu-devel] [PATCH 0/2] migration/postcopy: cleanup function postcopy_chunk_hostpages_pass

[Dr. David Alan Gilbert]

* Wei Yang (richardw.yang@linux.intel.com) wrote:
> Here are two trivial function cleanup.

Queued

> BTW, I didn't test them since TPS == HPS. How could I setup a guest with
> TPS != HPS?
> 
> Wei Yang (2):
>   migration/postcopy: reduce one operation to calculate fixup_start_addr
>   migration/postcopy: do_fixup is true when host_offset is non-zero
> 
>  migration/ram.c | 15 +++++++--------
>  1 file changed, 7 insertions(+), 8 deletions(-)
> 
> -- 
> 2.17.1
> 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK