* [Qemu-devel] [PATCH] Fix calculation of number of bits in the migration bitmap
@ 2012-10-31 11:19 Orit Wasserman
2012-10-31 11:24 ` Avi Kivity
2012-10-31 11:25 ` Peter Maydell
0 siblings, 2 replies; 5+ messages in thread
From: Orit Wasserman @ 2012-10-31 11:19 UTC (permalink / raw)
To: qemu-devel; +Cc: pbonzini, aliguori, Orit Wasserman, avi, quintela
The number of bits is off by one, for example if last_ram_offset
is 0x1000 (the guest has one page) we get 0 bits instead of 1.
Signed-off-by: Orit Wasserman <owasserm@redhat.com>
---
arch_init.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch_init.c b/arch_init.c
index b75a4c5..a80c3c8 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -565,7 +565,7 @@ static void reset_ram_globals(void)
static int ram_save_setup(QEMUFile *f, void *opaque)
{
RAMBlock *block;
- int64_t ram_pages = last_ram_offset() >> TARGET_PAGE_BITS;
+ int64_t ram_pages = (last_ram_offset() >> TARGET_PAGE_BITS) + 1;
migration_bitmap = bitmap_new(ram_pages);
bitmap_set(migration_bitmap, 0, ram_pages);
--
1.7.11.7
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [Qemu-devel] [PATCH] Fix calculation of number of bits in the migration bitmap
2012-10-31 11:19 [Qemu-devel] [PATCH] Fix calculation of number of bits in the migration bitmap Orit Wasserman
@ 2012-10-31 11:24 ` Avi Kivity
2012-10-31 12:00 ` Orit Wasserman
2012-10-31 11:25 ` Peter Maydell
1 sibling, 1 reply; 5+ messages in thread
From: Avi Kivity @ 2012-10-31 11:24 UTC (permalink / raw)
To: Orit Wasserman; +Cc: pbonzini, aliguori, qemu-devel, quintela
On 10/31/2012 01:19 PM, Orit Wasserman wrote:
> The number of bits is off by one, for example if last_ram_offset
> is 0x1000 (the guest has one page) we get 0 bits instead of 1.
>
> Signed-off-by: Orit Wasserman <owasserm@redhat.com>
> ---
> arch_init.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch_init.c b/arch_init.c
> index b75a4c5..a80c3c8 100644
> --- a/arch_init.c
> +++ b/arch_init.c
> @@ -565,7 +565,7 @@ static void reset_ram_globals(void)
> static int ram_save_setup(QEMUFile *f, void *opaque)
> {
> RAMBlock *block;
> - int64_t ram_pages = last_ram_offset() >> TARGET_PAGE_BITS;
> + int64_t ram_pages = (last_ram_offset() >> TARGET_PAGE_BITS) + 1;
>
The original code calculates 1 for your example case.
--
error compiling committee.c: too many arguments to function
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [Qemu-devel] [PATCH] Fix calculation of number of bits in the migration bitmap
2012-10-31 11:24 ` Avi Kivity
@ 2012-10-31 12:00 ` Orit Wasserman
0 siblings, 0 replies; 5+ messages in thread
From: Orit Wasserman @ 2012-10-31 12:00 UTC (permalink / raw)
To: Avi Kivity; +Cc: pbonzini, aliguori, qemu-devel, quintela
On 10/31/2012 01:24 PM, Avi Kivity wrote:
> On 10/31/2012 01:19 PM, Orit Wasserman wrote:
>> The number of bits is off by one, for example if last_ram_offset
>> is 0x1000 (the guest has one page) we get 0 bits instead of 1.
>>
>> Signed-off-by: Orit Wasserman <owasserm@redhat.com>
>> ---
>> arch_init.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch_init.c b/arch_init.c
>> index b75a4c5..a80c3c8 100644
>> --- a/arch_init.c
>> +++ b/arch_init.c
>> @@ -565,7 +565,7 @@ static void reset_ram_globals(void)
>> static int ram_save_setup(QEMUFile *f, void *opaque)
>> {
>> RAMBlock *block;
>> - int64_t ram_pages = last_ram_offset() >> TARGET_PAGE_BITS;
>> + int64_t ram_pages = (last_ram_offset() >> TARGET_PAGE_BITS) + 1;
>>
>
> The original code calculates 1 for your example case.
You correct ...
sorry ...
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [Qemu-devel] [PATCH] Fix calculation of number of bits in the migration bitmap
2012-10-31 11:19 [Qemu-devel] [PATCH] Fix calculation of number of bits in the migration bitmap Orit Wasserman
2012-10-31 11:24 ` Avi Kivity
@ 2012-10-31 11:25 ` Peter Maydell
2012-10-31 12:04 ` Orit Wasserman
1 sibling, 1 reply; 5+ messages in thread
From: Peter Maydell @ 2012-10-31 11:25 UTC (permalink / raw)
To: Orit Wasserman; +Cc: pbonzini, aliguori, quintela, qemu-devel, avi
On 31 October 2012 12:19, Orit Wasserman <owasserm@redhat.com> wrote:
> The number of bits is off by one, for example if last_ram_offset
> is 0x1000 (the guest has one page) we get 0 bits instead of 1.
>
> Signed-off-by: Orit Wasserman <owasserm@redhat.com>
> ---
> arch_init.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch_init.c b/arch_init.c
> index b75a4c5..a80c3c8 100644
> --- a/arch_init.c
> +++ b/arch_init.c
> @@ -565,7 +565,7 @@ static void reset_ram_globals(void)
> static int ram_save_setup(QEMUFile *f, void *opaque)
> {
> RAMBlock *block;
> - int64_t ram_pages = last_ram_offset() >> TARGET_PAGE_BITS;
> + int64_t ram_pages = (last_ram_offset() >> TARGET_PAGE_BITS) + 1;
This will give you an extra bit if the last_ram_offset()
is an exact multiple of the page size, though. Try
int64_t ram_pages = DIV_ROUND_UP(last_ram_offset(), TARGET_PAGE_SIZE);
?
-- PMM
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [Qemu-devel] [PATCH] Fix calculation of number of bits in the migration bitmap
2012-10-31 11:25 ` Peter Maydell
@ 2012-10-31 12:04 ` Orit Wasserman
0 siblings, 0 replies; 5+ messages in thread
From: Orit Wasserman @ 2012-10-31 12:04 UTC (permalink / raw)
To: Peter Maydell; +Cc: pbonzini, aliguori, quintela, qemu-devel, avi
On 10/31/2012 01:25 PM, Peter Maydell wrote:
> On 31 October 2012 12:19, Orit Wasserman <owasserm@redhat.com> wrote:
>> The number of bits is off by one, for example if last_ram_offset
>> is 0x1000 (the guest has one page) we get 0 bits instead of 1.
>>
>> Signed-off-by: Orit Wasserman <owasserm@redhat.com>
>> ---
>> arch_init.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch_init.c b/arch_init.c
>> index b75a4c5..a80c3c8 100644
>> --- a/arch_init.c
>> +++ b/arch_init.c
>> @@ -565,7 +565,7 @@ static void reset_ram_globals(void)
>> static int ram_save_setup(QEMUFile *f, void *opaque)
>> {
>> RAMBlock *block;
>> - int64_t ram_pages = last_ram_offset() >> TARGET_PAGE_BITS;
>> + int64_t ram_pages = (last_ram_offset() >> TARGET_PAGE_BITS) + 1;
>
> This will give you an extra bit if the last_ram_offset()
> is an exact multiple of the page size, though. Try
> int64_t ram_pages = DIV_ROUND_UP(last_ram_offset(), TARGET_PAGE_SIZE);
Good idea ...
> ?
>
> -- PMM
>
^ permalink raw reply [flat|nested] 5+ messages in thread
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2012-10-31 11:19 [Qemu-devel] [PATCH] Fix calculation of number of bits in the migration bitmap Orit Wasserman
2012-10-31 11:24 ` Avi Kivity
2012-10-31 12:00 ` Orit Wasserman
2012-10-31 11:25 ` Peter Maydell
2012-10-31 12:04 ` Orit Wasserman
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