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Re: [Qemu-devel] [PATCH 1/2] migration: bitmap_set is unnecessary as bit
From: |
Wen Congyang |
Subject: |
Re: [Qemu-devel] [PATCH 1/2] migration: bitmap_set is unnecessary as bitmap_new uses g_try_malloc0 |
Date: |
Fri, 25 Sep 2015 17:24:04 +0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 |
On 09/25/2015 05:09 PM, Denis V. Lunev wrote:
> we can omit calling of bitmap_set in migration_bitmap_extend and
> ram_save_setup just after bitmap_new, which properly zeroes memory
> inside.
This patch is wrong. bitmap_set() is set all bits of the memory to 1,
not 0.
>
> Signed-off-by: Denis V. Lunev <address@hidden>
> CC: Igor Redko <address@hidden>
> CC: Anna Melekhova <address@hidden>
> CC: Juan Quintela <address@hidden>
> CC: Amit Shah <address@hidden>
> CC: Wen Congyang <address@hidden>
> ---
> migration/ram.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index 7f007e6..a712c68 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -1081,7 +1081,6 @@ void migration_bitmap_extend(ram_addr_t old, ram_addr_t
> new)
> */
> qemu_mutex_lock(&migration_bitmap_mutex);
> bitmap_copy(bitmap, old_bitmap, old);
> - bitmap_set(bitmap, old, new - old);
> atomic_rcu_set(&migration_bitmap, bitmap);
> qemu_mutex_unlock(&migration_bitmap_mutex);
> migration_dirty_pages += new - old;
> @@ -1146,7 +1145,6 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
>
> ram_bitmap_pages = last_ram_offset() >> TARGET_PAGE_BITS;
> migration_bitmap = bitmap_new(ram_bitmap_pages);
> - bitmap_set(migration_bitmap, 0, ram_bitmap_pages);
>
> /*
> * Count the total number of pages used by ram blocks not including any
>
- [Qemu-devel] [PATCH 1/1] migration: fix deadlock, Denis V. Lunev, 2015/09/24
- Re: [Qemu-devel] [PATCH 1/1] migration: fix deadlock, Wen Congyang, 2015/09/24
- Re: [Qemu-devel] [PATCH 1/1] migration: fix deadlock, Denis V. Lunev, 2015/09/25
- Re: [Qemu-devel] [PATCH 1/1] migration: fix deadlock, Wen Congyang, 2015/09/25
- [Qemu-devel] [PATCH v2 0/2] migration: fix deadlock, Denis V. Lunev, 2015/09/25
- [Qemu-devel] [PATCH 1/2] migration: bitmap_set is unnecessary as bitmap_new uses g_try_malloc0, Denis V. Lunev, 2015/09/25
- Re: [Qemu-devel] [PATCH 1/2] migration: bitmap_set is unnecessary as bitmap_new uses g_try_malloc0,
Wen Congyang <=
- Re: [Qemu-devel] [PATCH 1/2] migration: bitmap_set is unnecessary as bitmap_new uses g_try_malloc0, Denis V. Lunev, 2015/09/25
- Re: [Qemu-devel] [PATCH 1/2] migration: bitmap_set is unnecessary as bitmap_new uses g_try_malloc0, Wen Congyang, 2015/09/25
- Re: [Qemu-devel] [PATCH 1/2] migration: bitmap_set is unnecessary as bitmap_new uses g_try_malloc0, Denis V. Lunev, 2015/09/25
- [Qemu-devel] [PATCH 2/2] migration: fix deadlock, Denis V. Lunev, 2015/09/25
- Re: [Qemu-devel] [PATCH 2/2] migration: fix deadlock, Wen Congyang, 2015/09/25
- Re: [Qemu-devel] [PATCH v2 0/2] migration: fix deadlock, Wen Congyang, 2015/09/25
- Re: [Qemu-devel] [PATCH v2 0/2] migration: fix deadlock, Igor Redko, 2015/09/29
- Re: [Qemu-devel] [PATCH v2 0/2] migration: fix deadlock, Igor Redko, 2015/09/29