Re: [Qemu-devel] [PATCH v3 14/29] exec: use memory_region_get_dirty_log_mask to optimize dirty tracking

[Fam Zheng <famz@redhat.com>]

On Tue, 05/26 18:54, Paolo Bonzini wrote:
> The memory API can now return the exact set of bitmaps that have to
> be tracked.  Use it instead of the in_migration variable.
> 
> In the next patches, we will also use it to set only DIRTY_MEMORY_VGA
> or DIRTY_MEMORY_MIGRATION if necessary.  This can make a difference
> for dataplane, especially after the dirty bitmap is changed to use
> more expensive atomic operations.
> 
> Of some interest is the change to stl_phys_notdirty.  When migration
> was introduced, stl_phys_notdirty was changed to effectively behave
> as stl_phys during migration.  In fact, if one looks at the function as it
> was in the beginning (commit 8df1cd0, physical memory access functions,
> 2005-01-28), at the time the dirty bitmap was the equivalent of
> DIRTY_MEMORY_CODE nowadays; hence, the function simply should not touch
> the dirty code bits.  This patch changes it to do the intended thing.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Reviewed-by: Fam Zheng <famz@redhat.com>