Re: [Qemu-devel] [PATCH 1/3] exec: store RAMBlock pointer into memory region

[Gonglei (Arei)]

Hi Fam,

> From: Fam Zheng [mailto:address@hidden
> Sent: Monday, February 22, 2016 10:46 AM
> 
> On Sat, 02/20 10:35, Gonglei wrote:
> > Each RAM memory region has a unique corresponding RAMBlock.
> > In the current realization, the memory region only stored
> > the ram_addr which means the offset of RAM address space,
> > We need to qurey the global ram.list to find the ram block
> > by ram_addr if we want to get the ram block, which is very
> > expensive.
> >
> > Now, we store the RAMBlock pointer into memory region
> > structure. So, if we know the mr, we can easily get the
> > RAMBlock.
> >
> > Signed-off-by: Gonglei <address@hidden>
> > ---
> >  exec.c                | 2 ++
> >  include/exec/memory.h | 1 +
> >  memory.c              | 1 +
> >  3 files changed, 4 insertions(+)
> >
> > diff --git a/exec.c b/exec.c
> > index 1f24500..e29e369 100644
> > --- a/exec.c
> > +++ b/exec.c
> > @@ -1717,6 +1717,8 @@ ram_addr_t
> qemu_ram_alloc_internal(ram_addr_t size, ram_addr_t max_size,
> >          error_propagate(errp, local_err);
> >          return -1;
> >      }
> > +    /* store the ram block pointer into memroy region */
> 
> The comment is superfluous IMHO, the code is quite self-explanatory.
> 
Yes, agree.

> > +    mr->ram_block = new_block;
> >      return addr;
> >  }
> >
> > diff --git a/include/exec/memory.h b/include/exec/memory.h
> > index c92734a..23e2e3e 100644
> > --- a/include/exec/memory.h
> > +++ b/include/exec/memory.h
> > @@ -172,6 +172,7 @@ struct MemoryRegion {
> >      bool global_locking;
> >      uint8_t dirty_log_mask;
> >      ram_addr_t ram_addr;
> > +    void *ram_block;   /* RAMBlock pointer */
> 
> Why not add
> 
>     typedef struct RAMBlock RAMBlock;
> 
> then
> 
>     RAMBlock *ram_block;
> 
> ?
> 
It's clearer. Will fix in v2, thanks :)

Regards,
-Gonglei

> >      Object *owner;
> >      const MemoryRegionIOMMUOps *iommu_ops;
> >
> > diff --git a/memory.c b/memory.c
> > index 09041ed..b4451dd 100644
> > --- a/memory.c
> > +++ b/memory.c
> > @@ -912,6 +912,7 @@ void memory_region_init(MemoryRegion *mr,
> >      }
> >      mr->name = g_strdup(name);
> >      mr->owner = owner;
> > +    mr->ram_block = NULL;
> >
> >      if (name) {
> >          char *escaped_name = memory_region_escape_name(name);
> > --
> > 1.8.5.2
> >
> >
> >