Re: [Qemu-devel] [PATCH v4] socket: Allocating Large sized arrays to heap

[Paolo Bonzini <pbonzini@redhat.com>]

On 17/03/2016 16:31, Pooja Dhannawat wrote:
> 
> 
> On Thu, Mar 17, 2016 at 8:20 PM, Stefan Hajnoczi <stefanha@gmail.com
> <mailto:stefanha@gmail.com>> wrote:
> 
>     On Tue, Mar 15, 2016 at 09:29:58PM +0530, Pooja Dhannawat wrote:
>     > @@ -170,8 +170,8 @@ static void net_socket_send(void *opaque)
>     >          s->index = 0;
>     >          s->packet_len = 0;
>     >          s->nc.link_down = true;
>     > -        memset(s->buf, 0, sizeof(s->buf));
> 
>     This change is unrelated to allocating buf1 on the heap.  What is the
>     purpose of this line?
> 
> 
> I moved buf from stack to Heap, used g_new(), but I got your point if we
> need to initialize it with 0 then I have to keep that one.
> 
> Other wise doing so it gets whatever garbage it has already.  

This is s->buf, not buf.  Also, the BiteSizedTasks page says "Make the
stack array smaller and allocate on the heap in the rare case that the
data does not fit in the small array".

Paolo