Re: [PATCH] ipc 1/3: Add refcount to ipc_rcu_alloc

[Manfred Spraul]

Andrew Morton wrote:

> Manfred Spraul <manfred@xxxxxxxxxxxxxxxx> wrote:
>  
>
> > +struct ipc_rcu_hdr
> > +{
> > +	int refcount;
> > +	int is_vmalloc;
> > +	void *data[0];
> > +};
> >    
>
> That's not what I meant ;)
>
> struct ipc_rcu_hdr
> {
> 	int refcount;
> 	int is_vmalloc;
> };
>
> Then place one of these inside struct msg_queue, one inside struct
> sem_array, etc.
>
>  
No. The size of the headers depends on the allocation size: 8 bytes for 
allocs < 4088 bytes, 60 bytes for larger allocs. I don't want to expose 
that implementation detail outside of util.c.
ipc_rcu_alloc allocates an arbitrary sized refcounted memory block that 
is released through the rcu framework. Everything else is hidden in util.c.

--
   Manfred
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