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

[Manfred Spraul <manfred@colorfullife.com>]

Andrew Morton wrote:

>Manfred Spraul <manfred@colorfullife.com> 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