Re: [PATCH] perf-event/cgroup: explicitly init the early_init field

[Li Zefan <lizefan@huawei.com>]

On 2014/4/22 15:12, Jianyu Zhan wrote:
> On Tue, Apr 22, 2014 at 2:06 PM, Ingo Molnar <mingo@kernel.org> wrote:
>> How can that field ever be nonzero?
>>
>> I.e. under what exact circumstances does this patch make sense?
> 
> Hi, Ingo,
> 
> More explanation.
> 
> Sure, for this global variable struct, if not initailized, its all
> fields will be initialized
> to 0 or null(depending on its type).  The point here is no to deprive
> the rights of compiler/linker of doing this initialization, it is mainly for
> documentation reason. Actually this field's value would affect how ->css_alloc
> should implemented.
> 
> Concretely, if early_init is nonzero, then ->css_alloc *must not* call kzalloc,
> because in cgroup implementation, ->css_alloc will be called earlier before
> mm_init().
> 
> I don't think that the value of one field(early_init) has a so subtle
> restrition on the another field(css_alloc) is a good thing,
> but since
> it is there,
> docment it should be needed.
> 
> I could resend the patch with  more comment.
> 

nack

As I said in another mail thread, this change makes no sense.