Re: [PATCH 1/3 v5] kernel/fork.c: new function for max_threads

[Heinrich Schuchardt <xypron.glpk@gmx.de>]

On 24.02.2015 23:16, David Rientjes wrote:
> On Tue, 24 Feb 2015, Heinrich Schuchardt wrote:
> 
>>> I'm afraid I don't understand this.  The intent of the patch is to 
>>> separate the max_threads logic into a new function, correct?  If that's 
>>> true, then I don't understand why UINT_MAX is being introduced into this 
>>> path and passed to the new function when it is ignored.
>>>
>>> I think it would be better to simply keep passing mempages to fork_init() 
>>> and then pass it to set_max_threads() where max_threads actually gets set 
>>> using the argument passed.  At least, the code would then match the intent 
>>> of the patch.
>>>
>> Please, read patch 2/3 which provides support for the argument,
>> and patch 3/3 that finally needs it.
>>
> 
> The problem is with the structure of your patchset.  You want three 
> patches.  There's one bugfix patch, a preparation patch, and a feature 
> patch.  The bugfix patch should come first so that it can be applied, 
> possibly, to stable kernels and doesn't depend on unnecessary preparation 
> patches for features.
> 
> 1/3: change the implementation of fork_init(), with commentary, to avoid 
> the divide by zero on certain arches, enforce the limits, and deal with 
> variable types to prevent overflow.  This is the most urgent patch and 
> fixes a bug.
> 
> 2/3: simply extract the fixed fork_init() implementation into a new 
> set_max_threads() in preparation to use it for threads-max, (hint: 
> UINT_MAX and ignored arguments should not appear in this patch),
> 
> 3/3: use the new set_max_threads() implementation for threads-max with an 
> update to the documentation.
> 
Hello Ingo,

the current structure of the patch set is based on your suggestion in
https://lkml.org/lkml/2015/2/22/22

Would you agree with the sequence of patches proposed by David?

Best regards

Heinrich