Re: [PATCH v6 5/7] zsmalloc/zram: introduce zs_pool_stats api

[Minchan Kim <minchan@kernel.org>]

On Tue, Jul 07, 2015 at 11:32:56PM +0900, Sergey Senozhatsky wrote:
> On (07/07/15 22:36), Minchan Kim wrote:
> [..]
> > >  	struct zram *zram = dev_to_zram(dev);
> > > +	struct zs_pool_stats pool_stats = {0};
> > 
> > Does it work even if first member of the structure is non-scalar?
> > Personally I prefer memset for initliazation.
> > I believe modern compiler would optimize that quite well.
> 
> zs_pool_stats contains only one member now, so I didn't bother.
> 
> [..]
> > >  struct zs_pool {
> > > -	char *name;
> > > +	char			*name;
> > 
> > huge tab?
> > 
> > >  
> > > -	struct size_class **size_class;
> > > -	struct kmem_cache *handle_cachep;
> > > +	struct size_class	**size_class;
> > > +	struct kmem_cache	*handle_cachep;
> > 
> > tab?
> > tab?
> > 
> > >  
> > > -	gfp_t flags;	/* allocation flags used when growing pool */
> > > -	atomic_long_t pages_allocated;
> > 
> > Why changes comment position?
> 
> Because otherwise it breaks 80-cols rule.
> 
> > > +	/* Allocation flags used when growing pool */
> > > +	gfp_t			flags;
> > > +	atomic_long_t		pages_allocated;
> > >  
> > 
> > Why blank line?
> 
> To make it more readable? Separating logically different
> struct members. That's why the original code contains blank
> lines between `char *name' and `struct size_class **size_class;
> struct kmem_cache *handle_cachep;` and so on.
> 
> I see no issue.
> 

Okay, I am not against aboves you mentioned.
But please don't squeeze cleanup patch into core patchset from next time.
It really hate to review and make confused git-blame.

> 
> > > +	struct zs_pool_stats	stats;
> > >  #ifdef CONFIG_ZSMALLOC_STAT
> > > -	struct dentry *stat_dentry;
> > > +	struct dentry		*stat_dentry;
> > 
> > Tab.
> 
> Well, I see no issue with aligned struct members. Looks less
> hairy and less messy than the original one.

But this is that I'm strongly against with you.
It depends on the person coding style.

I have been used white space.
As well, when I look at current code under mm which I'm getting used,
almost everything use just white space.

> 
> clean:
> 
> struct zs_pool {
>         char                    *name;
> 
>         struct size_class       **size_class;
>         struct kmem_cache       *handle_cachep;
> 
>         /* Allocation flags used when growing pool */
>         gfp_t                   flags;
>         atomic_long_t           pages_allocated;
> 
>         struct zs_pool_stats    stats;
> 
>         /* Compact classes */
>         struct shrinker         shrinker;
>         bool                    shrinker_enabled;
> #ifdef CONFIG_ZSMALLOC_STAT
>         struct dentry           *stat_dentry;
> #endif
> };
> 
> 
> 
> dirty:

Never dirty. It's more readable.

> 
> struct zs_pool {
>         char *name;
> 
>         struct size_class **size_class;
>         struct kmem_cache *handle_cachep;
> 
>         gfp_t flags;    /* allocation flags used when growing pool */
>         atomic_long_t pages_allocated;
> 
> #ifdef CONFIG_ZSMALLOC_STAT
>         struct dentry *stat_dentry;
> #endif
> };
> 
> 	-ss

-- 
Kind regards,
Minchan Kim

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