Re: [PATCH 5/8] mm/slub: Factor out some common code.

[Matt Mackall]

On Mon, 2011-03-14 at 21:58 -0400, George Spelvin wrote:
> For sysfs files that map a boolean to a flags bit.

This one's actually pretty nice. You should really try to put all the
uncontroversial bits of a series first.

> ---
>  mm/slub.c |   93 ++++++++++++++++++++++++++++--------------------------------
>  1 files changed, 43 insertions(+), 50 deletions(-)
> 
> diff --git a/mm/slub.c b/mm/slub.c
> index e15aa7f..856246f 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -3982,38 +3982,61 @@ static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
>  }
>  SLAB_ATTR_RO(objects_partial);
>  
> +static ssize_t flag_show(struct kmem_cache *s, char *buf, unsigned flag)
> +{
> +	return sprintf(buf, "%d\n", !!(s->flags & flag));
> +}
> +
> +static ssize_t flag_store(struct kmem_cache *s,
> +				const char *buf, size_t length, unsigned flag)
> +{
> +	s->flags &= ~flag;
> +	if (buf[0] == '1')
> +		s->flags |= flag;
> +	return length;
> +}
> +
> +/* Like above, but changes allocation size; so only allowed on empty slab */
> +static ssize_t flag_store_sizechange(struct kmem_cache *s,
> +				const char *buf, size_t length, unsigned flag)
> +{
> +	if (any_slab_objects(s))
> +		return -EBUSY;
> +
> +	flag_store(s, buf, length, flag);
> +	calculate_sizes(s, -1);
> +	return length;
> +}
> +
>  static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
>  {
> -	return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
> +	return flag_show(s, buf, SLAB_RECLAIM_ACCOUNT);
>  }
>  
>  static ssize_t reclaim_account_store(struct kmem_cache *s,
>  				const char *buf, size_t length)
>  {
> -	s->flags &= ~SLAB_RECLAIM_ACCOUNT;
> -	if (buf[0] == '1')
> -		s->flags |= SLAB_RECLAIM_ACCOUNT;
> -	return length;
> +	return flag_store(s, buf, length, SLAB_RECLAIM_ACCOUNT);
>  }
>  SLAB_ATTR(reclaim_account);
>  
>  static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
>  {
> -	return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
> +	return flag_show(s, buf, SLAB_HWCACHE_ALIGN);
>  }
>  SLAB_ATTR_RO(hwcache_align);
>  
>  #ifdef CONFIG_ZONE_DMA
>  static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
>  {
> -	return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
> +	return flag_show(s, buf, SLAB_CACHE_DMA);
>  }
>  SLAB_ATTR_RO(cache_dma);
>  #endif
>  
>  static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
>  {
> -	return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
> +	return flag_show(s, buf, SLAB_DESTROY_BY_RCU);
>  }
>  SLAB_ATTR_RO(destroy_by_rcu);
>  
> @@ -4032,88 +4055,61 @@ SLAB_ATTR_RO(total_objects);
>  
>  static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
>  {
> -	return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE));
> +	return flag_show(s, buf, SLAB_DEBUG_FREE);
>  }
>  
>  static ssize_t sanity_checks_store(struct kmem_cache *s,
>  				const char *buf, size_t length)
>  {
> -	s->flags &= ~SLAB_DEBUG_FREE;
> -	if (buf[0] == '1')
> -		s->flags |= SLAB_DEBUG_FREE;
> -	return length;
> +	return flag_store(s, buf, length, SLAB_DEBUG_FREE);
>  }
>  SLAB_ATTR(sanity_checks);
>  
>  static ssize_t trace_show(struct kmem_cache *s, char *buf)
>  {
> -	return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
> +	return flag_show(s, buf, SLAB_TRACE);
>  }
>  
>  static ssize_t trace_store(struct kmem_cache *s, const char *buf,
>  							size_t length)
>  {
> -	s->flags &= ~SLAB_TRACE;
> -	if (buf[0] == '1')
> -		s->flags |= SLAB_TRACE;
> -	return length;
> +	return flag_store(s, buf, length, SLAB_TRACE);
>  }
>  SLAB_ATTR(trace);
>  
>  static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
>  {
> -	return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
> +	return flag_show(s, buf, SLAB_RED_ZONE);
>  }
>  
>  static ssize_t red_zone_store(struct kmem_cache *s,
>  				const char *buf, size_t length)
>  {
> -	if (any_slab_objects(s))
> -		return -EBUSY;
> -
> -	s->flags &= ~SLAB_RED_ZONE;
> -	if (buf[0] == '1')
> -		s->flags |= SLAB_RED_ZONE;
> -	calculate_sizes(s, -1);
> -	return length;
> +	return flag_store_sizechange(s, buf, length, SLAB_RED_ZONE);
>  }
>  SLAB_ATTR(red_zone);
>  
>  static ssize_t poison_show(struct kmem_cache *s, char *buf)
>  {
> -	return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
> +	return flag_show(s, buf, SLAB_POISON);
>  }
>  
>  static ssize_t poison_store(struct kmem_cache *s,
>  				const char *buf, size_t length)
>  {
> -	if (any_slab_objects(s))
> -		return -EBUSY;
> -
> -	s->flags &= ~SLAB_POISON;
> -	if (buf[0] == '1')
> -		s->flags |= SLAB_POISON;
> -	calculate_sizes(s, -1);
> -	return length;
> +	return flag_store_sizechange(s, buf, length, SLAB_POISON);
>  }
>  SLAB_ATTR(poison);
>  
>  static ssize_t store_user_show(struct kmem_cache *s, char *buf)
>  {
> -	return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
> +	return flag_show(s, buf, SLAB_STORE_USER);
>  }
>  
>  static ssize_t store_user_store(struct kmem_cache *s,
>  				const char *buf, size_t length)
>  {
> -	if (any_slab_objects(s))
> -		return -EBUSY;
> -
> -	s->flags &= ~SLAB_STORE_USER;
> -	if (buf[0] == '1')
> -		s->flags |= SLAB_STORE_USER;
> -	calculate_sizes(s, -1);
> -	return length;
> +	return flag_store_sizechange(s, buf, length, SLAB_STORE_USER);
>  }
>  SLAB_ATTR(store_user);
>  
> @@ -4156,16 +4152,13 @@ SLAB_ATTR_RO(free_calls);
>  #ifdef CONFIG_FAILSLAB
>  static ssize_t failslab_show(struct kmem_cache *s, char *buf)
>  {
> -	return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
> +	return flag_show(s, buf, SLAB_FAILSLAB);
>  }
>  
>  static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
>  							size_t length)
>  {
> -	s->flags &= ~SLAB_FAILSLAB;
> -	if (buf[0] == '1')
> -		s->flags |= SLAB_FAILSLAB;
> -	return length;
> +	return flag_store(s, buf, length, SLAB_FAILSLAB);
>  }
>  SLAB_ATTR(failslab);
>  #endif


-- 
Mathematics is the supreme nostalgia of our time.


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