Re: [PATCH RFC] mm: simplify frontswap_init()

2012-10-31 Thread Konrad Rzeszutek Wilk 
On Tue, Oct 30, 2012 at 09:12:53PM -0200, Cesar Eduardo Barros wrote:
> The function frontswap_init() uses the passed parameter only to check
> for the presence of the frontswap_map. It is also passed down to
> frontswap_ops.init(), but all implementations of it in the kernel ignore
> the parameter.
> 
> Do the check for frontswap_map in the caller instead and remove the
> parameter from frontswap_init() and frontswap_ops.init().
> 
> Also, __frontswap_init() was exported, but its only caller (via an
> inline function) is mm/swapfile.c, which cannot be built as a module.
> Remove the unnecessary export.
> 
> Signed-off-by: Cesar Eduardo Barros 
> ---
> 
> Not even compile tested, just a quick patch to show what I was thinking
> of, but feel free to apply if you think it is good.

That looks good.
> 
> I might write another patch to move it outside the lock later, but I
> would have to read the frontswap code more carefully first.
> 
>  drivers/staging/ramster/zcache-main.c |  2 +-
>  drivers/staging/zcache/zcache-main.c  |  2 +-
>  drivers/xen/tmem.c|  2 +-
>  include/linux/frontswap.h |  8 
>  mm/frontswap.c| 10 ++
>  mm/swapfile.c |  3 ++-
>  6 files changed, 11 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/staging/ramster/zcache-main.c 
> b/drivers/staging/ramster/zcache-main.c
> index a09dd5c..b3f01c9 100644
> --- a/drivers/staging/ramster/zcache-main.c
> +++ b/drivers/staging/ramster/zcache-main.c
> @@ -1610,7 +1610,7 @@ static void zcache_frontswap_flush_area(unsigned type)
>   }
>  }
>  
> -static void zcache_frontswap_init(unsigned ignored)
> +static void zcache_frontswap_init(void)
>  {
>   /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
>   if (zcache_frontswap_poolid < 0)
> diff --git a/drivers/staging/zcache/zcache-main.c 
> b/drivers/staging/zcache/zcache-main.c
> index 52b43b7..cb67635 100644
> --- a/drivers/staging/zcache/zcache-main.c
> +++ b/drivers/staging/zcache/zcache-main.c
> @@ -1903,7 +1903,7 @@ static void zcache_frontswap_flush_area(unsigned type)
>   }
>  }
>  
> -static void zcache_frontswap_init(unsigned ignored)
> +static void zcache_frontswap_init(void)
>  {
>   /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
>   if (zcache_frontswap_poolid < 0)
> diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
> index 144564e..7156ff0 100644
> --- a/drivers/xen/tmem.c
> +++ b/drivers/xen/tmem.c
> @@ -343,7 +343,7 @@ static void tmem_frontswap_flush_area(unsigned type)
>   (void)xen_tmem_flush_object(pool, oswiz(type, ind));
>  }
>  
> -static void tmem_frontswap_init(unsigned ignored)
> +static void tmem_frontswap_init(void)
>  {
>   struct tmem_pool_uuid private = TMEM_POOL_PRIVATE_UUID;
>  
> diff --git a/include/linux/frontswap.h b/include/linux/frontswap.h
> index 3044254..6374c80 100644
> --- a/include/linux/frontswap.h
> +++ b/include/linux/frontswap.h
> @@ -6,7 +6,7 @@
>  #include 
>  
>  struct frontswap_ops {
> - void (*init)(unsigned);
> + void (*init)(void);
>   int (*store)(unsigned, pgoff_t, struct page *);
>   int (*load)(unsigned, pgoff_t, struct page *);
>   void (*invalidate_page)(unsigned, pgoff_t);
> @@ -22,7 +22,7 @@ extern void frontswap_writethrough(bool);
>  #define FRONTSWAP_HAS_EXCLUSIVE_GETS
>  extern void frontswap_tmem_exclusive_gets(bool);
>  
> -extern void __frontswap_init(unsigned type);
> +extern void __frontswap_init(void);
>  extern int __frontswap_store(struct page *page);
>  extern int __frontswap_load(struct page *page);
>  extern void __frontswap_invalidate_page(unsigned, pgoff_t);
> @@ -120,10 +120,10 @@ static inline void frontswap_invalidate_area(unsigned 
> type)
>   __frontswap_invalidate_area(type);
>  }
>  
> -static inline void frontswap_init(unsigned type)
> +static inline void frontswap_init(void)
>  {
>   if (frontswap_enabled)
> - __frontswap_init(type);
> + __frontswap_init();
>  }
>  
>  #endif /* _LINUX_FRONTSWAP_H */
> diff --git a/mm/frontswap.c b/mm/frontswap.c
> index 2890e67..d13661b 100644
> --- a/mm/frontswap.c
> +++ b/mm/frontswap.c
> @@ -115,16 +115,10 @@ EXPORT_SYMBOL(frontswap_tmem_exclusive_gets);
>  /*
>   * Called when a swap device is swapon'd.
>   */
> -void __frontswap_init(unsigned type)
> +void __frontswap_init(void)
>  {
> - struct swap_info_struct *sis = swap_info[type];
> -
> - BUG_ON(sis == NULL);
> - if (sis->frontswap_map == NULL)
> - return;
> - frontswap_ops.init(type);
> + frontswap_ops.init();
>  }
> -EXPORT_SYMBOL(__frontswap_init);
>  
>  static inline void __frontswap_clear(struct swap_info_struct *sis, pgoff_t 
> offset)
>  {
> diff --git a/mm/swapfile.c b/mm/swapfile.c
> index 088daf4..28c26bd 100644
> --- a/mm/swapfile.c
> +++ b/mm/swapfile.c
> @@ -1479,7 +1479,8 @@ static void enable_swap_info(struct

Re: [PATCH RFC] mm: simplify frontswap_init()

2012-10-31 Thread Konrad Rzeszutek Wilk 
On Tue, Oct 30, 2012 at 09:12:53PM -0200, Cesar Eduardo Barros wrote:
 The function frontswap_init() uses the passed parameter only to check
 for the presence of the frontswap_map. It is also passed down to
 frontswap_ops.init(), but all implementations of it in the kernel ignore
 the parameter.
 
 Do the check for frontswap_map in the caller instead and remove the
 parameter from frontswap_init() and frontswap_ops.init().
 
 Also, __frontswap_init() was exported, but its only caller (via an
 inline function) is mm/swapfile.c, which cannot be built as a module.
 Remove the unnecessary export.
 
 Signed-off-by: Cesar Eduardo Barros ces...@cesarb.net
 ---
 
 Not even compile tested, just a quick patch to show what I was thinking
 of, but feel free to apply if you think it is good.

That looks good.
 
 I might write another patch to move it outside the lock later, but I
 would have to read the frontswap code more carefully first.
 
  drivers/staging/ramster/zcache-main.c |  2 +-
  drivers/staging/zcache/zcache-main.c  |  2 +-
  drivers/xen/tmem.c|  2 +-
  include/linux/frontswap.h |  8 
  mm/frontswap.c| 10 ++
  mm/swapfile.c |  3 ++-
  6 files changed, 11 insertions(+), 16 deletions(-)
 
 diff --git a/drivers/staging/ramster/zcache-main.c 
 b/drivers/staging/ramster/zcache-main.c
 index a09dd5c..b3f01c9 100644
 --- a/drivers/staging/ramster/zcache-main.c
 +++ b/drivers/staging/ramster/zcache-main.c
 @@ -1610,7 +1610,7 @@ static void zcache_frontswap_flush_area(unsigned type)
   }
  }
  
 -static void zcache_frontswap_init(unsigned ignored)
 +static void zcache_frontswap_init(void)
  {
   /* a single tmem poolid is used for all frontswap types (swapfiles) */
   if (zcache_frontswap_poolid  0)
 diff --git a/drivers/staging/zcache/zcache-main.c 
 b/drivers/staging/zcache/zcache-main.c
 index 52b43b7..cb67635 100644
 --- a/drivers/staging/zcache/zcache-main.c
 +++ b/drivers/staging/zcache/zcache-main.c
 @@ -1903,7 +1903,7 @@ static void zcache_frontswap_flush_area(unsigned type)
   }
  }
  
 -static void zcache_frontswap_init(unsigned ignored)
 +static void zcache_frontswap_init(void)
  {
   /* a single tmem poolid is used for all frontswap types (swapfiles) */
   if (zcache_frontswap_poolid  0)
 diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
 index 144564e..7156ff0 100644
 --- a/drivers/xen/tmem.c
 +++ b/drivers/xen/tmem.c
 @@ -343,7 +343,7 @@ static void tmem_frontswap_flush_area(unsigned type)
   (void)xen_tmem_flush_object(pool, oswiz(type, ind));
  }
  
 -static void tmem_frontswap_init(unsigned ignored)
 +static void tmem_frontswap_init(void)
  {
   struct tmem_pool_uuid private = TMEM_POOL_PRIVATE_UUID;
  
 diff --git a/include/linux/frontswap.h b/include/linux/frontswap.h
 index 3044254..6374c80 100644
 --- a/include/linux/frontswap.h
 +++ b/include/linux/frontswap.h
 @@ -6,7 +6,7 @@
  #include linux/bitops.h
  
  struct frontswap_ops {
 - void (*init)(unsigned);
 + void (*init)(void);
   int (*store)(unsigned, pgoff_t, struct page *);
   int (*load)(unsigned, pgoff_t, struct page *);
   void (*invalidate_page)(unsigned, pgoff_t);
 @@ -22,7 +22,7 @@ extern void frontswap_writethrough(bool);
  #define FRONTSWAP_HAS_EXCLUSIVE_GETS
  extern void frontswap_tmem_exclusive_gets(bool);
  
 -extern void __frontswap_init(unsigned type);
 +extern void __frontswap_init(void);
  extern int __frontswap_store(struct page *page);
  extern int __frontswap_load(struct page *page);
  extern void __frontswap_invalidate_page(unsigned, pgoff_t);
 @@ -120,10 +120,10 @@ static inline void frontswap_invalidate_area(unsigned 
 type)
   __frontswap_invalidate_area(type);
  }
  
 -static inline void frontswap_init(unsigned type)
 +static inline void frontswap_init(void)
  {
   if (frontswap_enabled)
 - __frontswap_init(type);
 + __frontswap_init();
  }
  
  #endif /* _LINUX_FRONTSWAP_H */
 diff --git a/mm/frontswap.c b/mm/frontswap.c
 index 2890e67..d13661b 100644
 --- a/mm/frontswap.c
 +++ b/mm/frontswap.c
 @@ -115,16 +115,10 @@ EXPORT_SYMBOL(frontswap_tmem_exclusive_gets);
  /*
   * Called when a swap device is swapon'd.
   */
 -void __frontswap_init(unsigned type)
 +void __frontswap_init(void)
  {
 - struct swap_info_struct *sis = swap_info[type];
 -
 - BUG_ON(sis == NULL);
 - if (sis-frontswap_map == NULL)
 - return;
 - frontswap_ops.init(type);
 + frontswap_ops.init();
  }
 -EXPORT_SYMBOL(__frontswap_init);
  
  static inline void __frontswap_clear(struct swap_info_struct *sis, pgoff_t 
 offset)
  {
 diff --git a/mm/swapfile.c b/mm/swapfile.c
 index 088daf4..28c26bd 100644
 --- a/mm/swapfile.c
 +++ b/mm/swapfile.c
 @@ -1479,7 +1479,8 @@ static void enable_swap_info(struct swap_info_struct 
 *p, int prio,
  {
   spin_lock(swap_lock);
   _enable_swap_info(p, prio, swap_map, frontswap_map);

[PATCH RFC] mm: simplify frontswap_init()

2012-10-30 Thread Cesar Eduardo Barros 
The function frontswap_init() uses the passed parameter only to check
for the presence of the frontswap_map. It is also passed down to
frontswap_ops.init(), but all implementations of it in the kernel ignore
the parameter.

Do the check for frontswap_map in the caller instead and remove the
parameter from frontswap_init() and frontswap_ops.init().

Also, __frontswap_init() was exported, but its only caller (via an
inline function) is mm/swapfile.c, which cannot be built as a module.
Remove the unnecessary export.

Signed-off-by: Cesar Eduardo Barros 
---

Not even compile tested, just a quick patch to show what I was thinking
of, but feel free to apply if you think it is good.

I might write another patch to move it outside the lock later, but I
would have to read the frontswap code more carefully first.

 drivers/staging/ramster/zcache-main.c |  2 +-
 drivers/staging/zcache/zcache-main.c  |  2 +-
 drivers/xen/tmem.c|  2 +-
 include/linux/frontswap.h |  8 
 mm/frontswap.c| 10 ++
 mm/swapfile.c |  3 ++-
 6 files changed, 11 insertions(+), 16 deletions(-)

diff --git a/drivers/staging/ramster/zcache-main.c 
b/drivers/staging/ramster/zcache-main.c
index a09dd5c..b3f01c9 100644
--- a/drivers/staging/ramster/zcache-main.c
+++ b/drivers/staging/ramster/zcache-main.c
@@ -1610,7 +1610,7 @@ static void zcache_frontswap_flush_area(unsigned type)
}
 }
 
-static void zcache_frontswap_init(unsigned ignored)
+static void zcache_frontswap_init(void)
 {
/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
if (zcache_frontswap_poolid < 0)
diff --git a/drivers/staging/zcache/zcache-main.c 
b/drivers/staging/zcache/zcache-main.c
index 52b43b7..cb67635 100644
--- a/drivers/staging/zcache/zcache-main.c
+++ b/drivers/staging/zcache/zcache-main.c
@@ -1903,7 +1903,7 @@ static void zcache_frontswap_flush_area(unsigned type)
}
 }
 
-static void zcache_frontswap_init(unsigned ignored)
+static void zcache_frontswap_init(void)
 {
/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
if (zcache_frontswap_poolid < 0)
diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
index 144564e..7156ff0 100644
--- a/drivers/xen/tmem.c
+++ b/drivers/xen/tmem.c
@@ -343,7 +343,7 @@ static void tmem_frontswap_flush_area(unsigned type)
(void)xen_tmem_flush_object(pool, oswiz(type, ind));
 }
 
-static void tmem_frontswap_init(unsigned ignored)
+static void tmem_frontswap_init(void)
 {
struct tmem_pool_uuid private = TMEM_POOL_PRIVATE_UUID;
 
diff --git a/include/linux/frontswap.h b/include/linux/frontswap.h
index 3044254..6374c80 100644
--- a/include/linux/frontswap.h
+++ b/include/linux/frontswap.h
@@ -6,7 +6,7 @@
 #include 
 
 struct frontswap_ops {
-   void (*init)(unsigned);
+   void (*init)(void);
int (*store)(unsigned, pgoff_t, struct page *);
int (*load)(unsigned, pgoff_t, struct page *);
void (*invalidate_page)(unsigned, pgoff_t);
@@ -22,7 +22,7 @@ extern void frontswap_writethrough(bool);
 #define FRONTSWAP_HAS_EXCLUSIVE_GETS
 extern void frontswap_tmem_exclusive_gets(bool);
 
-extern void __frontswap_init(unsigned type);
+extern void __frontswap_init(void);
 extern int __frontswap_store(struct page *page);
 extern int __frontswap_load(struct page *page);
 extern void __frontswap_invalidate_page(unsigned, pgoff_t);
@@ -120,10 +120,10 @@ static inline void frontswap_invalidate_area(unsigned 
type)
__frontswap_invalidate_area(type);
 }
 
-static inline void frontswap_init(unsigned type)
+static inline void frontswap_init(void)
 {
if (frontswap_enabled)
-   __frontswap_init(type);
+   __frontswap_init();
 }
 
 #endif /* _LINUX_FRONTSWAP_H */
diff --git a/mm/frontswap.c b/mm/frontswap.c
index 2890e67..d13661b 100644
--- a/mm/frontswap.c
+++ b/mm/frontswap.c
@@ -115,16 +115,10 @@ EXPORT_SYMBOL(frontswap_tmem_exclusive_gets);
 /*
  * Called when a swap device is swapon'd.
  */
-void __frontswap_init(unsigned type)
+void __frontswap_init(void)
 {
-   struct swap_info_struct *sis = swap_info[type];
-
-   BUG_ON(sis == NULL);
-   if (sis->frontswap_map == NULL)
-   return;
-   frontswap_ops.init(type);
+   frontswap_ops.init();
 }
-EXPORT_SYMBOL(__frontswap_init);
 
 static inline void __frontswap_clear(struct swap_info_struct *sis, pgoff_t 
offset)
 {
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 088daf4..28c26bd 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1479,7 +1479,8 @@ static void enable_swap_info(struct swap_info_struct *p, 
int prio,
 {
spin_lock(_lock);
_enable_swap_info(p, prio, swap_map, frontswap_map);
-   frontswap_init(p->type);
+   if (frontswap_map)
+   frontswap_init();
spin_unlock(_lock);
 }
 
-- 
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[PATCH RFC] mm: simplify frontswap_init()

2012-10-30 Thread Cesar Eduardo Barros 
The function frontswap_init() uses the passed parameter only to check
for the presence of the frontswap_map. It is also passed down to
frontswap_ops.init(), but all implementations of it in the kernel ignore
the parameter.

Do the check for frontswap_map in the caller instead and remove the
parameter from frontswap_init() and frontswap_ops.init().

Also, __frontswap_init() was exported, but its only caller (via an
inline function) is mm/swapfile.c, which cannot be built as a module.
Remove the unnecessary export.

Signed-off-by: Cesar Eduardo Barros ces...@cesarb.net
---

Not even compile tested, just a quick patch to show what I was thinking
of, but feel free to apply if you think it is good.

I might write another patch to move it outside the lock later, but I
would have to read the frontswap code more carefully first.

 drivers/staging/ramster/zcache-main.c |  2 +-
 drivers/staging/zcache/zcache-main.c  |  2 +-
 drivers/xen/tmem.c|  2 +-
 include/linux/frontswap.h |  8 
 mm/frontswap.c| 10 ++
 mm/swapfile.c |  3 ++-
 6 files changed, 11 insertions(+), 16 deletions(-)

diff --git a/drivers/staging/ramster/zcache-main.c 
b/drivers/staging/ramster/zcache-main.c
index a09dd5c..b3f01c9 100644
--- a/drivers/staging/ramster/zcache-main.c
+++ b/drivers/staging/ramster/zcache-main.c
@@ -1610,7 +1610,7 @@ static void zcache_frontswap_flush_area(unsigned type)
}
 }
 
-static void zcache_frontswap_init(unsigned ignored)
+static void zcache_frontswap_init(void)
 {
/* a single tmem poolid is used for all frontswap types (swapfiles) */
if (zcache_frontswap_poolid  0)
diff --git a/drivers/staging/zcache/zcache-main.c 
b/drivers/staging/zcache/zcache-main.c
index 52b43b7..cb67635 100644
--- a/drivers/staging/zcache/zcache-main.c
+++ b/drivers/staging/zcache/zcache-main.c
@@ -1903,7 +1903,7 @@ static void zcache_frontswap_flush_area(unsigned type)
}
 }
 
-static void zcache_frontswap_init(unsigned ignored)
+static void zcache_frontswap_init(void)
 {
/* a single tmem poolid is used for all frontswap types (swapfiles) */
if (zcache_frontswap_poolid  0)
diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
index 144564e..7156ff0 100644
--- a/drivers/xen/tmem.c
+++ b/drivers/xen/tmem.c
@@ -343,7 +343,7 @@ static void tmem_frontswap_flush_area(unsigned type)
(void)xen_tmem_flush_object(pool, oswiz(type, ind));
 }
 
-static void tmem_frontswap_init(unsigned ignored)
+static void tmem_frontswap_init(void)
 {
struct tmem_pool_uuid private = TMEM_POOL_PRIVATE_UUID;
 
diff --git a/include/linux/frontswap.h b/include/linux/frontswap.h
index 3044254..6374c80 100644
--- a/include/linux/frontswap.h
+++ b/include/linux/frontswap.h
@@ -6,7 +6,7 @@
 #include linux/bitops.h
 
 struct frontswap_ops {
-   void (*init)(unsigned);
+   void (*init)(void);
int (*store)(unsigned, pgoff_t, struct page *);
int (*load)(unsigned, pgoff_t, struct page *);
void (*invalidate_page)(unsigned, pgoff_t);
@@ -22,7 +22,7 @@ extern void frontswap_writethrough(bool);
 #define FRONTSWAP_HAS_EXCLUSIVE_GETS
 extern void frontswap_tmem_exclusive_gets(bool);
 
-extern void __frontswap_init(unsigned type);
+extern void __frontswap_init(void);
 extern int __frontswap_store(struct page *page);
 extern int __frontswap_load(struct page *page);
 extern void __frontswap_invalidate_page(unsigned, pgoff_t);
@@ -120,10 +120,10 @@ static inline void frontswap_invalidate_area(unsigned 
type)
__frontswap_invalidate_area(type);
 }
 
-static inline void frontswap_init(unsigned type)
+static inline void frontswap_init(void)
 {
if (frontswap_enabled)
-   __frontswap_init(type);
+   __frontswap_init();
 }
 
 #endif /* _LINUX_FRONTSWAP_H */
diff --git a/mm/frontswap.c b/mm/frontswap.c
index 2890e67..d13661b 100644
--- a/mm/frontswap.c
+++ b/mm/frontswap.c
@@ -115,16 +115,10 @@ EXPORT_SYMBOL(frontswap_tmem_exclusive_gets);
 /*
  * Called when a swap device is swapon'd.
  */
-void __frontswap_init(unsigned type)
+void __frontswap_init(void)
 {
-   struct swap_info_struct *sis = swap_info[type];
-
-   BUG_ON(sis == NULL);
-   if (sis-frontswap_map == NULL)
-   return;
-   frontswap_ops.init(type);
+   frontswap_ops.init();
 }
-EXPORT_SYMBOL(__frontswap_init);
 
 static inline void __frontswap_clear(struct swap_info_struct *sis, pgoff_t 
offset)
 {
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 088daf4..28c26bd 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1479,7 +1479,8 @@ static void enable_swap_info(struct swap_info_struct *p, 
int prio,
 {
spin_lock(swap_lock);
_enable_swap_info(p, prio, swap_map, frontswap_map);
-   frontswap_init(p-type);
+   if (frontswap_map)
+   frontswap_init();
spin_unlock(swap_lock);
 }
 
-- 
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