Re: [PATCH 3/5] lockdep: Apply bit_spin_lock lockdep to zram

[Byungchul Park]

On Tue, Jun 21, 2016 at 12:36:19AM +0900, Sergey Senozhatsky wrote:
> 
> Hello,
> 
> just for information

Thank you for informing it.

> 
> there was a proposal from -rt people to use normal spinlocks
> for table's entries, rather that bitspinlock. I had a patch
> some time ago, will obtain some performance data and post
> RFC [may be tomorrow].
> 
>   -ss
> 

Re: [PATCH 3/5] lockdep: Apply bit_spin_lock lockdep to zram

[Sergey Senozhatsky]

On (06/20/16 13:55), Byungchul Park wrote:
> In order to use lockdep-enabled bit_spin_lock, we have to call
> bit_spin_init() when a instance including the bit used as lock
> creates, and bit_spin_free() when the instance including the bit
> destroys.
> 
> The zram is one of bit_spin_lock users. And this patch adds
> bit_spin_init() and bit_spin_free() properly to apply the lock
> correctness validator to bit_spin_lock the rzam is using.

Hello,

just for information

there was a proposal from -rt people to use normal spinlocks
for table's entries, rather that bitspinlock. I had a patch
some time ago, will obtain some performance data and post
RFC [may be tomorrow].

-ss

> Signed-off-by: Byungchul Park 
> ---
>  drivers/block/zram/zram_drv.c | 10 ++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index 370c2f7..2bc3bde 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -495,6 +495,11 @@ static void zram_meta_free(struct zram_meta *meta, u64 
> disksize)
>   }
>  
>   zs_destroy_pool(meta->mem_pool);
> +
> + for (index = 0; index < num_pages; index++) {
> + bit_spin_free(ZRAM_ACCESS, &meta->table[index].value);
> + }
> +
>   vfree(meta->table);
>   kfree(meta);
>  }
> @@ -503,6 +508,7 @@ static struct zram_meta *zram_meta_alloc(char *pool_name, 
> u64 disksize)
>  {
>   size_t num_pages;
>   struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL);
> + int index;
>  
>   if (!meta)
>   return NULL;
> @@ -520,6 +526,10 @@ static struct zram_meta *zram_meta_alloc(char 
> *pool_name, u64 disksize)
>   goto out_error;
>   }
>  
> + for (index = 0; index < num_pages; index++) {
> + bit_spin_init(ZRAM_ACCESS, &meta->table[index].value);
> + }
> +
>   return meta;
>  
>  out_error:
> -- 
> 1.9.1
> 

[PATCH 3/5] lockdep: Apply bit_spin_lock lockdep to zram

[Byungchul Park]

In order to use lockdep-enabled bit_spin_lock, we have to call
bit_spin_init() when a instance including the bit used as lock
creates, and bit_spin_free() when the instance including the bit
destroys.

The zram is one of bit_spin_lock users. And this patch adds
bit_spin_init() and bit_spin_free() properly to apply the lock
correctness validator to bit_spin_lock the rzam is using.

Signed-off-by: Byungchul Park 
---
 drivers/block/zram/zram_drv.c | 10 ++
 1 file changed, 10 insertions(+)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 370c2f7..2bc3bde 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -495,6 +495,11 @@ static void zram_meta_free(struct zram_meta *meta, u64 
disksize)
}
 
zs_destroy_pool(meta->mem_pool);
+
+   for (index = 0; index < num_pages; index++) {
+   bit_spin_free(ZRAM_ACCESS, &meta->table[index].value);
+   }
+
vfree(meta->table);
kfree(meta);
 }
@@ -503,6 +508,7 @@ static struct zram_meta *zram_meta_alloc(char *pool_name, 
u64 disksize)
 {
size_t num_pages;
struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL);
+   int index;
 
if (!meta)
return NULL;
@@ -520,6 +526,10 @@ static struct zram_meta *zram_meta_alloc(char *pool_name, 
u64 disksize)
goto out_error;
}
 
+   for (index = 0; index < num_pages; index++) {
+   bit_spin_init(ZRAM_ACCESS, &meta->table[index].value);
+   }
+
return meta;
 
 out_error:
-- 
1.9.1