Hi Minchan,
Sorry for late reply.
On 4/25/12 9:42 PM, Minchan Kim wrote:
On 04/25/2012 09:53 PM, Nitin Gupta wrote:
On 04/25/2012 02:23 AM, Minchan Kim wrote:
It isn't necessary to align pool size with PAGE_SIZE.
If I missed something, please let me know it.
Signed-off-by: Minchan Kim<minchan@xxxxxxxxxx>
---
drivers/staging/zsmalloc/zsmalloc-main.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/zsmalloc/zsmalloc-main.c b/drivers/staging/zsmalloc/zsmalloc-main.c
index 504b6c2..b99ad9e 100644
--- a/drivers/staging/zsmalloc/zsmalloc-main.c
+++ b/drivers/staging/zsmalloc/zsmalloc-main.c
@@ -489,14 +489,13 @@ fail:
struct zs_pool *zs_create_pool(const char *name, gfp_t flags)
{
- int i, error, ovhd_size;
+ int i, error;
struct zs_pool *pool;
if (!name)
return NULL;
- ovhd_size = roundup(sizeof(*pool), PAGE_SIZE);
- pool = kzalloc(ovhd_size, GFP_KERNEL);
+ pool = kzalloc(sizeof(*pool), GFP_KERNEL);
if (!pool)
return NULL;
pool metadata is rounded-up to avoid potential false-sharing problem
(though we could just roundup to cache_line_size()).
Do you really have any hurt by false-sharing problem?
If so, we can change it with
I've never been hit by this false-sharing in any testing but this is
really just a random chance. Apart from aligning to cache-line size,
there is no way to ensure some unfortunate read-mostly object never
falls in the same line.
kzalloc(ALIGN(sizeof(*pool), cache_line_size()), GFP_KERNEL);
Yes, looks better than aligning to PAGE_SIZE.
Thanks,
Nitin
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