lkml.org 
[lkml]   [2013]   [Mar]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH] block: replace kmalloc and then memcpy with kmemdup
From
Hi Konrad,

The performance is the same using kmemdup, but we have the following advantages:
* code is cleaner
* kmemdup adds additional debugging info useful for tracking the real
place where memory was allocated [1] [2].

thanks,
Daniel.

[1] http://lxr.linux.no/#linux+v3.8.2/mm/util.c#L61
[2] http://lxr.linux.no/#linux+v3.8.2/include/linux/slab.h#L363

On Mon, Mar 11, 2013 at 4:54 PM, Konrad Rzeszutek Wilk
<konrad.wilk@oracle.com> wrote:
> On Mon, Mar 11, 2013 at 01:23:36PM +0200, Mihnea Dobrescu-Balaur wrote:
>
> Are there performance improvements to doing it this way?
>
>> Signed-off-by: Mihnea Dobrescu-Balaur <mihneadb@gmail.com>
>> ---
>> drivers/block/xen-blkfront.c | 3 +--
>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
>> index c3dae2e..9620644 100644
>> --- a/drivers/block/xen-blkfront.c
>> +++ b/drivers/block/xen-blkfront.c
>> @@ -1203,11 +1203,10 @@ static int blkif_recover(struct blkfront_info *info)
>> int j;
>>
>> /* Stage 1: Make a safe copy of the shadow state. */
>> - copy = kmalloc(sizeof(info->shadow),
>> + copy = kmemdup(info->shadow, sizeof(info->shadow),
>> GFP_NOIO | __GFP_REPEAT | __GFP_HIGH);
>> if (!copy)
>> return -ENOMEM;
>> - memcpy(copy, info->shadow, sizeof(info->shadow));
>>
>> /* Stage 2: Set up free list. */
>> memset(&info->shadow, 0, sizeof(info->shadow));
>> --
>> 1.7.10.4
>>
> _______________________________________________
> Virtualization mailing list
> Virtualization@lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/virtualization


\
 
 \ /
  Last update: 2013-03-11 17:01    [W:1.509 / U:0.752 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site