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Message-ID: <378a9c14-744f-4192-9229-0132ddc97b15@kylinos.cn>
Date: Thu, 6 Jun 2024 15:25:21 +0800
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Subject: Re: [PATCH] tools/virtio: Use the __GFP_ZERO flag of kmalloc to
 complete the memory initialization.
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: jasowang@redhat.com, virtualization@lists.linux.dev,
 xuanzhuo@linux.alibaba.com, eperezma@redhat.com, linux-kernel@vger.kernel.org
References: <20240605135245.14921-1-cuitao@kylinos.cn>
 <20240606031810-mutt-send-email-mst@kernel.org>
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From: cuitao <cuitao@kylinos.cn>
In-Reply-To: <20240606031810-mutt-send-email-mst@kernel.org>
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Sorry, maybe I'm wrong.

I wonder if the gfp parameter in static inline void *kmalloc(size_t s, 
gfp_t gfp) can be deleted if it is not used.

Or would be better to move memset to kmalloc.

Like this:
#define __GFP_ZERO 0x1
static inline void *kmalloc(size_t s, gfp_t gfp)
{
     void *p;
     if (__kmalloc_fake)
         return __kmalloc_fake;

     p = malloc(s);
     if (!p)
             return p;

     if (gfp & __GFP_ZERO)
         memset(p, 0, s);
     return p;
}

在 2024/6/6 15:18, Michael S. Tsirkin 写道:
> On Wed, Jun 05, 2024 at 09:52:45PM +0800, cuitao wrote:
>> Use the __GFP_ZERO flag of kmalloc to initialize memory while allocating it,
>> without the need for an additional memset call.
>>
>> Signed-off-by: cuitao <cuitao@kylinos.cn>
>> ---
>>   tools/virtio/linux/kernel.h | 5 +----
>>   1 file changed, 1 insertion(+), 4 deletions(-)
>>
>> diff --git a/tools/virtio/linux/kernel.h b/tools/virtio/linux/kernel.h
>> index 6702008f7f5c..9e401fb7c215 100644
>> --- a/tools/virtio/linux/kernel.h
>> +++ b/tools/virtio/linux/kernel.h
>> @@ -66,10 +66,7 @@ static inline void *kmalloc_array(unsigned n, size_t s, gfp_t gfp)
>>   
>>   static inline void *kzalloc(size_t s, gfp_t gfp)
>>   {
>> -	void *p = kmalloc(s, gfp);
>> -
>> -	memset(p, 0, s);
>> -	return p;
>> +	return kmalloc(s, gfp | __GFP_ZERO);
>>   }
>
> Why do we care? It's just here to make things compile. The simpler the
> better.
>
>>   static inline void *alloc_pages_exact(size_t s, gfp_t gfp)
>> -- 
>> 2.25.1