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Date: Fri, 14 Aug 2015 20:14:46 +0300
From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
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Subject: Re: [Qemu-devel] [PATCH 2/8] qcow2: add dirty-bitmaps feature
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To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: kwolf@redhat.com, qemu-devel@nongnu.org, Vladimir Sementsov-Ogievskiy <vsementsov@parallels.com>, pbonzini@redhat.com, den@openvz.org, jsnow@redhat.com

On 10.06.2015 17:30, Stefan Hajnoczi wrote:
> On Mon, Jun 08, 2015 at 06:21:20PM +0300, Vladimir Sementsov-Ogievskiy wrote:
>
>
>
>> +    ret = bdrv_pread(bs->file, bm->l1_table_offset, l1_table,
>> +                     bm->l1_size * sizeof(uint64_t));
>> +    if (ret < 0) {
>> +        goto fail;
>> +    }
>> +
>> +    buf = g_malloc0(bm->l1_size * s->cluster_size);
> What is the maximum l1_size value?  cluster_size and l1_size are 32-bit
> so with 64 KB cluster_size this overflows if l1_size > 65535.  Do you
> want to cast to size_t?

Hmm. What the maximum RAM space we'd like to spend on dirty bitmap? I 
think 4Gb is too much.. So here should be limited not the l1_size but 
number of bytes needed to store the bitmap. What is maximum disk size we 
are dealing with?


-- 
Best regards,
Vladimir
* now, @virtuozzo.com instead of @parallels.com. Sorry for this inconvenience.