Date: Tue, 16 Jun 2015 23:14:20 +0200
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Igor Mammedov <imammedo@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, pbonzini@redhat.com
Subject: Re: [PATCH 3/5] vhost: support upto 509 memory regions
Message-ID: <20150616231201-mutt-send-email-mst@redhat.com>
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 <1434472419-148742-4-git-send-email-imammedo@redhat.com>
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On Tue, Jun 16, 2015 at 06:33:37PM +0200, Igor Mammedov wrote:
> since commit
>  1d4e7e3 kvm: x86: increase user memory slots to 509
> 
> it became possible to use a bigger amount of memory
> slots, which is used by memory hotplug for
> registering hotplugged memory.
> However QEMU crashes if it's used with more than ~60
> pc-dimm devices and vhost-net since host kernel
> in module vhost-net refuses to accept more than 65
> memory regions.
> 
> Increase VHOST_MEMORY_MAX_NREGIONS from 65 to 509

It was 64, not 65.

> to match KVM_USER_MEM_SLOTS fixes issue for vhost-net.
> 
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>

Still thinking about this: can you reorder this to
be the last patch in the series please?

Also - 509?
I think if we are changing this, it'd be nice to
create a way for userspace to discover the support
and the # of regions supported.


> ---
>  drivers/vhost/vhost.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index 99931a0..6a18c92 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -30,7 +30,7 @@
>  #include "vhost.h"
>  
>  enum {
> -	VHOST_MEMORY_MAX_NREGIONS = 64,
> +	VHOST_MEMORY_MAX_NREGIONS = 509,
>  	VHOST_MEMORY_F_LOG = 0x1,
>  };
>  
> -- 
> 1.8.3.1
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