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From: David Vrabel <david.vrabel@citrix.com>
To: Wei Liu <wei.liu2@citrix.com>
Cc: netdev@vger.kernel.org, konrad.wilk@oracle.com,
	ian.campbell@citrix.com, xen-devel@lists.xen.org
Subject: Re: [PATCH net-next 1/3] xen-netback: page pool support
Date: Fri, 24 May 2013 13:44:31 +0100	[thread overview]
Message-ID: <519F60AF.5020705__30657.5783099563$1369399611$gmane$org@citrix.com> (raw)
In-Reply-To: <1369391553-16835-2-git-send-email-wei.liu2@citrix.com>

On 24/05/13 11:32, Wei Liu wrote:
> This patch implements a page pool for all vifs. It has two functionalities:
>  a) to limit the amount of pages used by all vifs
>  b) to track pages belong to vifs

This adds a global spin lock.  This doesn't seem very scalable.

It's also not clear how this is usefully limiting the memory usage by
guest network traffic.  It limits the number of pages that netback can
use during the grant copy from the guest pages but this is only short
time compared to the lifetime of the network packet within the rest of
the network stack.

If you didn't have this page pool stuff then each thread/VIF is limited
to at most 256 pages anyway and I think 1 MiB of memory per VIF is
perfectly acceptable.

David

  reply	other threads:[~2013-05-24 12:44 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-24 10:32 [PATCH net-next 0/3] xen-netback: switch to NAPI + kthread 1:1 model Wei Liu
2013-05-24 10:32 ` [PATCH net-next 1/3] xen-netback: page pool support Wei Liu
2013-05-24 10:32 ` Wei Liu
2013-05-24 12:44   ` David Vrabel [this message]
2013-05-24 12:44   ` [Xen-devel] " David Vrabel
2013-05-24 13:25     ` Wei Liu
2013-05-24 13:25     ` Wei Liu
2013-05-24 13:34     ` Wei Liu
2013-05-24 13:34     ` [Xen-devel] " Wei Liu
2013-05-24 10:32 ` [PATCH net-next 2/3] xen-netback: switch to per-cpu scratch space Wei Liu
2013-05-24 10:32 ` Wei Liu
2013-05-24 12:24   ` David Vrabel
2013-05-24 12:24   ` [Xen-devel] " David Vrabel
2013-05-24 12:31     ` Wei Liu
2013-05-24 12:31     ` Wei Liu
2013-05-24 10:32 ` [PATCH net-next 3/3] xen-netback: switch to NAPI + kthread 1:1 model Wei Liu
2013-05-24 10:32 ` Wei Liu

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