From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: [PATCH v2 1/1] tools: Handle xc_maxmem adjustments Date: Wed, 15 Apr 2015 11:03:53 +0100 Message-ID: <552E3789.1010809@citrix.com> References: <20150414175437.GB11717@zion.uk.xensource.com> <1429049186-27343-1-git-send-email-dslutz@verizon.com> <552E3509.8010107@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Stefano Stabellini Cc: Wei Liu , Ian Campbell , Ian Jackson , Don Slutz , xen-devel@lists.xen.org, Shriram Rajagopalan , Yang Hongyang List-Id: xen-devel@lists.xenproject.org On 15/04/15 10:57, Stefano Stabellini wrote: > On Wed, 15 Apr 2015, Andrew Cooper wrote: >> On 14/04/15 23:06, Don Slutz wrote: >>> This fixes an issue where "xl save" followed by "xl restore" reports: >>> "xc: error: Failed to allocate memory for batch.!: Internal error" >>> >>> One of the ways to get into this state is to have more then 4 e1000 >>> nics configured. >>> >>> Signed-off-by: Don Slutz >> I still don't think this is the correct solution, although I will >> concede that this is a far better patch than v1. >> >> Going back to the original problem, why does Qemu need to change maxmem >> in the first place? You talk about e1000 option roms, but the option >> roms themselves must be allocated in an appropriate PCI bridge window. > QEMU allocates actual memory to store the option roms using > xc_domain_populate_physmap_exact, increasing the total amount of ram > allocated to the guest. QEMU needs to increase maxmem too, otherwise > memory allocations will fail after a few option roms. It doesn't need to. The domain already has that much ram allocated to itself and otherwise wasted. Qemu should reuse that ram rather than wasting more. ~Andrew