From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olaf Hering Subject: Re: Paging/sharing in 4.2 (Was: Re: 4.2 TODO update) Date: Tue, 13 Mar 2012 11:54:26 +0100 Message-ID: <20120313105426.GA26167@aepfle.de> References: <1331554278.23971.63.camel@zakaz.uk.xensource.com> <1331554805.23971.70.camel@zakaz.uk.xensource.com> <20120312130403.GA6270@aepfle.de> <1331559700.23971.106.camel@zakaz.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1331559700.23971.106.camel@zakaz.uk.xensource.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell Cc: "Tim (Xen.org)" , Andres Lagar-Cavilla , "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org On Mon, Mar 12, Ian Campbell wrote: > On Mon, 2012-03-12 at 13:04 +0000, Olaf Hering wrote: > > On Mon, Mar 12, Ian Campbell wrote: > > > > > On Mon, 2012-03-12 at 12:11 +0000, Ian Campbell wrote: > > > > hypervisor, nice to have: > > > > * solid implementation of sharing/paging/mem-events (using work > > > > queues) (Tim Deegan, Olaf Herring et al -- is this happening? is > > > > it DONE even?) > > > > The last patch to use a waitqueue in __get_gfn_type_access() from Tim > > works. However, there are a few users who call __get_gfn_type_access > > with the domain_lock held. > > Thanks. > > > This part needs to be addressed in some way. > > This is happening? To me its not clear what the domain_lock() protects: Just a guest: XENMEM_remove_from_physmap should be ok with the gfn_lock taken in guest_physmap_remove_page(), so the domain_lock() could be removed there. I'm not sure about the domain_lock in xenmem_add_to_physmap_once() and emulate_privileged_op(). > > > > tools, nice to have: > > > > [...] > > > > * Configure/control paging via xl/libxl (Olaf Herring, lots of > > > > discussion around interface) > > > > > > Is this a reasonable summary of the state of the paging/sharing & > > > friends world for 4.2? Is there anything missing? > > > > There are indeed alot of ideas regarding the interface, and its > > currently not clear to me if there is an agreement yet. Was there any > > outcome where to proceed? > > I've mostly swapped it out while I was away so I need to go back to the > thread and figure out where we got to. I don't think we had discussed > the libxl interface, only xl. I think the proposal Andres made sense in > this respect when he described it to me (although I've not read the mail > yet). So is this something we should work out for the 4.2 release? If I understand it right, there should be a .cfg option mem_policy=, where string could be "paging" or "balloon". In case of balloon the target value would be whats in use now (memory+maxmem). In case of paging these values could be reused in the same way, just that maxmem+memory would not create a PoD guest. If mem_policy= is not given it will default to balloon to retain current behaviour. Olaf