From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: [PATCH] privcmd: MMAPBATCH: Fix error handling/reporting Date: Thu, 21 May 2009 10:14:51 -0700 Message-ID: <4A158C0B.8070100@goop.org> References: <1242830676.22654.66.camel@zakaz.uk.xensource.com> <1242830730-3341-1-git-send-email-ian.campbell@citrix.com> <4A145B12.4050408@goop.org> <1242895899.22654.92.camel@zakaz.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1242895899.22654.92.camel@zakaz.uk.xensource.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Ian Campbell Cc: "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org Ian Campbell wrote: >> The noise is just for debugging; if failure is expected, then maybe we >> can extend it to be quiet about those cases. >> > > In this specific instance going directly at the mmu_udpate interface is > probably better since the propagation of errors from the multicall > infrastructure is tricky (well, currently non-existent). I don't think > multicalls would buy us anything here anyhow since mmu_update is batched > already. > Yeah. The generic multicall stuff is (should be) tuned for the common case of no errors. I think this is the first instance of something where we expect errors back. The multicall path is fairly hot, and I suspect it's going to need some trimming when the real performance work starts, so keeping it low-feature is a good idea. (Though we could make use of maybe-fail to deal with vmap aliases in pte-pinning...) >> This breaks compiling xenfs as a module; neither flush_tlb_all or >> arbitrary_virt_to_machine are exported, I think. >> > > Rather than exporting those I think moving remap_domain_mfn_range() to > core code (with xen_ on the front of the name) and exporting that would > be cleaner. Thoughts? > Yes, seems reasonable to me. Though if its arch-neutral, drivers/xen would be better. J