From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Ahern Date: Wed, 04 Mar 2015 19:32:32 +0000 Subject: Re: [PATCH v2 0/2] sparc: IOMMU pools for better scalability Message-Id: <54F75DD0.2010902@gmail.com> List-Id: References: <20150303142202.GA7696@oracle.com> In-Reply-To: <20150303142202.GA7696@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: sparclinux@vger.kernel.org On 3/4/15 12:15 PM, David Miller wrote: > From: Sowmini Varadhan > Date: Wed, 4 Mar 2015 14:10:17 -0500 > >> On (03/03/15 17:15), David Miller wrote: >>> Please don't put "ifdef notyet" kind of stuff into your changes, >>> that is not appropriate. In any event, I want you to translate all >>> of the PCI DMA implementations, because it is the only way you can >>> show me that your abstractions are sufficient. >> >> That means I have to fix all kinds of dinosaurs in the neighborhood, >> things like pci_fire, pci_schizo, pci_psycho, sun4u. Some of this >> hardware was EOL'ed a long time ago. And the last time I remember >> using a sun4u was back in 2008 (and even then, it was really not >> very useful for any sort of non-trivial SMP/perf development). >> >> But whatever floats your boat. > > It's a conversion that has to be done anyways, and otherwise you'll > have no idea whether your abstractions are sufficient or not. Doesn't that run the risk of breaking older platforms, which cannot realistically be tested? Why not refactor the code such that old platforms are not touched and focus on abstractions for modern h/w? David