From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Date: Wed, 14 Sep 2016 08:44:22 -0600 From: Jon Derrick To: "Busch, Keith" Cc: Bjorn Helgaas , "linux-pci@vger.kernel.org" Subject: Re: [RFCv2 0/3] vmd irq list shortening, map allocation Message-ID: <20160914144422.GA8315@localhost.localdomain> References: <1472838786-3441-1-git-send-email-jonathan.derrick@intel.com> <20160913205745.GF4138@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: List-ID: Hi Keith, Thanks for the review On Tue, Sep 13, 2016 at 04:16:19PM -0600, Busch, Keith wrote: > Sorry for the delay. I've been looking into these new PCI IRQ API's and found an unrelated issue that I stuck myself with working through with Christoph and Thomas. :) > > Patches 1/3 and 2/3 look good to me. > > I'm not convinced 3/3 is an improvement. At the very least, we don't want to BUG_ON from a failed kmalloc when we can return an appropriate error instead. I'll take a closer look at 3/3 and get back to Jon with more feedback. > Yes the BUG_ON was a mistake I would have removed for the next rev. But I agree with you where I am not convinced either. I have been trying to put together a test vehicle to prove that this is actually an improvement, but I have not had much luck yet. Also, from what I can tell as well, nobody is using ida for indexing into a map, so that would be converted to the bitmap api instead. I'll follow up in a (long) while when I get the test case figured out and some real results. If it's not clear yet, 3/3 can be killed :) > > > -----Original Message----- > From: Bjorn Helgaas [mailto:helgaas@kernel.org] > Sent: Tuesday, September 13, 2016 2:58 PM > To: Derrick, Jonathan > Cc: Busch, Keith ; linux-pci@vger.kernel.org > Subject: Re: [RFCv2 0/3] vmd irq list shortening, map allocation > > On Fri, Sep 02, 2016 at 11:53:03AM -0600, Jon Derrick wrote: > > V2: > > Added a map for vmd irqs to attempt to allocate all vmd irqs within an > > irq list into a single page. Once we start getting many devices > > sharing the irq in an irq list, this may help the list traversal latency. > > > > V1: > > Couple of RFC patches here. I don't really notice a positive benefit but > > it does reduce the struct size of vmd_irq_list and hopefully we gain some > > cache benefits from that. > > > > Both are based on: > > https://patchwork.kernel.org/patch/9304179/ > > https://patchwork.kernel.org/patch/9304181/ > > > > Jon Derrick (3): > > vmd: eliminate vmd_vector member from list type > > vmd: eliminate index member from irq list > > pci/vmd: Create irq map for irq nodes > > > > arch/x86/pci/vmd.c | 94 ++++++++++++++++++++++++++++++++++++++++++------------ > > 1 file changed, 73 insertions(+), 21 deletions(-) > > These look OK to me, so if Keith acks them I'll merge them.