From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752802AbbCYUjY (ORCPT ); Wed, 25 Mar 2015 16:39:24 -0400 Received: from cantor2.suse.de ([195.135.220.15]:56855 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751212AbbCYUjS (ORCPT ); Wed, 25 Mar 2015 16:39:18 -0400 Date: Wed, 25 Mar 2015 21:39:14 +0100 From: "Luis R. Rodriguez" To: Konrad Rzeszutek Wilk , Arjan van de Ven , Arjan van de Ven Cc: "Luis R. Rodriguez" , luto@amacapital.net, mingo@redhat.com, tglx@linutronix.de, hpa@zytor.com, jgross@suse.com, JBeulich@suse.com, bp@suse.de, suresh.b.siddha@intel.com, venkatesh.pallipadi@intel.com, airlied@redhat.com, linux-fbdev@vger.kernel.org, Antonino Daplas , Daniel Vetter , x86@kernel.org, linux-kernel@vger.kernel.org, Tomi Valkeinen , xen-devel@lists.xenproject.org, Ingo Molnar , Jean-Christophe Plagniol-Villard Subject: Re: [Xen-devel] [PATCH v1 04/47] pci: add pci_ioremap_wc_bar() Message-ID: <20150325203914.GD12247@wotan.suse.de> References: <1426893517-2511-1-git-send-email-mcgrof@do-not-panic.com> <1426893517-2511-5-git-send-email-mcgrof@do-not-panic.com> <20150325200346.GO25884@l.oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150325200346.GO25884@l.oracle.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 25, 2015 at 04:03:46PM -0400, Konrad Rzeszutek Wilk wrote: > On Fri, Mar 20, 2015 at 04:17:54PM -0700, Luis R. Rodriguez wrote: > > From: "Luis R. Rodriguez" > > > > This lets drivers take advanate of PAT when available. This > > s/advanate/advantage/ Amended. > > should help with the transition of converting video drivers over > > to ioremap_wc() to help with the goal of eventually using > > _PAGE_CACHE_UC over _PAGE_CACHE_UC_MINUS on x86 on > > ioremap_nocache() (de33c442e) > > Please mention the title of the patch too: > > "x86 PAT: fix performance drop for glx, use UC minus for ioremap(), ioremap_nocache() and pci_mmap_page_range()" Added. > > > > Cc: Suresh Siddha > > Cc: Venkatesh Pallipadi > > Cc: Ingo Molnar > > Cc: Thomas Gleixner > > Cc: Juergen Gross > > Cc: Daniel Vetter > > Cc: Andy Lutomirski > > Cc: Dave Airlie > > Cc: Antonino Daplas > > Cc: Jean-Christophe Plagniol-Villard > > Cc: Tomi Valkeinen > > Cc: linux-fbdev@vger.kernel.org > > Cc: linux-kernel@vger.kernel.org > > Signed-off-by: Luis R. Rodriguez > > --- > > drivers/pci/pci.c | 14 ++++++++++++++ > > include/linux/pci.h | 1 + > > 2 files changed, 15 insertions(+) > > > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > > index 81f06e8..6afd507 100644 > > --- a/drivers/pci/pci.c > > +++ b/drivers/pci/pci.c > > @@ -137,6 +137,20 @@ void __iomem *pci_ioremap_bar(struct pci_dev *pdev, int bar) > > pci_resource_len(pdev, bar)); > > } > > EXPORT_SYMBOL_GPL(pci_ioremap_bar); > > + > > +void __iomem *pci_ioremap_wc_bar(struct pci_dev *pdev, int bar) > > +{ > > + /* > > + * Make sure the BAR is actually a memory resource, not an IO resource > > + */ > > + if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM)) { > > + WARN_ON(1); > > Would it be better to use dev_warn ? That way you can see which BDF it is? > > Thought WARN will give a nice stack-trace that should easily point to the > driver so perhaps not.. Either way - up to you. I'm sticking to the style and use as with pci_ioremap_bar(). Whatever we pick we should make both use the same. More information is always better and since we do have dev_warn(), it would be nice to use that however within its use on both pci_ioremap_wc_bar() and pci_ioremap_bar() we have a use of the pdev with pci_resource_flags() and I believe if pdev is NULL we'd get a NULL dereference (dev_driver_string() is used), so it would seem it might be best to stick with a simple WARN_ON(). Arjan, any preference? Obviously if pdev is NULL your driver is dumb but as folks develop drivers this should be expected. Luis From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Luis R. Rodriguez" Date: Wed, 25 Mar 2015 20:39:14 +0000 Subject: Re: [Xen-devel] [PATCH v1 04/47] pci: add pci_ioremap_wc_bar() Message-Id: <20150325203914.GD12247@wotan.suse.de> List-Id: References: <1426893517-2511-1-git-send-email-mcgrof@do-not-panic.com> <1426893517-2511-5-git-send-email-mcgrof@do-not-panic.com> <20150325200346.GO25884@l.oracle.com> In-Reply-To: <20150325200346.GO25884@l.oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Konrad Rzeszutek Wilk , Arjan van de Ven , Arjan van de Ven Cc: "Luis R. Rodriguez" , luto@amacapital.net, mingo@redhat.com, tglx@linutronix.de, hpa@zytor.com, jgross@suse.com, JBeulich@suse.com, bp@suse.de, suresh.b.siddha@intel.com, venkatesh.pallipadi@intel.com, airlied@redhat.com, linux-fbdev@vger.kernel.org, Antonino Daplas , Daniel Vetter , x86@kernel.org, linux-kernel@vger.kernel.org, Tomi Valkeinen , xen-devel@lists.xenproject.org, Ingo Molnar , Jean-Christophe Plagniol-Villard On Wed, Mar 25, 2015 at 04:03:46PM -0400, Konrad Rzeszutek Wilk wrote: > On Fri, Mar 20, 2015 at 04:17:54PM -0700, Luis R. Rodriguez wrote: > > From: "Luis R. Rodriguez" > > > > This lets drivers take advanate of PAT when available. This > > s/advanate/advantage/ Amended. > > should help with the transition of converting video drivers over > > to ioremap_wc() to help with the goal of eventually using > > _PAGE_CACHE_UC over _PAGE_CACHE_UC_MINUS on x86 on > > ioremap_nocache() (de33c442e) > > Please mention the title of the patch too: > > "x86 PAT: fix performance drop for glx, use UC minus for ioremap(), ioremap_nocache() and pci_mmap_page_range()" Added. > > > > Cc: Suresh Siddha > > Cc: Venkatesh Pallipadi > > Cc: Ingo Molnar > > Cc: Thomas Gleixner > > Cc: Juergen Gross > > Cc: Daniel Vetter > > Cc: Andy Lutomirski > > Cc: Dave Airlie > > Cc: Antonino Daplas > > Cc: Jean-Christophe Plagniol-Villard > > Cc: Tomi Valkeinen > > Cc: linux-fbdev@vger.kernel.org > > Cc: linux-kernel@vger.kernel.org > > Signed-off-by: Luis R. Rodriguez > > --- > > drivers/pci/pci.c | 14 ++++++++++++++ > > include/linux/pci.h | 1 + > > 2 files changed, 15 insertions(+) > > > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > > index 81f06e8..6afd507 100644 > > --- a/drivers/pci/pci.c > > +++ b/drivers/pci/pci.c > > @@ -137,6 +137,20 @@ void __iomem *pci_ioremap_bar(struct pci_dev *pdev, int bar) > > pci_resource_len(pdev, bar)); > > } > > EXPORT_SYMBOL_GPL(pci_ioremap_bar); > > + > > +void __iomem *pci_ioremap_wc_bar(struct pci_dev *pdev, int bar) > > +{ > > + /* > > + * Make sure the BAR is actually a memory resource, not an IO resource > > + */ > > + if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM)) { > > + WARN_ON(1); > > Would it be better to use dev_warn ? That way you can see which BDF it is? > > Thought WARN will give a nice stack-trace that should easily point to the > driver so perhaps not.. Either way - up to you. I'm sticking to the style and use as with pci_ioremap_bar(). Whatever we pick we should make both use the same. More information is always better and since we do have dev_warn(), it would be nice to use that however within its use on both pci_ioremap_wc_bar() and pci_ioremap_bar() we have a use of the pdev with pci_resource_flags() and I believe if pdev is NULL we'd get a NULL dereference (dev_driver_string() is used), so it would seem it might be best to stick with a simple WARN_ON(). Arjan, any preference? Obviously if pdev is NULL your driver is dumb but as folks develop drivers this should be expected. Luis