Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759481AbYCZRz0 (ORCPT ); Wed, 26 Mar 2008 13:55:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753342AbYCZRzL (ORCPT ); Wed, 26 Mar 2008 13:55:11 -0400 Received: from mga03.intel.com ([143.182.124.21]:36163 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752485AbYCZRzJ (ORCPT ); Wed, 26 Mar 2008 13:55:09 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.25,559,1199692800"; d="scan'208";a="223534673" Date: Wed, 26 Mar 2008 10:55:00 -0700 From: Suresh Siddha To: Ingo Molnar Cc: Suresh Siddha , Andrew Morton , Thomas Gleixner , bugme-daemon@bugzilla.kernel.org, linux-kernel@vger.kernel.org, "Rafael J. Wysocki" , venkatesh.pallipadi@intel.com, arjan@linux.intel.com, bug-track@fisher-privat.net Subject: Re: [Bug 10328] New: [regression] performance drop for glx Message-ID: <20080326175500.GD3313@linux-os.sc.intel.com> References: <20080325152809.e2b07251.akpm@linux-foundation.org> <20080326003912.GB3313@linux-os.sc.intel.com> <20080326052911.GA8173@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080326052911.GA8173@elte.hu> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4461 Lines: 102 On Wed, Mar 26, 2008 at 06:29:11AM +0100, Ingo Molnar wrote: > > * Suresh Siddha wrote: > > > fb drivers are using ioremap()/ioremap_nocache(), followed by mtrr_add > > with WC attribute. Recent changes in page attribute code made both > > ioremap()/ioremap_nocache() mappings as UC (instead of previous UC-). > > This breaks the graphics performance, as the effective memory type is > > UC instead of expected WC. > > > > The correct way to fix this is to add ioremap_wc() (which uses UC- in > > the absence of PAT kernel support and WC with PAT) and change all the > > fb drivers to use this new ioremap_wc() API. > > > > We can take this correct and longer route for post 2.6.25. For now, > > revert back to the UC- behavior for ioremap/ioremap_nocache. > > thanks Suresh, applied. Well, we need to take care of set_memory_uc() aswell, as the previous version didn't fix Alexey's issue. Alexey, can you please test and ack this, before Andrew/Ingo can push relevant bits to their trees. Thanks. --- fb drivers are using ioremap()/ioremap_nocache(), followed by mtrr_add with WC attribute. Recent changes in page attribute code made both ioremap()/ioremap_nocache() mappings as UC (instead of previous UC-). This breaks the graphics performance, as the effective memory type is UC instead of expected WC. The correct way to fix this is to add ioremap_wc() (which uses UC- in the absence of PAT kernel support and WC with PAT) and change all the drivers to use this new ioremap_wc() API. We can take this correct and longer route for post 2.6.25. For now, revert back to the UC- behavior for ioremap/ioremap_nocache. Signed-off-by: Suresh Siddha Signed-off-by: Venkatesh Pallipadi Cc: Arjan van de Ven Cc: Alexey Fisher Cc: Ingo Molnar Cc: Thomas Gleixner --- diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index 4afaba0..794895c 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -137,7 +137,11 @@ static void __iomem *__ioremap(resource_size_t phys_addr, unsigned long size, switch (mode) { case IOR_MODE_UNCACHED: default: - prot = PAGE_KERNEL_NOCACHE; + /* + * FIXME: we will use UC MINUS for now, as video fb drivers + * depend on it. Upcoming ioremap_wc() will fix this behavior. + */ + prot = PAGE_KERNEL_UC_MINUS; break; case IOR_MODE_CACHED: prot = PAGE_KERNEL; diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 14e48b5..7b79f6b 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -771,7 +771,7 @@ static inline int change_page_attr_clear(unsigned long addr, int numpages, int set_memory_uc(unsigned long addr, int numpages) { return change_page_attr_set(addr, numpages, - __pgprot(_PAGE_PCD | _PAGE_PWT)); + __pgprot(_PAGE_PCD)); } EXPORT_SYMBOL(set_memory_uc); diff --git a/include/asm-x86/pgtable.h b/include/asm-x86/pgtable.h index 174b877..9cf472a 100644 --- a/include/asm-x86/pgtable.h +++ b/include/asm-x86/pgtable.h @@ -85,6 +85,7 @@ extern pteval_t __PAGE_KERNEL, __PAGE_KERNEL_EXEC; #define __PAGE_KERNEL_RX (__PAGE_KERNEL_EXEC & ~_PAGE_RW) #define __PAGE_KERNEL_EXEC_NOCACHE (__PAGE_KERNEL_EXEC | _PAGE_PCD | _PAGE_PWT) #define __PAGE_KERNEL_NOCACHE (__PAGE_KERNEL | _PAGE_PCD | _PAGE_PWT) +#define __PAGE_KERNEL_UC_MINUS (__PAGE_KERNEL | _PAGE_PCD) #define __PAGE_KERNEL_VSYSCALL (__PAGE_KERNEL_RX | _PAGE_USER) #define __PAGE_KERNEL_VSYSCALL_NOCACHE (__PAGE_KERNEL_VSYSCALL | _PAGE_PCD | _PAGE_PWT) #define __PAGE_KERNEL_LARGE (__PAGE_KERNEL | _PAGE_PSE) @@ -101,6 +102,7 @@ extern pteval_t __PAGE_KERNEL, __PAGE_KERNEL_EXEC; #define PAGE_KERNEL_EXEC MAKE_GLOBAL(__PAGE_KERNEL_EXEC) #define PAGE_KERNEL_RX MAKE_GLOBAL(__PAGE_KERNEL_RX) #define PAGE_KERNEL_NOCACHE MAKE_GLOBAL(__PAGE_KERNEL_NOCACHE) +#define PAGE_KERNEL_UC_MINUS MAKE_GLOBAL(__PAGE_KERNEL_UC_MINUS) #define PAGE_KERNEL_EXEC_NOCACHE MAKE_GLOBAL(__PAGE_KERNEL_EXEC_NOCACHE) #define PAGE_KERNEL_LARGE MAKE_GLOBAL(__PAGE_KERNEL_LARGE) #define PAGE_KERNEL_LARGE_EXEC MAKE_GLOBAL(__PAGE_KERNEL_LARGE_EXEC) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/