Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933173AbZDAXJG (ORCPT ); Wed, 1 Apr 2009 19:09:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933732AbZDAXEJ (ORCPT ); Wed, 1 Apr 2009 19:04:09 -0400 Received: from mga09.intel.com ([134.134.136.24]:62623 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933697AbZDAXEE (ORCPT ); Wed, 1 Apr 2009 19:04:04 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.39,309,1235980800"; d="scan'208";a="399538921" Date: Wed, 1 Apr 2009 16:04:01 -0700 From: "Pallipadi, Venkatesh" To: Arkadiusz Miskiewicz Cc: "Pallipadi, Venkatesh" , "Siddha, Suresh B" , "linux-kernel@vger.kernel.org" Subject: Re: 2.6.29 git master and PAT problems Message-ID: <20090401230401.GD10490@linux-os.sc.intel.com> References: <200903302317.04515.a.miskiewicz@gmail.com> <200903310944.32883.a.miskiewicz@gmail.com> <20090331232109.GA11980@linux-os.sc.intel.com> <200904011223.50050.a.miskiewicz@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200904011223.50050.a.miskiewicz@gmail.com> 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: 8263 Lines: 187 On Wed, Apr 01, 2009 at 03:23:49AM -0700, Arkadiusz Miskiewicz wrote: > On Wednesday 01 of April 2009, Pallipadi, Venkatesh wrote: > > On Tue, Mar 31, 2009 at 12:44:32AM -0700, Arkadiusz Miskiewicz wrote: > > > On Tuesday 31 of March 2009, Pallipadi, Venkatesh wrote: > > > > On Mon, Mar 30, 2009 at 04:25:11PM -0700, Arkadiusz Miskiewicz wrote: > > > > > On Tuesday 31 of March 2009, Arkadiusz Miskiewicz wrote: > > > > > > On Monday 30 of March 2009, Pallipadi, Venkatesh wrote: > > > > > > > > > > > > More info follows. Now I've switched to > > > > > > e1c502482853f84606928f5a2f2eb6da1993cda1 which contains latest drm > > > > > > fixes and now I get much lower numbers of PAT errors but still. > > > > > > > > > > Also when I switch t400 into discrete mode (radeon hd 3400 instead > > > > > of integrated intel GM45) I get such errors (probably unrelated > > > > > to these seen when using intel): > > > > > > > > > > [ 419.187657] X:10550 conflicting memory types cfff0000-d0000000 > > > > > uncached<->uncached-minus [ 419.187670] reserve_memtype failed > > > > > 0xcfff0000-0xd0000000, track uncached, req write-back [ 419.553914] > > > > > X:10550 conflicting memory types cfff0000-d0000000 > > > > > uncached<->uncached-minus [ 419.553923] reserve_memtype failed > > > > > 0xcfff0000-0xd0000000, track uncached, req write-back [ 419.813592] > > > > > X:10550 conflicting memory types cfff0000-d0000000 > > > > > uncached<->uncached-minus [ 419.813601] reserve_memtype failed > > > > > 0xcfff0000-0xd0000000, track uncached, req write-back [ 420.100102] > > > > > X:10550 conflicting memory types cfff0000-d0000000 > > > > > uncached<->uncached-minus [ 420.100111] reserve_memtype failed > > > > > 0xcfff0000-0xd0000000, track uncached, req write-back > > > > > > > > Yes. This is a different problem than the freeing invalid type one. Are > > > > these errors also with latest git kernel? Can you try the patch below > > > > (which is a part of a bigger cleanup patch I have lined up). > > > > > > It's a latest git kernel as of today morning > > > (latest commit is 15f7176eb1cccec0a332541285ee752b935c1c85) > > > + your patch. Problem persists: > > > > > > [ 74.696353] [drm] Setting GART location based on new memory map > > > [ 74.711520] [drm] Loading RV620 CP Microcode > > > [ 74.711792] [drm] Loading RV620 PFP Microcode > > > [ 74.726719] [drm] Resetting GPU > > > [ 74.726776] [drm] writeback test succeeded in 1 usecs > > > [ 75.256034] X:5366 conflicting memory types d0000000-e0000000 > > > uncached-minus<->write-combining [ 75.256043] reserve_memtype failed > > > 0xd0000000-0xe0000000, track uncached-minus, req write-back [ > > > 75.849951] X:5366 conflicting memory types d0000000-e0000000 > > > uncached-minus<->write-combining [ 75.849960] reserve_memtype failed > > > 0xd0000000-0xe0000000, track uncached-minus, req write-back [ > > > 76.054374] X:5366 conflicting memory types d0000000-e0000000 > > > uncached-minus<->write-combining [ 76.054377] reserve_memtype failed > > > 0xd0000000-0xe0000000, track uncached-minus, req write-back [ > > > 76.074481] X:5378 freeing invalid memtype d0000000-e0000000 > > > [ 76.176881] X:5366 conflicting memory types d0000000-e0000000 > > > uncached-minus<->write-combining [ 76.176885] reserve_memtype failed > > > 0xd0000000-0xe0000000, track uncached-minus, req write-back [ > > > 76.207734] X:5380 freeing invalid memtype d0000000-e0000000 > > > > OK. We now have a theory on what is going wrong here. > > > > The problem seems to be pci mmap uses vm_page_prot flag to remember the > > memtype for this region. Looks like that memtype is somehow getting cleared > > in this case. We still don't know where it is getting cleared. But, with > > debug patch below we can be sure that it is indeed getting cleared, which > > is causing problems on fork() as child wont know the memtype that parent > > got. > > > > Can you please try the below debug patch over upstream git and check > > whether you indeed hit the warnon. > > warns triggered: > OK. Below patch should resolve this problem. Thanks, Venki From: Suresh Siddha Subject: [PATCH] x86, PAT: Remove duplicate memtype reserve in pci mmap pci mmap code was doing memtype reserve for a while now. Recently we added memtype tracking in remap_pfn_range, and pci code indirectly calls remap_pfn_range. So, we don't need seperate tracking in pci code anymore. Which means a patch that removes ~50 lines of code :-). Also, recently we found out that the pci tracking is not working as we expect it to work in some cases. Specifically, userlevel X mmap of pci, with some recent version of X, is having a problem with vm_page_prot getting reset. The pci tracking uses vm_page_prot to pass on the protection type from parent to child during fork. a) Parent does a pci mmap b) We look at PAT and get either UC_MINUS or WC mapping for parent c) Store that mapping type in vma vm_page_prot for future use d) This thread does a fork e) Fork results in mmap_ops ->open for the child process f) We get the vm_page_prot from vma and reserve that type for the child process But, between c) and e) above, the vma vm_page_prot is getting reset to zero. This results in PAT reserve failing at the time of fork as in here. http://marc.info/?l=linux-kernel&m=123858163103240&w=2 This cleanup makes the above problem go away as we do not depend on vm_page_prot in our PAT code anymore. Signed-off-by: Suresh Siddha Signed-off-by: Venkatesh Pallipadi --- arch/x86/pci/i386.c | 46 ---------------------------------------------- 1 file changed, 46 deletions(-) Index: linux-2.6/arch/x86/pci/i386.c =================================================================== --- linux-2.6.orig/arch/x86/pci/i386.c 2009-04-01 10:29:49.000000000 -0700 +++ linux-2.6/arch/x86/pci/i386.c 2009-04-01 10:33:18.000000000 -0700 @@ -258,24 +258,7 @@ void pcibios_set_master(struct pci_dev * pci_write_config_byte(dev, PCI_LATENCY_TIMER, lat); } -static void pci_unmap_page_range(struct vm_area_struct *vma) -{ - u64 addr = (u64)vma->vm_pgoff << PAGE_SHIFT; - free_memtype(addr, addr + vma->vm_end - vma->vm_start); -} - -static void pci_track_mmap_page_range(struct vm_area_struct *vma) -{ - u64 addr = (u64)vma->vm_pgoff << PAGE_SHIFT; - unsigned long flags = pgprot_val(vma->vm_page_prot) - & _PAGE_CACHE_MASK; - - reserve_memtype(addr, addr + vma->vm_end - vma->vm_start, flags, NULL); -} - static struct vm_operations_struct pci_mmap_ops = { - .open = pci_track_mmap_page_range, - .close = pci_unmap_page_range, .access = generic_access_phys, }; @@ -283,11 +266,6 @@ int pci_mmap_page_range(struct pci_dev * enum pci_mmap_state mmap_state, int write_combine) { unsigned long prot; - u64 addr = vma->vm_pgoff << PAGE_SHIFT; - unsigned long len = vma->vm_end - vma->vm_start; - unsigned long flags; - unsigned long new_flags; - int retval; /* I/O space cannot be accessed via normal processor loads and * stores on this platform. @@ -308,30 +286,6 @@ int pci_mmap_page_range(struct pci_dev * vma->vm_page_prot = __pgprot(prot); - flags = pgprot_val(vma->vm_page_prot) & _PAGE_CACHE_MASK; - retval = reserve_memtype(addr, addr + len, flags, &new_flags); - if (retval) - return retval; - - if (flags != new_flags) { - if (!is_new_memtype_allowed(flags, new_flags)) { - free_memtype(addr, addr+len); - return -EINVAL; - } - flags = new_flags; - vma->vm_page_prot = __pgprot( - (pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK) | - flags); - } - - if (((vma->vm_pgoff < max_low_pfn_mapped) || - (vma->vm_pgoff >= (1UL<<(32 - PAGE_SHIFT)) && - vma->vm_pgoff < max_pfn_mapped)) && - ioremap_change_attr((unsigned long)__va(addr), len, flags)) { - free_memtype(addr, addr + len); - return -EINVAL; - } - if (io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, vma->vm_end - vma->vm_start, vma->vm_page_prot)) -- 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/