From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx200.postini.com [74.125.245.200]) by kanga.kvack.org (Postfix) with SMTP id BBA396B00E7 for ; Tue, 3 Apr 2012 02:03:28 -0400 (EDT) Received: by bkwq16 with SMTP id q16so3858979bkw.14 for ; Mon, 02 Apr 2012 23:03:27 -0700 (PDT) Message-ID: <4F7A92AB.5010809@openvz.org> Date: Tue, 03 Apr 2012 10:03:23 +0400 From: Konstantin Khlebnikov MIME-Version: 1.0 Subject: Re: [x86 PAT PATCH 0/2] x86 PAT vm_flag code refactoring References: <20120331170947.7773.46399.stgit@zurg> <1333413969-30761-1-git-send-email-suresh.b.siddha@intel.com> In-Reply-To: <1333413969-30761-1-git-send-email-suresh.b.siddha@intel.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Suresh Siddha Cc: Konstantin Khlebnikov , "linux-mm@kvack.org" , Andrew Morton , "linux-kernel@vger.kernel.org" , Andi Kleen , Pallipadi Venkatesh , Ingo Molnar , "H. Peter Anvin" , Linus Torvalds , Nick Piggin Suresh Siddha wrote: > Konstantin, > > On Sat, 2012-03-31 at 21:09 +0400, Konstantin Khlebnikov wrote: >> v2: Do not use batched pfn reserving for single-page VMA. This is not optimal >> and breaks something, because I see glitches on the screen with i915/drm driver. >> With this version glitches are gone, and I see the same regions in >> /sys/kernel/debug/x86/pat_memtype_list as before patch. So, please review this >> carefully, probably I'm wrong somewhere, or I have triggered some hidden bug. > > Actually it is not a hidden bug. In the original code, we were setting > VM_PFN_AT_MMAP only for remap_pfn_range() but not for the vm_insert_pfn(). > Also the value of 'vm_pgoff' depends on the driver/mmap_region() in the case of > vm_insert_pfn(). But with your proposed code, you were setting > the VM_PAT for the single-page VMA also and end-up using wrong vm_pgoff in > untrack_pfn_vma(). But I set correct vma->vm_pgoff together with VM_PAT. But, it shouldn't work if vma is expandable... > > We can simplify the track/untrack pfn routines and can remove the > dependency on vm_pgoff completely. Am appending a patch which does this > and also modified your x86 PAT patch based on this. Can you please > check and if you are ok, merge these bits with the rest of your patches. Ok, I'll checks this. > > thanks, > suresh > --- > > Konstantin Khlebnikov (1): > mm, x86, PAT: rework linear pfn-mmap tracking > > Suresh Siddha (1): > x86, pat: remove the dependency on 'vm_pgoff' in track/untrack pfn > vma routines > > arch/x86/mm/pat.c | 38 ++++++++++++++++++++++++-------------- > include/asm-generic/pgtable.h | 4 ++-- > include/linux/mm.h | 15 +-------------- > mm/huge_memory.c | 7 +++---- > mm/memory.c | 15 ++++++++------- > 5 files changed, 38 insertions(+), 41 deletions(-) > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org