Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758816Ab2KWB0O (ORCPT ); Thu, 22 Nov 2012 20:26:14 -0500 Received: from mail-ob0-f174.google.com ([209.85.214.174]:45395 "EHLO mail-ob0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756862Ab2KWB0J (ORCPT ); Thu, 22 Nov 2012 20:26:09 -0500 MIME-Version: 1.0 In-Reply-To: <20121120160918.GA18167@gmail.com> References: <1353291284-2998-1-git-send-email-mingo@kernel.org> <20121119162909.GL8218@suse.de> <20121119191339.GA11701@gmail.com> <20121119211804.GM8218@suse.de> <20121119223604.GA13470@gmail.com> <20121120071704.GA14199@gmail.com> <20121120152933.GA17996@gmail.com> <20121120160918.GA18167@gmail.com> Date: Fri, 23 Nov 2012 09:26:08 +0800 Message-ID: Subject: Re: [PATCH, v2] mm, numa: Turn 4K pte NUMA faults into effective hugepage ones From: Alex Shi To: Ingo Molnar Cc: Linus Torvalds , David Rientjes , Mel Gorman , Linux Kernel Mailing List , linux-mm , Peter Zijlstra , Paul Turner , Lee Schermerhorn , Christoph Lameter , Rik van Riel , Andrew Morton , Andrea Arcangeli , Thomas Gleixner , Johannes Weiner , Hugh Dickins , Alex Shi Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8721 Lines: 239 This patch cause boot hang on our SNB EP 2 sockets machine with some segmentation fault. revert it recovers booting. ============ [ 8.290147] Freeing unused kernel memory: 1264k freed [ 8.306140] Freeing unused kernel memory: 1592k freed [ 8.342668] init[250]: segfault at 20da510 ip 00000000020da510 sp 00007fff26788040 error 15[ 8.350983] usb 2-1: New USB device found, idVendor=8087, idProduct=0024 [ 8.350987] usb 2-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0 [ 8.351266] hub 2-1:1.0: USB hub found [ 8.351346] hub 2-1:1.0: 8 ports detected Segmentation fault [ 8.626633] usb 2-1.4: new full-speed USB device number 3 using ehci_hcd [ 8.721391] usb 2-1.4: New USB device found, idVendor=046b, idProduct=ff10 [ 8.729536] usb 2-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 8.738540] usb 2-1.4: Product: Virtual Keyboard and Mouse [ 8.745134] usb 2-1.4: Manufacturer: American Megatrends Inc. [ 8.752026] usb 2-1.4: SerialNumber: serial [ 8.758877] input: American Megatrends Inc. Virtual Keyboard and Mouse as /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.0/input/input1 [ 8.774428] hid-generic 0003:046B:FF10.0001: input,hidraw0: USB HID v1.10 Keyboard [American Megatrends Inc. Virtual Keyboard and Mouse] on usb-0000:00:1d.0-1.4/input0 [ 8.793393] input: American Megatrends Inc. Virtual Keyboard and Mouse as /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.1/input/input2 [ 8.809140] hid-generic 0003:046B:FF10.0002: input,hidraw1: USB HID v1.10 Mouse [American Megatrends Inc. Virtual Keyboard and Mouse] on usb-0000:00:1d.0-1.4/input1 [ 8.899511] usb 2-1.7: new low-speed USB device number 4 using ehci_hcd [ 9.073473] usb 2-1.7: New USB device found, idVendor=0557, idProduct=2220 [ 9.081633] usb 2-1.7: New USB device strings: Mfr=1, Product=2, SerialNumber=0 [ 9.090643] usb 2-1.7: Product: ATEN CS-1758/54 [ 9.096258] usb 2-1.7: Manufacturer: ATEN [ 9.134093] input: ATEN ATEN CS-1758/54 as /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.7/2-1.7:1.0/input/input3 [ 9.146804] hid-generic 0003:0557:2220.0003: input,hidraw2: USB HID v1.10 Keyboard [ATEN ATEN CS-1758/54] on usb-0000:00:1d.0-1.7/input0 [ 9.184396] input: ATEN ATEN CS-1758/54 as /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.7/2-1.7:1.1/input/input4 [ 9.197210] hid-generic 0003:0557:2220.0004: input,hidraw3: USB HID v1.10 Mouse [ATEN ATEN CS-1758/54] on usb-0000:00:1d.0-1.7/input1 On Wed, Nov 21, 2012 at 12:09 AM, Ingo Molnar wrote: > > Ok, the patch withstood a bit more testing as well. Below is a > v2 version of it, with a couple of cleanups (no functional > changes). > > Thanks, > > Ingo > > -----------------> > Subject: mm, numa: Turn 4K pte NUMA faults into effective hugepage ones > From: Ingo Molnar > Date: Tue Nov 20 15:48:26 CET 2012 > > Reduce the 4K page fault count by looking around and processing > nearby pages if possible. > > To keep the logic and cache overhead simple and straightforward > we do a couple of simplifications: > > - we only scan in the HPAGE_SIZE range of the faulting address > - we only go as far as the vma allows us > > Also simplify the do_numa_page() flow while at it and fix the > previous double faulting we incurred due to not properly fixing > up freshly migrated ptes. > > Suggested-by: Mel Gorman > Cc: Linus Torvalds > Cc: Andrew Morton > Cc: Peter Zijlstra > Cc: Andrea Arcangeli > Cc: Rik van Riel > Cc: Hugh Dickins > Signed-off-by: Ingo Molnar > --- > mm/memory.c | 99 ++++++++++++++++++++++++++++++++++++++---------------------- > 1 file changed, 64 insertions(+), 35 deletions(-) > > Index: linux/mm/memory.c > =================================================================== > --- linux.orig/mm/memory.c > +++ linux/mm/memory.c > @@ -3455,64 +3455,93 @@ static int do_nonlinear_fault(struct mm_ > return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); > } > > -static int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, > +static int __do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, > unsigned long address, pte_t *ptep, pmd_t *pmd, > - unsigned int flags, pte_t entry) > + unsigned int flags, pte_t entry, spinlock_t *ptl) > { > - struct page *page = NULL; > - int node, page_nid = -1; > - int last_cpu = -1; > - spinlock_t *ptl; > - > - ptl = pte_lockptr(mm, pmd); > - spin_lock(ptl); > - if (unlikely(!pte_same(*ptep, entry))) > - goto out_unlock; > + struct page *page; > + int new_node; > > page = vm_normal_page(vma, address, entry); > if (page) { > - get_page(page); > - page_nid = page_to_nid(page); > - last_cpu = page_last_cpu(page); > - node = mpol_misplaced(page, vma, address); > - if (node != -1 && node != page_nid) > + int page_nid = page_to_nid(page); > + int last_cpu = page_last_cpu(page); > + > + task_numa_fault(page_nid, last_cpu, 1); > + > + new_node = mpol_misplaced(page, vma, address); > + if (new_node != -1 && new_node != page_nid) > goto migrate; > } > > -out_pte_upgrade_unlock: > +out_pte_upgrade: > flush_cache_page(vma, address, pte_pfn(entry)); > - > ptep_modify_prot_start(mm, address, ptep); > entry = pte_modify(entry, vma->vm_page_prot); > + if (pte_dirty(entry)) > + entry = pte_mkwrite(entry); > ptep_modify_prot_commit(mm, address, ptep, entry); > - > /* No TLB flush needed because we upgraded the PTE */ > - > update_mmu_cache(vma, address, ptep); > - > -out_unlock: > - pte_unmap_unlock(ptep, ptl); > - > - if (page) { > - task_numa_fault(page_nid, last_cpu, 1); > - put_page(page); > - } > out: > return 0; > > migrate: > + get_page(page); > pte_unmap_unlock(ptep, ptl); > > - if (migrate_misplaced_page(page, node)) { > + migrate_misplaced_page(page, new_node); /* Drops the page reference */ > + > + /* Re-check after migration: */ > + > + ptl = pte_lockptr(mm, pmd); > + spin_lock(ptl); > + entry = ACCESS_ONCE(*ptep); > + > + if (!pte_numa(vma, entry)) > goto out; > - } > - page = NULL; > > - ptep = pte_offset_map_lock(mm, pmd, address, &ptl); > - if (!pte_same(*ptep, entry)) > - goto out_unlock; > + goto out_pte_upgrade; > +} > + > +/* > + * Add a simple loop to also fetch ptes within the same pmd: > + */ > +static int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, > + unsigned long addr0, pte_t *ptep0, pmd_t *pmd, > + unsigned int flags, pte_t entry0) > +{ > + unsigned long addr0_pmd; > + unsigned long addr_start; > + unsigned long addr; > + spinlock_t *ptl; > + pte_t *ptep; > + > + addr0_pmd = addr0 & PMD_MASK; > + addr_start = max(addr0_pmd, vma->vm_start); > > - goto out_pte_upgrade_unlock; > + ptep = pte_offset_map(pmd, addr_start); > + ptl = pte_lockptr(mm, pmd); > + spin_lock(ptl); > + > + for (addr = addr_start; addr < vma->vm_end; addr += PAGE_SIZE, ptep++) { > + pte_t entry; > + > + entry = ACCESS_ONCE(*ptep); > + > + if ((addr & PMD_MASK) != addr0_pmd) > + break; > + if (!pte_present(entry)) > + continue; > + if (!pte_numa(vma, entry)) > + continue; > + > + __do_numa_page(mm, vma, addr, ptep, pmd, flags, entry, ptl); > + } > + > + pte_unmap_unlock(ptep, ptl); > + > + return 0; > } > > /* > > -- > 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/ . > Don't email: email@kvack.org -- Thanks Alex -- 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/