From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pb0-f49.google.com (mail-pb0-f49.google.com [209.85.160.49]) by kanga.kvack.org (Postfix) with ESMTP id 7309C6B0039 for ; Thu, 29 May 2014 21:35:21 -0400 (EDT) Received: by mail-pb0-f49.google.com with SMTP id jt11so1128436pbb.22 for ; Thu, 29 May 2014 18:35:21 -0700 (PDT) Received: from ozlabs.org (ozlabs.org. [103.22.144.67]) by mx.google.com with ESMTPS id oq10si3313601pac.48.2014.05.29.18.35.19 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 29 May 2014 18:35:19 -0700 (PDT) Message-ID: <1401413716.29324.2.camel@concordia> Subject: Re: [PATCH] hugetlb: restrict hugepage_migration_support() to x86_64 (Re: BUG at mm/memory.c:1489!) From: Michael Ellerman Date: Fri, 30 May 2014 11:35:16 +1000 In-Reply-To: <1401388474-mqnis5cp@n-horiguchi@ah.jp.nec.com> References: <1401265922.3355.4.camel@concordia> <1401353983.4930.15.camel@concordia> <1401388474-mqnis5cp@n-horiguchi@ah.jp.nec.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Naoya Horiguchi Cc: Hugh Dickins , Andrew Morton , benh@kernel.crashing.org, Tony Luck , linux-mm@kvack.org, linux-kernel@vger.kernel.org, trinity@vger.kernel.org On Thu, 2014-05-29 at 14:34 -0400, Naoya Horiguchi wrote: > On Thu, May 29, 2014 at 06:59:43PM +1000, Michael Ellerman wrote: > > Applying your patch and running trinity pretty immediately results in the > > following, which looks related (sys_move_pages() again) ? > > > > Unable to handle kernel paging request for data at address 0xf2000f80000000 > > Faulting instruction address: 0xc0000000001e29bc > > cpu 0x1b: Vector: 300 (Data Access) at [c0000003c70f76f0] > > pc: c0000000001e29bc: .remove_migration_pte+0x9c/0x320 > > lr: c0000000001e29b8: .remove_migration_pte+0x98/0x320 > > sp: c0000003c70f7970 > > msr: 8000000000009032 > > dar: f2000f80000000 > > dsisr: 40000000 > > current = 0xc0000003f9045800 > > paca = 0xc000000001dc6c00 softe: 0 irq_happened: 0x01 > > pid = 3585, comm = trinity-c27 > > enter ? for help > > [c0000003c70f7a20] c0000000001bce88 .rmap_walk+0x328/0x470 > > [c0000003c70f7ae0] c0000000001e2904 .remove_migration_ptes+0x44/0x60 > > [c0000003c70f7b80] c0000000001e4ce8 .migrate_pages+0x6d8/0xa00 > > [c0000003c70f7cc0] c0000000001e55ec .SyS_move_pages+0x5dc/0x7d0 > > [c0000003c70f7e30] c00000000000a1d8 syscall_exit+0x0/0x98 > > --- Exception: c01 (System Call) at 00003fff7b2b30a8 > > SP (3fffe09728a0) is in userspace > > 1b:mon> > > Sorry for inconvenience on your testing. That's fine, it's good to find bugs :) > Hugepage migration is enabled for archs which have pmd-level hugepage > (including ppc64,) but not tested except for x86_64. > hugepage_migration_support() controls this so the following patch should > help you avoid the problem, I believe. > Could you try to test with it? Sure. So this patch, in addition to Hugh's patch to remove the BUG_ON(), does avoid the crash above (remove_migration_pte()). I dropped Hugh's patch, as he has decided he doesn't like it, and added the following hunk instead: diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h index 3c1b968..f230a97 100644 --- a/include/linux/mempolicy.h +++ b/include/linux/mempolicy.h @@ -175,6 +175,12 @@ static inline int vma_migratable(struct vm_area_struct *vma) { if (vma->vm_flags & (VM_IO | VM_PFNMAP)) return 0; + +#ifndef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION + if (vma->vm_flags & VM_HUGETLB) + return 0; +#endif + /* * Migration allocates pages in the highest zone. If we cannot * do so then migration (at least from node to node) is not Which seems to be what Hugh was referring to in his mail - correct me if I'm wrong Hugh. With your patch and the above hunk I can run trinity happily for a while, whereas without it crashes almost immediately. So with the above hunk you can add my tested-by. cheers -- 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