From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-we0-f178.google.com (mail-we0-f178.google.com [74.125.82.178]) by kanga.kvack.org (Postfix) with ESMTP id 97B016B003C for ; Tue, 1 Jul 2014 14:07:57 -0400 (EDT) Received: by mail-we0-f178.google.com with SMTP id x48so10033708wes.9 for ; Tue, 01 Jul 2014 11:07:57 -0700 (PDT) Received: from jenni2.inet.fi (mta-out1.inet.fi. [62.71.2.198]) by mx.google.com with ESMTP id b6si29006789wjy.38.2014.07.01.11.07.51 for ; Tue, 01 Jul 2014 11:07:51 -0700 (PDT) Date: Tue, 1 Jul 2014 21:07:39 +0300 From: "Kirill A. Shutemov" Subject: Re: [PATCH] rmap: fix pgoff calculation to handle hugepage correctly Message-ID: <20140701180739.GA4985@node.dhcp.inet.fi> References: <1404225982-22739-1-git-send-email-n-horiguchi@ah.jp.nec.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1404225982-22739-1-git-send-email-n-horiguchi@ah.jp.nec.com> Sender: owner-linux-mm@kvack.org List-ID: To: Naoya Horiguchi Cc: Andrew Morton , Joonsoo Kim , Hugh Dickins , Rik van Riel , Hillf Danton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Naoya Horiguchi On Tue, Jul 01, 2014 at 10:46:22AM -0400, Naoya Horiguchi wrote: > I triggered VM_BUG_ON() in vma_address() when I try to migrate an anonymous > hugepage with mbind() in the kernel v3.16-rc3. This is because pgoff's > calculation in rmap_walk_anon() fails to consider compound_order() only to > have an incorrect value. So this patch fixes it. > > Signed-off-by: Naoya Horiguchi > --- > mm/rmap.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git v3.16-rc3.orig/mm/rmap.c v3.16-rc3/mm/rmap.c > index b7e94ebbd09e..8cc964c6bd8d 100644 > --- v3.16-rc3.orig/mm/rmap.c > +++ v3.16-rc3/mm/rmap.c > @@ -1639,7 +1639,7 @@ static struct anon_vma *rmap_walk_anon_lock(struct page *page, > static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc) > { > struct anon_vma *anon_vma; > - pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); > + pgoff_t pgoff = page->index << compound_order(page); > struct anon_vma_chain *avc; > int ret = SWAP_AGAIN; Hm. It will not work with THP: ->index there is in PAGE_SIZE units. Why do we need this special case for hugetlb page ->index? Why not use PAGE_SIZE units there too? Or I miss something? -- Kirill A. Shutemov -- 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