From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx169.postini.com [74.125.245.169]) by kanga.kvack.org (Postfix) with SMTP id 476DB6B002B for ; Fri, 10 Aug 2012 09:48:14 -0400 (EDT) Date: Fri, 10 Aug 2012 15:48:11 +0200 From: Michal Hocko Subject: Re: [patch] hugetlb: correct page offset index for sharing pmd Message-ID: <20120810134811.GD1425@dhcp22.suse.cz> References: <20120803133235.GA8434@dhcp22.suse.cz> <20120810094825.GA1440@dhcp22.suse.cz> <20120810122730.GA1425@dhcp22.suse.cz> <20120810125102.GB1425@dhcp22.suse.cz> <20120810131643.GC1425@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Hillf Danton Cc: Mel Gorman , Andrew Morton , Linux-MM , LKML , KAMEZAWA Hiroyuki , David Rientjes On Fri 10-08-12 21:21:15, Hillf Danton wrote: > On Fri, Aug 10, 2012 at 9:16 PM, Michal Hocko wrote: > > Subject: [PATCH] hugetlb: do not use vma_hugecache_offset for > > vma_prio_tree_foreach > > > > 0c176d5 (mm: hugetlb: fix pgoff computation when unmapping page > > from vma) fixed pgoff calculation but it has replaced it by > > vma_hugecache_offset which is not approapriate for offsets used for > > vma_prio_tree_foreach because that one expects index in page units > > rather than in huge_page_shift. > > Using vma_hugecache_offset is not incorrect because the pgoff will fit > > into the same vmas but it is confusing. > > > > Well, how is the patch tested? It's been compile tested because it only restores the previous code with a simple and obvious bug fix. Do you see any issue in the patch? > > Cc: Hillf Danton > > Cc: Mel Gorman > > Cc: KAMEZAWA Hiroyuki > > Cc: David Rientjes > > Signed-off-by: Michal Hocko > > --- > > mm/hugetlb.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > > index c39e4be..a74ea31 100644 > > --- a/mm/hugetlb.c > > +++ b/mm/hugetlb.c > > @@ -2462,7 +2462,8 @@ static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, > > * from page cache lookup which is in HPAGE_SIZE units. > > */ > > address = address & huge_page_mask(h); > > - pgoff = vma_hugecache_offset(h, vma, address); > > + pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + > > + vma->vm_pgoff; > > mapping = vma->vm_file->f_dentry->d_inode->i_mapping; > > > > /* > > -- > > 1.7.10.4 > > > > > > -- > > Michal Hocko > > SUSE Labs -- Michal Hocko SUSE Labs -- 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