From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752986AbbC3Pp5 (ORCPT ); Mon, 30 Mar 2015 11:45:57 -0400 Received: from e28smtp05.in.ibm.com ([122.248.162.5]:39180 "EHLO e28smtp05.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752930AbbC3Ppz (ORCPT ); Mon, 30 Mar 2015 11:45:55 -0400 From: "Aneesh Kumar K.V" To: "Kirill A. Shutemov" Cc: "Kirill A. Shutemov" , Andrew Morton , Andrea Arcangeli , Dave Hansen , Hugh Dickins , Mel Gorman , Rik van Riel , Vlastimil Babka , Christoph Lameter , Naoya Horiguchi , Steve Capper , Johannes Weiner , Michal Hocko , Jerome Marchand , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCHv4 19/24] thp, mm: use migration entries to freeze page counts on split In-Reply-To: <20150330152652.GC5849@node.dhcp.inet.fi> References: <1425486792-93161-1-git-send-email-kirill.shutemov@linux.intel.com> <1425486792-93161-20-git-send-email-kirill.shutemov@linux.intel.com> <87h9t2le07.fsf@linux.vnet.ibm.com> <20150330152652.GC5849@node.dhcp.inet.fi> User-Agent: Notmuch/0.19+30~gd241a48 (http://notmuchmail.org) Emacs/24.4.1 (x86_64-pc-linux-gnu) Date: Mon, 30 Mar 2015 21:15:47 +0530 Message-ID: <87bnjalc9g.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15033015-0017-0000-0000-0000045B74EC Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org "Kirill A. Shutemov" writes: > On Mon, Mar 30, 2015 at 08:38:08PM +0530, Aneesh Kumar K.V wrote: >> .... >> .... >> +static void freeze_page(struct anon_vma *anon_vma, struct page *page) >> > +{ >> > + struct anon_vma_chain *avc; >> > + struct vm_area_struct *vma; >> > + pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); >> >> So this get called only with head page, We also do >> BUG_ON(PageTail(page)) in the caller. But >> >> >> > + unsigned long addr, haddr; >> > + unsigned long mmun_start, mmun_end; >> > + pgd_t *pgd; >> > + pud_t *pud; >> > + pmd_t *pmd; >> > + pte_t *start_pte, *pte; >> > + spinlock_t *ptl; >> ...... >> >> >> > + >> > +static void unfreeze_page(struct anon_vma *anon_vma, struct page *page) >> > +{ >> > + struct anon_vma_chain *avc; >> > + pgoff_t pgoff = page_to_pgoff(page); >> >> Why ? Can this get called for tail pages ? > > It cannot. pgoff is offset of head page (and therefore whole compound > page) within rmapping. > This we can use pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); similar to what we do in freeze_page(). The difference between freeze/unfreeze confused me. -aneesh From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f46.google.com (mail-pa0-f46.google.com [209.85.220.46]) by kanga.kvack.org (Postfix) with ESMTP id C42166B0073 for ; Mon, 30 Mar 2015 11:45:55 -0400 (EDT) Received: by pacgg7 with SMTP id gg7so41447558pac.0 for ; Mon, 30 Mar 2015 08:45:55 -0700 (PDT) Received: from e28smtp01.in.ibm.com (e28smtp01.in.ibm.com. [122.248.162.1]) by mx.google.com with ESMTPS id ex2si15281834pbb.31.2015.03.30.08.45.53 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 30 Mar 2015 08:45:55 -0700 (PDT) Received: from /spool/local by e28smtp01.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 30 Mar 2015 21:15:51 +0530 Received: from d28relay01.in.ibm.com (d28relay01.in.ibm.com [9.184.220.58]) by d28dlp01.in.ibm.com (Postfix) with ESMTP id 32C14E0045 for ; Mon, 30 Mar 2015 21:18:06 +0530 (IST) Received: from d28av04.in.ibm.com (d28av04.in.ibm.com [9.184.220.66]) by d28relay01.in.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t2UFjl5F29884648 for ; Mon, 30 Mar 2015 21:15:47 +0530 Received: from d28av04.in.ibm.com (localhost [127.0.0.1]) by d28av04.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t2UFjke1007718 for ; Mon, 30 Mar 2015 21:15:47 +0530 From: "Aneesh Kumar K.V" Subject: Re: [PATCHv4 19/24] thp, mm: use migration entries to freeze page counts on split In-Reply-To: <20150330152652.GC5849@node.dhcp.inet.fi> References: <1425486792-93161-1-git-send-email-kirill.shutemov@linux.intel.com> <1425486792-93161-20-git-send-email-kirill.shutemov@linux.intel.com> <87h9t2le07.fsf@linux.vnet.ibm.com> <20150330152652.GC5849@node.dhcp.inet.fi> Date: Mon, 30 Mar 2015 21:15:47 +0530 Message-ID: <87bnjalc9g.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: "Kirill A. Shutemov" , Andrew Morton , Andrea Arcangeli , Dave Hansen , Hugh Dickins , Mel Gorman , Rik van Riel , Vlastimil Babka , Christoph Lameter , Naoya Horiguchi , Steve Capper , Johannes Weiner , Michal Hocko , Jerome Marchand , linux-kernel@vger.kernel.org, linux-mm@kvack.org "Kirill A. Shutemov" writes: > On Mon, Mar 30, 2015 at 08:38:08PM +0530, Aneesh Kumar K.V wrote: >> .... >> .... >> +static void freeze_page(struct anon_vma *anon_vma, struct page *page) >> > +{ >> > + struct anon_vma_chain *avc; >> > + struct vm_area_struct *vma; >> > + pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); >> >> So this get called only with head page, We also do >> BUG_ON(PageTail(page)) in the caller. But >> >> >> > + unsigned long addr, haddr; >> > + unsigned long mmun_start, mmun_end; >> > + pgd_t *pgd; >> > + pud_t *pud; >> > + pmd_t *pmd; >> > + pte_t *start_pte, *pte; >> > + spinlock_t *ptl; >> ...... >> >> >> > + >> > +static void unfreeze_page(struct anon_vma *anon_vma, struct page *page) >> > +{ >> > + struct anon_vma_chain *avc; >> > + pgoff_t pgoff = page_to_pgoff(page); >> >> Why ? Can this get called for tail pages ? > > It cannot. pgoff is offset of head page (and therefore whole compound > page) within rmapping. > This we can use pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); similar to what we do in freeze_page(). The difference between freeze/unfreeze confused me. -aneesh -- 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