Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754283AbbKXJ5u (ORCPT ); Tue, 24 Nov 2015 04:57:50 -0500 Received: from mail-wm0-f41.google.com ([74.125.82.41]:35257 "EHLO mail-wm0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753182AbbKXJ5Y (ORCPT ); Tue, 24 Nov 2015 04:57:24 -0500 Date: Tue, 24 Nov 2015 11:57:20 +0200 From: "Kirill A. Shutemov" To: Vladimir Davydov Cc: Sergey Senozhatsky , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH -mm v2] mm: add page_check_address_transhuge helper Message-ID: <20151124095720.GD15712@node.shutemov.name> References: <1448011913-12121-1-git-send-email-vdavydov@virtuozzo.com> <20151124042941.GE705@swordfish> <20151124090930.GB15712@node.shutemov.name> <20151124093617.GE29014@esperanza> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151124093617.GE29014@esperanza> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2953 Lines: 84 On Tue, Nov 24, 2015 at 12:36:17PM +0300, Vladimir Davydov wrote: > On Tue, Nov 24, 2015 at 11:09:30AM +0200, Kirill A. Shutemov wrote: > > On Tue, Nov 24, 2015 at 01:29:41PM +0900, Sergey Senozhatsky wrote: > ... > > > mm/built-in.o: In function `page_referenced_one': > > > rmap.c:(.text+0x32070): undefined reference to `pmdp_clear_flush_young' > > > > Something like this? > ... > > @@ -929,9 +929,12 @@ static int page_referenced_one(struct page *page, struct vm_area_struct *vma, > > referenced++; > > } > > pte_unmap(pte); > > - } else { > > + } else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) { > > if (pmdp_clear_flush_young_notify(vma, address, pmd)) > > referenced++; > > + } else { > > + /* unexpected pmd-mapped page? */ > > + WARN_ON_ONCE(1); > > } > > spin_unlock(ptl); > > I think we'd better compile out page_check_address_transhuge altogether if > CONFIG_TRANSPARENT_HUGEPAGE is disabled and use page_check_address instead. > This would also reduce the kernel size a bit. Looks good to me, if compiler is clever enough to remove pmdp_clear_flush_young_notify() call for !THP. I'm not sure it is. > --- > diff --git a/include/linux/rmap.h b/include/linux/rmap.h > index b9eedc63e9e6..77d1ba57d495 100644 > --- a/include/linux/rmap.h > +++ b/include/linux/rmap.h > @@ -219,9 +219,20 @@ static inline pte_t *page_check_address(struct page *page, struct mm_struct *mm, > * Used by idle page tracking to check if a page was referenced via page > * tables. > */ > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > bool page_check_address_transhuge(struct page *page, struct mm_struct *mm, > unsigned long address, pmd_t **pmdp, > pte_t **ptep, spinlock_t **ptlp); > +#else > +static inline bool page_check_address_transhuge(struct page *page, > + struct mm_struct *mm, unsigned long address, > + pmd_t **pmdp, pte_t **ptep, spinlock_t **ptlp) > +{ > + *ptep = page_check_address(page, mm, address, ptlp, 0); > + *pmdp = NULL; > + return !!*ptep; > +} > +#endif > > /* > * Used by swapoff to help locate where page is expected in vma. > diff --git a/mm/rmap.c b/mm/rmap.c > index 27916086ac50..6f371261dd12 100644 > --- a/mm/rmap.c > +++ b/mm/rmap.c > @@ -798,6 +798,7 @@ int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma) > return 1; > } > > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > /* > * Check that @page is mapped at @address into @mm. In contrast to > * page_check_address(), this function can handle transparent huge pages. > @@ -885,6 +886,7 @@ found: > *ptlp = ptl; > return true; > } > +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ > > struct page_referenced_arg { > int mapcount; -- Kirill A. Shutemov -- 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/