Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965001AbZGQR2K (ORCPT ); Fri, 17 Jul 2009 13:28:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964993AbZGQR2H (ORCPT ); Fri, 17 Jul 2009 13:28:07 -0400 Received: from mx2.redhat.com ([66.187.237.31]:49205 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934752AbZGQR2E (ORCPT ); Fri, 17 Jul 2009 13:28:04 -0400 From: Izik Eidus To: akpm@linux-foundation.org Cc: hugh.dickins@tiscali.co.uk, aarcange@redhat.com, chrisw@redhat.com, avi@redhat.com, riel@redhat.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, nickpiggin@yahoo.com.au, ieidus@redhat.com, Nick Piggin Subject: [PATCH 05/10] ksm: no debug in page_dup_rmap() Date: Fri, 17 Jul 2009 20:30:45 +0300 Message-Id: <1247851850-4298-6-git-send-email-ieidus@redhat.com> In-Reply-To: <1247851850-4298-5-git-send-email-ieidus@redhat.com> References: <1247851850-4298-1-git-send-email-ieidus@redhat.com> <1247851850-4298-2-git-send-email-ieidus@redhat.com> <1247851850-4298-3-git-send-email-ieidus@redhat.com> <1247851850-4298-4-git-send-email-ieidus@redhat.com> <1247851850-4298-5-git-send-email-ieidus@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3250 Lines: 97 From: Hugh Dickins page_dup_rmap(), used on each mapped page when forking, was originally just an inline atomic_inc of mapcount. 2.6.22 added CONFIG_DEBUG_VM out-of-line checks to it, which would need to be ever-so-slightly complicated to allow for the PageKsm() we're about to define. But I think these checks never caught anything. And if it's coding errors we're worried about, such checks should be in page_remove_rmap() too, not just when forking; whereas if it's pagetable corruption we're worried about, then they shouldn't be limited to CONFIG_DEBUG_VM. Oh, just revert page_dup_rmap() to an inline atomic_inc of mapcount. Signed-off-by: Hugh Dickins Signed-off-by: Chris Wright Signed-off-by: Izik Eidus Cc: Nick Piggin --- include/linux/rmap.h | 6 +----- mm/memory.c | 2 +- mm/rmap.c | 21 --------------------- 3 files changed, 2 insertions(+), 27 deletions(-) diff --git a/include/linux/rmap.h b/include/linux/rmap.h index bf116d0..477841d 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -71,14 +71,10 @@ void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned lon void page_add_file_rmap(struct page *); void page_remove_rmap(struct page *); -#ifdef CONFIG_DEBUG_VM -void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address); -#else -static inline void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address) +static inline void page_dup_rmap(struct page *page) { atomic_inc(&page->_mapcount); } -#endif /* * Called from mm/vmscan.c to handle paging out diff --git a/mm/memory.c b/mm/memory.c index 8159a62..8b1922c 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -595,7 +595,7 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, page = vm_normal_page(vma, addr, pte); if (page) { get_page(page); - page_dup_rmap(page, vma, addr); + page_dup_rmap(page); rss[!!PageAnon(page)]++; } diff --git a/mm/rmap.c b/mm/rmap.c index 836c6c6..ab84e45 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -709,27 +709,6 @@ void page_add_file_rmap(struct page *page) } } -#ifdef CONFIG_DEBUG_VM -/** - * page_dup_rmap - duplicate pte mapping to a page - * @page: the page to add the mapping to - * @vma: the vm area being duplicated - * @address: the user virtual address mapped - * - * For copy_page_range only: minimal extract from page_add_file_rmap / - * page_add_anon_rmap, avoiding unnecessary tests (already checked) so it's - * quicker. - * - * The caller needs to hold the pte lock. - */ -void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address) -{ - if (PageAnon(page)) - __page_check_anon_rmap(page, vma, address); - atomic_inc(&page->_mapcount); -} -#endif - /** * page_remove_rmap - take down pte mapping from a page * @page: page to remove mapping from -- 1.5.6.5 -- 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/