From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932141Ab0KCPaG (ORCPT ); Wed, 3 Nov 2010 11:30:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:7470 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755801Ab0KCP35 (ORCPT ); Wed, 3 Nov 2010 11:29:57 -0400 Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [PATCH 43 of 66] don't leave orhpaned swap cache after ksm merging X-Mercurial-Node: d5aefe85d1dab1bb7e99f672afe68fb6a034effd Message-Id: In-Reply-To: References: User-Agent: Mercurial-patchbomb/1.4.1 Date: Wed, 03 Nov 2010 16:28:18 +0100 From: Andrea Arcangeli To: linux-mm@kvack.org, Linus Torvalds , Andrew Morton , linux-kernel@vger.kernel.org Cc: Marcelo Tosatti , Adam Litke , Avi Kivity , Hugh Dickins , Rik van Riel , Mel Gorman , Dave Hansen , Benjamin Herrenschmidt , Ingo Molnar , Mike Travis , KAMEZAWA Hiroyuki , Christoph Lameter , Chris Wright , bpicco@redhat.com, KOSAKI Motohiro , Balbir Singh , "Michael S. Tsirkin" , Peter Zijlstra , Johannes Weiner , Daisuke Nishimura , Chris Mason , Borislav Petkov Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andrea Arcangeli When swapcache is replaced by a ksm page don't leave orhpaned swap cache. Signed-off-by: Andrea Arcangeli Reviewed-by: Rik van Riel --- diff --git a/mm/ksm.c b/mm/ksm.c --- a/mm/ksm.c +++ b/mm/ksm.c @@ -800,7 +800,7 @@ static int replace_page(struct vm_area_s set_pte_at_notify(mm, addr, ptep, mk_pte(kpage, vma->vm_page_prot)); page_remove_rmap(page); - put_page(page); + free_page_and_swap_cache(page); pte_unmap_unlock(ptep, ptl); err = 0; @@ -846,7 +846,18 @@ static int try_to_merge_one_page(struct * ptes are necessarily already write-protected. But in either * case, we need to lock and check page_count is not raised. */ - if (write_protect_page(vma, page, &orig_pte) == 0) { + err = write_protect_page(vma, page, &orig_pte); + + /* + * After this mapping is wrprotected we don't need further + * checks for PageSwapCache vs page_count unlock_page(page) + * and we rely only on the pte_same() check run under PT lock + * to ensure the pte didn't change since when we wrprotected + * it under PG_lock. + */ + unlock_page(page); + + if (!err) { if (!kpage) { /* * While we hold page lock, upgrade page from @@ -855,22 +866,22 @@ static int try_to_merge_one_page(struct */ set_page_stable_node(page, NULL); mark_page_accessed(page); - err = 0; } else if (pages_identical(page, kpage)) err = replace_page(vma, page, kpage, orig_pte); - } + } else + err = -EFAULT; if ((vma->vm_flags & VM_LOCKED) && kpage && !err) { + lock_page(page); /* for LRU manipulation */ munlock_vma_page(page); + unlock_page(page); if (!PageMlocked(kpage)) { - unlock_page(page); lock_page(kpage); mlock_vma_page(kpage); - page = kpage; /* for final unlock */ + unlock_page(kpage); } } - unlock_page(page); out: return err; } From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id 384266B00BA for ; Wed, 3 Nov 2010 11:29:33 -0400 (EDT) Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [PATCH 43 of 66] don't leave orhpaned swap cache after ksm merging Message-Id: In-Reply-To: References: Date: Wed, 03 Nov 2010 16:28:18 +0100 From: Andrea Arcangeli Sender: owner-linux-mm@kvack.org To: linux-mm@kvack.org, Linus Torvalds , Andrew Morton , linux-kernel@vger.kernel.org Cc: Marcelo Tosatti , Adam Litke , Avi Kivity , Hugh Dickins , Rik van Riel , Mel Gorman , Dave Hansen , Benjamin Herrenschmidt , Ingo Molnar , Mike Travis , KAMEZAWA Hiroyuki , Christoph Lameter , Chris Wright , bpicco@redhat.com, KOSAKI Motohiro , Balbir Singh , "Michael S. Tsirkin" , Peter Zijlstra , Johannes Weiner , Daisuke Nishimura , Chris Mason , Borislav Petkov List-ID: From: Andrea Arcangeli When swapcache is replaced by a ksm page don't leave orhpaned swap cache. Signed-off-by: Andrea Arcangeli Reviewed-by: Rik van Riel --- diff --git a/mm/ksm.c b/mm/ksm.c --- a/mm/ksm.c +++ b/mm/ksm.c @@ -800,7 +800,7 @@ static int replace_page(struct vm_area_s set_pte_at_notify(mm, addr, ptep, mk_pte(kpage, vma->vm_page_prot)); page_remove_rmap(page); - put_page(page); + free_page_and_swap_cache(page); pte_unmap_unlock(ptep, ptl); err = 0; @@ -846,7 +846,18 @@ static int try_to_merge_one_page(struct * ptes are necessarily already write-protected. But in either * case, we need to lock and check page_count is not raised. */ - if (write_protect_page(vma, page, &orig_pte) == 0) { + err = write_protect_page(vma, page, &orig_pte); + + /* + * After this mapping is wrprotected we don't need further + * checks for PageSwapCache vs page_count unlock_page(page) + * and we rely only on the pte_same() check run under PT lock + * to ensure the pte didn't change since when we wrprotected + * it under PG_lock. + */ + unlock_page(page); + + if (!err) { if (!kpage) { /* * While we hold page lock, upgrade page from @@ -855,22 +866,22 @@ static int try_to_merge_one_page(struct */ set_page_stable_node(page, NULL); mark_page_accessed(page); - err = 0; } else if (pages_identical(page, kpage)) err = replace_page(vma, page, kpage, orig_pte); - } + } else + err = -EFAULT; if ((vma->vm_flags & VM_LOCKED) && kpage && !err) { + lock_page(page); /* for LRU manipulation */ munlock_vma_page(page); + unlock_page(page); if (!PageMlocked(kpage)) { - unlock_page(page); lock_page(kpage); mlock_vma_page(kpage); - page = kpage; /* for final unlock */ + unlock_page(kpage); } } - unlock_page(page); out: return err; } -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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