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 681F26B0055 for ; Tue, 21 Jul 2009 13:55:14 -0400 (EDT) Message-ID: <4A660101.3000307@redhat.com> Date: Tue, 21 Jul 2009 13:55:13 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH 06/10] ksm: identify PageKsm pages 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> <1247851850-4298-6-git-send-email-ieidus@redhat.com> <1247851850-4298-7-git-send-email-ieidus@redhat.com> <20090721175139.GE2239@random.random> In-Reply-To: <20090721175139.GE2239@random.random> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Andrea Arcangeli Cc: Izik Eidus , akpm@linux-foundation.org, hugh.dickins@tiscali.co.uk, chrisw@redhat.com, avi@redhat.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, nickpiggin@yahoo.com.au, Wu Fengguang List-ID: Andrea Arcangeli wrote: >> +static inline void page_add_ksm_rmap(struct page *page) >> +{ >> + if (atomic_inc_and_test(&page->_mapcount)) { >> + page->mapping = (void *) PAGE_MAPPING_ANON; >> + __inc_zone_page_state(page, NR_ANON_PAGES); >> + } >> +} > > Is it correct to account them as anon pages? Yes, but ... >> - if (PageAnon(old_page)) { >> + if (PageAnon(old_page) && !PageKsm(old_page)) { >> if (!trylock_page(old_page)) { >> page_cache_get(old_page); >> pte_unmap_unlock(page_table, ptl); > > What exactly does it buy to have PageAnon return 1 on ksm pages, > besides requiring the above additional check (that if we stick to the > above code, I would find safer to move inside reuse_swap_page). I guess that if they are to remain unswappable, they should go onto the unevictable list. Then again, I'm guessing this is all about to change in not too much time :) -- All rights reversed. -- 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