From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753255Ab1I0KOQ (ORCPT ); Tue, 27 Sep 2011 06:14:16 -0400 Received: from smtp-out.google.com ([74.125.121.67]:8448 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752327Ab1I0KOP (ORCPT ); Tue, 27 Sep 2011 06:14:15 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=dkim-signature:mime-version:in-reply-to:references:date: message-id:subject:from:to:cc:content-type:x-system-of-record; b=sJnmJYN6bs3T8OYRDmSxauOUpO8culvLdho/AQ5GCydd7M0Oks93jaqZ6hdX01KYz QOgOrPz8KPEvLKfPm6f9A== MIME-Version: 1.0 In-Reply-To: References: <1316230753-8693-1-git-send-email-walken@google.com> Date: Tue, 27 Sep 2011 03:14:09 -0700 Message-ID: Subject: Re: [PATCH 0/8] idle page tracking / working set estimation From: Michel Lespinasse To: Balbir Singh Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , KAMEZAWA Hiroyuki , Dave Hansen , Andrea Arcangeli , Rik van Riel , Johannes Weiner , KOSAKI Motohiro , Hugh Dickins , Peter Zijlstra , Michael Wolf Content-Type: text/plain; charset=ISO-8859-1 X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 27, 2011 at 3:03 AM, Balbir Singh wrote: > On Sat, Sep 17, 2011 at 9:09 AM, Michel Lespinasse wrote: >> Patch 3 introduces page_referenced_kstaled(), which is similar to >> page_referenced() but is used for idle page tracking rather than >> for memory reclaimation. Since both functions clear the pte_young bits >> and we don't want them to interfere with each other, two new page flags >> are introduced that track when young pte references have been cleared by >> each of the page_referenced variants. > > Sorry, I have trouble parsing this sentence, could you elaborate on "when"? page_referenced() indicates if a page was accessed since the previous page_referenced() call. page_referenced_kstaled() indicates if a page was accessed since the previous page_referenced_kstaled() call. Both of the functions need to clear PTE young bits; however we don't want the two functions to interfere with each other. To achieve this, we add two page bits to indicate when a young PTE has been observed by one of the functions but not by the other. -- Michel "Walken" Lespinasse A program is never fully debugged until the last user dies. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta12.messagelabs.com (mail6.bemta12.messagelabs.com [216.82.250.247]) by kanga.kvack.org (Postfix) with ESMTP id 1C66F9000BD for ; Tue, 27 Sep 2011 06:14:19 -0400 (EDT) Received: from wpaz21.hot.corp.google.com (wpaz21.hot.corp.google.com [172.24.198.85]) by smtp-out.google.com with ESMTP id p8RAEF3g009251 for ; Tue, 27 Sep 2011 03:14:15 -0700 Received: from qyk27 (qyk27.prod.google.com [10.241.83.155]) by wpaz21.hot.corp.google.com with ESMTP id p8RADrZ1019324 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=NOT) for ; Tue, 27 Sep 2011 03:14:14 -0700 Received: by qyk27 with SMTP id 27so8214320qyk.14 for ; Tue, 27 Sep 2011 03:14:10 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <1316230753-8693-1-git-send-email-walken@google.com> Date: Tue, 27 Sep 2011 03:14:09 -0700 Message-ID: Subject: Re: [PATCH 0/8] idle page tracking / working set estimation From: Michel Lespinasse Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Balbir Singh Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , KAMEZAWA Hiroyuki , Dave Hansen , Andrea Arcangeli , Rik van Riel , Johannes Weiner , KOSAKI Motohiro , Hugh Dickins , Peter Zijlstra , Michael Wolf On Tue, Sep 27, 2011 at 3:03 AM, Balbir Singh wrote: > On Sat, Sep 17, 2011 at 9:09 AM, Michel Lespinasse wrote: >> Patch 3 introduces page_referenced_kstaled(), which is similar to >> page_referenced() but is used for idle page tracking rather than >> for memory reclaimation. Since both functions clear the pte_young bits >> and we don't want them to interfere with each other, two new page flags >> are introduced that track when young pte references have been cleared by >> each of the page_referenced variants. > > Sorry, I have trouble parsing this sentence, could you elaborate on "when"? page_referenced() indicates if a page was accessed since the previous page_referenced() call. page_referenced_kstaled() indicates if a page was accessed since the previous page_referenced_kstaled() call. Both of the functions need to clear PTE young bits; however we don't want the two functions to interfere with each other. To achieve this, we add two page bits to indicate when a young PTE has been observed by one of the functions but not by the other. -- Michel "Walken" Lespinasse A program is never fully debugged until the last user dies. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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