From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5ADD8C67863 for ; Wed, 24 Oct 2018 12:52:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2A87E2054F for ; Wed, 24 Oct 2018 12:52:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2A87E2054F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=surriel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727747AbeJXVUS (ORCPT ); Wed, 24 Oct 2018 17:20:18 -0400 Received: from shelob.surriel.com ([96.67.55.147]:41738 "EHLO shelob.surriel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727177AbeJXVUS (ORCPT ); Wed, 24 Oct 2018 17:20:18 -0400 Received: from imladris.surriel.com ([96.67.55.152]) by shelob.surriel.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1gFIds-0002F8-NC; Wed, 24 Oct 2018 08:52:08 -0400 Message-ID: <3faac660df4f52a0a4e140cd51715f0efede56d1.camel@surriel.com> Subject: Re: [PATCH 0/7] x86/mm/tlb: make lazy TLB mode even lazier From: Rik van Riel To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, kernel-team@fb.com, songliubraving@fb.com, will.deacon@arm.com, hpa@zytor.com, luto@kernel.org, npiggin@gmail.com, Linus Torvalds , Thomas Gleixner , Peter Zijlstra , Borislav Petkov Date: Wed, 24 Oct 2018 08:52:08 -0400 In-Reply-To: <20181024055319.GA73309@gmail.com> References: <20180924183759.23955-1-riel@surriel.com> <20181024055319.GA73309@gmail.com> Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-DOaT8WT9ap6L9LGur/AZ" X-Mailer: Evolution 3.28.5 (3.28.5-1.fc28) Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-DOaT8WT9ap6L9LGur/AZ Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2018-10-24 at 07:53 +0200, Ingo Molnar wrote: > * Rik van Riel wrote: >=20 > > The big thing remaining is the reference count overhead of > > the lazy TLB mm_struct, but getting rid of that is rather a > > lot of code for a small performance gain. Not quite what > > Linus asked for :) >=20 > BTW., what would be the plan to improve scalability there, > is it even possible? One thing I looked at was shooting down the lazy TLB MM from the exit code path, that way the MM would no longer be referenced from any CPU by the time the memory gets freed. Once we do that, we no longer need to do any refcounting for the lazy TLB MM. --=20 All Rights Reversed. --=-DOaT8WT9ap6L9LGur/AZ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQEzBAABCAAdFiEEKR73pCCtJ5Xj3yADznnekoTE3oMFAlvQavgACgkQznnekoTE 3oNMAQgAiHFXw8tNipEdZT3mvRm42r5nHzbL9sCNEQeza8ZQW7de/pz4lfFOepN4 dBJFODEEAYLpjoBzJpAtQohZl3fZoPO5eE/1Q3fAi3q1tpdbnzyguTSgQgIaYF5r Ab8jDKKSNw3OEt8kwCq6oyvvNc118ZmZ1ktJWhaA90n9Xutfc+9bHrreSTrNeg6f YhDPG814O7m5Ys9ZFQLRdw8gSlmr8Gvn4mNOZrQgt8sKhzUCrdNVDIq4tBQisKVq ivoDNksry7L3HFa/UD13EboHXU6SH2MMsAsKyLDbc5lzmfALV3toSkECE5QaFQBX faIhrPN8GdTRYtwLiPzuZ/K1P6kIrg== =HFGi -----END PGP SIGNATURE----- --=-DOaT8WT9ap6L9LGur/AZ--