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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 9EAD5C47255 for ; Mon, 11 May 2020 17:07:00 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4372820714 for ; Mon, 11 May 2020 17:07:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="28Ffg6OR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4372820714 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id CC0EE90006C; Mon, 11 May 2020 13:06:59 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C221A900036; Mon, 11 May 2020 13:06:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AEAAD90006C; Mon, 11 May 2020 13:06:59 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0028.hostedemail.com [216.40.44.28]) by kanga.kvack.org (Postfix) with ESMTP id 93470900036 for ; Mon, 11 May 2020 13:06:59 -0400 (EDT) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 5C24D180AD807 for ; Mon, 11 May 2020 17:06:59 +0000 (UTC) X-FDA: 76805068158.09.help84_7730dc7cb1050 X-HE-Tag: help84_7730dc7cb1050 X-Filterd-Recvd-Size: 4304 Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by imf14.hostedemail.com (Postfix) with ESMTP for ; Mon, 11 May 2020 17:06:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=bXc6/TC/fZd2A0tKIOuFHMPLNl2BdCBVGsE8fSj7QXY=; b=28Ffg6ORBIyHGTftSfOhouhHMk Tf6ecTJhdIajQ7tRRE5NmP+qKfDtEpdZqHsg1bIEjirRoF04iCG8I8WLGSm1Gw9pmxsrPQ2IdIFpY VKbR0W/fH6z41vCLkx8zhHyHRWCJOsavPXoNvuHkJnV4yc7HdLXSQ2ODzRIjk6cPZb4/BzPp9tNQs QWtW1PJTDA1PJFTLBCTPGXUkNSk8AxJtjyijDCBoKVBmyxwwmKP00bSlhHnUnSydU0IEKovGUGlvO zJ3qYS/6jVxeMgQas8m1UMDn8FODT5RlJejjWdTV4esB8mYPiId7Zv94MjBPSXjRltpaNDKSyMpyE 4YST0k2A==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jYBtB-00043D-UG; Mon, 11 May 2020 17:06:50 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id D0CA4301A66; Mon, 11 May 2020 19:06:46 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id BCF2B29DA4B49; Mon, 11 May 2020 19:06:46 +0200 (CEST) Date: Mon, 11 May 2020 19:06:46 +0200 From: Peter Zijlstra To: Andy Lutomirski Cc: Joerg Roedel , Joerg Roedel , X86 ML , "H. Peter Anvin" , Dave Hansen , "Rafael J. Wysocki" , Arnd Bergmann , Andrew Morton , Steven Rostedt , Vlastimil Babka , Michal Hocko , LKML , Linux ACPI , linux-arch , Linux-MM Subject: Re: [RFC PATCH 0/7] mm: Get rid of vmalloc_sync_(un)mappings() Message-ID: <20200511170646.GJ2957@hirez.programming.kicks-ass.net> References: <20200508144043.13893-1-joro@8bytes.org> <20200508213609.GU8135@suse.de> <20200509175217.GV8135@suse.de> <20200511074243.GE2957@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, May 11, 2020 at 08:36:31AM -0700, Andy Lutomirski wrote: > On Mon, May 11, 2020 at 12:42 AM Peter Zijlstra wrote: > > > > On Sat, May 09, 2020 at 12:05:29PM -0700, Andy Lutomirski wrote: > > > > > On x86_64, the only real advantage is that the handful of corner cases > > > that make vmalloc faults unpleasant (mostly relating to vmap stacks) > > > go away. On x86_32, a bunch of mind-bending stuff (everything your > > > series deletes but also almost everything your series *adds*) goes > > > away. There may be a genuine tiny performance hit on 2-level systems > > > due to the loss of huge pages in vmalloc space, but I'm not sure I > > > care or that we use them anyway on these systems. And PeterZ can stop > > > even thinking about RCU. > > > > > > Am I making sense? > > > > I think it'll work for x86_64 and that is really all I care about :-) > > Sadly, I think that Joerg has convinced my that this doesn't really > work for 32-bit unless we rework the LDT code or drop support for > something that we might not want to drop support for. I was thinking keep these patches for 32bit and fix 64bit 'proper'. But sure, if we can get rid of it all by stripping 32bit features I'm not going to object either.