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=-2.4 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT 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 97D10C4321D for ; Fri, 24 Aug 2018 08:47:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4E0EA216C4 for ; Fri, 24 Aug 2018 08:47:46 +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="XGdxXXks" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4E0EA216C4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org 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 S1727427AbeHXMVW (ORCPT ); Fri, 24 Aug 2018 08:21:22 -0400 Received: from merlin.infradead.org ([205.233.59.134]:38138 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726382AbeHXMVV (ORCPT ); Fri, 24 Aug 2018 08:21:21 -0400 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:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=W4K9GHyio6iakjM4D7I305435E1QN4Pp7/tITQv6UZY=; b=XGdxXXksplvMvTL3jjwhT0SlW Cnq3i2GZTTpLZ4UvaaVTYWtWLveLSqtzSAm94fJNJ6/6fQfY8lku3+RLzESsWO9NIjgxJQq234HTH 5xDEqCsLTFMzFDzrhP1MhRtwJZIG1ku1zqhUG9Qc4es/pY2R7qpA4Wqyi7oI9P1NM2IE/JlHbjSwi RDPc7Orb0tcQS0JwmtQI/hjtCGgAuzEdxFCXO/uH6Ghauo5vaOTB4myxS5yidH1NtxJbFDM3Sa3ER U80NBEgCVtyq3ZZkfbolqpDRYny5URW7VU8/XN/ZtV4xsOqVEgVzL/y0X8RIv+91Gh1hflcJmtTvj vpPZWr17g==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1ft7kV-0007JV-7j; Fri, 24 Aug 2018 08:47:19 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 0D53A202E65E0; Fri, 24 Aug 2018 10:47:18 +0200 (CEST) Date: Fri, 24 Aug 2018 10:47:17 +0200 From: Peter Zijlstra To: Will Deacon Cc: Linus Torvalds , Benjamin Herrenschmidt , Nick Piggin , Andrew Lutomirski , the arch/x86 maintainers , Borislav Petkov , Rik van Riel , Jann Horn , Adin Scannell , Dave Hansen , Linux Kernel Mailing List , linux-mm , David Miller , Martin Schwidefsky , Michael Ellerman Subject: Re: [PATCH 3/4] mm/tlb, x86/mm: Support invalidating TLB caches for RCU_TABLE_FREE Message-ID: <20180824084717.GK24124@hirez.programming.kicks-ass.net> References: <20180822153012.173508681@infradead.org> <20180822154046.823850812@infradead.org> <20180822155527.GF24124@hirez.programming.kicks-ass.net> <20180823134525.5f12b0d3@roar.ozlabs.ibm.com> <776104d4c8e4fc680004d69e3a4c2594b638b6d1.camel@au1.ibm.com> <20180823133958.GA1496@brain-police> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180823133958.GA1496@brain-police> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 23, 2018 at 02:39:59PM +0100, Will Deacon wrote: > The only problem with this approach is that we've lost track of the granule > size by the point we get to the tlb_flush(), so we can't adjust the stride of > the TLB invalidations for huge mappings, which actually works nicely in the > synchronous case (e.g. we perform a single invalidation for a 2MB mapping, > rather than iterating over it at a 4k granule). > > One thing we could do is switch to synchronous mode if we detect a change in > granule (i.e. treat it like a batch failure). We could use tlb_start_vma() to track that, I think. Shouldn't be too hard.