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=-3.5 required=3.0 tests=BAYES_00,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 6EFE1C433DB for ; Mon, 1 Feb 2021 12:50:29 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8036364E9C for ; Mon, 1 Feb 2021 12:50:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8036364E9C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4DTnq06lx6zDrRH for ; Mon, 1 Feb 2021 23:50:20 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=infradead.org (client-ip=2001:8b0:10b:1236::1; helo=casper.infradead.org; envelope-from=peterz@infradead.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=casper.20170209 header.b=m7ji0VO1; dkim-atps=neutral Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4DTnhp1QYLzDqm6 for ; Mon, 1 Feb 2021 23:44:55 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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=iS8iy+q7Izh8AM4pbDoHtBgYLQUACj4slse1odTb8Xw=; b=m7ji0VO1MSn1lX6BI0jJ/Yb9pR 9LbSnyqEyG+WShVFDi6LLpOxh725y4TN5ZOzvkdZzaqe2VLLrMyA0w5DmjmAmnD9zsr9kHInq0sjB ii38K9XKQhFn7sOI40UlVOovRxxAgm9h9jejp9eCBLKegUodvH0TprmeRQ27HIdL/dZ9Y9TeAXH+T AH4kD9PgJxscyRe30c+nsFbhAUZbIF86CVRIvrNnDHqiAHo82ZC5vwPaZdUNJSPPkp0ldDsBPBc8P BJXcBzycInlMsr0+a7N0JA8WObI/EMjH6YDE79gmnKGPIcRn4F4Lq0ejsbhou5qIjm5vd3EqnQ2UW /oN5DJpg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1l6YZH-00Dm54-Iu; Mon, 01 Feb 2021 12:44:36 +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 7D8C9303A02; Mon, 1 Feb 2021 13:44:34 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 65B2620C8E303; Mon, 1 Feb 2021 13:44:34 +0100 (CET) Date: Mon, 1 Feb 2021 13:44:34 +0100 From: Peter Zijlstra To: Nadav Amit Subject: Re: [RFC 00/20] TLB batching consolidation and enhancements Message-ID: References: <20210131001132.3368247-1-namit@vmware.com> <1612063149.2awdsvvmhj.astroid@bobo.none> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andrea Arcangeli , linux-s390 , X86 ML , Yu Zhao , Will Deacon , Mel Gorman , Dave Hansen , LKML , Nicholas Piggin , Linux-MM , "linux-csky@vger.kernel.org" , Andy Lutomirski , Andrew Morton , linuxppc-dev , Thomas Gleixner Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Sun, Jan 31, 2021 at 07:57:01AM +0000, Nadav Amit wrote: > > On Jan 30, 2021, at 7:30 PM, Nicholas Piggin wrote: > > I'll go through the patches a bit more closely when they all come > > through. Sparc and powerpc of course need the arch lazy mode to get > > per-page/pte information for operations that are not freeing pages, > > which is what mmu gather is designed for. > > IIUC you mean any PTE change requires a TLB flush. Even setting up a new PTE > where no previous PTE was set, right? These are the HASH architectures. Their hardware doesn't walk the page-tables, but it consults a hash-table to resolve page translations. They _MUST_ flush the entries under the PTL to avoid ever seeing conflicting information, which will make them really unhappy. They can do this because they have TLBI broadcast. There's a few more details I'm sure, but those seem to have slipped from my mind.