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_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 DAC1DC31E40 for ; Tue, 6 Aug 2019 13:37:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AFE3E20B1F for ; Tue, 6 Aug 2019 13:37:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731725AbfHFNhH (ORCPT ); Tue, 6 Aug 2019 09:37:07 -0400 Received: from mail-qk1-f195.google.com ([209.85.222.195]:46802 "EHLO mail-qk1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726092AbfHFNhH (ORCPT ); Tue, 6 Aug 2019 09:37:07 -0400 Received: by mail-qk1-f195.google.com with SMTP id r4so62758583qkm.13 for ; Tue, 06 Aug 2019 06:37:06 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=+EmwYezlru/6l1RGke6OfmjMerhgmwmHntHPbq6+2AE=; b=X9jivODWgvbrVW3YnABVDFkAgfLbnFTLsljL+72r/VTHs+S38Gtw2F650AAzjbuoep uoU5VEZHCt6dVtI3isF4NZKv0ebdWx57yeO4hbg5cjPulpMsNw4jCECVl3F//4kgCsaS r69yCb44T5QnAzO18neujO8CYh14nl+wKhkAfuA01Uvj23tn8jghxvzhK/tQBDUqjeDK inZTz2+ivmrMmDcrXMkN4TNSQBb8RfbygyON6V5TNQqArE8me2M+FlekHrNH+odaHZS2 S8myt5DTVgV76eXKKFsmlt1tn0Vgi9y2ecp8LoXxLttwc2wmvMm7MxHQriyLXxD/088H vR5g== X-Gm-Message-State: APjAAAWly5YGNwEherX3bE0KAU6ifUUVW86E8riHlbS/Fz+GTdAEOSDd RWMCvNz0JxPXPkYS1SpX5wEoJQ== X-Google-Smtp-Source: APXvYqwQogResfBtEcBuAcFTuCtTWGzeNFF/0eeIOxkxJPkA8JpnI8WBDTcUIzFbb3AvBDILVnFfYQ== X-Received: by 2002:ae9:efc6:: with SMTP id d189mr2946499qkg.323.1565098625407; Tue, 06 Aug 2019 06:37:05 -0700 (PDT) Received: from redhat.com ([147.234.38.1]) by smtp.gmail.com with ESMTPSA id q73sm24068906qke.90.2019.08.06.06.37.01 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Tue, 06 Aug 2019 06:37:04 -0700 (PDT) Date: Tue, 6 Aug 2019 09:36:58 -0400 From: "Michael S. Tsirkin" To: Jason Gunthorpe Cc: Jason Wang , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH V2 7/9] vhost: do not use RCU to synchronize MMU notifier with worker Message-ID: <20190806093633-mutt-send-email-mst@kernel.org> References: <20190801141512.GB23899@ziepe.ca> <42ead87b-1749-4c73-cbe4-29dbeb945041@redhat.com> <20190802124613.GA11245@ziepe.ca> <20190802100414-mutt-send-email-mst@kernel.org> <20190802172418.GB11245@ziepe.ca> <20190803172944-mutt-send-email-mst@kernel.org> <20190804001400.GA25543@ziepe.ca> <20190804040034-mutt-send-email-mst@kernel.org> <20190806115317.GA11627@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190806115317.GA11627@ziepe.ca> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 06, 2019 at 08:53:17AM -0300, Jason Gunthorpe wrote: > On Sun, Aug 04, 2019 at 04:07:17AM -0400, Michael S. Tsirkin wrote: > > > > > Also, why can't this just permanently GUP the pages? In fact, where > > > > > does it put_page them anyhow? Worrying that 7f466 adds a get_user page > > > > > but does not add a put_page?? > > > > > > You didn't answer this.. Why not just use GUP? > > > > > > Jason > > > > Sorry I misunderstood the question. Permanent GUP breaks lots of > > functionality we need such as THP and numa balancing. > > Really? It doesn't look like that many pages are involved.. > > Jason Yea. But they just might happen to be heavily accessed ones.... -- MST