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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2A4B6C433EF for ; Fri, 12 Nov 2021 09:56:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 02BD260F5B for ; Fri, 12 Nov 2021 09:56:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234824AbhKLJ71 (ORCPT ); Fri, 12 Nov 2021 04:59:27 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:52372 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234778AbhKLJ71 (ORCPT ); Fri, 12 Nov 2021 04:59:27 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1636710996; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=WxrAi7/iU9HpI4uD/sEf88WQfsgTnECF0i+pXrLm63E=; b=KIWVB70LJdpzVmzV24ggXYKkgLoFuQIDRiUTs4fVuselNSA5Z/VqP43HPyxiMUXNkPqwyq XiSyVQfgzdtk83S1bxyMfsii0esgZqR1XaahDMRaqIjG8ewESIZ+xoHrkvO/Wkis1IPfwh ixy7QvH0qpouvxsDO2WEoslFWGvO5dU= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-493-ueKjipUcPuaWd2h-fA-zMA-1; Fri, 12 Nov 2021 04:56:35 -0500 X-MC-Unique: ueKjipUcPuaWd2h-fA-zMA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0936C102C84E; Fri, 12 Nov 2021 09:56:34 +0000 (UTC) Received: from sirius.home.kraxel.org (unknown [10.39.193.245]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1B7E95F4EC; Fri, 12 Nov 2021 09:56:31 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id 5F83018000AA; Fri, 12 Nov 2021 10:56:29 +0100 (CET) Date: Fri, 12 Nov 2021 10:56:29 +0100 From: Gerd Hoffmann To: "Michael S. Tsirkin" Cc: linux-pci@vger.kernel.org, Bjorn Helgaas , open list Subject: Re: [PATCH] pciehp: fast unplug for virtual machines Message-ID: <20211112095629.uoxfuhsvhicsdxgd@sirius.home.kraxel.org> References: <20211111090225.946381-1-kraxel@redhat.com> <20211111115931-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211111115931-mutt-send-email-mst@kernel.org> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Hi, > > This patch adds the fast_virtual_unplug module parameter to the > > pciehp driver. When enabled (which is the default) the linux > > kernel will simply skip the delay for virtual pcie ports, which > > reduces the total time for the unplug operation from 6-7 seconds > > to 1-2 seconds. > > BTW how come it's still taking seconds, not milliseconds? I've tackled the 5 seconds only, biggest chunk and easy target because the only reason to have that is to allow operators press the attention button again to cancel, so the risk to break something here is rather low. There are some more wait times elsewhere, to give the hardware the time needed when powering up/down slots, which sum up to roughly one second, and the time the driver needs to shutdown the device goes on top of that (typically not much). take care, Gerd