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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 E186CC4743F for ; Mon, 7 Jun 2021 07:51:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CC696611AB for ; Mon, 7 Jun 2021 07:51:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230173AbhFGHx0 (ORCPT ); Mon, 7 Jun 2021 03:53:26 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:43898 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229436AbhFGHxY (ORCPT ); Mon, 7 Jun 2021 03:53:24 -0400 Received: from relay2.suse.de (unknown [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 52B6A21A6E; Mon, 7 Jun 2021 07:51:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1623052292; h=from:from:reply-to: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=4NT4tA15Kh2qCvhPPggvZbVmruQWfYW04SuZbrBoVAs=; b=STYpI1vFrANTBQnqKzXLAEPgUwzTjWefqYRZlHuDkLXe1VkAqJfoTf9bOEXOG6fH8B7wHc v7AFnEz6LKr2igzamTg4DukabHg2nvjhoSACUD1tq76XpIUNTM+xjX0O6Xpk9D3nQeY/i6 aKbyyCxdGP/ijP1I0vnLVTGAEO5bKNI= Received: from suse.cz (unknown [10.100.201.86]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 2318CA3B85; Mon, 7 Jun 2021 07:51:31 +0000 (UTC) Date: Mon, 7 Jun 2021 09:51:30 +0200 From: Michal Hocko To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Oscar Salvador , Mike Kravetz , Mike Rapoport , Dave Hansen , Matthew Wilcox , Anshuman Khandual , Muchun Song , Pavel Tatashin , Jonathan Corbet , Stephen Rothwell , linux-doc@vger.kernel.org Subject: Re: [PATCH v1] memory-hotplug.rst: complete admin-guide overhaul Message-ID: References: <20210525102604.8770-1-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210525102604.8770-1-david@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [Sorry this somehow slipped through cracks] On Tue 25-05-21 12:26:04, David Hildenbrand wrote: > The memory hot(un)plug documentation is outdated and incomplete. Most of > the content dates back to 2007, so it's time for a major overhaul. > > Let's rewrite, reorganize and update most parts of the documentation. In > addition to memory hot(un)plug, also add some details regarding > ZONE_MOVABLE, with memory hotunplug being one of its main consumers. > > The style of the document is also properly fixed that e.g., "restview" > renders it cleanly now. > > In the future, we might add some more details about virt users like > virtio-mem, the XEN balloon, the Hyper-V balloon and ppc64 dlpar. I haven't really checked the diff but rather looked at the final outcome. I have to say I like it a lot. Some places are going a bit too technical for an admin-guide but they are in minority (e.g. locking or altmap reference). If somebody feels strong then this could get into its own file but I wouldn't lose sleep over that. I would make one thing slightly more explicit though diff --git a/Documentation/admin-guide/mm/memory-hotplug.rst b/Documentation/admin-guide/mm/memory-hotplug.rst index c95f5c2b30dd..5b462aba89cc 100644 --- a/Documentation/admin-guide/mm/memory-hotplug.rst +++ b/Documentation/admin-guide/mm/memory-hotplug.rst @@ -568,6 +568,10 @@ Even with ZONE_MOVABLE, there are some corner cases where offlining a memory Further, when running into out of memory situations while migrating pages, or when still encountering permanently unmovable pages within ZONE_MOVABLE (-> BUG), memory offlining will keep retrying until it eventually succeeds. +The offlining context can be terminated by a fatal signal. A timeout based +offlining can be easily implemented by + + % timeout $TIMEOUT offline_block | failure_handling Locking Internals ================= In the future I would find some examples of a failure cases we have seen so far. E.g. offlining failure with dump_page example. > Cc: Andrew Morton > Cc: Oscar Salvador > Cc: Michal Hocko > Cc: Mike Kravetz > Cc: Mike Rapoport > Cc: Dave Hansen > Cc: Matthew Wilcox > Cc: Anshuman Khandual > Cc: Muchun Song > Cc: Pavel Tatashin > Cc: Jonathan Corbet > Cc: Stephen Rothwell > Cc: linux-doc@vger.kernel.org > Signed-off-by: David Hildenbrand Acked-by: Michal Hocko Thanks a lot David! -- Michal Hocko SUSE Labs