Received: by 2002:a05:6a10:f347:0:0:0:0 with SMTP id d7csp1069335pxu; Wed, 6 Jan 2021 11:23:52 -0800 (PST) X-Google-Smtp-Source: ABdhPJxTUpfJAzmzFhZvv7Tbb45xDBzui1kWCjRWgTO7h0dEUdQbj0ZvzpOc9wXoRyaWZsmdHrLC X-Received: by 2002:a17:906:48a:: with SMTP id f10mr3279648eja.33.1609961032487; Wed, 06 Jan 2021 11:23:52 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1609961032; cv=none; d=google.com; s=arc-20160816; b=fTFvUIQEvLSmotg7pAgvkjtB1AD3VpwcuN23VfK2vLs7v/j0vJwzfJBSjqD4pSu4il Gvkyod33IpbQ5HKiXynJhsQK8+6s75sk9ZJDLLi5Hp2qtP/lFxpDs1UCND/nvnmZtfBO aic8fYcD7oz6Gzemsfh7/M8y5/gkAwH4Drv6i+gsiEjVO1DQvJqi+CEDe6X6CX89g/Ln krXNynhMAOwLBF6jtCHXv1ZFGP+q4wHwdeCYfwQEMmRHVrKtV5vTzWrZL9J+YmsvAgTz vz95BIEEcgwJy/IZAjXsW2i9lPUFNdP9dOdJgoHq8u19iz9D2jC67kzMmL7oRB1fWqq/ GiFA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:mime-version:user-agent:references:message-id :in-reply-to:subject:cc:to:from:date; bh=Lm2RyKaLW2oHykdv4WzSE3UxLZZM1nxhbLmAUdBLMfw=; b=OdXDOxH5f96KdV9Lo/8oN38w5TuePkEdrM3qJFJz7ZzndBGlUdLowIgV1FZe7cye2v 0adGd2dPndrbuhIYN3XGeZy04MN9eIjSWC/B06lOgkloo4gO+ZCxnzypivNNIx5fyVy8 HaiwiYO+MJgXqJZ1orHZq7kb+h+/9kLc9KV554cQgnW5sa7tPeNxQhbqi7XWDp24b03l 1pXpjTMub7ot6CpLcGJOlHguZjMN2qQ9MONvG9Tn95VnPZaURy59lBGAJmAT8GXAi2vQ fVF0CyjcCXgjxVSNfGZqgMmirpsI579SZ6XS6aJpS9EqM01JibnhD/AZzDVDOgeSLsKU CUyw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id kt11si1230522ejb.445.2021.01.06.11.23.25; Wed, 06 Jan 2021 11:23:52 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726754AbhAFTTT (ORCPT + 99 others); Wed, 6 Jan 2021 14:19:19 -0500 Received: from gentwo.org ([3.19.106.255]:56954 "EHLO gentwo.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726466AbhAFTTT (ORCPT ); Wed, 6 Jan 2021 14:19:19 -0500 X-Greylist: delayed 548 seconds by postgrey-1.27 at vger.kernel.org; Wed, 06 Jan 2021 14:19:19 EST Received: by gentwo.org (Postfix, from userid 1002) id 02B783F551; Wed, 6 Jan 2021 19:09:25 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by gentwo.org (Postfix) with ESMTP id 007B53F550; Wed, 6 Jan 2021 19:09:25 +0000 (UTC) Date: Wed, 6 Jan 2021 19:09:25 +0000 (UTC) From: Christoph Lameter X-X-Sender: cl@www.lameter.com To: Vlastimil Babka cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Pekka Enberg , David Rientjes , Joonsoo Kim , Vladimir Davydov , Qian Cai , David Hildenbrand , Michal Hocko Subject: Re: [RFC 0/3] mm, slab, slub: remove cpu and memory hotplug locks In-Reply-To: <20210106174029.12654-1-vbabka@suse.cz> Message-ID: References: <20210106174029.12654-1-vbabka@suse.cz> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 6 Jan 2021, Vlastimil Babka wrote: > rather accept some wasted memory in scenarios that should be rare anyway (full > memory hot remove), as we do the same in other contexts already. It's all RFC > for now, as I might have missed some reason why it's not safe. Looks good to me. My only concern is the kernel that has hotplug disabled. Current code allows the online/offline checks to be optimized away. Can this patch be enhanced to do the same?