From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f47.google.com (mail-ej1-f47.google.com [209.85.218.47]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5C6AC22DA0B for ; Tue, 29 Jul 2025 09:19:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.47 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753780762; cv=none; b=WheWBSd5zcw1uDFna0ip8ZxjPsLeroLoG3E2RNJKZGIDBcT4pB+1kQ8d4IsJ193EmDGZCYYkwghHaDO6GVcekRxuRNOtPm/GVM8Gwv9X9kJmMOm2tu/Hx4/oN4ec82SnevM/mG7ga2JXx5gGYUTTJoilCY+NRuruY1Rt/xbuvYY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753780762; c=relaxed/simple; bh=rQvsWu+Pb8C/47+QetGvb0sbFiXZpTaN+Gpht+bmprk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=GpWu5xP360quqkVAwmvwfOojTFeo1MaVIZ5HPDwkST7vXOxDeHFGIABRq0vMVzUJuVj4g6bSxmqbxN4eBSEZ4fI+SA6EdaIG67yUe1b0Aj8QroBM4lurYaBgYdtZdjgZfLrWngO/QQXVXGpgONJRTzve/Hz2fkLQIEmTvWUeXPM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=SV3aZX+B; arc=none smtp.client-ip=209.85.218.47 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="SV3aZX+B" Received: by mail-ej1-f47.google.com with SMTP id a640c23a62f3a-ae360b6249fso956108466b.1 for ; Tue, 29 Jul 2025 02:19:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1753780756; x=1754385556; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=FrFwM1VTnba/UhHasFMl0CnHRVF7mL2ndb/lv3touvg=; b=SV3aZX+B0Bi/9pHgGlFcgmiBexuhw5Yqt+cn/8PRCkND3JCoUGFxm/7KR5J5MPIgLM iXc60vQhH+8uyTKNp1/r1Os3EczxWV0Hp0PNMRwkC1/8/Kty6CSwUpvyeNQ+C19Hvk1g 1t2l4OyBQUWpiB9o/pFy88/3L3EqrSWLDGwDn0HmmmzOaTx0ZDQLspftGGvDaWjEcu6L BiL3KP2F9sfqxwO9uegPzvA4juAnLF6C29d1E3OljagHTzdD5pcL7OcFDp9wLG8llWS7 NASI6JwpfQVQLZu36T7CzvuUF+h/LlFmB/vC50NFD4LPjMcHZiuE5nT7fX6erbn/6uNZ XqjQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1753780756; x=1754385556; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=FrFwM1VTnba/UhHasFMl0CnHRVF7mL2ndb/lv3touvg=; b=Fiv//L67pPJOncrIvkUJnTwqYWYikwMynRar5hhbtv9awfXSwJvOFjCeSlGXKX1+8o ehfvebPmQxFWPU+SBRwmf/0CbeD56VhX8vi5AKjlOG40KwbJG5RA7xPcmRHQNa7FLlAS 19hc9FihBiHBDabjP8+POSriTiwhwgAGb3p49Sy2l240vZStUvZCGDWK2IP0tSO9A82X HjzIaQli6ype03sst7Te3YprBxU6l7QmpU4JiU8H4EA6R5lO6R+6URrByhbJeTZS4GAS V0uAzZdRd+mRigMP6stQieTWSwJG+tWJ0vyXei8o1kl+YP4OfFPxIFlus7irmsA7MFvA dkHQ== X-Forwarded-Encrypted: i=1; AJvYcCX/ds6yTSVOlh5oD86tHGhoezzCLHw4nNGdu+rw4pb1B/1XXOcWIHMSvcLSRSQ98rJXwG1LVtNBliHAvdw=@vger.kernel.org X-Gm-Message-State: AOJu0YxmM4Ft20xFEBdTLPeNPH3IyrSvKI0QRcIbabwNhPfcT0yIFlH+ 4/qkwCzG6uFl02Qkz9kEUkmrG9w72iYcW6HlerUDg49dgVrlr/7NBin5q1jVhrDjZAo= X-Gm-Gg: ASbGncucVEsenHK/NjnoKktTF8bI6LFO31vCmdH2t4qIMYDZ6/6u57cJnTAtxQb3U/S Gj/ovNERR48SHV3721OeCdtUPx/cbODIsWwe8iUUBdMVP9/VHiqmDXIFaDjpyrEx+U4jqk+jyqV 4LchvfqYB9Nb7e7z+CWZtUoIrhuIiv/8aY2X+cNImnUz/JcTpXF09mSsAzgRx5eXdTRAaX+yzaQ QqcwgGtRUggg8cuIaZUE3aE/Ct+L7ry6uTaoVe0LqnpkRlsxfLuZti+8bXepLoWquKYvZEdqhm1 xa/4QKRS9E6PqmAwUq029SKjlwn1hZ+J7cDjcuZJuA6MwvZpRyOQipYYD0SVnVYsZjjtz41nfDu 3ixj2sO/HM0jDmnxNUE12z2p216UXqb2iVl8= X-Google-Smtp-Source: AGHT+IG5if8x6TzCm9A2O62HvaAVkznS6JFPkv75AtILJqhhNjqt74fPiYQzDCocAuv9abxq43Ts5A== X-Received: by 2002:a17:907:3f16:b0:ae0:da2d:44b9 with SMTP id a640c23a62f3a-af61c4b19c1mr1854043966b.7.1753780755612; Tue, 29 Jul 2025 02:19:15 -0700 (PDT) Received: from localhost (109-81-20-172.rct.o2.cz. [109.81.20.172]) by smtp.gmail.com with UTF8SMTPSA id a640c23a62f3a-af635af9967sm545754666b.131.2025.07.29.02.19.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 29 Jul 2025 02:19:15 -0700 (PDT) Date: Tue, 29 Jul 2025 11:19:14 +0200 From: Michal Hocko To: Hannes Reinecke Cc: David Hildenbrand , Oscar Salvador , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hannes Reinecke Subject: Re: [RFC] Disable auto_movable_ratio for selfhosted memmap Message-ID: References: <2f24e725-cddb-41c5-ba87-783930efb2aa@redhat.com> <79919ace-9cd2-4600-9615-6dc26ba19e19@redhat.com> <3e88642f-3914-42b0-b864-4ad374b659b5@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue 29-07-25 09:24:37, Hannes Reinecke wrote: > On 7/28/25 15:08, David Hildenbrand wrote: > > On 28.07.25 15:06, Michal Hocko wrote: > > > On Mon 28-07-25 11:37:46, Hannes Reinecke wrote: > > > > On 7/28/25 11:10, David Hildenbrand wrote: > > > > And to make matters worse, we have two competing user-space programs: > > > > - udev > > > > - daxctl > > > > neither of which is (or can be made) aware of each other. > > > > This leads to races and/or inconsistencies. > > > > > > Would it help if generic udev memory hotplug rule exclude anything that > > > is dax backed? Is there a way to check for that? Sorry if this is a > > > stupid question. > > Parsing /proc/iomem, it's indicated as "System RAM (kmem)". > > > I would rather do it the other way round, and make daxctl aware of > udev. In the end, even 'daxctl' uses the sysfs interface to online > memory, which really is the territory of udev and can easily be > done via udev rules (for static configuration). udev doesn't really have any context what user space wants to do with the memory and therefore how to online it. Therefore we have (arguably) ugly hacks like auto onlining and movable_ration etc. daxctl can take information from the admin directly and therfore it can do what is needed without further hacks. > Note, we do a similar thing on s/390; the configuration tool there > just spits out udev rules. Those were easy times when you just need to online memory without any more requirements where it should land. -- Michal Hocko SUSE Labs