From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f50.google.com (mail-wr1-f50.google.com [209.85.221.50]) (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 6F48BA55 for ; Thu, 29 May 2025 09:19:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.50 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748510400; cv=none; b=cY93QheaVz+JNKJMpFE0euj1pl+3nnxfOJZ3ucLCZ26N/4Fqz0j+0Actt3YPnV/qDdH4OUxSaRSWi3N6TFYdbuM7G+lkiczdrl4uaykYf90htBDOO45i+cUqCwffcv+L4zvRZ82y8mm47kDI8edl+0iKhF6tHRq8Q3oAWSJ9muQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748510400; c=relaxed/simple; bh=7ErKMfn0HYzjnh8ROxXwWnHBnT6eAFpTgcf8kV+OYUQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=PsGQSzYpaAZvJU/hOBvxA1ck3/SGr8DbnQAdeoL7mmkUYNc8+jrIAXV5vuiHtSkk7YbGlM58f1dKIyIySTxOScX+tM/t+O3CUawZ5vzHL6n5wBHyCpR8aOUd7ti1keiLLxVimDhP3jaRiPqGe42Zr2KKuzZdUmRcOOnVxs3i/tw= 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=MnynTusS; arc=none smtp.client-ip=209.85.221.50 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="MnynTusS" Received: by mail-wr1-f50.google.com with SMTP id ffacd0b85a97d-3a4e742dc97so1212240f8f.0 for ; Thu, 29 May 2025 02:19:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1748510396; x=1749115196; 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=Ptk4vf9TFuccydOqbTHwIit7Mi2XSLpvZwljdh3B7PQ=; b=MnynTusS9C0+5m9cTau9yzhY2HjR6fbB/68Us0nRgJyYOqVQg3SurmIL+qa1By0v3d 7uWUX5agFT8qOmQA6/+QBjXk0v2FCqBxnmZtpF6KmhfnT1cwGG6WvTB9tXDfXahwLmRo Y3oo94URbFdWsRn1fLcDZKo/NnuuTmoOOfdCpLEdXDvbedTTJDR+J1caFjG1phJFEjb0 mWixFRp8GYI0YvPqrvYeHpBXnDTw/hJZ8yjwgSIF2R9zHaxln9ewAnqSNtsfTIphzbmJ vuzlMNm+07QKCLnUPtmLdu8e/BFdgm0gLrijpMKIQ3ss1U85n6+eX+6fZIln7yX5YByB 6oAw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1748510396; x=1749115196; 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=Ptk4vf9TFuccydOqbTHwIit7Mi2XSLpvZwljdh3B7PQ=; b=ARNLhWIhdfMP4vdyWRFIYBhmSI1by3Ri9oSjwt+nsfyD/ZBlU+za5kje18C2f4wEL5 EEehcKOj/JDW0S6WCY/nX5gFXE2492PZSwUsfXQv8lxZyo0FN6Znw75S51ljg7yr7q5U QrZSKxO7RLlyemunx+3CwgjSfBQOL3Xh1LCC9k+cOxN/cGPN0u71LPzHTrnxMfVF5LSb DpMEbpYOpdH+vXDKiPsAwU2ko6ckw7CKwHFauh81X+MHGr66fZAOHz3RjnnUkpNYnjE2 mKKkJ96JajVpBcxNUjLxyGzTGf6EynrJYfjvf11AaCC5Q6XWa9wYbNVvG3D7uBho+ZBt pRJg== X-Forwarded-Encrypted: i=1; AJvYcCXE+h/MLbIfQ7fMndqjJ9y/UYCRIbzMCaiaVv3OWvhhEC17NRP5/mKPJq2C/hFP/Fj09G22VAWrRY3f95Q=@vger.kernel.org X-Gm-Message-State: AOJu0YxEb2LVYLFxhUQZdvI9iSxrzVg2uQhEkNU6ViA2Tdd8sky4SXqZ 8EfRho5DAi3A36a9iZKvN/fyW4mBAa/+kqxrFd4RIU3Xi1rqSRuNtDHbcql2m+7prp5s4e/kbr/ 59r9Q X-Gm-Gg: ASbGncubsx2zCUFgHm9EeTpXRdJuJLlzJb+AqEPpbhgfigvdZMc2kwouY2auH9diYQK oFvNfmTG3fWi1y77hpUvFhKVFAayTCZgXMjate8y8Eb7R4wEgau6jXCcKxSWPJF0oOHVA/jgUAn QmHQW7IuekmfKtCVWFspj5hICYabJxFv2V7NOCndtm/YJRXvZWdbZuqjjw2CJDdMwSXzO3p6uri aqfKpq0nuMckVfKZqnEKFtDDxa10UHdhjrHrcUqSJqTlFm4Wy62nW3EZtRhP2GbMtJp/K5xRUiw zyRLRgudyR1VNYY1D+/P6b7B6PJZA/DRsoyZCGVwe8CWtg4VtVC9/CJez6rjx27Q X-Google-Smtp-Source: AGHT+IHJBMhRQ+ovIFAhUhr16RkaKMXCgPSGtp8h/7Y6GpbhycWlqT6b5YEMAzolhz589ymnz6a4cA== X-Received: by 2002:a05:6000:310d:b0:3a4:d719:5be0 with SMTP id ffacd0b85a97d-3a4eed91301mr2424426f8f.2.1748510396572; Thu, 29 May 2025 02:19:56 -0700 (PDT) Received: from localhost (109-81-89-112.rct.o2.cz. [109.81.89.112]) by smtp.gmail.com with UTF8SMTPSA id 5b1f17b1804b1-450cfc3785bsm14479815e9.40.2025.05.29.02.19.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 29 May 2025 02:19:56 -0700 (PDT) Date: Thu, 29 May 2025 11:19:55 +0200 From: Michal Hocko To: David Hildenbrand Cc: Baoquan He , Donald Dutile , Jiri Bohac , Vivek Goyal , Dave Young , kexec@lists.infradead.org, Philipp Rudo , Pingfan Liu , Tao Liu , linux-kernel@vger.kernel.org, David Hildenbrand Subject: Re: [PATCH v2 0/5] kdump: crashkernel reservation from CMA Message-ID: References: <04904e86-5b5f-4aa1-a120-428dac119189@redhat.com> <427fec88-2a74-471e-aeb6-a108ca8c4336@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 Thu 29-05-25 09:46:28, Michal Hocko wrote: > On Wed 28-05-25 23:01:04, David Hildenbrand wrote: > [...] > > I think we just have to be careful to document it properly -- especially the > > shortcomings and that this feature might become a problem in the future. > > Movable user-space page tables getting placed on CMA memory would probably > > not be a problem if we don't care about ... user-space data either way. > > I think makedumpfile could refuse to capture a dump if userspace memory > is requested to enforce this. > > > The whole "Direct I/O takes max 1s" part is a bit shaky. Maybe it could be > > configurable how long to wait? 10s is certainly "safer". > > Quite honestly we will never know and rather than making this > configurable I would go with reasonably large. Couple of seconds > certainly do not matter for the kdump situations but I would go as far typo s@I would go@I would not go@ > as minutes. -- Michal Hocko SUSE Labs