From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f176.google.com (mail-pl1-f176.google.com [209.85.214.176]) (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 A24AB631 for ; Wed, 12 Jun 2024 00:25:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718151944; cv=none; b=BbSrSNN/XzVFt+sIgjsEIqFKCET34CG5K+6l+LlIZnaHfL6JA+cXvDWiy9jLevDM3I+v/rOCuzkK6fpcQ/cCshG367lFZCjr2uuyORQJwjmQdjjIYBUBKWK28GIgrVwxmTUriIdNOFyDkpRzK2SlEcD8NUKSYTYwFXYbTu61wDw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718151944; c=relaxed/simple; bh=z/2yRwkdCljaoKOGpO1d2golTaGcCNFoMOn1+YpkLfE=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=RwlCyco3h2h/f4x/Bm9MLY5qYRYXPUhowJuPgAMdFTmAIURW2SWvsg5+JMRpFZurUBazEJFRIbghT6YLhFaQpcY/4w5CSw4bUUSe4GEjt7wBwE75NVCIDzcYer2XSmRxl69/+T8/sQ5f2jvc8Mo0VPOY1ykMVYwSmwMkao3ZrPM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=i8X407/A; arc=none smtp.client-ip=209.85.214.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="i8X407/A" Received: by mail-pl1-f176.google.com with SMTP id d9443c01a7336-1f70ec6ff8bso71285ad.0 for ; Tue, 11 Jun 2024 17:25:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1718151941; x=1718756741; darn=vger.kernel.org; h=mime-version:references:message-id:in-reply-to:subject:cc:to:from :date:from:to:cc:subject:date:message-id:reply-to; bh=7Jx+dpbpF1izwf17SLEuAd5VzAXe6OlxL8ty7yz0tFc=; b=i8X407/A0YY/mdpWHqmmx/bhe9zB592ikYXDIffpV+sE/Q6AeHpRPLmLtRDwYTZlLd gjVDUfU9FRfoYMwf9Y6S660E1VSkp17kyFMxXlUyT5CWsSjDvSBKC+gy3KKS7if7aUV7 N/8EFZFNp2VZxPL/ww1n0JUnK63kH2lgeRXcGfMVRJjnn+srcrnOgOKxc6DjNthwnjpp +KZt8JdcPumhoP36Yf8oK2XvfoO9dDKifYXhlzxMaGQfvw8gkM0bq2fPubzKwq3heqf3 lh8VOWoKpzh9A9JhOhQcvfEp1seFLbn7C0IZXDSYxvvpIOZKWXTrTp3Z11dgr/hs++bR OS4w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1718151941; x=1718756741; h=mime-version:references:message-id:in-reply-to:subject:cc:to:from :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=7Jx+dpbpF1izwf17SLEuAd5VzAXe6OlxL8ty7yz0tFc=; b=HjaktgDSvf8e+fY+IU7hrHw6EvB80xS+J87r5S82f0eP+AfZL9wA73Ds708N1ng4RO f9gbUxfpSe57PI/hWzEf2PBbMEgRMNTJUqJ3bAK/r1e7mPKUNOqCXYSG3Ii93+8JJEda DXTOukK+nsvtWs7FyGlAKOPwmMc3eO3/4xZdFVCGHPiuuVGWPhPeiD2sy7QDaeLDu6Ga G1XqvRWvM0jb+P/Sstt05LNt5aWKCpB468bAhBKdPWMDqtnByLhJDyFpLViDgGTkElgO 24ytDZdBSNhlMBmm7fcu1lfZpXiC7NFhF8g8rKIsGt/lSbxW5OX/F1w5XkJvv64QkzjN Bsvw== X-Forwarded-Encrypted: i=1; AJvYcCVm+suyFXVwdV+M1WIvgQxASV2o6hWGnqhDJybAZCleUQjFFue9KdTDOu/gOaiy1TPyRFu0nWhxT5nQ7YwcSToMQPTc0/N5yg6e X-Gm-Message-State: AOJu0Ywn8Gd5phSQTVKX8cLhG+L0q/NI9sA8k93/9zhptxH9mm1xJnTa 5HpjRhrt4HTw+FhXRIyb4o6Nn3dyUez+rc9ltsM1o24McXcBbD5pWC37VfiK5g== X-Google-Smtp-Source: AGHT+IHlya7vwInxFDp0+EWhOLwMIyetA4gB6RV8l5p0Exjin5Bjm2songabBXlS19x4W+pEVmxc2Q== X-Received: by 2002:a17:902:9048:b0:1f7:1c96:d2e8 with SMTP id d9443c01a7336-1f838ddb9fcmr1323935ad.10.1718151940686; Tue, 11 Jun 2024 17:25:40 -0700 (PDT) Received: from [2620:0:1008:15:290:7df3:2a02:3982] ([2620:0:1008:15:290:7df3:2a02:3982]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-70595da2deesm4287777b3a.159.2024.06.11.17.25.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 Jun 2024 17:25:39 -0700 (PDT) Date: Tue, 11 Jun 2024 17:25:38 -0700 (PDT) From: David Rientjes To: Jiaqi Yan cc: nao.horiguchi@gmail.com, linmiaohe@huawei.com, jane.chu@oracle.com, muchun.song@linux.dev, akpm@linux-foundation.org, shuah@kernel.org, corbet@lwn.net, osalvador@suse.de, duenwen@google.com, fvdl@google.com, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: [PATCH v2 3/3] docs: mm: add enable_soft_offline sysctl In-Reply-To: <20240611215544.2105970-4-jiaqiyan@google.com> Message-ID: <9461874d-e2d6-25fc-813c-9c9bb0ad1aec@google.com> References: <20240611215544.2105970-1-jiaqiyan@google.com> <20240611215544.2105970-4-jiaqiyan@google.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII On Tue, 11 Jun 2024, Jiaqi Yan wrote: > @@ -267,6 +268,20 @@ used:: > These are informational only. They do not mean that anything is wrong > with your system. To disable them, echo 4 (bit 2) into drop_caches. > > +enable_soft_offline > +=================== > +Control whether to soft offline memory pages that have (excessive) correctable > +memory errors. It is your call to choose between reliability (stay away from > +fragile physical memory) vs performance (brought by HugeTLB or transparent > +hugepages). > + Could you expand upon the relevance of HugeTLB or THP in this documentation? I understand the need in some cases to soft offline memory after a number of correctable memory errors, but it's not clear how the performance implications plays into this. The paragraph below goes into a difference in the splitting behavior, are hugepage users the only ones that should be concerned with this? > +When setting to 1, kernel attempts to soft offline the page when it thinks > +needed. For in-use page, page content will be migrated to a new page. If > +the oringinal hugepage is a HugeTLB hugepage, regardless of in-use or free, s/oringinal/original/ > +it will be dissolved into raw pages, and the capacity of the HugeTLB pool > +will reduce by 1. If the original hugepage is a transparent hugepage, it > +will be split into raw pages. When setting to 0, kernel won't attempt to > +soft offline the page. Its default value is 1. > This behavior is the same for all architectures?