From nobody Sun Dec 14 19:33:10 2025 Received: from mail-pf1-f180.google.com (mail-pf1-f180.google.com [209.85.210.180]) (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 BE6BF1BE866 for ; Fri, 28 Jun 2024 13:09:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.180 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719580157; cv=none; b=CDtQcs28ySKorwqHIXNdnr+4iEiofnw3YROSBd/9KzjHBTl8CVJ9ffe74oN/QHpPTKbCvk0//Kv4MWmfkKCubvDY9KFmrfI+yoJpThccxPdAmqVSCnRByQ6G1ojInp9u47Fzt7T9SaAshxJcFWLO3IpBFsGXtPSOl4fjg4QTQA8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719580157; c=relaxed/simple; bh=P34R1pB8XobSuo2X2BneX9FQBqPF9KFTDzMIUatwRB4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qWTzB/rCWe8ZM3qfUi8VZ2L72d4DoucgIFSNK0JiZ4EOpIGbGg1GngI5hlmrTTTMtj1NUJAbnESpO+lSwd22rF975Ui+eQc2Q0K0JdPxeODGgj8pB4sl6KmwOmj2bnf3KRsPPw8z7CgDv4HVik+dUqbPdeT6AheQ4FPcv7nwt0Q= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=QQRJUbIy; arc=none smtp.client-ip=209.85.210.180 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="QQRJUbIy" Received: by mail-pf1-f180.google.com with SMTP id d2e1a72fcca58-7024d571d8eso489234b3a.0 for ; Fri, 28 Jun 2024 06:09:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1719580155; x=1720184955; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=8fwqZttwC+ZbW8FD7nFrsLap1fPEL7EKx4IYhcmZWAQ=; b=QQRJUbIyWLf+LdxRolTGPmbBXwkWa/Oge0yztewenVuzARcynjlcFC4WO5P2PKPxfK 1Cc8Hux6hvOQxuQLSOgC9iiFatRs1RnoYqlPfEdsWKz0dXjWwy0KhPKYboM7No7SZXzT udzhMTRdF3ucLlHhtZnSPU2iNZbhsvA3gVm+o5jl2OwmiZPHCcY3VD5GS9WPkdt7gXL9 WrFIu5ATrHXxTETL0zLFx0G6pOImF0yDuOZR7MEYcR8AiiDjfpoocEGjVoVQCRg2sWFE sCHD3x6gdpWAYfsHu6wuMBQ/E1e3cVZ1fjmCkU5oRHh6HAll7vZfbXVIRg71bcl/bxXO nKuA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1719580155; x=1720184955; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=8fwqZttwC+ZbW8FD7nFrsLap1fPEL7EKx4IYhcmZWAQ=; b=fiD8b4m7tGst98jjXRaZ6xkhlf6gqRHhuTYBAe8RMK/gglEo327qtr858gZciY+bqb 4VulfaPt5a6dSVPl+9TB873ZHsdUgxnbOVt4rfXw20nDqAO9jU5YwTHkeG062X/4PBoI BZ/ZfbmwbPShmhWLqjSe9tsTTe3uK6iTKkQJHps5kznMPXL9DH2Urjh5VmV5+wJ8xv5c ZvDtODxKX0nhRJ8oymgf5Gt+oVc+Rc88IY+P27recBJsOA4BkbFVQihL/at0TOsP8NBZ wnQE0uWRmlC/esWWMRh4nLedjAEWwxFRkvdNfMDwQk6uVLT4dvwFEQ/rZE+mD+5CXC05 LrHw== X-Forwarded-Encrypted: i=1; AJvYcCXoClhiXT507gSeSPExMh9I214nYm2EeDWQjXLAQwq7UOBFQMNlBwYnJ29F55Wflj7SSwWFBkg26xVmuQCcEXmpxfK3DGBWE8Zhsvi8 X-Gm-Message-State: AOJu0YxLt0hfaWxPuO8ogdi7UiKEV6WjaGO3rDQL3ydTuEN6MH8/OlSz peBdZq9WKihQIGRoIIDPy0VhJbUBrzULUT+8O+coUd5e9HFtgAtPOSiL9fPt X-Google-Smtp-Source: AGHT+IGn9DD50DNkYgejYoYqzKV81yY1R9ssvw1Q4pWXXVQ+kRqODZU3f60f4qTWaKwYCs6Dn2f3Ww== X-Received: by 2002:a05:6a00:3c94:b0:704:23dc:6473 with SMTP id d2e1a72fcca58-7067474dc86mr23147585b3a.30.1719580154982; Fri, 28 Jun 2024 06:09:14 -0700 (PDT) Received: from EBJ9932692.tcent.cn ([124.156.216.125]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-7080498946bsm1526102b3a.200.2024.06.28.06.09.10 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Fri, 28 Jun 2024 06:09:14 -0700 (PDT) From: Lance Yang To: akpm@linux-foundation.org Cc: dj456119@gmail.com, 21cnbao@gmail.com, ryan.roberts@arm.com, david@redhat.com, shy828301@gmail.com, ziy@nvidia.com, libang.li@antgroup.com, baolin.wang@linux.alibaba.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Lance Yang , Mingzhe Yang Subject: [PATCH v2 2/2] mm: add docs for per-order mTHP split counters Date: Fri, 28 Jun 2024 21:07:50 +0800 Message-ID: <20240628130750.73097-3-ioworker0@gmail.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240628130750.73097-1-ioworker0@gmail.com> References: <20240628130750.73097-1-ioworker0@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This commit introduces documentation for mTHP split counters in transhuge.rst. Signed-off-by: Mingzhe Yang Signed-off-by: Lance Yang Reviewed-by: Barry Song --- Documentation/admin-guide/mm/transhuge.rst | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/adm= in-guide/mm/transhuge.rst index 1f72b00af5d3..709fe10b60f4 100644 --- a/Documentation/admin-guide/mm/transhuge.rst +++ b/Documentation/admin-guide/mm/transhuge.rst @@ -514,6 +514,22 @@ file_fallback_charge falls back to using small pages even though the allocation was successful. =20 +split + is incremented every time a huge page is successfully split into + base pages. This can happen for a variety of reasons but a common + reason is that a huge page is old and is being reclaimed. + This action implies splitting any block mappings into PTEs. + +split_failed + is incremented if kernel fails to split huge + page. This can happen if the page was pinned by somebody. + +split_deferred + is incremented when a huge page is put onto split + queue. This happens when a huge page is partially unmapped and + splitting it would free up some memory. Pages on split queue are + going to be split under memory pressure. + As the system ages, allocating huge pages may be expensive as the system uses memory compaction to copy data around memory to free a huge page for use. There are some counters in ``/proc/vmstat`` to help --=20 2.45.2