From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f52.google.com (mail-ej1-f52.google.com [209.85.218.52]) (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 9917F3A1D2 for ; Sun, 23 Nov 2025 01:53:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.52 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763862802; cv=none; b=rn9MEloGaeOSjswgNT94P2rQNx2tyo53X8XEQB+pqKvCzCkHLgbf8lGMcRN8hRiBMuP8dSvtNoHctOZjZd56ihJyNekovhdZdl8zlR213wtuDkCm+Gow2hF6l/mMfUP6NQ0UMD6sadyJCtGcFuX5q3jUPy3QCB+ecGH8EgyUhUc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763862802; c=relaxed/simple; bh=p41RqmWldXOFnUychMw3jcrFoW7eIjCrQzrY6Hzkuvo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=SFL09dFwZ+GFZxFDSXdzOLREUHqs6Wkwhh8nAivcqKKVlcOfaz1O38srUFgCAgdKJlCSdilg8eMnWgwgXWxhy8WBTRFELHXCG5Z8Od/OyFdH1x0kKyxSc7gSicb83YRffLpNhJnKFLkVbpPjd5UlMp6/tN/4Glqu4QLwiiQmxfA= 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=j+BIX/Qu; arc=none smtp.client-ip=209.85.218.52 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="j+BIX/Qu" Received: by mail-ej1-f52.google.com with SMTP id a640c23a62f3a-b75c7cb722aso471378166b.1 for ; Sat, 22 Nov 2025 17:53:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1763862799; x=1764467599; darn=vger.kernel.org; h=user-agent:in-reply-to:content-disposition:mime-version:references :reply-to:message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=61f1zN5+IdmGzSxmoozO60LTdckIHSp2dJdbkwe3278=; b=j+BIX/QuRcdSvlLWUaUSdlR+YfEYBq4A142YkQQn4gNlVk8OGVgA+SsSwAq0csDi1S ZLULWEsvd0cehbggXmSGn0o6u5wcP6Qi8qvgZjUPSjRmtrZFOPuwjLS6XqAP77m+rImg +qND/yS3in8QvjRehoKQp5A9r4O6xX5qQEkvO6D8Wrbkot5MvNutLZoXs2NSf6ty+0zD EjprPld3Z9ndiQs7Onhg2/0TzdiwUIWzNP54gOi9uDCSO5fjZSX4j4P22YfWktDCwK+E AKMBp6eEtdAcjcpOJLWl8VFz2VPP/oEqcV7OUwPdeizwj7BjQIi+d5h2j7pHuebgP2Y6 nelw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763862799; x=1764467599; h=user-agent:in-reply-to:content-disposition:mime-version:references :reply-to:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=61f1zN5+IdmGzSxmoozO60LTdckIHSp2dJdbkwe3278=; b=A8z24rCbnGGXDpNb4BxJBI5QzmzWLE5umDG7IVZDwPEP3HjB2muQ1NgCZyDKVBiIly rFI50X5A3rC0NFaCUXuyLls9gEipAO3eOr9LUnem5wrrEWvY5uN4pouEexUCtzs2Fq0i OmTlOzGMa4ZXrH1RfPuOEVQqcIRB1pS8iAS2Qi/QnoRXo5OeFxWlCBLLoAYpFiiUksr0 k5Pk3XSG3ExvzFd+GUC1QdEEakLoD4oRZr6u3OglE+hf6k3HQhniw+tW5Od3bPdHsb7W rxYUH/m6izh7nGF7Y5dcxx/ZRd7OVbLNLEMx8N+mHmdeZsRm0bl1zLTmle+n9CcbdgxK ygfg== X-Forwarded-Encrypted: i=1; AJvYcCUFzjwttvxZWLzkZblFwNpy8qoh5wCH8p73SFmb8N+XzhKJM6pYs0McOfqhoq2VWVDGGq10EFLvPy3xYDg=@vger.kernel.org X-Gm-Message-State: AOJu0YxtTFKErpp5r/x5UswJj5zgDCbvz0vmUDmeqTdPN1vbQRmkq8TA 4g/9xesJL1DXBeiu96HrDLmG7LsnCgHew9CsuR+zxb1cPmu6apcNaUzc X-Gm-Gg: ASbGncuknutFC2mg4eQr3Xnv1slOIhoIuOYl6bIoiA7bwuQEa5piVrBafrdZp4jfDhL O36n/plx1AW0UsjvcEaaVq9Ey9mPStItJ+0380ikUQ+JK5etMVw6MORBkws1gM+K2WuEM0VtOTL SVfvsldvz7CwJITSm0hWaTd3wfk9UaHtvEPHE/RaJ9tBdPNUxxB2vfQC5FYDYNellI0e+/F/UQM jPmxl0kFK8w3KBm8XVqfXch/ZMvytjNtsS0iI+s+8rfjJ7kMu743/SLXFLOkRLFtwr5U6fjkyhg 6KhT7d/p9tROQVyw7uIn2Gr9CgU+1G6ziXCvwylpfYk+ONZD6HaiGPk4seEctEynvmQOqx5c2Kj fwAyFGowF4CkfjBuQoUlTjtEjJyC2hLKenItY3AsKi4KVnw83HH23S32XJUHN1y9huHWhzuXYOh l2y6J5s+WPeP8YWQ== X-Google-Smtp-Source: AGHT+IGgteEPtCFCVDHZnVsW65MCuOfGB9JQX9QyVGHeZGsz1UpMiB2lrj254YidAvxOylkmpxiJ1w== X-Received: by 2002:a17:907:7287:b0:b73:8cea:62bb with SMTP id a640c23a62f3a-b767170cceamr817025266b.31.1763862798912; Sat, 22 Nov 2025 17:53:18 -0800 (PST) Received: from localhost ([185.92.221.13]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b7654cdd659sm881230066b.7.2025.11.22.17.53.17 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Sat, 22 Nov 2025 17:53:18 -0800 (PST) Date: Sun, 23 Nov 2025 01:53:17 +0000 From: Wei Yang To: Zi Yan Cc: David Hildenbrand , Lorenzo Stoakes , Andrew Morton , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Miaohe Lin , Naoya Horiguchi , Wei Yang , Balbir Singh , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 3/4] mm/huge_memory: make min_order_for_split() always return an order Message-ID: <20251123015317.3pommq5h54xnau7e@master> Reply-To: Wei Yang References: <20251122025529.1562592-1-ziy@nvidia.com> <20251122025529.1562592-4-ziy@nvidia.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: <20251122025529.1562592-4-ziy@nvidia.com> User-Agent: NeoMutt/20170113 (1.7.2) On Fri, Nov 21, 2025 at 09:55:28PM -0500, Zi Yan wrote: >min_order_for_split() returns -EBUSY when the folio is truncated and cannot >be split. In commit 77008e1b2ef7 ("mm/huge_memory: do not change >split_huge_page*() target order silently"), memory_failure() does not >handle it and pass -EBUSY to try_to_split_thp_page() directly. >try_to_split_thp_page() returns -EINVAL since -EBUSY becomes 0xfffffff0 as >new_order is unsigned int in __folio_split() and this large new_order is >rejected as an invalid input. The code does not cause a bug. >soft_offline_in_use_page() also uses min_order_for_split() but it always >passes 0 as new_order for split. > >Fix it by making min_order_for_split() always return an order. When the >given folio is truncated, namely folio->mapping == NULL, return 0 and let >a subsequent split function handle the situation and return -EBUSY. > >Add kernel-doc to min_order_for_split() to clarify its use. > >Signed-off-by: Zi Yan LGTM, Thanks Reviewed-by: Wei Yang -- Wei Yang Help you, Help me