From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-182.mta1.migadu.com (out-182.mta1.migadu.com [95.215.58.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6AB792F616D for ; Tue, 14 Oct 2025 14:38:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760452699; cv=none; b=BQQP0h4Tk9HSgGt2DBsNSFUs8qGVjfU94zf5+K1Z0EEKRbyUZxHlz0dTMFmDwXyFjh5QUOOveQpblfuzwJVVBrXXO9bf37FLeKIBMbl5kn9VrHIEJ3JCHElJqgiOH3r3J4qomIkcrBD/2XBfPXmlitJmHXWNKYf3xylPtx/WUVY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760452699; c=relaxed/simple; bh=+Qfmzv4rdao135C/vjU0DMOsvnXXdVztZfhdDGXV1SQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=iVr+/1wRkWLzaVJ5LJmSEKKua7zBkPV2IhZgUXzQgajVPTQnDKTP9ejLH5Wbk96xdZq+uC1WsAftEf4fkxQEuLug+xW5f8YHsF9XwPc5bt0IbqCKKFXeqBkW7cVNm/4KJtWDnw+PWn158sNkbK6RjEEEsVGS94Z42Kt54jhiAI8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=G7KAczSk; arc=none smtp.client-ip=95.215.58.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="G7KAczSk" Message-ID: <2e22cff1-fad7-45a6-bdd4-d5921d12c5e2@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1760452693; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ph45ShvU5LxibAKmRwrd9NsEUxkKQysF0rWNW9JCj9E=; b=G7KAczSkogU8fLCXmjILNi+xkzGOvqobi5PzscfO4BTFXWU/rDzEBllPdzGmDpzXsyEFX9 Qlky5S9AdHOpkGfRZpQtuXjHWNCe4jYCqtZFYbrzEzbwbJiD7kct25j/TjTKMsKQwZ1ALy rgMcbkTVubIVoWzJjOAMjHNusy6wM64= Date: Tue, 14 Oct 2025 22:37:28 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH mm-new v3 1/1] mm/khugepaged: abort collapse scan on non-swap entries Content-Language: en-US To: Lorenzo Stoakes , David Hildenbrand Cc: akpm@linux-foundation.org, Liam.Howlett@oracle.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, dev.jain@arm.com, hughd@google.com, ioworker0@gmail.com, kirill@shutemov.name, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mpenttil@redhat.com, npache@redhat.com, ryan.roberts@arm.com, ziy@nvidia.com, richard.weiyang@gmail.com References: <20251008032657.72406-1-lance.yang@linux.dev> <0bfdbccd-9d4a-409f-ae43-b44bb7347d70@linux.dev> <6f448506-677f-4e0c-aa9c-d5da061e57ee@redhat.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Lance Yang In-Reply-To: <6f448506-677f-4e0c-aa9c-d5da061e57ee@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On 2025/10/14 22:32, David Hildenbrand wrote: > >> static inline int pte_protnone(pte_t pte) >> { >>     return (pte_flags(pte) & (_PAGE_PROTNONE | _PAGE_PRESENT)) >>         == _PAGE_PROTNONE; >> } >> >> static inline int pte_present(pte_t a) >> { >>     return pte_flags(a) & (_PAGE_PRESENT | _PAGE_PROTNONE); >> } >> ``` >> >> On x86, pte_present() returns true for a protnone pte. And I'd assume >> other archs behave similarly ... > > Applies to all architecture. prot-none entries must be present, > otherwise we'd have a lot of other issues :) Thanks for confirming, David! That's good to know ;p So @Lorenzo, looks like we're good here on the protnone front. Does that clear up your concern?