From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.16]) (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 04977184 for ; Fri, 11 Oct 2024 01:30:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.16 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728610256; cv=none; b=dkEaHkExdmFacvavOK1Jbdtq21mfVr5zLT0cJlnqmmJjvWBZoUtDlxNsVzyrWRZisASSyzlKAWotJpdiJEqzFsMr0huFRFs+EUKFw5eN8ZZYPmpOj2IGbORL1wDvGvrmbjxtyHkmoDDunubW6jkx6OSUnIjopt1jdJGG4WumiRg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728610256; c=relaxed/simple; bh=SoFr2Uk73M3n7QVtNXQOtS696p9j0c0ldjUt/ArdYPA=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=kAG1UEaNpEQcitVN5wygIs/8NC+m7SPfr2Ao7Bl/91dXTvtGHyIDJH8QltD/wy0Zv97Nd//cc+R+2ZJ6Pm/lQywwANfy8MopMm7A3SFNd9ahFRgeybm3uOcvZ7dR2SIhbUXILagNl1RqjiqRRpgDIO2rkRqr0/FYWSygnIyNOo0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=kkpi5tUE; arc=none smtp.client-ip=192.198.163.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="kkpi5tUE" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1728610254; x=1760146254; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=SoFr2Uk73M3n7QVtNXQOtS696p9j0c0ldjUt/ArdYPA=; b=kkpi5tUEZeo3avhVQOlsDb0rCGokvOf7mxs5KMgGk15cmdJjOvjs/3dp kLoeImDA4NVX9UCSyvIQw0tN2iM+7zvQOe2kQgsDSZoljgu053i/Q+qU8 rkUhZU4yndNBkPym1N1Wrg6xvU3bj6jWI5wxOEPHDdgbHJwWGw0uDqmGX lmlH/lbPgYQU9hhzIcUAuobzVpt5YlQ2tmiivCvyNGZ4Fo+MU13CJZzjQ IWc0SakZ/kJ67rXfejazRx8LU2FOrb6fw5lQdEn68apfoyZ0lZMoApmHc 5It9L10klQNqIoGIMeD6nSEIi/SZ6T22raSGIFrfRdPJz6yfvI0mrLSIr A==; X-CSE-ConnectionGUID: mRbyGO4rRHK8GwfQjm4aMA== X-CSE-MsgGUID: sykP02wJSf+Mku2Kz58Bkw== X-IronPort-AV: E=McAfee;i="6700,10204,11221"; a="15623328" X-IronPort-AV: E=Sophos;i="6.11,194,1725346800"; d="scan'208";a="15623328" Received: from orviesa005.jf.intel.com ([10.64.159.145]) by fmvoesa110.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Oct 2024 18:30:53 -0700 X-CSE-ConnectionGUID: M4hFXKFrTMOYIZwSaYDmCg== X-CSE-MsgGUID: XhqhavwrQXmcHQTZnBZbRw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.11,194,1725346800"; d="scan'208";a="81564379" Received: from yhuang6-desk2.sh.intel.com (HELO yhuang6-desk2.ccr.corp.intel.com) ([10.238.208.55]) by orviesa005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Oct 2024 18:30:49 -0700 From: "Huang, Ying" To: David Hildenbrand Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "Kirill A . Shutemov" , x86@kernel.org, linux-coco@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Dan Williams , Kai Huang , "H. Peter Anvin" , Andy Lutomirski , Oscar Salvador Subject: Re: [PATCH -V2] tdx, memory hotplug: Check whole hot-adding memory range for TDX In-Reply-To: <037801d9-8923-4d49-8423-072fd7c73069@redhat.com> (David Hildenbrand's message of "Thu, 10 Oct 2024 14:40:47 +0200") References: <20241010074726.1397820-1-ying.huang@intel.com> <037801d9-8923-4d49-8423-072fd7c73069@redhat.com> Date: Fri, 11 Oct 2024 09:27:16 +0800 Message-ID: <87o73ra0p7.fsf@yhuang6-desk2.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) 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=ascii David Hildenbrand writes: >> extern u64 max_mem_size; >> extern int mhp_online_type_from_str(const char *str); >> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c >> index 621ae1015106..c4769f24b1e2 100644 >> --- a/mm/memory_hotplug.c >> +++ b/mm/memory_hotplug.c >> @@ -1305,6 +1305,11 @@ int try_online_node(int nid) >> return ret; >> } >> +int __weak arch_check_hotplug_memory_range(u64 start, u64 size) >> +{ >> + return 0; >> +} > > BTW, I remember that "__weak" doesn't always behave the way it would > seem, which is the reason we're usually using > > #define arch_check_hotplug_memory_range arch_check_hotplug_memory_range > > #ifndef arch_check_hotplug_memory_range > ... > #endif > > > Not that I remember the details, just that it can result in rather > surprising outcomes (e.g., the wrong function getting called). I can replace __weak with #define/#ifndef. However, it appears that "__weak" is still widely used now. $ grep __weak -r mm kernel init | wc -l 231 -- Best Regards, Huang, Ying