From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 3F241337BAB; Mon, 31 Aug 2026 23:45:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788219934; cv=none; b=TAxmA7j4JBdlhxiYxnO8nDFi0SZXqyO4DcIBNw8+FgSWckwPMdO4CNIcWojihSVmw1myEZP7PvqsdSFDitGvxqdo80CMuUSvjJn8+OiDsWQJu17hXBOq+ckW1+2Na7kphnZorfhGv8mPECmq1uMWcq97bhp0dZQd3TTaxUeYNIY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788219934; c=relaxed/simple; bh=KFg9Z+cYzf+wgTjB4jP0frPMbh2Dw+RY49DZZp2ECaA=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=bPaJkXa4Evdf7YAKvFNza53irfpJy+KukKbIl6a6gHeJEEaQKXmcuxYVs7fMdhe6JCjo2DLp2sMPKIy2GSN1KRJX/Yzufy/Zfr79nNAeXidH8/gSytACqp7JvWQIiUUWUCrSLyXxfaF7ejakuxcKndUhTrmXf1dNV/tgaUUcD/w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=Vhuqq3dh; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="Vhuqq3dh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3B0781F000E9; Mon, 31 Aug 2026 23:45:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1788219932; bh=wj4I/MKj2L9b4J+c08D7cj7b3uNtuGqLdKw3zvVsGww=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=Vhuqq3dhS0xj/pd9jp9IoVKDsg24dq5X2+kEEIBjB+a3vki3RCwS4uXdfJC4jqTXJ thxERrpgvXlbZtgTioLwixWVxFgiZUzOmhCn0EbPB0XODc4QSl1IVOk2OzQ56ZULUD D/eOxK4ZSBkWfhM21240hACSxmQV00dGRsxfsSsg= Date: Mon, 31 Aug 2026 16:45:31 -0700 From: Andrew Morton To: "Li Zhe" Cc: , , , , , , , , , , , , , , , Subject: Re: [PATCH v11 0/7] mm: optimize zone-device memmap initialization Message-Id: <20260831164531.be5a8fa210401830e85eb974@linux-foundation.org> In-Reply-To: <20260831111638.76012-1-lizhe.67@bytedance.com> References: <20260831111638.76012-1-lizhe.67@bytedance.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) 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-Transfer-Encoding: 7bit On Mon, 31 Aug 2026 19:16:31 +0800 "Li Zhe" wrote: > memmap_init_zone_device() can take a noticeable amount of time when large > pmem namespaces are bound or rebound, because it initializes nearly > identical struct page descriptors one PFN at a time. This series reduces > that ZONE_DEVICE memmap initialization overhead by reusing prepared > struct page templates and, on x86, using memcpy_nontemporal() for the > template copy path. > > ... > > This reduces the average memmap initialization time measured during > rebind by about 48.0% for nd_pmem and 41.6% for dax_pmem on that arm64 > VM setup. Since this arm64 setup does not use the x86 MOVNTI fast paths, > the result also suggests that the generic template-copy optimization can > benefit architectures without an architecture-specific > memcpy_nontemporal() backend. Well that's nice. Sashiko seems to have found some new things to complain about: https://sashiko.dev/#/patchset/20260831111638.76012-1-lizhe.67@bytedance.com