From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 EA88A17BA5 for ; Thu, 10 Jul 2025 07:58:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752134317; cv=none; b=L7wFYSfzhY77TxpNd73fGewkECorF0X3kkDeFva5wZkeNGj0kwb4qqi8azG3D77PnpIfY2+2nzQkR53ZmsnlMaMPSmwXFiGpDeSRfDaTLkywITEZopNqFcf2/KDe6QH/g57EqztO6xXWSCIBjqLIQO79H1LuZHw2uFbEXnXiwBg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752134317; c=relaxed/simple; bh=T4aOFk2HlYkW9Tx5IukuhkeaDB0XlSLFudFbAn0/wbo=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=EEoaJE/uN/pj39QjMhECSjQs6wcsItN7rE7C9XBSkoT6esRp3dJMa4lDAPUHkN4zyTmPnH9qoxFUid2ycTveKl8tqVIt5n18upYl+advWZI4ztI80YJGlPfSOlc1HZ66RT1r+XKOx6Uw/v4JHFiL0dptDHr8D8vs1EKG2tqByZY= 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=K+pXULBk; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="K+pXULBk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C485AC4CEE3; Thu, 10 Jul 2025 07:58:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1752134316; bh=T4aOFk2HlYkW9Tx5IukuhkeaDB0XlSLFudFbAn0/wbo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=K+pXULBknDJf1alItbIBhTUryAu7HQG7VGCuVqDAVbE4HoFu0NzFPWI1aNoMimhKn dQ29tZ0J3aKYQzF+jJDM8FS3cWEhkCaEBmBAGH5EWM9Ow49ZsulXqkOa+lJtkcmQid sabIN8y6GtYK/2qnTrLH059fbULq7d1qcycX8gFg= Date: Thu, 10 Jul 2025 00:58:35 -0700 From: Andrew Morton To: Ankur Arora Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, david@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, mingo@redhat.com, mjguzik@gmail.com, luto@kernel.org, peterz@infradead.org, acme@kernel.org, namhyung@kernel.org, tglx@linutronix.de, willy@infradead.org, raghavendra.kt@amd.com, boris.ostrovsky@oracle.com, konrad.wilk@oracle.com Subject: Re: [PATCH v5 12/14] mm: add config option for clearing page-extents Message-Id: <20250710005835.8819c30579e37b90d79f4c53@linux-foundation.org> In-Reply-To: <20250710005926.1159009-13-ankur.a.arora@oracle.com> References: <20250710005926.1159009-1-ankur.a.arora@oracle.com> <20250710005926.1159009-13-ankur.a.arora@oracle.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 Wed, 9 Jul 2025 17:59:24 -0700 Ankur Arora wrote: > This is only available with !CONFIG_HIGHMEM because the intent is to > use architecture support to clear contiguous extents in a single > operation (ex. via FEAT_MOPS on arm64, string instructions on x86) > which excludes any possibility of interspersing kmap()/kunmap(). I'm feeling dumb. What does the use of a string instruction have to do with kmap/kunmap?