From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by oss.sgi.com id ; Tue, 9 Jan 2001 17:59:18 -0800 Received: from pobox.sibyte.com ([208.12.96.20]:33809 "HELO pobox.sibyte.com") by oss.sgi.com with SMTP id ; Tue, 9 Jan 2001 17:58:58 -0800 Received: from postal.sibyte.com (moat.sibyte.com [208.12.96.21]) by pobox.sibyte.com (Postfix) with SMTP id CEAAB205FC for ; Tue, 9 Jan 2001 17:58:52 -0800 (PST) Received: from SMTP agent by mail gateway Tue, 09 Jan 2001 17:53:31 -0800 Received: from plugh.sibyte.com (plugh.sibyte.com [10.21.64.158]) by postal.sibyte.com (Postfix) with ESMTP id 1ABC415961 for ; Tue, 9 Jan 2001 17:58:53 -0800 (PST) Received: by plugh.sibyte.com (Postfix, from userid 61017) id 5A970686D; Tue, 9 Jan 2001 17:59:01 -0800 (PST) From: Justin Carlson Reply-To: carlson@sibyte.com Organization: Sibyte To: linux-mips@oss.sgi.com Subject: _clear_page semantics Date: Tue, 9 Jan 2001 17:48:11 -0800 X-Mailer: KMail [version 1.0.29] Content-Type: text/plain MIME-Version: 1.0 Message-Id: <01010917590106.07691@plugh.sibyte.com> Content-Transfer-Encoding: 8bit Sender: owner-linux-mips@oss.sgi.com Precedence: bulk Return-Path: X-Orcpt: rfc822;linux-mips-outgoing Looking at the existing clear_page implementations for r4xx0, rm7k, and mips32 in the mips/ tree, I see everyone issuing cache op 0xd for the address range of the page being cleared. I'm wondering what the purpose is of these cache flushes...given a physically tagged dcache, my understanding of the semantics of clear_page are that it just zeros the page, in which case the cache ops are pointless overhead. Especially in the mips32 case, which uses cache op 0xd, which is undefined implementation dependent according to my mips32 spec. Am I missing something here? Thanks, Justin