From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933144Ab0JRTlY (ORCPT ); Mon, 18 Oct 2010 15:41:24 -0400 Received: from mail-qy0-f181.google.com ([209.85.216.181]:46590 "EHLO mail-qy0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932134Ab0JRTlX (ORCPT ); Mon, 18 Oct 2010 15:41:23 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=Q9OcaT/DwPbc3Rb5oMhPpW0m6vaCQgaeacBDb11ZJEb3mQ2GYGQRidFWHX8DikHSDz 40FNF3TUm4HuIvHcMV9pr7lTsUpjt6Q/P1GkCnodqnRJSLVLnYEYHdOCL5VyEYGB2k2A t8HOs/rk2Y9eOXzo61VutKCarQI6FoKUh6mS4= MIME-Version: 1.0 In-Reply-To: <20101018191936.GH27377@linux-mips.org> References: <17ebecce124618ddf83ec6fe8e526f93@localhost> <17d8d27a2356640a4359f1a7dcbb3b42@localhost> <4CBC4F4E.5010305@pobox.com> <20101018191936.GH27377@linux-mips.org> Date: Mon, 18 Oct 2010 12:41:20 -0700 Message-ID: Subject: Re: [PATCH resend 5/9] MIPS: sync after cacheflush From: Kevin Cernekee To: Ralf Baechle Cc: Shinya Kuribayashi , linux-mips@linux-mips.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 18, 2010 at 12:19 PM, Ralf Baechle wrote: > I'm trying to get a statement from the MIPS architecture guys if the > necessity to do anything beyond a cache flush is an architecture violation. IMO such a requirement would be unnecessarily strict. Larger flushes (e.g. page at a time) tend to benefit from some form of pipelining or write gathering. Forcing the processor to flush exactly 32 bytes at a time, synchronously, could really slow things down and thrash the memory controller. I have not been able to find any official statement from MIPS that says that CACHE + SYNC should be used, but that seems like the most intuitive way to implement things on the hardware side.