From mboxrd@z Thu Jan 1 00:00:00 1970 From: Randy Dunlap Subject: Re: + kmap_types-make-most-arches-use-generic-header-file.patch added to -mm tree Date: Thu, 28 May 2009 15:54:06 -0700 Message-ID: <4A1F160E.8060209@oracle.com> References: <200905282131.n4SLV7rj025720@imap1.linux-foundation.org> <200905282211.58997.arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from acsinet11.oracle.com ([141.146.126.233]:17771 "EHLO acsinet11.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751514AbZE1W4a (ORCPT ); Thu, 28 May 2009 18:56:30 -0400 In-Reply-To: <200905282211.58997.arnd@arndb.de> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Arnd Bergmann Cc: akpm@linux-foundation.org, mm-commits@vger.kernel.org, cooloney@kernel.org, davem@davemloft.net, dhowells@redhat.com, geert@linux-m68k.org, hpa@zytor.com, ink@jurassic.park.msu.ru, kyle@mcmartin.ca, lethal@linux-sh.org, linux-arch@vger.kernel.org, mingo@elte.hu, ralf@linux-mips.org, rth@twiddle.net, schwidefsky@de.ibm.com, starvik@axis.com, takata@linux-m32r.org, tglx@linutronix.de, tony.luck@intel.com, vapier@gentoo.org Arnd Bergmann wrote: > On Thursday 28 May 2009 21:31:06 akpm@linux-foundation.org wrote: >> The patch titled >> kmap_types: make most arches use generic header file >> has been added to the -mm tree. Its filename is >> kmap_types-make-most-arches-use-generic-header-file.patch > > Thanks for adding it back. > >> Move the KM_FENCE_ macro additions into asm-generic/kmap_types.h, >> controlled by __WITH_KM_FENCE from each arch's kmap_types.h file. > > I completely missed this part of the patch before. Is this actually useful? > All architectures that define it (x86 with a twist, the check for X86_32 is > an artifact from the x86 arch merge) do > > #ifdef CONFIG_DEBUG_HIGHMEM > #define __WITH_KM_FENCE > #endif > > However: alpha, ia64, m32r, parisc and sh don't even support CONFIG_HIGHMEM > and therefore also can't set CONFIG_DEBUG_HIGHMEM. Conversely, mn10300 and > sparc can set CONFIG_DEBUG_HIGHMEM but don't get the extra checking > from KM_FENCE without this. > > It seems to me that it would be at least as correct but simpler to just > leave the check for CONFIG_DEBUG_HIGHMEM. Yes, I noticed that's how it was in your patch. >> Would be nice to be able to add custom KM_types per arch, but I don't yet >> see a nice, clean way to do that. > > FWIW, the only types that are not in the generic file right now are > > arm: KM_L2_CACHE > powerpc: KM_PPC_SYNC_ICACHE, KM_PPC_SYNC_PAGE > um: KM_UML_USERCOPY > > We could easily add these as KM_SYNC_ICACHE, KM_SYNC_DCACHE and > KM_UML_USERCOPY in the generic file and get rid of all architecture > specific types here. OK by me. I'll update it... Thanks for looking. -- ~Randy LPC 2009, Sept. 23-25, Portland, Oregon http://linuxplumbersconf.org/2009/