From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: + kmap_types-make-most-arches-use-generic-header-file.patch added to -mm tree Date: Thu, 28 May 2009 22:11:56 +0000 Message-ID: <200905282211.58997.arnd@arndb.de> References: <200905282131.n4SLV7rj025720@imap1.linux-foundation.org> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Return-path: Received: from moutng.kundenserver.de ([212.227.126.187]:54753 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750811AbZE1WQd (ORCPT ); Thu, 28 May 2009 18:16:33 -0400 In-Reply-To: <200905282131.n4SLV7rj025720@imap1.linux-foundation.org> Content-Disposition: inline Sender: linux-arch-owner@vger.kernel.org List-ID: To: akpm@linux-foundation.org Cc: mm-commits@vger.kernel.org, randy.dunlap@oracle.com, 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 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. > 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. Arnd <><