From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id 35D846B01F1 for ; Thu, 19 Aug 2010 17:32:06 -0400 (EDT) Date: Thu, 19 Aug 2010 14:31:29 -0700 From: Andrew Morton Subject: Re: [RFC][PATCH 0/6] mm, highmem: kmap_atomic rework Message-Id: <20100819143129.81274c03.akpm@linux-foundation.org> In-Reply-To: <20100819201317.673172547@chello.nl> References: <20100819201317.673172547@chello.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Peter Zijlstra Cc: Linus Torvalds , Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , Russell King , David Howells , Ralf Baechle , David Miller , Paul Mackerras , Benjamin Herrenschmidt , Hugh Dickins , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org List-ID: On Thu, 19 Aug 2010 22:13:17 +0200 Peter Zijlstra wrote: > > This patch-set reworks the kmap_atomic API to be a stack based, instead of > static slot based. Some might remember this from last year, some not ;-) > > The advantage is that you no longer need to worry about KM_foo, the > disadvantage is that kmap_atomic/kunmap_atomic now needs to be strictly > nested (CONFIG_HIGHMEM_DEBUG should complain in case its not) -- and of > course its a big massive patch changing a widely used API. Nice. That fixes the "use of irq-only slots from interrupts-on context" bugs which people keep adding. We don't have any checks in there for the stack overflowing? Did you add every runtime check you could possibly think of? kmap_atomic_idx_push() and pop() don't have much in there. It'd be good to lard it up with runtime checks for at least a few weeks. > The patch-set is currently based on tip/master as of today, and compile > tested on: i386-all{mod,yes}config, mips-yosemite_defconfig, > sparc-sparc32_defconfig, powerpc-ppc6xx_defconfig, and some arm config. > > (Sorry dhowells, I again couldn't find frv/mn10300 compilers) > > Boot tested with i386-defconfig on kvm. > > Since its a rather large set, and somewhat tedious to rebase, I wanted to > ask how to go about getting this merged? Well, there's that monster conversion patch. How's about you temporarily do #define kmap_atomic(x, arg...) __kmap_atomic(x) so for a while, both kmap_atomic(a, KM_foo) and kmap_atomic(a) are turned into __kmap_atomic(a). Once all the dust has settled, pull that out again? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org