From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id A8D2D8D0039 for ; Tue, 8 Mar 2011 05:27:21 -0500 (EST) From: "Guan Xuetao" References: <20110302175004.222724818@chello.nl> <20110302175200.883953013@chello.nl> <03ca01cbda63$31930fd0$94b92f70$@mprc.pku.edu.cn> <1299241020.2428.13504.camel@twins> In-Reply-To: <1299241020.2428.13504.camel@twins> Subject: RE: [PATCH 09/13] unicore: mmu_gather rework Date: Tue, 8 Mar 2011 18:25:57 +0800 Message-ID: <010601cbdd7b$3e388b00$baa9a100$@mprc.pku.edu.cn> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: zh-cn Sender: owner-linux-mm@kvack.org List-ID: To: 'Peter Zijlstra' Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, 'Benjamin Herrenschmidt' , 'David Miller' , 'Hugh Dickins' , 'Mel Gorman' , 'Nick Piggin' , 'Paul McKenney' , 'Yanmin Zhang' , 'Andrea Arcangeli' , 'Avi Kivity' , 'Thomas Gleixner' , 'Rik van Riel' , 'Ingo Molnar' , akpm@linux-foundation.org, 'Linus Torvalds' , 'Arnd Bergmann' > -----Original Message----- > From: Peter Zijlstra [mailto:a.p.zijlstra@chello.nl] > Sent: Friday, March 04, 2011 8:17 PM > To: Guan Xuetao > Cc: linux-kernel@vger.kernel.org; linux-arch@vger.kernel.org; = linux-mm@kvack.org; 'Benjamin Herrenschmidt'; 'David Miller'; 'Hugh > Dickins'; 'Mel Gorman'; 'Nick Piggin'; 'Paul McKenney'; 'Yanmin = Zhang'; 'Andrea Arcangeli'; 'Avi Kivity'; 'Thomas Gleixner'; 'Rik van = Riel'; > 'Ingo Molnar'; akpm@linux-foundation.org; 'Linus Torvalds'; Arnd = Bergmann > Subject: RE: [PATCH 09/13] unicore: mmu_gather rework >=20 > On Fri, 2011-03-04 at 19:56 +0800, Guan Xuetao wrote: >=20 > > Thanks Peter. > > It looks good to me, though it is dependent on your patch set "mm: = Preemptible mmu_gather" >=20 > It is indeed, the split-out per arch is purely to ease review. The = final > commit should be a merge of the first 10 patches so as not to break > bisection. >=20 > > While I have another look to include/asm-generic/tlb.h, I found it = is also suitable for unicore32. > > And so, I rewrite the tlb.h to use asm-generic version, and then = your patch set will also work for me. >=20 > Awesome, I notice you're loosing flush_tlb_range() support for this, = if > you're fine with that I'm obviously not going to argue, but if its > better for your platform to keep doing this we can work on that as = well > as I'm trying to add generic support for range tracking into the = generic > tlb code. Yes, I think flush_tlb_range() have no effect in unicore32 architecture. Or perhaps, it is because no optimization, just as you point it below. >=20 > More importantly, you seem to loose your call to flush_cache_range() > which isn't a NOP on your platform. IMO, flush_cache_range() is only used in self-modified codes when = cachetype is vipt. So, it could be neglected here. Perhaps it's wrong. =20 >=20 > Furthermore, while arch/unicore32/mm/tlb-ucv2.S is mostly magic to me, = I > see unicore32 is one of the few architectures that actually uses > vm_flags in flush_tlb_range(). Do you have independent I/D-TLB flushes > or are you flushing I-cache on VM_EXEC? We have both independent and global I/D TLB flushes. And flushing I-cache on VM_EXEC is also needed in self-modified codes, = IMO. >=20 > Also, I notice your flush_tlb_range() implementation looks to be a = loop > invalidating individual pages, which I can imagine is cheaper for = small > ranges but large ranges might be better of with a full invalidate. Did > you think about this? >=20 Yes, it should be optimized. However, I doubt its effect in unicore32 which has no asid support. Thanks & Regards. Guan Xuetao -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org