From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760612AbaKAUZ7 (ORCPT ); Sat, 1 Nov 2014 16:25:59 -0400 Received: from gate.crashing.org ([63.228.1.57]:38170 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758469AbaKAUZ6 (ORCPT ); Sat, 1 Nov 2014 16:25:58 -0400 Message-ID: <1414873502.28356.80.camel@pasglop> Subject: Re: [RFC PATCH 1/2] zap_pte_range: update addr when forcing flush after TLB batching faiure From: Benjamin Herrenschmidt To: Linus Torvalds Cc: Will Deacon , Peter Zijlstra , Linux Kernel Mailing List , Russell King - ARM Linux Date: Sun, 02 Nov 2014 07:25:02 +1100 In-Reply-To: References: <1414496662-25202-1-git-send-email-will.deacon@arm.com> <1414496662-25202-2-git-send-email-will.deacon@arm.com> <20141029194738.GA29911@arm.com> <1414618065.4257.21.camel@pasglop> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.12.2 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2014-11-01 at 10:01 -0700, Linus Torvalds wrote: > On Wed, Oct 29, 2014 at 2:27 PM, Benjamin Herrenschmidt > wrote: > > > > TLB flushing is only me I think, I'll engage my brain after breakfast > > and see if is all good > > Ping? Breakfast is either long over, of you're starting to look a bit > like Mr Creosote... Argh... dropped that ball. > Anyway, Will, I assume this is not a correctness issue for you, just > an annoying performance issue. Right? Or is there actually some issue > with the actual range not being set to be sufficiently large? It should be fine for us in term of correctness I think. We rely on the lazy mmu bits for batching/flushing on hash64, we use __tlb_remove_tlb_entry() for immediate flush on hash32 and the SW loaded TLB cases are pretty dumb here and should be generally unaffected. > Also, it strikes me that I *think* that you might be able to extend > your patch to remove the whole "need_flush" field, since as far as I > can tell, "tlb->need_flush" is now equivalent to "tlb->start < > tlb->end". Of course, as long as we still require that > "need_flush_all", that doesn't actually save us any space, so maybe > it's not worth changing. Cheers, Ben. > Linus > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/