From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-x230.google.com (mail-pf0-x230.google.com [IPv6:2607:f8b0:400e:c00::230]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3ryQCY1Bf9zDqVg for ; Mon, 25 Jul 2016 12:28:09 +1000 (AEST) Received: by mail-pf0-x230.google.com with SMTP id y134so58769033pfg.0 for ; Sun, 24 Jul 2016 19:28:09 -0700 (PDT) Date: Mon, 25 Jul 2016 12:28:01 +1000 From: Nicholas Piggin To: Benjamin Herrenschmidt Cc: Balbir Singh , linuxppc-dev@lists.ozlabs.org, Anton Blanchard Subject: Re: [PATCH] powerpc/64: implement a slice mask cache Message-ID: <20160725122801.578622d6@roar.ozlabs.ibm.com> In-Reply-To: <1469263746.8568.185.camel@kernel.crashing.org> References: <1469192248-25141-1-git-send-email-npiggin@gmail.com> <20160723021937.GA13796@350D> <20160723171036.67144c5d@roar.ozlabs.ibm.com> <1469263746.8568.185.camel@kernel.crashing.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sat, 23 Jul 2016 18:49:06 +1000 Benjamin Herrenschmidt wrote: > On Sat, 2016-07-23 at 17:10 +1000, Nicholas Piggin wrote: > > I wanted to avoid doing more work under slice_convert_lock, but > > we should just make that a per-mm lock anyway shouldn't we? > > Aren't the readers under the mm sem taken for writing or has this > changed ? I don't think this has changed, but I look at the writers now, which aren't synchronized by mm sem. But neither are readers under the slice_convert_lock, so I'm looking at what the locking actually is. Is it just using atomicity of dword stores vs loads? Thanks, Nick