From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id A40272C00CF for ; Fri, 3 May 2013 23:01:46 +1000 (EST) Message-ID: <1367586018.4389.67.camel@pasglop> Subject: Re: [PATCH -V7 02/10] powerpc/THP: Implement transparent hugepages for ppc64 From: Benjamin Herrenschmidt To: David Gibson Date: Fri, 03 May 2013 23:00:18 +1000 In-Reply-To: <20130503115428.GW13041@truffula.fritz.box> References: <1367178711-8232-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <1367178711-8232-3-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <20130503045201.GO13041@truffula.fritz.box> <1367569143.4389.56.camel@pasglop> <20130503115428.GW13041@truffula.fritz.box> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, "Aneesh Kumar K.V" , paulus@samba.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, 2013-05-03 at 21:54 +1000, David Gibson wrote: > > _PAGE_BUSY is more like a read lock. It means it's being hashed, so what > > is not stable is _PAGE_HASHPTE, slot index, _ACCESSED and _DIRTY. The > > rest is stable and usually is what pmd_same looks at (though I have a > > small doubt vs. _ACCESSED and _DIRTY but at least x86 doesn't care since > > they are updated by HW). > > Ok. It still seems very odd to me that _PAGE_BUSY would be in the THP > version of _PAGE_HASHPTE, but not the normal one. Oh I agree, we should be consistent and it shouldn't be there, I was just correcting some other aspect of your statement :-) Cheers, Ben.