From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f199.google.com (mail-qk0-f199.google.com [209.85.220.199]) by kanga.kvack.org (Postfix) with ESMTP id 8789D6B000C for ; Mon, 23 Jul 2018 12:23:14 -0400 (EDT) Received: by mail-qk0-f199.google.com with SMTP id w126-v6so878519qka.11 for ; Mon, 23 Jul 2018 09:23:14 -0700 (PDT) Received: from mx1.redhat.com (mx3-rdu2.redhat.com. [66.187.233.73]) by mx.google.com with ESMTPS id s64-v6si8076569qkh.187.2018.07.23.09.23.13 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 23 Jul 2018 09:23:13 -0700 (PDT) Date: Mon, 23 Jul 2018 12:23:08 -0400 From: Jerome Glisse Subject: Re: [PATCH v6 06/13] mm, dev_pagemap: Do not clear ->mapping on final put Message-ID: <20180723162308.GA4704@redhat.com> References: <153154376846.34503.15480221419473501643.stgit@dwillia2-desk3.amr.corp.intel.com> <153154380137.34503.3754023882460956800.stgit@dwillia2-desk3.amr.corp.intel.com> <3fcb3c8a-2a41-7c78-edde-066c10110d34@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <3fcb3c8a-2a41-7c78-edde-066c10110d34@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Dave Jiang Cc: Dan Williams , linux-nvdimm@lists.01.org, Jan Kara , linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Andrew Morton , hch@lst.de On Mon, Jul 23, 2018 at 09:12:06AM -0700, Dave Jiang wrote: > Jerome, > Is it possible to get an ack for this? Thanks! > > On 07/13/2018 09:50 PM, Dan Williams wrote: > > MEMORY_DEVICE_FS_DAX relies on typical page semantics whereby ->mapping > > is only ever cleared by truncation, not final put. > > > > Without this fix dax pages may forget their mapping association at the > > end of every page pin event. > > > > Move this atypical behavior that HMM wants into the HMM ->page_free() > > callback. > > > > Cc: > > Cc: Jan Kara > > Cc: Andrew Morton > > Cc: Ross Zwisler > > Fixes: d2c997c0f145 ("fs, dax: use page->mapping...") > > Signed-off-by: Dan Williams Acked-by: Jerome Glisse > > --- > > kernel/memremap.c | 1 - > > mm/hmm.c | 2 ++ > > 2 files changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/kernel/memremap.c b/kernel/memremap.c > > index 5857267a4af5..62603634a1d2 100644 > > --- a/kernel/memremap.c > > +++ b/kernel/memremap.c > > @@ -339,7 +339,6 @@ void __put_devmap_managed_page(struct page *page) > > __ClearPageActive(page); > > __ClearPageWaiters(page); > > > > - page->mapping = NULL; > > mem_cgroup_uncharge(page); > > > > page->pgmap->page_free(page, page->pgmap->data); > > diff --git a/mm/hmm.c b/mm/hmm.c > > index de7b6bf77201..f9d1d89dec4d 100644 > > --- a/mm/hmm.c > > +++ b/mm/hmm.c > > @@ -963,6 +963,8 @@ static void hmm_devmem_free(struct page *page, void *data) > > { > > struct hmm_devmem *devmem = data; > > > > + page->mapping = NULL; > > + > > devmem->ops->free(devmem, page); > > } > > > > > > _______________________________________________ > > Linux-nvdimm mailing list > > Linux-nvdimm@lists.01.org > > https://lists.01.org/mailman/listinfo/linux-nvdimm > >