From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Hubbard Subject: Re: [Nouveau] [PATCH 22/22] mm: don't select MIGRATE_VMA_HELPER from HMM_MIRROR Date: Thu, 13 Jun 2019 18:53:15 -0700 Message-ID: <7f6c6837-93cd-3b89-63fb-7a60d906c70c@nvidia.com> References: <20190613094326.24093-1-hch@lst.de> <20190613094326.24093-23-hch@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190613094326.24093-23-hch@lst.de> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Christoph Hellwig , Dan Williams , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Jason Gunthorpe , Ben Skeggs Cc: linux-nvdimm@lists.01.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-mm@kvack.org, nouveau@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org On 6/13/19 2:43 AM, Christoph Hellwig wrote: > The migrate_vma helper is only used by noveau to migrate device private > pages around. Other HMM_MIRROR users like amdgpu or infiniband don't > need it. > > Signed-off-by: Christoph Hellwig > --- > drivers/gpu/drm/nouveau/Kconfig | 1 + > mm/Kconfig | 1 - > 2 files changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/nouveau/Kconfig b/drivers/gpu/drm/nouveau/Kconfig > index 66c839d8e9d1..96b9814e6d06 100644 > --- a/drivers/gpu/drm/nouveau/Kconfig > +++ b/drivers/gpu/drm/nouveau/Kconfig > @@ -88,6 +88,7 @@ config DRM_NOUVEAU_SVM > depends on DRM_NOUVEAU > depends on HMM_MIRROR > depends on STAGING > + select MIGRATE_VMA_HELPER > default n > help > Say Y here if you want to enable experimental support for > diff --git a/mm/Kconfig b/mm/Kconfig > index 73676cb4693f..eca88679b624 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -679,7 +679,6 @@ config HMM_MIRROR > bool "HMM mirror CPU page table into a device page table" > depends on MMU > select MMU_NOTIFIER > - select MIGRATE_VMA_HELPER > help > Select HMM_MIRROR if you want to mirror range of the CPU page table of a > process into a device page table. Here, mirror means "keep synchronized". > For those who have out of tree drivers that need migrate_vma(), but are not Nouveau, could we pretty please allow a way to select that independently? It's not a big deal, as I expect the Nouveau option will normally be selected, but it would be nice. Because there is a valid configuration that involves Nouveau not being selected, but our driver still wanting to run. Maybe we can add something like this on top of what you have? diff --git a/mm/Kconfig b/mm/Kconfig index eca88679b624..330996632513 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -670,7 +670,10 @@ config ZONE_DEVICE If FS_DAX is enabled, then say Y. config MIGRATE_VMA_HELPER - bool + bool "migrate_vma() helper routine" + help + Provides a migrate_vma() routine that GPUs and other + device drivers may need. config DEV_PAGEMAP_OPS bool thanks, -- John Hubbard NVIDIA