From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 86C36C0650F for ; Thu, 8 Aug 2019 21:29:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4EE0C216C8 for ; Thu, 8 Aug 2019 21:29:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="MJZge7m/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390409AbfHHV3k (ORCPT ); Thu, 8 Aug 2019 17:29:40 -0400 Received: from hqemgate15.nvidia.com ([216.228.121.64]:6286 "EHLO hqemgate15.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729780AbfHHV3j (ORCPT ); Thu, 8 Aug 2019 17:29:39 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate15.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Thu, 08 Aug 2019 14:29:47 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Thu, 08 Aug 2019 14:29:37 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Thu, 08 Aug 2019 14:29:37 -0700 Received: from rcampbell-dev.nvidia.com (10.124.1.5) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Thu, 8 Aug 2019 21:29:35 +0000 Subject: Re: [PATCH] nouveau/hmm: map pages after migration To: Christoph Hellwig CC: , , , , , Jason Gunthorpe , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Ben Skeggs References: <20190807150214.3629-1-rcampbell@nvidia.com> <20190808070701.GC29382@lst.de> From: Ralph Campbell X-Nvconfidentiality: public Message-ID: <0b96a8d8-86b5-3ce0-db95-669963c1f8a7@nvidia.com> Date: Thu, 8 Aug 2019 14:29:34 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20190808070701.GC29382@lst.de> X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL101.nvidia.com (172.20.187.10) To HQMAIL107.nvidia.com (172.20.187.13) Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1565299787; bh=PhGH3Fz3U6BG9IYzpAywsfQn2QaZDVfO/PlIuALj3rM=; h=X-PGP-Universal:Subject:To:CC:References:From:X-Nvconfidentiality: Message-ID:Date:User-Agent:MIME-Version:In-Reply-To: X-Originating-IP:X-ClientProxiedBy:Content-Type:Content-Language: Content-Transfer-Encoding; b=MJZge7m/9mkhZU4etBnQu2xchsH9bJVmIBhjlhBUSEeMEVfNkuCDij6bxrmYac4g9 9l00U+eic6gmLzXQPVqAn8j019mz/QqxOeYW/JKoLsBdEaVKz9RLkiSkpT8P2/nyQY dJY3ZCzRLOOHHVCKzT1PdhiSUdG6plqyGdTnWLRTmmvPZ9RbteRLOLtOtrEFZ9RIKB GzTGB8MM7HtJk/XeAG4akQYZ8yLwq74YHxldhk5dOYfCxGuneF/GePqweBWsMaiObR Tzk5KikVIGjzbxE8Sq3t0NvbeP7bOgXH/SLMeMxad6ZhJxTHatunatImUt79RWsrWT 66U0nG6r9iVXA== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/8/19 12:07 AM, Christoph Hellwig wrote: > On Wed, Aug 07, 2019 at 08:02:14AM -0700, Ralph Campbell wrote: >> When memory is migrated to the GPU it is likely to be accessed by GPU >> code soon afterwards. Instead of waiting for a GPU fault, map the >> migrated memory into the GPU page tables with the same access permission= s >> as the source CPU page table entries. This preserves copy on write >> semantics. >> >> Signed-off-by: Ralph Campbell >> Cc: Christoph Hellwig >> Cc: Jason Gunthorpe >> Cc: "J=C3=A9r=C3=B4me Glisse" >> Cc: Ben Skeggs >> --- >> >> This patch is based on top of Christoph Hellwig's 9 patch series >> https://lore.kernel.org/linux-mm/20190729234611.GC7171@redhat.com/T/#u >> "turn the hmm migrate_vma upside down" but without patch 9 >> "mm: remove the unused MIGRATE_PFN_WRITE" and adds a use for the flag. >=20 > This looks useful. I've already dropped that patch for the pending > resend. Thanks. >=20 >> static unsigned long nouveau_dmem_migrate_copy_one(struct nouveau_drm = *drm, >> - struct vm_area_struct *vma, unsigned long addr, >> - unsigned long src, dma_addr_t *dma_addr) >> + struct vm_area_struct *vma, unsigned long src, >> + dma_addr_t *dma_addr, u64 *pfn) >=20 > I'll pick up the removal of the not needed addr argument for the patch > introducing nouveau_dmem_migrate_copy_one, thanks, >=20 >> static void nouveau_dmem_migrate_chunk(struct migrate_vma *args, >> - struct nouveau_drm *drm, dma_addr_t *dma_addrs) >> + struct nouveau_drm *drm, dma_addr_t *dma_addrs, u64 *pfns) >> { >> struct nouveau_fence *fence; >> unsigned long addr =3D args->start, nr_dma =3D 0, i; >> =20 >> for (i =3D 0; addr < args->end; i++) { >> args->dst[i] =3D nouveau_dmem_migrate_copy_one(drm, args->vma, >> - addr, args->src[i], &dma_addrs[nr_dma]); >> + args->src[i], &dma_addrs[nr_dma], &pfns[i]); >=20 > Nit: I find the &pfns[i] way to pass the argument a little weird to read. > Why not "pfns + i"? OK, will do in v2. Should I convert to "dma_addrs + nr_dma" too? >> +u64 * >> +nouveau_pfns_alloc(unsigned long npages) >> +{ >> + struct nouveau_pfnmap_args *args; >> + >> + args =3D kzalloc(sizeof(*args) + npages * sizeof(args->p.phys[0]), >=20 > Can we use struct_size here? Yes, good suggestion. >=20 >> + int ret; >> + >> + if (!svm) >> + return; >> + >> + mutex_lock(&svm->mutex); >> + svmm =3D nouveau_find_svmm(svm, mm); >> + if (!svmm) { >> + mutex_unlock(&svm->mutex); >> + return; >> + } >> + mutex_unlock(&svm->mutex); >=20 > Given that nouveau_find_svmm doesn't take any kind of reference, what > gurantees svmm doesn't go away after dropping the lock? I asked Ben and Jerome about this too. I'm still looking into it. >=20 >> @@ -44,5 +49,19 @@ static inline int nouveau_svmm_bind(struct drm_device= *device, void *p, >> { >> return -ENOSYS; >> } >> + >> +u64 *nouveau_pfns_alloc(unsigned long npages) >> +{ >> + return NULL; >> +} >> + >> +void nouveau_pfns_free(u64 *pfns) >> +{ >> +} >> + >> +void nouveau_pfns_map(struct nouveau_drm *drm, struct mm_struct *mm, >> + unsigned long addr, u64 *pfns, unsigned long npages) >> +{ >> +} >> #endif /* IS_ENABLED(CONFIG_DRM_NOUVEAU_SVM) */ >=20 > nouveau_dmem.c and nouveau_svm.c are both built conditional on > CONFIG_DRM_NOUVEAU_SVM, so there is no need for stubs here. >=20 Good point. I'll remove them in v2.