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=-6.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 37F05C433E0 for ; Mon, 22 Jun 2020 09:41:09 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0AA3B20716 for ; Mon, 22 Jun 2020 09:41:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="bmf235iK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0AA3B20716 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ffwll.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=amd-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4BBC96E13B; Mon, 22 Jun 2020 09:41:08 +0000 (UTC) Received: from mail-wr1-x443.google.com (mail-wr1-x443.google.com [IPv6:2a00:1450:4864:20::443]) by gabe.freedesktop.org (Postfix) with ESMTPS id BB6526E12D for ; Mon, 22 Jun 2020 09:41:06 +0000 (UTC) Received: by mail-wr1-x443.google.com with SMTP id o11so8240538wrv.9 for ; Mon, 22 Jun 2020 02:41:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=cPOjN1RgR1/QvtDhOaRjif3zZdMDq5ibV4Mtk4nxrcw=; b=bmf235iKEZumcIhA7e2S5sxJxpIBKgrKUH0MZOkNNHnVdeMckIWsg6MHr5H9KLwZyA wBC+dfnLRaW3JhnhelFrNqZ77ubOMI/jZtfIiMdrsAfAQ6IXyghwrjSmgkwnquIi7Yr2 7fv/HEDx73l0Mp6nAlEi+1I1HklVLeTgwWvao= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=cPOjN1RgR1/QvtDhOaRjif3zZdMDq5ibV4Mtk4nxrcw=; b=H0E5GsXJLxoyi4aICjUPqyrgqyeO32xUr6o7m9c46GQ+zN4yS91BOS/bqD9NbjWnON MRe364NeYNCqcsIiyGvBQl+WMTrPrtiujvb6HnPkYZlTaMSEPDeCe9Xpiwab8d3B3ow8 zSdzQhcRtyf90HSdOGPIT2nZAFukFuEJ36iKL32ygjCIgHwE24+Ox+l4EMxzFatGsALv BCBlmWYA5gjpT7wjw2zzvyQZd2je1R3J//Enn/vsFsIEMQQE9K4TBDhYLXPq8OSG97hl 4owGzehAGI9F4hDIFrmX8ubfcR8+F77QlMn9QDSY+YI7soBdP+BscCFuXNPcmvV4Jjos +bMA== X-Gm-Message-State: AOAM531sIvVaU9gGRiZIBsoX0Rzp2qUWEcrAVPkUCBE7X46vaLawNXjn A6/MycTcfmnbzyHifJKKJkg+rQ== X-Google-Smtp-Source: ABdhPJwv9lPgdZ22lP+wVMRCN6L8yQW/brQnUetwwH+hsqa42fLeNZaPOxblsPGTirqOh4FbUFhrYQ== X-Received: by 2002:a5d:5642:: with SMTP id j2mr11057936wrw.19.1592818865480; Mon, 22 Jun 2020 02:41:05 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id 138sm16379039wma.23.2020.06.22.02.41.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Jun 2020 02:41:04 -0700 (PDT) Date: Mon, 22 Jun 2020 11:41:03 +0200 From: Daniel Vetter To: Andrey Grodzovsky Subject: Re: [PATCH v2 2/8] drm/ttm: Remap all page faults to per process dummy page. Message-ID: <20200622094103.GA20149@phenom.ffwll.local> References: <1592719388-13819-1-git-send-email-andrey.grodzovsky@amd.com> <1592719388-13819-3-git-send-email-andrey.grodzovsky@amd.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1592719388-13819-3-git-send-email-andrey.grodzovsky@amd.com> X-Operating-System: Linux phenom 5.6.0-1-amd64 X-BeenThere: amd-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: daniel.vetter@ffwll.ch, michel@daenzer.net, dri-devel@lists.freedesktop.org, ppaalanen@gmail.com, amd-gfx@lists.freedesktop.org, ckoenig.leichtzumerken@gmail.com, alexdeucher@gmail.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: amd-gfx-bounces@lists.freedesktop.org Sender: "amd-gfx" On Sun, Jun 21, 2020 at 02:03:02AM -0400, Andrey Grodzovsky wrote: > On device removal reroute all CPU mappings to dummy page per drm_file > instance or imported GEM object. > > Signed-off-by: Andrey Grodzovsky > --- > drivers/gpu/drm/ttm/ttm_bo_vm.c | 65 ++++++++++++++++++++++++++++++++++++----- > 1 file changed, 57 insertions(+), 8 deletions(-) > > diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c > index 389128b..2f8bf5e 100644 > --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c > +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c > @@ -35,6 +35,8 @@ > #include > #include > #include > +#include > +#include > #include > #include > #include > @@ -328,19 +330,66 @@ vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf) Hm I think diff and code flow look a bit bad now. What about renaming the current function to __ttm_bo_vm_fault and then having something like the below: ttm_bo_vm_fault(args) { if (drm_dev_enter()) { __ttm_bo_vm_fault(args); drm_dev_exit(); } else { drm_gem_insert_dummy_pfn(); } } I think drm_gem_insert_dummy_pfn(); should be portable across drivers, so another nice point to try to unifiy drivers as much as possible. -Daniel > pgprot_t prot; > struct ttm_buffer_object *bo = vma->vm_private_data; > vm_fault_t ret; > + int idx; > + struct drm_device *ddev = bo->base.dev; > > - ret = ttm_bo_vm_reserve(bo, vmf); > - if (ret) > - return ret; > + if (drm_dev_enter(ddev, &idx)) { > + ret = ttm_bo_vm_reserve(bo, vmf); > + if (ret) > + goto exit; > + > + prot = vma->vm_page_prot; > > - prot = vma->vm_page_prot; > - ret = ttm_bo_vm_fault_reserved(vmf, prot, TTM_BO_VM_NUM_PREFAULT); > - if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) > + ret = ttm_bo_vm_fault_reserved(vmf, prot, TTM_BO_VM_NUM_PREFAULT); > + if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) > + goto exit; > + > + dma_resv_unlock(bo->base.resv); > + > +exit: > + drm_dev_exit(idx); > return ret; > + } else { > > - dma_resv_unlock(bo->base.resv); > + struct drm_file *file = NULL; > + struct page *dummy_page = NULL; > + int handle; > > - return ret; > + /* We are faulting on imported BO from dma_buf */ > + if (bo->base.dma_buf && bo->base.import_attach) { > + dummy_page = bo->base.dummy_page; > + /* We are faulting on non imported BO, find drm_file owning the BO*/ Uh, we can't fish that out of the vma->vm_file pointer somehow? Or is that one all wrong? Doing this kind of list walk looks pretty horrible. If the vma doesn't have the right pointer I guess next option is that we store the drm_file page in gem_bo->dummy_page, and replace it on first export. But that's going to be tricky to track ... > + } else { > + struct drm_gem_object *gobj; > + > + mutex_lock(&ddev->filelist_mutex); > + list_for_each_entry(file, &ddev->filelist, lhead) { > + spin_lock(&file->table_lock); > + idr_for_each_entry(&file->object_idr, gobj, handle) { > + if (gobj == &bo->base) { > + dummy_page = file->dummy_page; > + break; > + } > + } > + spin_unlock(&file->table_lock); > + } > + mutex_unlock(&ddev->filelist_mutex); > + } > + > + if (dummy_page) { > + /* > + * Let do_fault complete the PTE install e.t.c using vmf->page > + * > + * TODO - should i call free_page somewhere ? Nah, instead don't call get_page. The page will be around as long as there's a reference for the drm_file or gem_bo, which is longer than any mmap. Otherwise yes this would like really badly. > + */ > + get_page(dummy_page); > + vmf->page = dummy_page; > + return 0; > + } else { > + return VM_FAULT_SIGSEGV; Hm that would be a kernel bug, wouldn't it? WARN_ON() required here imo. -Daniel > + } > + } > } > EXPORT_SYMBOL(ttm_bo_vm_fault); > > -- > 2.7.4 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ amd-gfx mailing list amd-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/amd-gfx