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=-8.5 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,USER_AGENT_GIT 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 22AE4C31E5B for ; Mon, 17 Jun 2019 20:27:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E483A20861 for ; Mon, 17 Jun 2019 20:27:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=shipmail.org header.i=@shipmail.org header.b="DgKGvIHD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728011AbfFQU1K (ORCPT ); Mon, 17 Jun 2019 16:27:10 -0400 Received: from pio-pvt-msa3.bahnhof.se ([79.136.2.42]:60376 "EHLO pio-pvt-msa3.bahnhof.se" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726023AbfFQU1J (ORCPT ); Mon, 17 Jun 2019 16:27:09 -0400 Received: from localhost (localhost [127.0.0.1]) by pio-pvt-msa3.bahnhof.se (Postfix) with ESMTP id 8CF103F96D; Mon, 17 Jun 2019 22:18:19 +0200 (CEST) Authentication-Results: pio-pvt-msa3.bahnhof.se; dkim=pass (1024-bit key; unprotected) header.d=shipmail.org header.i=@shipmail.org header.b=DgKGvIHD; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at bahnhof.se Received: from pio-pvt-msa3.bahnhof.se ([127.0.0.1]) by localhost (pio-pvt-msa3.bahnhof.se [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id wJgy2N-cuyPz; Mon, 17 Jun 2019 22:18:05 +0200 (CEST) Received: from mail1.shipmail.org (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) (Authenticated sender: mb878879) by pio-pvt-msa3.bahnhof.se (Postfix) with ESMTPA id 460C43F9AD; Mon, 17 Jun 2019 22:18:05 +0200 (CEST) Received: from localhost.localdomain.localdomain (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) by mail1.shipmail.org (Postfix) with ESMTPSA id DABBF36196F; Mon, 17 Jun 2019 22:18:04 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=shipmail.org; s=mail; t=1560802684; bh=Yjmtl92sLAlEoB99F5XOnCklObajAbb4hpy0froOh7I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DgKGvIHD+BQzCinbcZ00LwMWVT8XN0GXc9j1aYJM7nBZYRwIDReixcJ3mCGKHZ/Hi g18grOyedUJBk5IQVHCEkGOA9L462r1skv8BFNOgXYe45woAv57pFF2NjMJIuzv/1f Myo6q5Sz8915On8lU5DVdop7iP+FLs1b1WS0t+9I= From: =?UTF-8?q?Thomas=20Hellstr=C3=B6m=20=28VMware=29?= To: dri-devel@lists.freedesktop.org Cc: linux-graphics-maintainer@vmware.com, pv-drivers@vmware.com, linux-kernel@vger.kernel.org Subject: [PATCH v7 1/9] mm: Allow the [page|pfn]_mkwrite callbacks to drop the mmap_sem Date: Mon, 17 Jun 2019 22:17:48 +0200 Message-Id: <20190617201756.12587-2-thomas@shipmail.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190617201756.12587-1-thomas@shipmail.org> References: <20190617201756.12587-1-thomas@shipmail.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thomas Hellstrom Driver fault callbacks are allowed to drop the mmap_sem when expecting long hardware waits to avoid blocking other mm users. Allow the mkwrite callbacks to do the same by returning early on VM_FAULT_RETRY. In particular we want to be able to drop the mmap_sem when waiting for a reservation object lock on a GPU buffer object. These locks may be held while waiting for the GPU. Cc: Andrew Morton Cc: Matthew Wilcox Cc: Will Deacon Cc: Peter Zijlstra Cc: Rik van Riel Cc: Minchan Kim Cc: Michal Hocko Cc: Huang Ying Cc: Souptick Joarder Cc: "Jérôme Glisse" Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Thomas Hellstrom Reviewed-by: Ralph Campbell --- mm/memory.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index ddf20bd0c317..168f546af1ad 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2238,7 +2238,7 @@ static vm_fault_t do_page_mkwrite(struct vm_fault *vmf) ret = vmf->vma->vm_ops->page_mkwrite(vmf); /* Restore original flags so that caller is not surprised */ vmf->flags = old_flags; - if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) + if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) return ret; if (unlikely(!(ret & VM_FAULT_LOCKED))) { lock_page(page); @@ -2515,7 +2515,7 @@ static vm_fault_t wp_pfn_shared(struct vm_fault *vmf) pte_unmap_unlock(vmf->pte, vmf->ptl); vmf->flags |= FAULT_FLAG_MKWRITE; ret = vma->vm_ops->pfn_mkwrite(vmf); - if (ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)) + if (ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)) return ret; return finish_mkwrite_fault(vmf); } @@ -2536,7 +2536,8 @@ static vm_fault_t wp_page_shared(struct vm_fault *vmf) pte_unmap_unlock(vmf->pte, vmf->ptl); tmp = do_page_mkwrite(vmf); if (unlikely(!tmp || (tmp & - (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { + (VM_FAULT_ERROR | VM_FAULT_NOPAGE | + VM_FAULT_RETRY)))) { put_page(vmf->page); return tmp; } @@ -3601,7 +3602,8 @@ static vm_fault_t do_shared_fault(struct vm_fault *vmf) unlock_page(vmf->page); tmp = do_page_mkwrite(vmf); if (unlikely(!tmp || - (tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { + (tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | + VM_FAULT_RETRY)))) { put_page(vmf->page); return tmp; } -- 2.20.1