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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 72012C5B56A for ; Tue, 11 Aug 2026 12:31:05 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id CB5D410EB81; Tue, 11 Aug 2026 12:31:04 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=picoheart.com header.i=@picoheart.com header.b="qKPKT2wB"; dkim-atps=neutral Received: from va-2-27.ptr.blmpb.com (va-2-27.ptr.blmpb.com [209.127.231.27]) by gabe.freedesktop.org (Postfix) with ESMTPS id 7381E10EB81 for ; Tue, 11 Aug 2026 12:31:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; s=feishu2604151535; d=picoheart.com; t=1786451458; h=from:subject: mime-version:from:date:message-id:subject:to:cc:reply-to:content-type: mime-version:in-reply-to:message-id; bh=aRaFxfP5cQJyd0CyQHN0/SWA5n0kScYk6WSqEKPcIR8=; b=qKPKT2wBXEZlRbDi7hJtvAUWmhjMs1ti3pXlEXORqUQRX0UnuIihWd7OnyPaXqxSgOOBUY F7l9HxRsNJUPmEXuiyxOhr1YqWh7pvYD9VF20ApJLcByEc8mri34UaVWjVSDq4L5HByXiD PkiSu5p3v5fdgBkFFkwyF2IyJchTGtmBdHTMxV5bIRC2r9LaoUNabXcno1avk0emGVV7k4 vfhXjBNVqYZ/PWFnDg2S+z6SH4gpT2+zC9pt6Kmv6x8EpCCFTyL/1XlHabfisExJHZHuAW 6FCsSAdaWwPKBAOIiu6JdoCfUpHtanNTDopY27aOvx0PlcjN/enHz7bGfA3P6w== To: , , , , , Content-Disposition: inline References: From: "Zhaoyu Liu" Subject: Re: [PATCH v2] drm/pagemap: no need to recheck own pagemap in migrate_to_devmem Received: from hostpc ([124.160.26.250]) by smtp.feishu.cn with ESMTPS; Tue, 11 Aug 2026 20:30:55 +0800 X-Lms-Return-Path: Cc: , Date: Tue, 11 Aug 2026 20:30:53 +0800 Message-Id: Content-Type: text/plain; charset=UTF-8 X-Original-From: Zhaoyu Liu In-Reply-To: Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hi, Could you please help review this patch? Thanks, zackary On Thu, Aug 06, 2026 at 09:21:41PM +0800, Zhaoyu Liu wrote: > The second loop in drm_pagemap_migrate_to_devmem() checks > `page_pgmap(src_page) == pagemap && !can_migrate_same_pagemap` to skip > pages already on the target pagemap. However, this condition is always > false at this point: if can_migrate_same_pagemap is false and any own > pages exist, the first loop already returns -EBUSY before reaching here. > > v2: > - Skip the no-op migrate_vma_pages() when all pages already reside on > the target pagemap. > > Signed-off-by: Zhaoyu Liu > --- > drivers/gpu/drm/drm_pagemap.c | 21 ++++++--------------- > 1 file changed, 6 insertions(+), 15 deletions(-) > > diff --git a/drivers/gpu/drm/drm_pagemap.c b/drivers/gpu/drm/drm_pagemap.c > index 15c78eca180b..64922b944092 100644 > --- a/drivers/gpu/drm/drm_pagemap.c > +++ b/drivers/gpu/drm/drm_pagemap.c > @@ -698,7 +698,7 @@ int drm_pagemap_migrate_to_devmem(struct drm_pagemap_devmem *devmem_allocation, > * nothing. Raced or unknown device pages. > */ > err = -EBUSY; > - goto err_aborted_migration; > + goto direct_finalize; > } > > /* Count device-private pages to migrate */ > @@ -719,19 +719,17 @@ int drm_pagemap_migrate_to_devmem(struct drm_pagemap_devmem *devmem_allocation, > if (own_pages == npages) { > err = 0; > drm_dbg(dpagemap->drm, "Migration wasn't necessary.\n"); > - goto err_aborted_migration; > + goto direct_finalize; > } else if (own_pages && !mdetails->can_migrate_same_pagemap) { > err = -EBUSY; > drm_dbg(dpagemap->drm, "Migration aborted due to fragmentation.\n"); > - goto err_aborted_migration; > + goto direct_finalize; > } > > err = ops->populate_devmem_pfn(devmem_allocation, npages, migrate.dst); > if (err) > goto err_aborted_migration; > > - own_pages = 0; > - > for (i = 0; i < npages;) { > unsigned long j; > struct page *page = pfn_to_page(migrate.dst[i]); > @@ -744,12 +742,7 @@ int drm_pagemap_migrate_to_devmem(struct drm_pagemap_devmem *devmem_allocation, > struct drm_pagemap_zdd *src_zdd = > drm_pagemap_page_zone_device_data(src_page); > > - if (page_pgmap(src_page) == pagemap && > - !mdetails->can_migrate_same_pagemap) { > - migrate.dst[i] = 0; > - own_pages++; > - goto next; > - } > + /* Own or peer device private page */ > cur.dpagemap = src_zdd->dpagemap; > cur.ops = src_zdd->devmem_allocation->ops; > cur.device = cur.dpagemap->drm->dev; > @@ -786,7 +779,6 @@ int drm_pagemap_migrate_to_devmem(struct drm_pagemap_devmem *devmem_allocation, > goto err_finalize; > } > > -next: > i += NR_PAGES(order); > } > > @@ -797,8 +789,6 @@ int drm_pagemap_migrate_to_devmem(struct drm_pagemap_devmem *devmem_allocation, > if (err) > goto err_finalize; > > - drm_WARN_ON(dpagemap->drm, !!own_pages); > - > dma_fence_put(devmem_allocation->pre_migrate_fence); > devmem_allocation->pre_migrate_fence = NULL; > > @@ -822,11 +812,12 @@ int drm_pagemap_migrate_to_devmem(struct drm_pagemap_devmem *devmem_allocation, > i += nr_pages; > } > > - if (!err && migrated_pages < npages - own_pages) { > + if (!err && migrated_pages < npages) { > drm_dbg(dpagemap->drm, "Raced while finalizing migration.\n"); > err = -EBUSY; > } > > +direct_finalize: > migrate_vma_finalize(&migrate); > err_free: > drm_pagemap_zdd_put(zdd); > -- > 2.34.1