From patchwork Sun Aug 27 17:54:42 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Osipenko X-Patchwork-Id: 13367360 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 F1191C83F01 for ; Sun, 27 Aug 2023 17:56:53 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0065910E1F2; Sun, 27 Aug 2023 17:56:52 +0000 (UTC) Received: from madras.collabora.co.uk (madras.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e5ab]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8271310E1E1; Sun, 27 Aug 2023 17:56:19 +0000 (UTC) Received: from workpc.. (109-252-153-31.dynamic.spd-mgts.ru [109.252.153.31]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: dmitry.osipenko) by madras.collabora.co.uk (Postfix) with ESMTPSA id E0EA16607290; Sun, 27 Aug 2023 18:56:16 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1693158978; bh=h5zA3QI6jLEZ04+CP8fo0PuRIMQ8t88TtCG2qT9Ffo4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iNSLxgqeiOzrV7VF4qOrkWsdZCcWTuFLRrgcZCerj/ELf3jnTGlBOGcdBAwdbbV4M LxQRiFJDoIik2S5Mg5DeDD8nXez4oPLNRkByEi4uL0mnSyQdkI/7vxizflqS3pLmHP bKatwdAxCtUKg9KKLCt9VSWQJlQwP2is/SdpyYXy8GBAn1IIHXmKLI8EUqtpNnY2dR fLs9waVIfpYJdEm6AwmzeT8k4iBxuw+n6cH+kxkaBuWXvgRTS3RW0hB+Xf4Yc4fTv5 oQpbrMIXU/X7HN1iz+7Rj1arfSLy3/4vXakAAYjguctPqTCOw4KBdnk+gfJ33suU1A pBzCP7to1zYsA== From: Dmitry Osipenko To: David Airlie , Gerd Hoffmann , Gurchetan Singh , Chia-I Wu , Daniel Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , =?utf-8?q?Christian_K=C3=B6nig?= , Qiang Yu , Steven Price , Boris Brezillon , Emma Anholt , Melissa Wen , Will Deacon , Peter Zijlstra , Boqun Feng , Mark Rutland Subject: [PATCH v15 16/23] drm/shmem-helper: Use kref for vmap_use_count Date: Sun, 27 Aug 2023 20:54:42 +0300 Message-ID: <20230827175449.1766701-17-dmitry.osipenko@collabora.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230827175449.1766701-1-dmitry.osipenko@collabora.com> References: <20230827175449.1766701-1-dmitry.osipenko@collabora.com> MIME-Version: 1.0 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: , Cc: intel-gfx@lists.freedesktop.org, kernel@collabora.com, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, virtualization@lists.linux-foundation.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Use kref helper for vmap_use_count to make refcounting consistent with pages_use_count and pages_pin_count that use kref. This will allow to optimize unlocked vmappings by skipping reservation locking if refcnt > 1. Suggested-by: Boris Brezillon Signed-off-by: Dmitry Osipenko --- drivers/gpu/drm/drm_gem_shmem_helper.c | 37 ++++++++++++++------------ include/drm/drm_gem_shmem_helper.h | 2 +- 2 files changed, 21 insertions(+), 18 deletions(-) diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c index 17a0177acb5d..d96fee3d6166 100644 --- a/drivers/gpu/drm/drm_gem_shmem_helper.c +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c @@ -144,7 +144,7 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem) } else if (!shmem->imported_sgt) { dma_resv_lock(shmem->base.resv, NULL); - drm_WARN_ON(obj->dev, shmem->vmap_use_count); + drm_WARN_ON(obj->dev, kref_read(&shmem->vmap_use_count)); if (shmem->sgt) { dma_unmap_sgtable(obj->dev->dev, shmem->sgt, @@ -359,23 +359,25 @@ int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem, dma_resv_assert_held(shmem->base.resv); - if (shmem->vmap_use_count++ > 0) { + if (kref_get_unless_zero(&shmem->vmap_use_count)) { iosys_map_set_vaddr(map, shmem->vaddr); return 0; } ret = drm_gem_shmem_pin_locked(shmem); if (ret) - goto err_zero_use; + return ret; if (shmem->map_wc) prot = pgprot_writecombine(prot); shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT, VM_MAP, prot); - if (!shmem->vaddr) + if (!shmem->vaddr) { ret = -ENOMEM; - else + } else { iosys_map_set_vaddr(map, shmem->vaddr); + kref_init(&shmem->vmap_use_count); + } } if (ret) { @@ -388,13 +390,22 @@ int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem, err_put_pages: if (!obj->import_attach) drm_gem_shmem_unpin_locked(shmem); -err_zero_use: - shmem->vmap_use_count = 0; return ret; } EXPORT_SYMBOL_GPL(drm_gem_shmem_vmap_locked); +static void drm_gem_shmem_kref_vunmap(struct kref *kref) +{ + struct drm_gem_shmem_object *shmem; + + shmem = container_of(kref, struct drm_gem_shmem_object, + vmap_use_count); + + vunmap(shmem->vaddr); + drm_gem_shmem_unpin_locked(shmem); +} + /* * drm_gem_shmem_vunmap_locked - Unmap a virtual mapping for a shmem GEM object * @shmem: shmem GEM object @@ -416,15 +427,7 @@ void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem, dma_buf_vunmap(obj->import_attach->dmabuf, map); } else { dma_resv_assert_held(shmem->base.resv); - - if (drm_WARN_ON_ONCE(obj->dev, !shmem->vmap_use_count)) - return; - - if (--shmem->vmap_use_count > 0) - return; - - vunmap(shmem->vaddr); - drm_gem_shmem_unpin_locked(shmem); + kref_put(&shmem->vmap_use_count, drm_gem_shmem_kref_vunmap); } shmem->vaddr = NULL; @@ -663,7 +666,7 @@ void drm_gem_shmem_print_info(const struct drm_gem_shmem_object *shmem, return; drm_printf_indent(p, indent, "pages_use_count=%u\n", kref_read(&shmem->pages_use_count)); - drm_printf_indent(p, indent, "vmap_use_count=%u\n", shmem->vmap_use_count); + drm_printf_indent(p, indent, "vmap_use_count=%u\n", kref_read(&shmem->vmap_use_count)); drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr); } EXPORT_SYMBOL_GPL(drm_gem_shmem_print_info); diff --git a/include/drm/drm_gem_shmem_helper.h b/include/drm/drm_gem_shmem_helper.h index 400ecd63f45f..0e0ccd380f66 100644 --- a/include/drm/drm_gem_shmem_helper.h +++ b/include/drm/drm_gem_shmem_helper.h @@ -81,7 +81,7 @@ struct drm_gem_shmem_object { * Reference count on the virtual address. * The address are un-mapped when the count reaches zero. */ - unsigned int vmap_use_count; + struct kref vmap_use_count; /** * @got_sgt: