From patchwork Sun Sep 3 17:07:30 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Osipenko X-Patchwork-Id: 13373299 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 86C3CC83F2D for ; Sun, 3 Sep 2023 17:09:12 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 1069810E110; Sun, 3 Sep 2023 17:09:11 +0000 (UTC) Received: from madras.collabora.co.uk (madras.collabora.co.uk [46.235.227.172]) by gabe.freedesktop.org (Postfix) with ESMTPS id EB01510E0FF for ; Sun, 3 Sep 2023 17:08:58 +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 7847D66072BD; Sun, 3 Sep 2023 18:08:56 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1693760937; bh=xQ3O/CfREx8/y3+iseLMLFtv6DQyEDqz0Qz5SBzkNCs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PAWer2Cm6um14QGdE5M6gF/ecL4RwBbsky+uRZ7fffx/i0+iiJITSXEpwCCjbE5VJ 3vpOi4EDBiEF05gwol3iejTQoACZxMbOC9VS63xSlWd8WqJ1pZMnye8AbG04n0oKwL wccl2eCQ8bShoDC5TlK9RxzFVduee5AJIBSvOUy/vJjBydpMOIu8WFvKes068rKEvg olGmE/5BsWUftt4R40OSOBO/S3WTnYHMz3DhB3cMe/xukEAhTEe/lHZ0POrJ5qacfs oET/5IFgzJrZBHI1hBfVHzKqCOm0Lj32RQRe58qif/IGCm8i0E/jgjsNz/t0cbnQNs SEiR+UCrPNaMA== 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 Subject: [PATCH v16 14/20] drm/shmem-helper: Use refcount_t for vmap_use_count Date: Sun, 3 Sep 2023 20:07:30 +0300 Message-ID: <20230903170736.513347-15-dmitry.osipenko@collabora.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230903170736.513347-1-dmitry.osipenko@collabora.com> References: <20230903170736.513347-1-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: 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 refcount_t helper for vmap_use_count to make refcounting consistent with pages_use_count and pages_pin_count that use refcount_t. This will allow to optimize unlocked vmappings by skipping reservation locking if refcnt > 1 and also makes vmapping to benefit from the refcount_t's overflow checks. Suggested-by: Boris Brezillon Signed-off-by: Dmitry Osipenko Reviewed-by: Boris Brezillon --- drivers/gpu/drm/drm_gem_shmem_helper.c | 28 +++++++++++--------------- include/drm/drm_gem_shmem_helper.h | 2 +- 2 files changed, 13 insertions(+), 17 deletions(-) diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c index 899f655a65bb..4633a418faba 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, refcount_read(&shmem->vmap_use_count)); if (shmem->sgt) { dma_unmap_sgtable(obj->dev->dev, shmem->sgt, @@ -345,23 +345,25 @@ 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 (refcount_inc_not_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); + refcount_set(&shmem->vmap_use_count, 1); + } } if (ret) { @@ -374,8 +376,6 @@ 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; } @@ -403,14 +403,10 @@ void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem, } 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); + if (refcount_dec_and_test(&shmem->vmap_use_count)) { + vunmap(shmem->vaddr); + drm_gem_shmem_unpin_locked(shmem); + } } shmem->vaddr = NULL; @@ -656,7 +652,7 @@ void drm_gem_shmem_print_info(const struct drm_gem_shmem_object *shmem, drm_printf_indent(p, indent, "pages_pin_count=%u\n", refcount_read(&shmem->pages_pin_count)); drm_printf_indent(p, indent, "pages_use_count=%u\n", refcount_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", refcount_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 396958a98c34..63e91e8f2d5c 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; + refcount_t vmap_use_count; /** * @got_pages_sgt: