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 C3195C4332F for ; Fri, 10 Nov 2023 10:16:10 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 2C98B10E964; Fri, 10 Nov 2023 10:16:10 +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 0C33E10E964 for ; Fri, 10 Nov 2023 10:16:07 +0000 (UTC) Received: from localhost (cola.collaboradmins.com [195.201.22.229]) (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: bbrezillon) by madras.collabora.co.uk (Postfix) with ESMTPSA id A8B3E66073FE; Fri, 10 Nov 2023 10:16:04 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1699611365; bh=bhKTkPpbRe4c7/93JBUfBNKrd7X4LpGsLretpqpBw30=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=fpe/8ClVsoQUU2PiDztG/jFexCdkqB1LrlzjG4YGx/gyBm3Rkj7AayOFFB1QoAB9t afAaqsuQISlGYEJtoRrDr+SShX1QVBswhmmFmDk562JdUn4ZEBILCVApST6BgmMHN4 xeJzhqqF5Z/LKLCmidHC8AMJVxf5ZC3TxrwmijMC4Wgz2fsonru2uYBQVaLGjV/02Y qFt0L7mPVYDxSKqdKJm963/4BCo2xbKROTSHDFYRVwVxQjuofHWkTjwi4UKtg4Ym9Y wiDLK+bij25avAC4Sk86JdawidztntTjx9jYmSYAIk+lJSvHyxVKfaC73ejZK07WIh HdNV1UrIcK4cA== Date: Fri, 10 Nov 2023 11:16:01 +0100 From: Boris Brezillon To: Dmitry Osipenko Subject: Re: [PATCH v18 11/26] drm/shmem-helper: Prepare drm_gem_shmem_free() to shrinker addition Message-ID: <20231110111601.5d6bd1ab@collabora.com> In-Reply-To: <20231029230205.93277-12-dmitry.osipenko@collabora.com> References: <20231029230205.93277-1-dmitry.osipenko@collabora.com> <20231029230205.93277-12-dmitry.osipenko@collabora.com> Organization: Collabora X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII 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: , Cc: kernel@collabora.com, Thomas Zimmermann , Emma Anholt , Christian =?UTF-8?B?S8O2bmln?= , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Maxime Ripard , Gurchetan Singh , Melissa Wen , Gerd Hoffmann , Steven Price , virtualization@lists.linux-foundation.org, Qiang Yu Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Mon, 30 Oct 2023 02:01:50 +0300 Dmitry Osipenko wrote: > Prepare drm_gem_shmem_free() to addition of memory shrinker support > to drm-shmem by adding and using variant of put_pages() that doesn't > touch reservation lock. Reservation shouldn't be touched because lockdep > will trigger a bogus warning about locking contention with fs_reclaim > code paths that can't happen during the time when GEM is freed and > lockdep doesn't know about that. > > Signed-off-by: Dmitry Osipenko > --- > drivers/gpu/drm/drm_gem_shmem_helper.c | 35 +++++++++++++------------- > 1 file changed, 18 insertions(+), 17 deletions(-) > > diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c > index 08b5a57c59d8..24ff2b99e75b 100644 > --- a/drivers/gpu/drm/drm_gem_shmem_helper.c > +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c > @@ -128,6 +128,22 @@ struct drm_gem_shmem_object *drm_gem_shmem_create(struct drm_device *dev, size_t > } > EXPORT_SYMBOL_GPL(drm_gem_shmem_create); > > +static void > +drm_gem_shmem_free_pages(struct drm_gem_shmem_object *shmem) > +{ > + struct drm_gem_object *obj = &shmem->base; > + > +#ifdef CONFIG_X86 > + if (shmem->map_wc) > + set_pages_array_wb(shmem->pages, obj->size >> PAGE_SHIFT); > +#endif > + > + drm_gem_put_pages(obj, shmem->pages, > + shmem->pages_mark_dirty_on_put, > + shmem->pages_mark_accessed_on_put); > + shmem->pages = NULL; > +} > + > /** > * drm_gem_shmem_free - Free resources associated with a shmem GEM object > * @shmem: shmem GEM object to free > @@ -142,8 +158,6 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem) > if (obj->import_attach) { > drm_prime_gem_destroy(obj, shmem->sgt); > } else { > - dma_resv_lock(shmem->base.resv, NULL); > - > drm_WARN_ON(obj->dev, refcount_read(&shmem->vmap_use_count)); > > if (shmem->sgt) { > @@ -157,8 +171,6 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem) > If you drop the dma_resv_lock/unlock(), you should also replace the drm_gem_shmem_put_pages_locked() by a drm_gem_shmem_free_pages() in this commit. > drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_use_count)); > drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_pin_count)); > - > - dma_resv_unlock(shmem->base.resv); > } > > drm_gem_object_release(obj); > @@ -208,21 +220,10 @@ static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem) > */ > void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem) > { > - struct drm_gem_object *obj = &shmem->base; > - > dma_resv_assert_held(shmem->base.resv); > > - if (refcount_dec_and_test(&shmem->pages_use_count)) { > -#ifdef CONFIG_X86 > - if (shmem->map_wc) > - set_pages_array_wb(shmem->pages, obj->size >> PAGE_SHIFT); > -#endif > - > - drm_gem_put_pages(obj, shmem->pages, > - shmem->pages_mark_dirty_on_put, > - shmem->pages_mark_accessed_on_put); > - shmem->pages = NULL; > - } > + if (refcount_dec_and_test(&shmem->pages_use_count)) > + drm_gem_shmem_free_pages(shmem); > } > EXPORT_SYMBOL_GPL(drm_gem_shmem_put_pages_locked); >