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Date: Thu, 25 Jan 2024 11:19:46 +0100
From: Boris Brezillon <boris.brezillon@collabora.com>
To: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Cc: David Airlie <airlied@gmail.com>, Gerd Hoffmann <kraxel@redhat.com>,
 Gurchetan Singh <gurchetansingh@chromium.org>, Chia-I Wu
 <olvaffe@gmail.com>, Daniel Vetter <daniel@ffwll.ch>, Maarten Lankhorst
 <maarten.lankhorst@linux.intel.com>, Maxime Ripard <mripard@kernel.org>,
 Thomas Zimmermann <tzimmermann@suse.de>, Christian =?UTF-8?B?S8O2bmln?=
 <christian.koenig@amd.com>, Qiang Yu <yuq825@gmail.com>, Steven Price
 <steven.price@arm.com>, Emma Anholt <emma@anholt.net>, Melissa Wen
 <mwen@igalia.com>, dri-devel@lists.freedesktop.org,
 linux-kernel@vger.kernel.org, kernel@collabora.com,
 virtualization@lists.linux-foundation.org
Subject: Re: [PATCH v19 22/30] drm/shmem-helper: Add common memory shrinker
Message-ID: <20240125111946.797a1e1e@collabora.com>
In-Reply-To: <20240105184624.508603-23-dmitry.osipenko@collabora.com>
References: <20240105184624.508603-1-dmitry.osipenko@collabora.com>
	<20240105184624.508603-23-dmitry.osipenko@collabora.com>
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On Fri,  5 Jan 2024 21:46:16 +0300
Dmitry Osipenko <dmitry.osipenko@collabora.com> wrote:

> +static bool drm_gem_shmem_is_evictable(struct drm_gem_shmem_object *shmem)
> +{
> +	return (shmem->madv >= 0) && shmem->base.funcs->evict &&
> +		refcount_read(&shmem->pages_use_count) &&
> +		!refcount_read(&shmem->pages_pin_count) &&
> +		!shmem->base.dma_buf && !shmem->base.import_attach &&
> +		!shmem->evicted;

Are we missing

                && dma_resv_test_signaled(shmem->base.resv,
					  DMA_RESV_USAGE_BOOKKEEP)

to make sure the GPU is done using the BO?
The same applies to drm_gem_shmem_is_purgeable() BTW.

If you don't want to do this test here, we need a way to let drivers
provide a custom is_{evictable,purgeable}() test.

I guess we should also expose drm_gem_shmem_shrinker_update_lru_locked()
to let drivers move the GEMs that were used most recently (those
referenced by a GPU job) at the end of the evictable LRU.

> +}
> +