From: Boris Brezillon <boris.brezillon@collabora.com>
To: Thomas Zimmermann <tzimmermann@suse.de>
Cc: "Adrián Larumbe" <adrian.larumbe@collabora.com>,
"Qiang Yu" <yuq825@gmail.com>,
"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
"Maxime Ripard" <mripard@kernel.org>,
"David Airlie" <airlied@gmail.com>,
"Daniel Vetter" <daniel@ffwll.ch>,
"Rob Herring" <robh@kernel.org>,
"Steven Price" <steven.price@arm.com>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
"Christian Koenig=" <christian.koenig@amd.com>,
"Dmitry Osipenko" <dmitry.osipenko@collabora.com>,
"Zack Rusin" <zack.rusin@broadcom.com>,
kernel@collabora.com, dri-devel@lists.freedesktop.org,
lima@lists.freedesktop.org, linux-kernel@vger.kernel.org,
linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org
Subject: Re: [PATCH v3 0/2] drm: Fix dma_resv deadlock at drm object pin time
Date: Thu, 2 May 2024 13:59:41 +0200 [thread overview]
Message-ID: <20240502135941.136ad639@collabora.com> (raw)
In-Reply-To: <84a5f7b6-d20a-4c69-83a8-d8394fea2b68@suse.de>
Hi Thomas,
On Thu, 2 May 2024 13:51:16 +0200
Thomas Zimmermann <tzimmermann@suse.de> wrote:
> Hi,
>
> ignoring my r-b on patch 1, I'd like to rethink the current patches in
> general.
>
> I think drm_gem_shmem_pin() should become the locked version of _pin(),
> so that drm_gem_shmem_object_pin() can call it directly. The existing
> _pin_unlocked() would not be needed any longer. Same for the _unpin()
> functions. This change would also fix the consistency with the semantics
> of the shmem _vmap() functions, which never take reservation locks.
>
> There are only two external callers of drm_gem_shmem_pin(): the test
> case and panthor. These assume that drm_gem_shmem_pin() acquires the
> reservation lock. The test case should likely call drm_gem_pin()
> instead. That would acquire the reservation lock and the test would
> validate that shmem's pin helper integrates well into the overall GEM
> framework. The way panthor uses drm_gem_shmem_pin() looks wrong to me.
> For now, it could receive a wrapper that takes the lock and that's it.
I do agree that the current inconsistencies in the naming is
troublesome (sometimes _unlocked, sometimes _locked, with the version
without any suffix meaning either _locked or _unlocked depending on
what the suffixed version does), and that's the very reason I asked
Dmitry to address that in his shrinker series [1]. So, ideally I'd
prefer if patches from Dmitry's series were applied instead of
trying to fix that here (IIRC, we had an ack from Maxime).
Regards,
Boris
next prev parent reply other threads:[~2024-05-02 11:59 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-01 6:55 [PATCH v3 0/2] drm: Fix dma_resv deadlock at drm object pin time Adrián Larumbe
2024-05-01 6:55 ` [PATCH v3 1/2] drm/panfrost: " Adrián Larumbe
2024-05-02 7:09 ` Boris Brezillon
2024-05-02 11:14 ` Thomas Zimmermann
2024-05-01 6:56 ` [PATCH v3 2/2] drm/gem-shmem: Add import attachment warning to locked pin function Adrián Larumbe
2024-05-02 7:01 ` Boris Brezillon
2024-05-02 11:51 ` [PATCH v3 0/2] drm: Fix dma_resv deadlock at drm object pin time Thomas Zimmermann
2024-05-02 11:59 ` Boris Brezillon [this message]
2024-05-02 12:00 ` Boris Brezillon
2024-05-02 12:18 ` Thomas Zimmermann
2024-05-17 18:16 ` Adrián Larumbe
2024-05-21 16:18 ` Boris Brezillon
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