From: Daniel Vetter <daniel@ffwll.ch>
To: Kenny Levinsen <kl@kl.wtf>
Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
daniel@ffwll.ch, airlied@linux.ie, tzimmermann@suse.de,
mripard@kernel.org, maarten.lankhorst@linux.intel.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] drm: make drm_file use keyed wakeups
Date: Tue, 28 Apr 2020 17:14:10 +0200 [thread overview]
Message-ID: <20200428151410.GU3456981@phenom.ffwll.local> (raw)
In-Reply-To: <20200424162615.10461-1-kl@kl.wtf>
On Fri, Apr 24, 2020 at 06:26:15PM +0200, Kenny Levinsen wrote:
> Some processes, such as systemd, are only polling for EPOLLERR|EPOLLHUP.
> As drm_file uses unkeyed wakeups, such a poll can receive many spurious
> wakeups from uninteresting events if, for example, the file description
> is subscribed to vblank events. This is the case with systemd, as it
> polls a file description from logind that is shared with the users'
> compositor.
>
> Use keyed wakeups to allow the wakeup target to more efficiently discard
> these uninteresting events.
>
> Signed-off-by: Kenny Levinsen <kl@kl.wtf>
Hm I applied v1 and I'm not spotting what's different here, and there's no
changelog explaining what changed ...
Please send a fixup if there's anything important missing.
-Daniel
> ---
> drivers/gpu/drm/drm_file.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
> index c4c704e01961..ec25b3d979d9 100644
> --- a/drivers/gpu/drm/drm_file.c
> +++ b/drivers/gpu/drm/drm_file.c
> @@ -608,7 +608,8 @@ ssize_t drm_read(struct file *filp, char __user *buffer,
> file_priv->event_space -= length;
> list_add(&e->link, &file_priv->event_list);
> spin_unlock_irq(&dev->event_lock);
> - wake_up_interruptible(&file_priv->event_wait);
> + wake_up_interruptible_poll(&file_priv->event_wait,
> + EPOLLIN | EPOLLRDNORM);
> break;
> }
>
> @@ -804,7 +805,8 @@ void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event *e)
> list_del(&e->pending_link);
> list_add_tail(&e->link,
> &e->file_priv->event_list);
> - wake_up_interruptible(&e->file_priv->event_wait);
> + wake_up_interruptible_poll(&e->file_priv->event_wait,
> + EPOLLIN | EPOLLRDNORM);
> }
> EXPORT_SYMBOL(drm_send_event_locked);
>
> --
> 2.26.1
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
next prev parent reply other threads:[~2020-04-28 15:14 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-24 16:26 [PATCH v2] drm: make drm_file use keyed wakeups Kenny Levinsen
2020-04-28 15:14 ` Daniel Vetter [this message]
2020-04-29 11:19 ` kl
2020-04-30 14:04 ` Daniel Vetter
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