Hello Mr. Torokhov,
Could you please help to update about below patch ?
Thanks,
Aniroop Mathur
On Tue, Jan 5, 2016 at 3:26 AM, Aniroop Mathur <a.mathur@xxxxxxxxxxx> wrote:
> This patch introduces concept to drop partial events in evdev handler
> itself after emptying the buffer which are dropped by all evdev
> clients in userspace after SYN_DROPPED occurs and this in turn reduces
> evdev client reading requests plus saves memory space filled by partial
> events in evdev handler buffer.
> Also, this patch prevents dropping of full packet by evdev client after
> SYN_DROPPED occurs in case last stored event was SYN_REPORT.
> (like after clock change request)
>
> --
> Please ignore v3.
>
> Signed-off-by: Aniroop Mathur <a.mathur@xxxxxxxxxxx>
> ---
> drivers/input/evdev.c | 53 ++++++++++++++++++++++++++++++++++++++-------------
> 1 file changed, 40 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
> index e9ae3d5..15b6eb2 100644
> --- a/drivers/input/evdev.c
> +++ b/drivers/input/evdev.c
> @@ -58,6 +58,7 @@ struct evdev_client {
> struct list_head node;
> unsigned int clk_type;
> bool revoked;
> + bool drop_pevent; /* specifies if partial events need to be dropped */
> unsigned long *evmasks[EV_CNT];
> unsigned int bufsize;
> struct input_event buffer[];
> @@ -156,7 +157,12 @@ static void __evdev_flush_queue(struct evdev_client *client, unsigned int type)
> static void __evdev_queue_syn_dropped(struct evdev_client *client)
> {
> struct input_event ev;
> + struct input_event *prev_ev;
> ktime_t time;
> + unsigned int mask = client->bufsize - 1;
> +
> + /* Store previous event */
> + prev_ev = &client->buffer[(client->head - 1) & mask];
>
> time = client->clk_type == EV_CLK_REAL ?
> ktime_get_real() :
> @@ -170,13 +176,33 @@ static void __evdev_queue_syn_dropped(struct evdev_client *client)
> ev.value = 0;
>
> client->buffer[client->head++] = ev;
> - client->head &= client->bufsize - 1;
> + client->head &= mask;
>
> if (unlikely(client->head == client->tail)) {
> /* drop queue but keep our SYN_DROPPED event */
> - client->tail = (client->head - 1) & (client->bufsize - 1);
> + client->tail = (client->head - 1) & mask;
> client->packet_head = client->tail;
> }
> +
> + /*
> + * If last packet is NOT fully stored, set drop_pevent to true to
> + * ignore partial events and if last packet is fully stored, queue
> + * SYN_REPORT so that clients would not ignore next full packet.
> + */
> + if (prev_ev->type != EV_SYN && prev_ev->code != SYN_REPORT) {
> + client->drop_pevent = true;
> + } else if (prev_ev->type == EV_SYN && prev_ev->code == SYN_REPORT) {
> + prev_ev->time = ev.time;
> + client->buffer[client->head++] = *prev_ev;
> + client->head &= mask;
> + client->packet_head = client->head;
> +
> + /* drop queue but keep our SYN_DROPPED & SYN_REPORT event */
> + if (unlikely(client->head == client->tail)) {
> + client->tail = (client->head - 2) & mask;
> + client->packet_head = client->tail;
> + }
> + }
> }
>
> static void evdev_queue_syn_dropped(struct evdev_client *client)
> @@ -235,18 +261,8 @@ static void __pass_event(struct evdev_client *client,
> client->head &= client->bufsize - 1;
>
> if (unlikely(client->head == client->tail)) {
> - /*
> - * This effectively "drops" all unconsumed events, leaving
> - * EV_SYN/SYN_DROPPED plus the newest event in the queue.
> - */
> - client->tail = (client->head - 2) & (client->bufsize - 1);
> -
> - client->buffer[client->tail].time = event->time;
> - client->buffer[client->tail].type = EV_SYN;
> - client->buffer[client->tail].code = SYN_DROPPED;
> - client->buffer[client->tail].value = 0;
> -
> client->packet_head = client->tail;
> + __evdev_queue_syn_dropped(client);
> }
>
> if (event->type == EV_SYN && event->code == SYN_REPORT) {
> @@ -284,6 +300,17 @@ static void evdev_pass_values(struct evdev_client *client,
> wakeup = true;
> }
>
> + /*
> + * drop partial events of last packet but queue SYN_REPORT
> + * so that clients would not ignore extra full packet.
> + */
> + if (client->drop_pevent) {
> + if (v->type == EV_SYN && v->code == SYN_REPORT)
> + client->drop_pevent = false;
> + else
> + continue;
> + }
> +
> event.type = v->type;
> event.code = v->code;
> event.value = v->value;
> --
> 2.6.2
>
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