diff mbox series

[Xen-devel,15/25,v7] xen/arm: vpl011: Add a new console_evtchn_unmask function in xenconsole

Message ID 1502095997-31219-16-git-send-email-bhupinder.thakur@linaro.org
State Superseded
Headers show
Series SBSA UART emulation support in Xen | expand

Commit Message

Bhupinder Thakur Aug. 7, 2017, 8:53 a.m. UTC
This patch introduces a new console_evtchn_unmask function. This function
unmasks the console event channel if it is masked for some timeout
period.

One optimization that has been done is to merge the two 'for' loops.

One 'for' loop was used to iterate through all domains and
unmask the domain event channels which had been rate limited for a
specified duration.

The other 'for' loop was run to add the event channel fd and the tty fd to
the poll list.

These two 'for' loops were merged so that the these operations can be done
in one iteration instead of two iterations.

Signed-off-by: Bhupinder Thakur <bhupinder.thakur@linaro.org>
---
CC: Ian Jackson <ian.jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Julien Grall <julien.grall@arm.com>

Changes since v5:
- Split this change in a separate patch.

 tools/console/daemon/io.c | 44 +++++++++++++++++++++++++++-----------------
 1 file changed, 27 insertions(+), 17 deletions(-)

Comments

Wei Liu Aug. 8, 2017, 1:15 p.m. UTC | #1
On Mon, Aug 07, 2017 at 02:23:07PM +0530, Bhupinder Thakur wrote:
> This patch introduces a new console_evtchn_unmask function. This function
> unmasks the console event channel if it is masked for some timeout
> period.
> 
> One optimization that has been done is to merge the two 'for' loops.
> 
> One 'for' loop was used to iterate through all domains and
> unmask the domain event channels which had been rate limited for a
> specified duration.
> 
> The other 'for' loop was run to add the event channel fd and the tty fd to
> the poll list.
> 
> These two 'for' loops were merged so that the these operations can be done
> in one iteration instead of two iterations.
> 
> Signed-off-by: Bhupinder Thakur <bhupinder.thakur@linaro.org>

Acked-by: Wei Liu <wei.liu2@citrix.com>
diff mbox series

Patch

diff --git a/tools/console/daemon/io.c b/tools/console/daemon/io.c
index a0b35da..2dcaee6 100644
--- a/tools/console/daemon/io.c
+++ b/tools/console/daemon/io.c
@@ -117,6 +117,11 @@  struct domain {
 
 static struct domain *dom_head;
 
+static inline bool console_enabled(struct console *con)
+{
+	return con->local_port != -1;
+}
+
 static int write_all(int fd, const char* buf, size_t len)
 {
 	while (len) {
@@ -908,6 +913,27 @@  static void handle_tty_write(struct console *con)
 	}
 }
 
+static void console_evtchn_unmask(struct console *con, void *data)
+{
+	long long now = (long long)data;
+
+	if (!console_enabled(con))
+		return;
+
+	/* CS 16257:955ee4fa1345 introduces a 5ms fuzz
+	 * for select(), it is not clear poll() has
+	 * similar behavior (returning a couple of ms
+	 * sooner than requested) as well. Just leave
+	 * the fuzz here. Remove it with a separate
+	 * patch if necessary */
+	if ((now+5) > con->next_period) {
+		con->next_period = now + RATE_LIMIT_PERIOD;
+		if (con->event_count >= RATE_LIMIT_ALLOWANCE)
+			(void)xenevtchn_unmask(con->xce_handle, con->local_port);
+		con->event_count = 0;
+	}
+}
+
 static void handle_ring_read(struct domain *dom)
 {
 	xenevtchn_port_or_error_t port;
@@ -1142,23 +1168,7 @@  void handle_io(void)
 		for (d = dom_head; d; d = d->next) {
 			struct console *con = &d->console;
 
-			/* CS 16257:955ee4fa1345 introduces a 5ms fuzz
-			 * for select(), it is not clear poll() has
-			 * similar behavior (returning a couple of ms
-			 * sooner than requested) as well. Just leave
-			 * the fuzz here. Remove it with a separate
-			 * patch if necessary */
-			if ((now+5) > con->next_period) {
-				con->next_period = now + RATE_LIMIT_PERIOD;
-				if (con->event_count >= RATE_LIMIT_ALLOWANCE) {
-					(void)xenevtchn_unmask(con->xce_handle, con->local_port);
-				}
-				con->event_count = 0;
-			}
-		}
-
-		for (d = dom_head; d; d = d->next) {
-			struct console *con = &d->console;
+			console_evtchn_unmask(con, (void *)now);
 
 			maybe_add_console_evtchn_fd(con, (void *)&next_timeout);