diff options
| author | Phil Elwell <phil@raspberrypi.org> | 2017-01-17 20:56:15 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-01-19 11:08:57 +0100 |
| commit | a2db578bc07468a28d213fed37057ce1e182112e (patch) | |
| tree | 2a1c81d855734a36a9be06f19d812aa64d71460a | |
| parent | ca3df03b83f2abaf0c50d777eccf4d12bc4d4dec (diff) | |
| download | linux-a2db578bc07468a28d213fed37057ce1e182112e.tar.bz2 | |
staging: vchiq_arm: Avoid premature message stalls
The constants MAX_COMPLETIONS and MSG_QUEUE_SIZE control
the number of messages that can be outstanding to each client
before the system as a whole stalls. If the numbers are too
small then unnecessary thread switching will occur while
waiting for a (potentially low priority) client thread to
consume some data; badly written clients can even lead to
deadlock.
For services that carry many short messages, 16 messages can
represent a very small amount of data. Since the resources
are small - 16 bytes for a completion, 4 bytes for a message
pointer - increase the limits so they are unlikely to be hit
except in exceptional circumstances.
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c index b02dc4b1e76c..1dc8627e65b0 100644 --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c @@ -64,10 +64,10 @@ #define VCHIQ_MINOR 0 /* Some per-instance constants */ -#define MAX_COMPLETIONS 16 +#define MAX_COMPLETIONS 128 #define MAX_SERVICES 64 #define MAX_ELEMENTS 8 -#define MSG_QUEUE_SIZE 64 +#define MSG_QUEUE_SIZE 128 #define KEEPALIVE_VER 1 #define KEEPALIVE_VER_MIN KEEPALIVE_VER |