bql: Avoid unneeded limit decrement.
When below pattern is observed,
TIME
dql_queued() dql_completed() |
a) initial state |
|
b) X bytes queued V
c) Y bytes queued
d) X bytes completed
e) Z bytes queued
f) Y bytes completed
a) dql->limit has already some value and there is no in-flight packet.
b) X bytes queued.
c) Y bytes queued and excess limit.
d) X bytes completed and dql->prev_ovlimit is set and also
dql->prev_num_queued is set Y.
e) Z bytes queued.
f) Y bytes completed. inprogress and prev_inprogress are true.
At f), according to the comment, all_prev_completed becomes
true and limit should be increased. But POSDIFF() ignores
(completed == dql->prev_num_queued) case, so limit is decreased.
Signed-off-by: Hiroaki SHIMODA <[email protected]>
Cc: Tom Herbert <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Denys Fedoryshchenko <[email protected]>
Acked-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
1 file changed
