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authorVineeth Vijayan <vneethv@linux.ibm.com>2020-06-18 17:42:45 +0300
committerHeiko Carstens <hca@linux.ibm.com>2020-08-17 14:17:00 +0300
commit0b8eb2ee9da1e8c9b8082f404f3948aa82a057b2 (patch)
tree51ace6d3133d2649737b44d9e35e1ba7d5ffd580 /drivers/s390
parent9123e3a74ec7b934a4a099e98af6a61c2f80bbf5 (diff)
downloadlinux-0b8eb2ee9da1e8c9b8082f404f3948aa82a057b2.tar.xz
s390/cio: add cond_resched() in the slow_eval_known_fn() loop
The scanning through subchannels during the time of an event could take significant amount of time in case of platforms with lots of known subchannels. This might result in higher scheduling latencies for other tasks especially on systems with a single CPU. Add cond_resched() call, as the loop in slow_eval_known_fn() can be executed for a longer duration. Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com> Signed-off-by: Vineeth Vijayan <vneethv@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Diffstat (limited to 'drivers/s390')
-rw-r--r--drivers/s390/cio/css.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index 94edbb33d0d1..aca022239b33 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -677,6 +677,11 @@ static int slow_eval_known_fn(struct subchannel *sch, void *data)
rc = css_evaluate_known_subchannel(sch, 1);
if (rc == -EAGAIN)
css_schedule_eval(sch->schid);
+ /*
+ * The loop might take long time for platforms with lots of
+ * known devices. Allow scheduling here.
+ */
+ cond_resched();
}
return 0;
}