Hi,
On 30/06/17 17:45, Bob Peterson wrote:
Hi,
This patch reorganizes some of the hokey logic in gfs2_logd.
It also tries to only fetch the logd_secs tunable only once per
second to avoid too many spinlock conflicts.
Signed-off-by: Bob Peterson <[email protected]>
Again, please explain what the benefit is. The tunable should only every
be accessed by gfs2_logd and by a userland process that is updating the
tunable. If there is contention here, something is very wrong. The patch
appears to remove the check for whether a journal or ail flush is
required before gfs2_logd sleeps, so this appears that it would likely
make performance worse,
Steve.
---
diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 32aa1f0..3f18db4 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -915,15 +915,12 @@ int gfs2_logd(void *data)
struct gfs2_sbd *sdp = data;
unsigned long t = 1;
DEFINE_WAIT(wait);
- bool did_flush;
+ unsigned long tune_time = 0;
while (!kthread_should_stop()) {
-
- did_flush = false;
if (gfs2_jrnl_flush_reqd(sdp) || t == 0) {
gfs2_ail1_empty(sdp);
gfs2_log_flush(sdp, NULL, NORMAL_FLUSH);
- did_flush = true;
}
if (gfs2_ail_flush_reqd(sdp)) {
@@ -931,26 +928,22 @@ int gfs2_logd(void *data)
gfs2_ail1_wait(sdp);
gfs2_ail1_empty(sdp);
gfs2_log_flush(sdp, NULL, NORMAL_FLUSH);
- did_flush = true;
}
- if (!gfs2_ail_flush_reqd(sdp) || did_flush)
- wake_up(&sdp->sd_log_waitq);
-
- t = gfs2_tune_get(sdp, gt_logd_secs) * HZ;
+ wake_up(&sdp->sd_log_waitq);
try_to_freeze();
- do {
- prepare_to_wait(&sdp->sd_logd_waitq, &wait,
- TASK_INTERRUPTIBLE);
- if (!gfs2_ail_flush_reqd(sdp) &&
- !gfs2_jrnl_flush_reqd(sdp) &&
- !kthread_should_stop())
- t = schedule_timeout(t);
- } while(t && !gfs2_ail_flush_reqd(sdp) &&
- !gfs2_jrnl_flush_reqd(sdp) &&
- !kthread_should_stop());
+ if (kthread_should_stop())
+ break;
+
+ if (time_after(jiffies, tune_time + HZ)) {
+ t = gfs2_tune_get(sdp, gt_logd_secs) * HZ;
+ tune_time = jiffies;
+ }
+ prepare_to_wait(&sdp->sd_logd_waitq, &wait,
+ TASK_INTERRUPTIBLE);
+ t = schedule_timeout(t);
finish_wait(&sdp->sd_logd_waitq, &wait);
}
