[Cluster-devel] [GFS2 PATCH] GFS2: Rework gfs2_logd daemon

[Bob Peterson <rpeterso@redhat.com>]

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 <rpeterso@redhat.com>
---
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);
 	}