From c35065fe9783a0b41ac5c86190d338c9e8c3d7f5 Mon Sep 17 00:00:00 2001
From: Thomas Schoebel-Theuer <tst@1und1.de>
Date: Tue, 10 Feb 2015 11:33:20 +0100
Subject: [PATCH] infra: report global IO hangs

---
 kernel/lib_timing.c       |  8 ++++++++
 kernel/lib_timing.h       | 17 ++++++++++++-----
 kernel/mars_aio.c         |  3 +++
 kernel/mars_bio.c         |  3 +++
 kernel/sy_old/mars_proc.c |  1 +
 5 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/kernel/lib_timing.c b/kernel/lib_timing.c
index 6f8cf364..b2811342 100644
--- a/kernel/lib_timing.c
+++ b/kernel/lib_timing.c
@@ -63,3 +63,11 @@ int report_timing(struct timing_stats *tim, char *str, int maxlen)
 EXPORT_SYMBOL_GPL(report_timing);
 
 #endif
+
+struct threshold global_io_threshold = {
+	.thr_limit = 30 * 1000000, // 30 seconds
+	.thr_factor = 100,
+	.thr_plus = 0,
+};
+EXPORT_SYMBOL_GPL(global_io_threshold);
+
diff --git a/kernel/lib_timing.h b/kernel/lib_timing.h
index 25ee79a5..51cd6922 100644
--- a/kernel/lib_timing.h
+++ b/kernel/lib_timing.h
@@ -152,6 +152,7 @@ void banning_reset(struct banning *ban)
  */
 struct threshold {
 	struct banning *thr_ban;
+	struct threshold *thr_parent; /* support hierarchies */
 	// tunables
 	int  thr_limit;   // in us
 	int  thr_factor;  // in %
@@ -164,12 +165,18 @@ struct threshold {
 extern inline
 void threshold_check(struct threshold *thr, long long latency)
 {
-	if (thr->thr_limit &&
-	    latency > (long long)thr->thr_limit * 1000) {
-		thr->thr_triggered++;
-		if (!banning_hit(thr->thr_ban, latency * thr->thr_factor / 100 + thr->thr_plus * 1000))
-			thr->thr_true_hit++;
+	while (thr) {
+		if (thr->thr_limit &&
+		    latency > (long long)thr->thr_limit * 1000) {
+			thr->thr_triggered++;
+			if (thr->thr_ban &&
+			    !banning_hit(thr->thr_ban, latency * thr->thr_factor / 100 + thr->thr_plus * 1000))
+				thr->thr_true_hit++;
+		}
+		thr = thr->thr_parent;
 	}
 }
 
+extern struct threshold global_io_threshold;
+
 #endif
diff --git a/kernel/mars_aio.c b/kernel/mars_aio.c
index 24b21cf2..949c6a66 100644
--- a/kernel/mars_aio.c
+++ b/kernel/mars_aio.c
@@ -50,6 +50,7 @@ static struct timing_stats timings[3] = {};
 
 struct threshold aio_submit_threshold = {
 	.thr_ban = &mars_global_ban,
+	.thr_parent = &global_io_threshold,
 	.thr_limit = AIO_SUBMIT_MAX_LATENCY,
 	.thr_factor = 10,
 	.thr_plus = 10000,
@@ -59,12 +60,14 @@ EXPORT_SYMBOL_GPL(aio_submit_threshold);
 struct threshold aio_io_threshold[2] = {
 	[0] = {
 		.thr_ban = &mars_global_ban,
+		.thr_parent = &global_io_threshold,
 		.thr_limit = AIO_IO_R_MAX_LATENCY,
 		.thr_factor = 100,
 		.thr_plus = 0,
 	},
 	[1] = {
 		.thr_ban = &mars_global_ban,
+		.thr_parent = &global_io_threshold,
 		.thr_limit = AIO_IO_W_MAX_LATENCY,
 		.thr_factor = 100,
 		.thr_plus = 0,
diff --git a/kernel/mars_bio.c b/kernel/mars_bio.c
index e56ba118..6f7f17ac 100644
--- a/kernel/mars_bio.c
+++ b/kernel/mars_bio.c
@@ -51,6 +51,7 @@ static struct timing_stats timings[2] = {};
 
 struct threshold bio_submit_threshold = {
 	.thr_ban = &mars_global_ban,
+	.thr_parent = &global_io_threshold,
 	.thr_limit = BIO_SUBMIT_MAX_LATENCY,
 	.thr_factor = 100,
 	.thr_plus = 0,
@@ -60,12 +61,14 @@ EXPORT_SYMBOL_GPL(bio_submit_threshold);
 struct threshold bio_io_threshold[2] = {
 	[0] = {
 		.thr_ban = &mars_global_ban,
+		.thr_parent = &global_io_threshold,
 		.thr_limit = BIO_IO_R_MAX_LATENCY,
 		.thr_factor = 10,
 		.thr_plus = 10000,
 	},
 	[1] = {
 		.thr_ban = &mars_global_ban,
+		.thr_parent = &global_io_threshold,
 		.thr_limit = BIO_IO_W_MAX_LATENCY,
 		.thr_factor = 10,
 		.thr_plus = 10000,
diff --git a/kernel/sy_old/mars_proc.c b/kernel/sy_old/mars_proc.c
index 44d311c0..22435e67 100644
--- a/kernel/sy_old/mars_proc.c
+++ b/kernel/sy_old/mars_proc.c
@@ -234,6 +234,7 @@ static
 ctl_table io_tuning_table[] = {
 	LIMITER_ENTRIES(&global_writeback.limiter, "writeback",       "kb"),
 	INT_ENTRY("writeback_until_percent", global_writeback.until_percent, 0600),
+	THRESHOLD_ENTRIES(&global_io_threshold,  "global_io"),
 	THRESHOLD_ENTRIES(&bio_submit_threshold, "bio_submit"),
 	THRESHOLD_ENTRIES(&bio_io_threshold[0],  "bio_io_r"),
 	THRESHOLD_ENTRIES(&bio_io_threshold[1],  "bio_io_w"),