From: Jens Axboe <axboe@fb.com>
Date: Fri, 24 Apr 2015 15:03:05 +0000 (-0600)
Subject: blktrace: fix bugs in accounting
X-Git-Tag: fio-2.2.8~28
X-Git-Url: https://git.kernel.dk/?p=fio.git;a=commitdiff_plain;h=a6eaf6c9101cd3f2895376944e6425a43613dbf6

blktrace: fix bugs in accounting

We need to clear the trim part of the accounting arrays, otherwise
we can use bogus values leading to attempting to allocate huge
amounts of memory. This causes fio to exit with:

fio: pid=21428, err=12/file:memory.c:242, func=iomem allocation,
error=Cannot allocate memory

Also improve the depth detection, by making it per data direction
instead of a global state.

Signed-off-by: Jens Axboe <axboe@fb.com>
---

diff --git a/blktrace.c b/blktrace.c
index e63c7086..8ffa9b0e 100644
--- a/blktrace.c
+++ b/blktrace.c
@@ -327,6 +327,47 @@ static int t_is_write(struct blk_io_trace *t)
 	return (t->action & BLK_TC_ACT(BLK_TC_WRITE | BLK_TC_DISCARD)) != 0;
 }
 
+static enum fio_ddir t_get_ddir(struct blk_io_trace *t)
+{
+	if (t->action & BLK_TC_ACT(BLK_TC_READ))
+		return DDIR_READ;
+	else if (t->action & BLK_TC_ACT(BLK_TC_WRITE))
+		return DDIR_WRITE;
+	else if (t->action & BLK_TC_ACT(BLK_TC_DISCARD))
+		return DDIR_TRIM;
+
+	return DDIR_INVAL;
+}
+
+static void depth_inc(struct blk_io_trace *t, int *depth)
+{
+	enum fio_ddir ddir;
+
+	ddir = t_get_ddir(t);
+	if (ddir != DDIR_INVAL)
+		depth[ddir]++;
+}
+
+static void depth_dec(struct blk_io_trace *t, int *depth)
+{
+	enum fio_ddir ddir;
+
+	ddir = t_get_ddir(t);
+	if (ddir != DDIR_INVAL)
+		depth[ddir]--;
+}
+
+static void depth_end(struct blk_io_trace *t, int *this_depth, int *depth)
+{
+	enum fio_ddir ddir = DDIR_INVAL;
+
+	ddir = t_get_ddir(t);
+	if (ddir != DDIR_INVAL) {
+		depth[ddir] = max(depth[ddir], this_depth[ddir]);
+		this_depth[ddir] = 0;
+	}
+}
+
 /*
  * Load a blktrace file by reading all the blk_io_trace entries, and storing
  * them as io_pieces like the fio text version would do.
@@ -339,7 +380,7 @@ int load_blktrace(struct thread_data *td, const char *filename, int need_swap)
 	struct fifo *fifo;
 	int fd, i, old_state;
 	struct fio_file *f;
-	int this_depth, depth;
+	int this_depth[DDIR_RWDIR_CNT], depth[DDIR_RWDIR_CNT], max_depth;
 
 	fd = open(filename, O_RDONLY);
 	if (fd < 0) {
@@ -353,10 +394,14 @@ int load_blktrace(struct thread_data *td, const char *filename, int need_swap)
 
 	td->o.size = 0;
 
-	ios[0] = ios[1] = 0;
-	rw_bs[0] = rw_bs[1] = 0;
+	for (i = 0; i < DDIR_RWDIR_CNT; i++) {
+		ios[i] = 0;
+		rw_bs[i] = 0;
+		this_depth[i] = 0;
+		depth[i] = 0;
+	}
+
 	skipped_writes = 0;
-	this_depth = depth = 0;
 	do {
 		int ret = trace_fifo_get(td, fifo, fd, &t, sizeof(t));
 
@@ -392,11 +437,12 @@ int load_blktrace(struct thread_data *td, const char *filename, int need_swap)
 		}
 		if ((t.action & BLK_TC_ACT(BLK_TC_NOTIFY)) == 0) {
 			if ((t.action & 0xffff) == __BLK_TA_QUEUE)
-				this_depth++;
-			else if ((t.action & 0xffff) == __BLK_TA_COMPLETE) {
-				depth = max(depth, this_depth);
-				this_depth = 0;
-			}
+				depth_inc(&t, this_depth);
+			else if (((t.action & 0xffff) == __BLK_TA_BACKMERGE) ||
+				((t.action & 0xffff) == __BLK_TA_FRONTMERGE))
+				depth_dec(&t, this_depth);
+			else if ((t.action & 0xffff) == __BLK_TA_COMPLETE)
+				depth_end(&t, this_depth, depth);
 
 			if (t_is_write(&t) && read_only) {
 				skipped_writes++;
@@ -426,8 +472,14 @@ int load_blktrace(struct thread_data *td, const char *filename, int need_swap)
 	 * For stacked devices, we don't always get a COMPLETE event so
 	 * the depth grows to insane values. Limit it to something sane(r).
 	 */
-	if (!depth || depth > 1024)
-		depth = 1024;
+	max_depth = 0;
+	for (i = 0; i < DDIR_RWDIR_CNT; i++) {
+		if (depth[i] > 1024)
+			depth[i] = 1024;
+		else if (!depth[i] && ios[i])
+			depth[i] = 1;
+		max_depth = max(depth[i], max_depth);
+	}
 
 	if (skipped_writes)
 		log_err("fio: %s skips replay of %lu writes due to read-only\n",
@@ -453,13 +505,14 @@ int load_blktrace(struct thread_data *td, const char *filename, int need_swap)
 	 * We need to do direct/raw ios to the device, to avoid getting
 	 * read-ahead in our way.
 	 */
-	td->o.odirect = 1;
+	if (!fio_option_is_set(&td->o, odirect))
+		td->o.odirect = 1;
 
 	/*
 	 * If depth wasn't manually set, use probed depth
 	 */
 	if (!fio_option_is_set(&td->o, iodepth))
-		td->o.iodepth = td->o.iodepth_low = depth;
+		td->o.iodepth = td->o.iodepth_low = max_depth;
 
 	return 0;
 err: