commit 4793e7c5e1c88382ead18db5ca072bac54467318
author Adrian Hunter <ext-adrian.hunter@nokia.com> Tue Sep 02 16:29:46 2008 +0300
committer Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Tue Sep 30 11:12:56 2008 +0300
tree 07e5e99d988b28fed07d5a01141169362c5a007d
parent a70948b564e9f6cb81115c606d46f5b74a77b7c2

UBIFS: add bulk-read facility

Some flash media are capable of reading sequentially at faster rates.
UBIFS bulk-read facility is designed to take advantage of that, by
reading in one go consecutive data nodes that are also located
consecutively in the same LEB.

Read speed on Arm platform with OneNAND goes from 17 MiB/s to
19 MiB/s.

Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>

fs/ubifs/super.c

diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index d87b0cf..b1c57e8 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -401,6 +401,11 @@
 	else if (c->mount_opts.unmount_mode == 1)
 		seq_printf(s, ",norm_unmount");
 
+	if (c->mount_opts.bulk_read == 2)
+		seq_printf(s, ",bulk_read");
+	else if (c->mount_opts.bulk_read == 1)
+		seq_printf(s, ",no_bulk_read");
+
 	return 0;
 }
 
@@ -538,6 +543,18 @@
 	 * calculations when reporting free space.
 	 */
 	c->leb_overhead = c->leb_size % UBIFS_MAX_DATA_NODE_SZ;
+	/* Buffer size for bulk-reads */
+	c->bulk_read_buf_size = UBIFS_MAX_BULK_READ * UBIFS_MAX_DATA_NODE_SZ;
+	if (c->bulk_read_buf_size > c->leb_size)
+		c->bulk_read_buf_size = c->leb_size;
+	if (c->bulk_read_buf_size > 128 * 1024) {
+		/* Check if we can kmalloc more than 128KiB */
+		void *try = kmalloc(c->bulk_read_buf_size, GFP_KERNEL);
+
+		kfree(try);
+		if (!try)
+			c->bulk_read_buf_size = 128 * 1024;
+	}
 	return 0;
 }
 
@@ -840,17 +857,23 @@
  *
  * Opt_fast_unmount: do not run a journal commit before un-mounting
  * Opt_norm_unmount: run a journal commit before un-mounting
+ * Opt_bulk_read: enable bulk-reads
+ * Opt_no_bulk_read: disable bulk-reads
  * Opt_err: just end of array marker
  */
 enum {
 	Opt_fast_unmount,
 	Opt_norm_unmount,
+	Opt_bulk_read,
+	Opt_no_bulk_read,
 	Opt_err,
 };
 
 static match_table_t tokens = {
 	{Opt_fast_unmount, "fast_unmount"},
 	{Opt_norm_unmount, "norm_unmount"},
+	{Opt_bulk_read, "bulk_read"},
+	{Opt_no_bulk_read, "no_bulk_read"},
 	{Opt_err, NULL},
 };
 
@@ -888,6 +911,14 @@
 			c->mount_opts.unmount_mode = 1;
 			c->fast_unmount = 0;
 			break;
+		case Opt_bulk_read:
+			c->mount_opts.bulk_read = 2;
+			c->bulk_read = 1;
+			break;
+		case Opt_no_bulk_read:
+			c->mount_opts.bulk_read = 1;
+			c->bulk_read = 0;
+			break;
 		default:
 			ubifs_err("unrecognized mount option \"%s\" "
 				  "or missing value", p);