[PATCH] fs: improve ramfs_truncate speed

Marcin Niestroj m.niestroj at grinn-global.com
Tue Sep 25 12:50:16 PDT 2018

During sequential writes into single file, fs layer is consequently
calling ramfs_truncate() function. When file size grows
ramfs_truncate() takes more and more time to complete, due to
interations through all already written data chunks. As an example
loading ~450M image using usb fastboot protocol took over 500s to

Use ramfs_find_chunk() function to search for last chunk of data in
ramfs_truncate() implementation, which saves a lot of loop
iterations. As a result loading ~450M image using usb fastboot
protocol takes around 25s now.

Tested-by: Maciej Zagrabski <m.zagrabski at grinn-global.com>
Signed-off-by: Marcin Niestroj <m.niestroj at grinn-global.com>
 fs/ramfs.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/ramfs.c b/fs/ramfs.c
index 7548bdac9..6f4aa0675 100644
--- a/fs/ramfs.c
+++ b/fs/ramfs.c
@@ -362,6 +362,9 @@ static int ramfs_truncate(struct device_d *dev, FILE *f, ulong size)
 			if (!node->data)
 				return -ENOMEM;
 			data = node->data;
+		} else {
+			data = ramfs_find_chunk(node, oldchunks - 1);
+			newchunks -= (oldchunks - 1);

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