[PATCH -v2 6/6] fuse: add documentation of sysfs parameter to limit maximum fuse request size

[Mitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com>]

Add an explanation about the sysfs parameter to limit the
maximum read/write request size.

Signed-off-by: Mitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com>
Cc: Rob Landley <rob@landley.net>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Nikolaus Rath <Nikolaus@rath.org>
Cc: Liu Yuan <namei.unix@gmail.com>
Cc: Has-Wen Nienhuys <hanwen@xs4all.nl>
---

 Documentation/filesystems/fuse.txt |   15 ++++++++++++++-
 1 files changed, 14 insertions(+), 1 deletions(-)

diff --git a/Documentation/filesystems/fuse.txt b/Documentation/filesystems/fuse.txt
index 13af4a4..4e706ec 100644
--- a/Documentation/filesystems/fuse.txt
+++ b/Documentation/filesystems/fuse.txt
@@ -108,13 +108,26 @@ Mount options
 
   With this option the maximum size of read operations can be set.
   The default is infinite.  Note that the size of read requests is
-  limited anyway to 32 pages (which is 128kbyte on i386).
+  limited by max_pages_per_req sysfs parameter (See below for details.)
 
 'blksize=N'
 
   Set the block size for the filesystem.  The default is 512.  This
   option is only valid for 'fuseblk' type mounts.
 
+Sysfs parameter
+~~~~~~~~~~~~~~~
+
+  '/sys/fs/fuse/max_pages_per_req'
+
+Specify max request size in pages, which limits max_read/max_write
+mount option. The default is 32 pages (which is 128kbyte on i386).
+It can be changed to arbitrary number between 32 and the number of
+pages equivalent to pipe_max_size.
+
+Changing it may improve read/write throughput on systems. Existing
+FUSE mount must be remounted for this change to take effect.
+
 Control filesystem
 ~~~~~~~~~~~~~~~~~~