orangefs: remember count when reading.

Browse source

Orangefs wins when it can do IO on large (up to four meg) blocks at a time,
and looses when it has to do tiny "small io" reads and writes. Accessing
Orangefs through the pagecache with the kernel module helps with small io,
both reading and writing, a great deal. Readpage generally tries to fetch a
page (four k) at a time. We'll let users use "count" (as in read(2) or
pread(2) for example) as a knob to control how much data they get from
Orangefs at a time and we'll try to use the data to fill extra
pagecache pages when we get to ->readpage, hopefully resulting in
fewer calls to readpage and Orangefs userspace.

We need a way to remember how they set count so that we can still have
it available when we get to ->readpage.

 - We'll use file->private_data to keep track of "count".
   We'll wrap generic_file_open with orangefs_file_open and
   initialize private_data to NULL there.

 - In ->read_iter we have access to both "count" and file, so
   we'll kmalloc some space onto file->private_data and store
   "count" there.

 - We'll kfree file->private_data each time we visit ->flush and
   reinitialize it to NULL.

Signed-off-by: Mike Marshall <hubcap@omnibond.com>
Signed-off-by: Martin Brandenburg <martin@omnibond.com>

...

This commit is contained in:

Mike Marshall 2019-03-25 15:52:29 -04:00

parent 8f04e1be78

commit c2549f8c7a

2 changed files with 29 additions and 1 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

26

fs/orangefs/file.c

View file

4

fs/orangefs/orangefs-kernel.h

View file