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orangefs: remember count when reading. 

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
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26
fs/orangefs/file.c
View File

@ -286,8 +286,23 @@ static ssize_t orangefs_file_read_iter(struct kiocb *iocb,
struct iov_iter *iter)
{
int ret;
struct orangefs_read_options *ro;
orangefs_stats.reads++;
/*
* Remember how they set "count" in read(2) or pread(2) or whatever -
* users can use count as a knob to control orangefs io size and later
* we can try to help them fill as many pages as possible in readpage.
*/
if (!iocb->ki_filp->private_data) {
iocb->ki_filp->private_data = kmalloc(sizeof *ro, GFP_KERNEL);
if (!iocb->ki_filp->private_data)
return(ENOMEM);
ro = iocb->ki_filp->private_data;
ro->blksiz = iter->count;
}
down_read(&file_inode(iocb->ki_filp)->i_rwsem);
ret = orangefs_revalidate_mapping(file_inode(iocb->ki_filp));
if (ret)
@ -556,6 +571,12 @@ static int orangefs_lock(struct file *filp, int cmd, struct file_lock *fl)
return rc;
}
static int orangefs_file_open(struct inode * inode, struct file *file)
{
file->private_data = NULL;
return generic_file_open(inode, file);
}
static int orangefs_flush(struct file *file, fl_owner_t id)
{
/*
@ -569,6 +590,9 @@ static int orangefs_flush(struct file *file, fl_owner_t id)
struct inode *inode = file->f_mapping->host;
int r;
kfree(file->private_data);
file->private_data = NULL;
if (inode->i_state & I_DIRTY_TIME) {
spin_lock(&inode->i_lock);
inode->i_state &= ~I_DIRTY_TIME;
@ -591,7 +615,7 @@ const struct file_operations orangefs_file_operations = {
.lock = orangefs_lock,
.unlocked_ioctl = orangefs_ioctl,
.mmap = orangefs_file_mmap,
.open = generic_file_open,
.open = orangefs_file_open,
.flush = orangefs_flush,
.release = orangefs_file_release,
.fsync = orangefs_fsync,

4
fs/orangefs/orangefs-kernel.h
View File

@ -239,6 +239,10 @@ struct orangefs_write_range {
kgid_t gid;
};
struct orangefs_read_options {
ssize_t blksiz;
};
extern struct orangefs_stats orangefs_stats;
/*