Re: [PATCH] NFS: account direct-io into task io accounting

[Konstantin Khlebnikov]

Chuck Lever wrote:
> On Feb 21, 2011, at 11:15 AM, Konstantin Khlebnikov wrote:
>
> > Account complete NFS direct-io reads and writes into Task I/O Accounting.
> >
> > NFS have unusual direct-io implementation,
> > thus accounting in generic code does not work.
> >
> > Signed-off-by: Konstantin Khlebnikov<khlebnikov@xxxxxxxxxx>
> > ---
> > fs/nfs/direct.c |    9 +++++++--
> > 1 files changed, 7 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
> > index 9943a75..bab4185 100644
> > --- a/fs/nfs/direct.c
> > +++ b/fs/nfs/direct.c
> > @@ -45,6 +45,7 @@
> > #include<linux/pagemap.h>
> > #include<linux/kref.h>
> > #include<linux/slab.h>
> > +#include<linux/task_io_accounting_ops.h>
> >
> > #include<linux/nfs_fs.h>
> > #include<linux/nfs_page.h>
> > @@ -939,8 +940,10 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, const struct iovec *iov,
> > 		goto out;
> >
> > 	retval = nfs_direct_read(iocb, iov, nr_segs, pos);
> > -	if (retval>  0)
> > +	if (retval>  0) {
> > 		iocb->ki_pos = pos + retval;
> > +		task_io_account_read(retval);
> > +	}
> >
> > out:
> > 	return retval;
> > @@ -1001,8 +1004,10 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
> >
> > 	retval = nfs_direct_write(iocb, iov, nr_segs, pos, count);
> >
> > -	if (retval>  0)
> > +	if (retval>  0) {
> > 		iocb->ki_pos = pos + retval;
> > +		task_io_account_write(retval);
> > +	}
>
> The async path always returns -EIOCBQUEUED.  How are those bytes accounted for?

Oh, thanks. I forget about aio.
So, there only one option -- always account whole requiest before completion.

> > out:
> > 	return retval;
>
> --
> Chuck Lever
> chuck[dot]lever[at]oracle[dot]com

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