Re: [RFC] generic_file_direct_IO() argument changes for AIO

[Badari Pulavarty <badari@us.ibm.com>]

> 
> On Tue, 29 Oct 2002, Badari Pulavarty wrote:
> 
> > Inorder to support AIO for raw/O_DIRECT, I need to add "struct kiocb *"
> > to generic_file_direct_IO() and all direct_IO() ops.
> >
> > generic_file_direct_IO(int rw, struct file *file, const struct iovec *iov,
> >         loff_t offset, unsigned long nr_segs)
> >
> > Instead of adding a new argument, I propose replace
> >
> > 	"struct file *file" argument with "struct kiocb *iocb"
> >
> > One can get "filp" from iocb->ki_filp.
> >
> > Any objections ?
> 
> here's a naive objection.  is there any preallocated data structure
> associated with a kiocb other than the struct itself?  if there is, that
> will have some scalability impact for applications like Oracle that like
> to create a very large database by opening thousands of files.
> 
> 	- Chuck Lever

If the application is not using Async IO, "kiocb" structure comes
from stack. Other than that, there are no preallocated strcutures
associated with kiocb.

- Badari