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

From: Badari Pulavarty (badari@us.ibm.com)
Date: Tue Oct 29 2002 - 14:28:55 EST


>
> 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
-
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