lkml.org 
[lkml]   [2004]   [Jun]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: kiocb->private is too large for kiocb's on-stack
William Lee Irwin III <wli@holomorphy.com> wrote:
>
> sizeof(struct kiocb) is dangerously large for a structure commonly
> allocated on-stack. This patch converts the 24*sizeof(long) field,
> ->private, to a void pointer for use by file_operations entrypoints.
> A ->dtor() method is added to the kiocb in order to support the release
> of dynamically allocated structures referred to by ->private.
>
> The sole in-tree users of ->private are async network read/write,
> which are not, in fact, async, and so need not handle preallocated
> ->private as they would need to if ->ki_retry were ever used. The sole
> truly async operations are direct IO pread()/pwrite() which do not
> now use ->ki_retry(). All they would need to do in that case is to
> check for ->private already being allocated for async kiocbs.
>
> This rips 88B off the stack on 32-bit in the common case.
>

> int sock_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
> {
> struct kiocb iocb;
> + struct sock_iocb siocb;
> int ret;
>
> init_sync_kiocb(&iocb, NULL);
> + iocb.private = &siocb;
> ret = __sock_sendmsg(&iocb, sock, msg, size);
> if (-EIOCBQUEUED == ret)
> ret = wait_on_sync_kiocb(&iocb);

That's so much better than what we had before it ain't funny.

Was this runtime tested?
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 14:04    [W:0.060 / U:0.784 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site