freebsd-skq/sys/sys/sf_base.h
adrian c46f73c7ae Implement a kqueue notification path for sendfile.
This fires off a kqueue note (of type sendfile) to the configured kqfd
when the sendfile transaction has completed and the relevant memory
backing the transaction is no longer in use by this transaction.
This is analogous to SF_SYNC waiting for the mbufs to complete -
except now you don't have to wait.

Both SF_SYNC and SF_KQUEUE should work together, even if it
doesn't necessarily make any practical sense.

This is designed for use by applications which use backing cache/store
files (eg Varnish) or POSIX shared memory (not sure anything is using
it yet!) to know when a region of memory is free for re-use.  Note
it doesn't mark the region as free overall - only free from this
transaction.  The application developer still needs to track which
ranges are in the process of being recycled and wait until all
pending transactions are completed.

TODO:

* documentation, as always

Sponsored by:	Netflix, Inc.
2014-01-17 05:26:55 +00:00

38 lines
1.7 KiB
C

/*-
* Copyright (c) 2013 Adrian Chadd <adrian@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _SYS_SF_BASE_H_
#define _SYS_SF_BASE_H_
extern int _do_sendfile(struct thread *, int src_fd, int sock_fd, int flags,
int compat, off_t offset, size_t nbytes, off_t *sbytes,
struct uio *hdr_uio, struct uio *trl_uio,
struct sf_hdtr_kq *hdtr_kq);
#endif /* _SYS_SF_BASE_H_ */