freebsd-dev/sys/sys/selinfo.h
Jeff Roberson ace8398da0 Refactor select to reduce contention and hide internal implementation
details from consumers.

 - Track individual selecters on a per-descriptor basis such that there
   are no longer collisions and after sleeping for events only those
   descriptors which triggered events must be rescaned.
 - Protect the selinfo (per descriptor) structure with a mtx pool mutex.
   mtx pool mutexes were chosen to preserve api compatibility with
   existing code which does nothing but bzero() to setup selinfo
   structures.
 - Use a per-thread wait channel rather than a global wait channel.
 - Hide select implementation details in a seltd structure which is
   opaque to the rest of the kernel.
 - Provide a 'selsocket' interface for those kernel consumers who wish to
   select on a socket when they have no fd so they no longer have to
   be aware of select implementation details.

Tested by:	kris
Reviewed on:	arch
2007-12-16 06:21:20 +00:00

61 lines
2.3 KiB
C

/*-
* Copyright (c) 1992, 1993
* The Regents of the University of California. 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.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* @(#)select.h 8.2 (Berkeley) 1/4/94
* $FreeBSD$
*/
#ifndef _SYS_SELINFO_H_
#define _SYS_SELINFO_H_
#include <sys/event.h> /* for struct klist */
struct selfd;
TAILQ_HEAD(selfdlist, selfd);
/*
* Used to maintain information about processes that wish to be
* notified when I/O becomes possible.
*/
struct selinfo {
struct selfdlist si_tdlist; /* List of sleeping threads. */
struct knlist si_note; /* kernel note list */
struct mtx *si_mtx; /* Lock for tdlist. */
};
#define SEL_WAITING(si) (!TAILQ_EMPTY(&(si)->si_tdlist))
#ifdef _KERNEL
void selrecord(struct thread *selector, struct selinfo *sip);
void selwakeup(struct selinfo *sip);
void selwakeuppri(struct selinfo *sip, int pri);
void seltdfini(struct thread *td);
#endif
#endif /* !_SYS_SELINFO_H_ */