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freebsd-skq/sys/sys/_rmlock.h

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Initial checkin for rmlock (read mostly lock) a multi reader single writer lock optimized for almost exclusive reader access. (see also rmlock.9) TODO: Convert to per cpu variables linkerset as soon as it is available. Optimize UP (single processor) case.
2007-11-08 14:47:55 +00:00
/*-
* Copyright (c) 2007 Stephan Uphoff <ups@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.
* 3. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* 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__RMLOCK_H_
#define _SYS__RMLOCK_H_
/*
* Mostly reader/occasional writer lock.
*/
LIST_HEAD(rmpriolist,rm_priotracker);
Remove namespace pollution in _rmlock.h by defining rm_queue structure directly in _rmlock.h and then including it (and its dependencies) in pcpu.h. This leads to few _*.h headers to be included in pcpu.h but this is not considered a big deal. Really pc_rm_queue should be implemented as a dynamic member with DPCPU interface, but we really want to keep the read acquisition as fast as possible, so even the further pc_dynamic indirection should be avoided, and the pollution is dealt like this. Discussed with: jhb MFC after: 1 week
2012-09-18 00:43:15 +00:00
struct rm_queue {
struct rm_queue *volatile rmq_next;
struct rm_queue *volatile rmq_prev;
};
Initial checkin for rmlock (read mostly lock) a multi reader single writer lock optimized for almost exclusive reader access. (see also rmlock.9) TODO: Convert to per cpu variables linkerset as soon as it is available. Optimize UP (single processor) case.
2007-11-08 14:47:55 +00:00
struct rmlock {
Several improvements to rmlock(9). Many of these are based on patches provided by Isilon. - Add an rm_assert() supporting various lock assertions similar to other locking primitives. Because rmlocks track readers the assertions are always fully accurate unlike rw_assert() and sx_assert(). - Flesh out the lock class methods for rmlocks to support sleeping via condvars and rm_sleep() (but only while holding write locks), rmlock details in 'show lock' in DDB, and the lc_owner method used by dtrace. - Add an internal destroyed cookie so that API functions can assert that an rmlock is not destroyed. - Make use of rm_assert() to add various assertions to the API (e.g. to assert locks are held when an unlock routine is called). - Give RM_SLEEPABLE locks their own lock class and always use the rmlock's own lock_object with WITNESS. - Use THREAD_NO_SLEEPING() / THREAD_SLEEPING_OK() to disallow sleeping while holding a read lock on an rmlock. Submitted by: andre Obtained from: EMC/Isilon
2013-06-25 18:44:15 +00:00
struct lock_object lock_object;
Commit the support for removing cpumask_t and replacing it directly with cpuset_t objects. That is going to offer the underlying support for a simple bump of MAXCPU and then support for number of cpus > 32 (as it is today). Right now, cpumask_t is an int, 32 bits on all our supported architecture. cpumask_t on the other side is implemented as an array of longs, and easilly extendible by definition. The architectures touched by this commit are the following: - amd64 - i386 - pc98 - arm - ia64 - XEN while the others are still missing. Userland is believed to be fully converted with the changes contained here. Some technical notes: - This commit may be considered an ABI nop for all the architectures different from amd64 and ia64 (and sparc64 in the future) - per-cpu members, which are now converted to cpuset_t, needs to be accessed avoiding migration, because the size of cpuset_t should be considered unknown - size of cpuset_t objects is different from kernel and userland (this is primirally done in order to leave some more space in userland to cope with KBI extensions). If you need to access kernel cpuset_t from the userland please refer to example in this patch on how to do that correctly (kgdb may be a good source, for example). - Support for other architectures is going to be added soon - Only MAXCPU for amd64 is bumped now The patch has been tested by sbruno and Nicholas Esborn on opteron 4 x 12 pack CPUs. More testing on big SMP is expected to came soon. pluknet tested the patch with his 8-ways on both amd64 and i386. Tested by: pluknet, sbruno, gianni, Nicholas Esborn Reviewed by: jeff, jhb, sbruno
2011-05-05 14:39:14 +00:00
volatile cpuset_t rm_writecpus;
Initial checkin for rmlock (read mostly lock) a multi reader single writer lock optimized for almost exclusive reader access. (see also rmlock.9) TODO: Convert to per cpu variables linkerset as soon as it is available. Optimize UP (single processor) case.
2007-11-08 14:47:55 +00:00
LIST_HEAD(,rm_priotracker) rm_activeReaders;
rmlock(9) two additions and one change/fix: - add rm_try_rlock(). - add RM_SLEEPABLE to use sx(9) as the back-end lock in order to sleep while holding the write lock. - change rm_noreadtoken to a cpu bitmask to indicate which CPUs need to go through the lock/unlock in order to synchronize. As a side effect, this also avoids IPI to CPUs without any readers during rm_wlock. Discussed with: ups@, rwatson@ on arch@ Sponsored by: Isilon Systems, Inc.
2010-09-01 19:50:03 +00:00
union {
Several improvements to rmlock(9). Many of these are based on patches provided by Isilon. - Add an rm_assert() supporting various lock assertions similar to other locking primitives. Because rmlocks track readers the assertions are always fully accurate unlike rw_assert() and sx_assert(). - Flesh out the lock class methods for rmlocks to support sleeping via condvars and rm_sleep() (but only while holding write locks), rmlock details in 'show lock' in DDB, and the lc_owner method used by dtrace. - Add an internal destroyed cookie so that API functions can assert that an rmlock is not destroyed. - Make use of rm_assert() to add various assertions to the API (e.g. to assert locks are held when an unlock routine is called). - Give RM_SLEEPABLE locks their own lock class and always use the rmlock's own lock_object with WITNESS. - Use THREAD_NO_SLEEPING() / THREAD_SLEEPING_OK() to disallow sleeping while holding a read lock on an rmlock. Submitted by: andre Obtained from: EMC/Isilon
2013-06-25 18:44:15 +00:00
struct lock_object _rm_wlock_object;
rmlock(9) two additions and one change/fix: - add rm_try_rlock(). - add RM_SLEEPABLE to use sx(9) as the back-end lock in order to sleep while holding the write lock. - change rm_noreadtoken to a cpu bitmask to indicate which CPUs need to go through the lock/unlock in order to synchronize. As a side effect, this also avoids IPI to CPUs without any readers during rm_wlock. Discussed with: ups@, rwatson@ on arch@ Sponsored by: Isilon Systems, Inc.
2010-09-01 19:50:03 +00:00
struct mtx _rm_lock_mtx;
struct sx _rm_lock_sx;
} _rm_lock;
Initial checkin for rmlock (read mostly lock) a multi reader single writer lock optimized for almost exclusive reader access. (see also rmlock.9) TODO: Convert to per cpu variables linkerset as soon as it is available. Optimize UP (single processor) case.
2007-11-08 14:47:55 +00:00
};
Several improvements to rmlock(9). Many of these are based on patches provided by Isilon. - Add an rm_assert() supporting various lock assertions similar to other locking primitives. Because rmlocks track readers the assertions are always fully accurate unlike rw_assert() and sx_assert(). - Flesh out the lock class methods for rmlocks to support sleeping via condvars and rm_sleep() (but only while holding write locks), rmlock details in 'show lock' in DDB, and the lc_owner method used by dtrace. - Add an internal destroyed cookie so that API functions can assert that an rmlock is not destroyed. - Make use of rm_assert() to add various assertions to the API (e.g. to assert locks are held when an unlock routine is called). - Give RM_SLEEPABLE locks their own lock class and always use the rmlock's own lock_object with WITNESS. - Use THREAD_NO_SLEEPING() / THREAD_SLEEPING_OK() to disallow sleeping while holding a read lock on an rmlock. Submitted by: andre Obtained from: EMC/Isilon
2013-06-25 18:44:15 +00:00
#define rm_wlock_object _rm_lock._rm_wlock_object
rmlock(9) two additions and one change/fix: - add rm_try_rlock(). - add RM_SLEEPABLE to use sx(9) as the back-end lock in order to sleep while holding the write lock. - change rm_noreadtoken to a cpu bitmask to indicate which CPUs need to go through the lock/unlock in order to synchronize. As a side effect, this also avoids IPI to CPUs without any readers during rm_wlock. Discussed with: ups@, rwatson@ on arch@ Sponsored by: Isilon Systems, Inc.
2010-09-01 19:50:03 +00:00
#define rm_lock_mtx _rm_lock._rm_lock_mtx
#define rm_lock_sx _rm_lock._rm_lock_sx
Initial checkin for rmlock (read mostly lock) a multi reader single writer lock optimized for almost exclusive reader access. (see also rmlock.9) TODO: Convert to per cpu variables linkerset as soon as it is available. Optimize UP (single processor) case.
2007-11-08 14:47:55 +00:00
struct rm_priotracker {
struct rm_queue rmp_cpuQueue; /* Must be first */
struct rmlock *rmp_rmlock;
struct thread *rmp_thread;
int rmp_flags;
LIST_ENTRY(rm_priotracker) rmp_qentry;
};
#endif /* !_SYS__RMLOCK_H_ */
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