449c2e92c9
into threads each processing queue in a single domain. The structure of the pagedaemons and queues is kept intact, most of the changes come from the need for code to find an owning page queue for given page, calculated from the segment containing the page. The tie between NUMA domain and pagedaemon thread/pagequeue split is rather arbitrary, the multithreaded daemon could be allowed for the single-domain machines, or one domain might be split into several page domains, to further increase concurrency. Right now, each pagedaemon thread tries to reach the global target, precalculated at the start of the pass. This is not optimal, since it could cause excessive page deactivation and freeing. The code should be changed to re-check the global page deficit state in the loop after some number of iterations. The pagedaemons reach the quorum before starting the OOM, since one thread inability to meet the target is normal for split queues. Only when all pagedaemons fail to produce enough reusable pages, OOM is started by single selected thread. Launder is modified to take into account the segments layout with regard to the region for which cleaning is performed. Based on the preliminary patch by jeff, sponsored by EMC / Isilon Storage Division. Reviewed by: alc Tested by: pho Sponsored by: The FreeBSD Foundation
164 lines
4.7 KiB
C
164 lines
4.7 KiB
C
/*-
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* Copyright (c) 1994 John Dyson
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* Copyright (c) 2001 Matt Dillon
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*
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* All Rights Reserved.
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* from: @(#)vm_machdep.c 7.3 (Berkeley) 5/13/91
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* Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
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* from: FreeBSD: .../i386/vm_machdep.c,v 1.165 2001/07/04 23:27:04 dillon
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <opt_sched.h>
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/proc.h>
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#include <sys/vmmeter.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/sched.h>
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#include <sys/sysctl.h>
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#include <sys/kthread.h>
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#include <sys/unistd.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/vm_page.h>
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#include <vm/vm_phys.h>
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static int idlezero_enable_default = 0;
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TUNABLE_INT("vm.idlezero_enable", &idlezero_enable_default);
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/* Defer setting the enable flag until the kthread is running. */
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static int idlezero_enable = 0;
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SYSCTL_INT(_vm, OID_AUTO, idlezero_enable, CTLFLAG_RW, &idlezero_enable, 0,
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"Allow the kernel to use idle cpu cycles to zero-out pages");
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/*
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* Implement the pre-zeroed page mechanism.
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*/
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#define ZIDLE_LO(v) ((v) * 2 / 3)
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#define ZIDLE_HI(v) ((v) * 4 / 5)
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static boolean_t wakeup_needed = FALSE;
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static int zero_state;
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static int
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vm_page_zero_check(void)
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{
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if (!idlezero_enable)
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return (0);
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/*
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* Attempt to maintain approximately 1/2 of our free pages in a
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* PG_ZERO'd state. Add some hysteresis to (attempt to) avoid
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* generally zeroing a page when the system is near steady-state.
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* Otherwise we might get 'flutter' during disk I/O / IPC or
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* fast sleeps. We also do not want to be continuously zeroing
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* pages because doing so may flush our L1 and L2 caches too much.
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*/
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if (zero_state && vm_page_zero_count >= ZIDLE_LO(cnt.v_free_count))
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return (0);
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if (vm_page_zero_count >= ZIDLE_HI(cnt.v_free_count))
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return (0);
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return (1);
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}
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static void
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vm_page_zero_idle(void)
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{
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mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
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zero_state = 0;
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if (vm_phys_zero_pages_idle()) {
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if (vm_page_zero_count >= ZIDLE_HI(cnt.v_free_count))
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zero_state = 1;
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}
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}
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/* Called by vm_page_free to hint that a new page is available. */
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void
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vm_page_zero_idle_wakeup(void)
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{
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mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
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if (wakeup_needed && vm_page_zero_check()) {
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wakeup_needed = FALSE;
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wakeup(&zero_state);
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}
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}
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static void
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vm_pagezero(void __unused *arg)
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{
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idlezero_enable = idlezero_enable_default;
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mtx_lock(&vm_page_queue_free_mtx);
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for (;;) {
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if (vm_page_zero_check()) {
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vm_page_zero_idle();
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#ifndef PREEMPTION
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if (sched_runnable()) {
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thread_lock(curthread);
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mi_switch(SW_VOL | SWT_IDLE, NULL);
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thread_unlock(curthread);
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}
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#endif
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} else {
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wakeup_needed = TRUE;
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msleep(&zero_state, &vm_page_queue_free_mtx, 0,
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"pgzero", hz * 300);
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}
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}
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}
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static void
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pagezero_start(void __unused *arg)
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{
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int error;
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struct proc *p;
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struct thread *td;
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error = kproc_create(vm_pagezero, NULL, &p, RFSTOPPED, 0, "pagezero");
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if (error)
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panic("pagezero_start: error %d\n", error);
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td = FIRST_THREAD_IN_PROC(p);
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thread_lock(td);
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/* We're an idle task, don't count us in the load. */
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td->td_flags |= TDF_NOLOAD;
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sched_class(td, PRI_IDLE);
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sched_prio(td, PRI_MAX_IDLE);
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sched_add(td, SRQ_BORING);
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thread_unlock(td);
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}
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SYSINIT(pagezero, SI_SUB_KTHREAD_VM, SI_ORDER_ANY, pagezero_start, NULL);
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