280d15cd0a
Both issues caused the page daemon to erroneously go to sleep when applications are consuming free pages at a high rate, leaving the application threads blocked in VM_WAIT. 1) After completing an inactive queue scan, concurrent allocations may have prevented the page daemon from meeting the v_free_min threshold. In this case, the page daemon was going to sleep even when the inactive queue contained plenty of clean pages. 2) pagedaemon_wakeup() may be called without the free queues lock held. This can lead to a lost wakeup if a call occurs after the page daemon clears vm_pageout_wanted but before going to sleep. Fix 1) by ensuring that we start a new inactive queue scan immediately if v_free_count < v_free_min after a prior scan. Fix 2) by adding a new subroutine, pagedaemon_wait(), called from vm_wait() and vm_waitpfault(). It wakes up the page daemon if either vm_pages_needed or vm_pageout_wanted is false, and atomically sleeps on v_free_count. Reported by: jeff Reviewed by: alc MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D13424
114 lines
3.7 KiB
C
114 lines
3.7 KiB
C
/*-
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* SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU)
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*
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* The Mach Operating System project at Carnegie-Mellon University.
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*
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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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* 3. 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 REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: @(#)vm_pageout.h 8.2 (Berkeley) 1/12/94
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*
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*
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* Copyright (c) 1987, 1990 Carnegie-Mellon University.
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* All rights reserved.
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*
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* Author: Avadis Tevanian, Jr.
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*
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* Permission to use, copy, modify and distribute this software and
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* its documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
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* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*
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* $FreeBSD$
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*/
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#ifndef _VM_VM_PAGEOUT_H_
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#define _VM_VM_PAGEOUT_H_
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/*
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* Header file for pageout daemon.
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*/
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/*
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* Exported data structures.
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*/
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extern int vm_page_max_wired;
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extern int vm_pageout_deficit;
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extern int vm_pageout_page_count;
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extern bool vm_pageout_wanted;
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extern bool vm_pages_needed;
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#define VM_OOM_MEM 1
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#define VM_OOM_SWAPZ 2
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/*
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* vm_lowmem flags.
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*/
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#define VM_LOW_KMEM 0x01
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#define VM_LOW_PAGES 0x02
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/*
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* Exported routines.
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*/
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/*
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* Signal pageout-daemon and wait for it.
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*/
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void pagedaemon_wait(int pri, const char *wmesg);
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void pagedaemon_wakeup(void);
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#define VM_WAIT vm_wait()
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#define VM_WAITPFAULT vm_waitpfault()
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void vm_wait(void);
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void vm_waitpfault(void);
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#ifdef _KERNEL
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int vm_pageout_flush(vm_page_t *, int, int, int, int *, boolean_t *);
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void vm_pageout_oom(int shortage);
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void vm_swapout_run(void);
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void vm_swapout_run_idle(void);
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#endif
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#endif /* _VM_VM_PAGEOUT_H_ */
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