freebsd-dev/sys/vm/vm_pagequeue.h
Mark Johnston 5cd29d0f3c Improve VM page queue scalability.
Currently both the page lock and a page queue lock must be held in
order to enqueue, dequeue or requeue a page in a given page queue.
The queue locks are a scalability bottleneck in many workloads. This
change reduces page queue lock contention by batching queue operations.
To detangle the page and page queue locks, per-CPU batch queues are
used to reference pages with pending queue operations. The requested
operation is encoded in the page's aflags field with the page lock
held, after which the page is enqueued for a deferred batch operation.
Page queue scans are similarly optimized to minimize the amount of
work performed with a page queue lock held.

Reviewed by:	kib, jeff (previous versions)
Tested by:	pho
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D14893
2018-04-24 21:15:54 +00:00

311 lines
9.6 KiB
C

/*-
* SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU)
*
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* The Mach Operating System project at Carnegie-Mellon University.
*
* 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 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.
*
* from: @(#)vm_page.h 8.2 (Berkeley) 12/13/93
*
*
* Copyright (c) 1987, 1990 Carnegie-Mellon University.
* All rights reserved.
*
* Authors: Avadis Tevanian, Jr., Michael Wayne Young
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
* $FreeBSD$
*/
#ifndef _VM_PAGEQUEUE_
#define _VM_PAGEQUEUE_
#ifdef _KERNEL
struct vm_pagequeue {
struct mtx pq_mutex;
struct pglist pq_pl;
int pq_cnt;
const char * const pq_name;
} __aligned(CACHE_LINE_SIZE);
#ifndef VM_BATCHQUEUE_SIZE
#define VM_BATCHQUEUE_SIZE 7
#endif
struct vm_batchqueue {
vm_page_t bq_pa[VM_BATCHQUEUE_SIZE];
int bq_cnt;
} __aligned(CACHE_LINE_SIZE);
#include <vm/uma.h>
#include <sys/pidctrl.h>
struct sysctl_oid;
/*
* One vm_domain per-numa domain. Contains pagequeues, free page structures,
* and accounting.
*
* Lock Key:
* f vmd_free_mtx
* p vmd_pageout_mtx
* d vm_domainset_lock
* a atomic
* c const after boot
* q page queue lock
*/
struct vm_domain {
struct vm_pagequeue vmd_pagequeues[PQ_COUNT];
struct mtx_padalign vmd_free_mtx;
struct mtx_padalign vmd_pageout_mtx;
uma_zone_t vmd_pgcache; /* (c) page free cache. */
struct vmem *vmd_kernel_arena; /* (c) per-domain kva arena. */
u_int vmd_domain; /* (c) Domain number. */
u_int vmd_page_count; /* (c) Total page count. */
long vmd_segs; /* (c) bitmask of the segments */
u_int __aligned(CACHE_LINE_SIZE) vmd_free_count; /* (a,f) free page count */
u_int vmd_pageout_deficit; /* (a) Estimated number of pages deficit */
uint8_t vmd_pad[CACHE_LINE_SIZE - (sizeof(u_int) * 2)];
/* Paging control variables, used within single threaded page daemon. */
struct pidctrl vmd_pid; /* Pageout controller. */
boolean_t vmd_oom;
int vmd_oom_seq;
int vmd_last_active_scan;
struct vm_page vmd_markers[PQ_COUNT]; /* (q) markers for queue scans */
struct vm_page vmd_inacthead; /* marker for LRU-defeating insertions */
struct vm_page vmd_clock[2]; /* markers for active queue scan */
int vmd_pageout_wanted; /* (a, p) pageout daemon wait channel */
int vmd_pageout_pages_needed; /* (d) page daemon waiting for pages? */
bool vmd_minset; /* (d) Are we in vm_min_domains? */
bool vmd_severeset; /* (d) Are we in vm_severe_domains? */
enum {
VM_LAUNDRY_IDLE = 0,
VM_LAUNDRY_BACKGROUND,
VM_LAUNDRY_SHORTFALL
} vmd_laundry_request;
/* Paging thresholds and targets. */
u_int vmd_clean_pages_freed; /* (q) accumulator for laundry thread */
u_int vmd_background_launder_target; /* (c) */
u_int vmd_free_reserved; /* (c) pages reserved for deadlock */
u_int vmd_free_target; /* (c) pages desired free */
u_int vmd_free_min; /* (c) pages desired free */
u_int vmd_inactive_target; /* (c) pages desired inactive */
u_int vmd_pageout_free_min; /* (c) min pages reserved for kernel */
u_int vmd_pageout_wakeup_thresh;/* (c) min pages to wake pagedaemon */
u_int vmd_interrupt_free_min; /* (c) reserved pages for int code */
u_int vmd_free_severe; /* (c) severe page depletion point */
/* Name for sysctl etc. */
struct sysctl_oid *vmd_oid;
char vmd_name[sizeof(__XSTRING(MAXMEMDOM))];
} __aligned(CACHE_LINE_SIZE);
extern struct vm_domain vm_dom[MAXMEMDOM];
#define VM_DOMAIN(n) (&vm_dom[(n)])
#define vm_pagequeue_assert_locked(pq) mtx_assert(&(pq)->pq_mutex, MA_OWNED)
#define vm_pagequeue_lock(pq) mtx_lock(&(pq)->pq_mutex)
#define vm_pagequeue_lockptr(pq) (&(pq)->pq_mutex)
#define vm_pagequeue_trylock(pq) mtx_trylock(&(pq)->pq_mutex)
#define vm_pagequeue_unlock(pq) mtx_unlock(&(pq)->pq_mutex)
#define vm_domain_free_assert_locked(n) \
mtx_assert(vm_domain_free_lockptr((n)), MA_OWNED)
#define vm_domain_free_assert_unlocked(n) \
mtx_assert(vm_domain_free_lockptr((n)), MA_NOTOWNED)
#define vm_domain_free_lock(d) \
mtx_lock(vm_domain_free_lockptr((d)))
#define vm_domain_free_lockptr(d) \
(&(d)->vmd_free_mtx)
#define vm_domain_free_trylock(d) \
mtx_trylock(vm_domain_free_lockptr((d)))
#define vm_domain_free_unlock(d) \
mtx_unlock(vm_domain_free_lockptr((d)))
#define vm_domain_pageout_lockptr(d) \
(&(d)->vmd_pageout_mtx)
#define vm_domain_pageout_assert_locked(n) \
mtx_assert(vm_domain_pageout_lockptr((n)), MA_OWNED)
#define vm_domain_pageout_assert_unlocked(n) \
mtx_assert(vm_domain_pageout_lockptr((n)), MA_NOTOWNED)
#define vm_domain_pageout_lock(d) \
mtx_lock(vm_domain_pageout_lockptr((d)))
#define vm_domain_pageout_unlock(d) \
mtx_unlock(vm_domain_pageout_lockptr((d)))
static __inline void
vm_pagequeue_cnt_add(struct vm_pagequeue *pq, int addend)
{
vm_pagequeue_assert_locked(pq);
pq->pq_cnt += addend;
}
#define vm_pagequeue_cnt_inc(pq) vm_pagequeue_cnt_add((pq), 1)
#define vm_pagequeue_cnt_dec(pq) vm_pagequeue_cnt_add((pq), -1)
static inline void
vm_batchqueue_init(struct vm_batchqueue *bq)
{
bq->bq_cnt = 0;
}
static inline bool
vm_batchqueue_insert(struct vm_batchqueue *bq, vm_page_t m)
{
if (bq->bq_cnt < nitems(bq->bq_pa)) {
bq->bq_pa[bq->bq_cnt++] = m;
return (true);
}
return (false);
}
static inline vm_page_t
vm_batchqueue_pop(struct vm_batchqueue *bq)
{
if (bq->bq_cnt == 0)
return (NULL);
return (bq->bq_pa[--bq->bq_cnt]);
}
void vm_domain_set(struct vm_domain *vmd);
void vm_domain_clear(struct vm_domain *vmd);
int vm_domain_allocate(struct vm_domain *vmd, int req, int npages);
/*
* vm_pagequeue_domain:
*
* Return the memory domain the page belongs to.
*/
static inline struct vm_domain *
vm_pagequeue_domain(vm_page_t m)
{
return (VM_DOMAIN(vm_phys_domain(m)));
}
/*
* Return the number of pages we need to free-up or cache
* A positive number indicates that we do not have enough free pages.
*/
static inline int
vm_paging_target(struct vm_domain *vmd)
{
return (vmd->vmd_free_target - vmd->vmd_free_count);
}
/*
* Returns TRUE if the pagedaemon needs to be woken up.
*/
static inline int
vm_paging_needed(struct vm_domain *vmd, u_int free_count)
{
return (free_count < vmd->vmd_pageout_wakeup_thresh);
}
/*
* Returns TRUE if the domain is below the min paging target.
*/
static inline int
vm_paging_min(struct vm_domain *vmd)
{
return (vmd->vmd_free_min > vmd->vmd_free_count);
}
/*
* Returns TRUE if the domain is below the severe paging target.
*/
static inline int
vm_paging_severe(struct vm_domain *vmd)
{
return (vmd->vmd_free_severe > vmd->vmd_free_count);
}
/*
* Return the number of pages we need to launder.
* A positive number indicates that we have a shortfall of clean pages.
*/
static inline int
vm_laundry_target(struct vm_domain *vmd)
{
return (vm_paging_target(vmd));
}
void pagedaemon_wakeup(int domain);
static inline void
vm_domain_freecnt_inc(struct vm_domain *vmd, int adj)
{
u_int old, new;
old = atomic_fetchadd_int(&vmd->vmd_free_count, adj);
new = old + adj;
/*
* Only update bitsets on transitions. Notice we short-circuit the
* rest of the checks if we're above min already.
*/
if (old < vmd->vmd_free_min && (new >= vmd->vmd_free_min ||
(old < vmd->vmd_free_severe && new >= vmd->vmd_free_severe) ||
(old < vmd->vmd_pageout_free_min &&
new >= vmd->vmd_pageout_free_min)))
vm_domain_clear(vmd);
}
#endif /* _KERNEL */
#endif /* !_VM_PAGEQUEUE_ */